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Molecules, Volume 16, Issue 1 (January 2011), Pages 1-1010

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Open AccessArticle Triterpenoid Contents and Anti-Inflammatory Properties of the Methanol Extracts of Ligustrum Species Leaves
Molecules 2011, 16(1), 1-15; doi:10.3390/molecules16010001
Received: 23 November 2010 / Revised: 16 December 2010 / Accepted: 21 December 2010 / Published: 23 December 2010
Cited by 15 | PDF Full-text (514 KB)
Abstract
Ligustrum (privet) plants are used by Chinese physicians to prevent and cure hepatitis and chronic bronchitis. Three common Ligustrum plant spp., namely Ligustrum lucidum Ait. (LL), L. pricei Hayata (LP) and L. sinensis Lour. (LS) were collected to assess their analgesic/anti-inflammatory properties on
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Ligustrum (privet) plants are used by Chinese physicians to prevent and cure hepatitis and chronic bronchitis. Three common Ligustrum plant spp., namely Ligustrum lucidum Ait. (LL), L. pricei Hayata (LP) and L. sinensis Lour. (LS) were collected to assess their analgesic/anti-inflammatory properties on chemical-induced nociception and carrageenan-induced inflammation in rodents. The methanol extracts from Ligustrum plants leaves effectively inhibited nociceptive responses induced by 1% acetic acid and 1% formalin. LP and LL reduced the edema induced by 1% carrageenan. LP exhibited the best potency of the Ligustrum plants. Furthermore, LP reduced the abdominal Evan’s blue extravasations caused by lipopolysaccharide, lipoteichoic acid, autocrines and sodium nitroprusside. The triterpenoid content of the three Ligustrum spp. was measured by high performance liquid chromatography using a photodiode array detector. LP contained the highest content of amyrin, betulinic acid and lupeol. LL had the highest content of oleanolic acid and ursolic acid. The various degrees of analgesic/anti-inflammatory effects among three Ligustrum plants may be related to their different triterpenoid contents. LP is a potential analgesic and anti-inflammatory Ligustrum plant. The effects of LP are partially related to the inhibition of cyclooxygenase-2 activity and a decrease in microvascular permeability via the actions of autocrines and kinins. Full article
(This article belongs to the Section Natural Products)
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Open AccessArticle Novel Synthesis of Hydrazide-Hydrazone Derivatives and Their Utilization in the Synthesis of Coumarin, Pyridine, Thiazole and Thiophene Derivatives with Antitumor Activity
Molecules 2011, 16(1), 16-27; doi:10.3390/molecules16010016
Received: 11 November 2010 / Revised: 5 December 2010 / Accepted: 8 December 2010 / Published: 23 December 2010
Cited by 41 | PDF Full-text (135 KB)
Abstract
The reaction of cyanoacetyl hydrazine (1) with 3-acetylpyridine (2) gave the hydrazide-hydrazone derivative 3. The latter compound undergoes a series of heterocyclization reactions to give new heterocyclic compounds. The antitumor evaluation of the newly synthesized products against three
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The reaction of cyanoacetyl hydrazine (1) with 3-acetylpyridine (2) gave the hydrazide-hydrazone derivative 3. The latter compound undergoes a series of heterocyclization reactions to give new heterocyclic compounds. The antitumor evaluation of the newly synthesized products against three cancer cell lines, namely breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and CNS cancer (SF-268) was performed. Most of the synthesized compounds showed high inhibitory effects. Full article
(This article belongs to the Section Organic Synthesis)
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Open AccessArticle Anti-Fatigue Activity of Extracts of Stem Bark from Acanthopanax senticosus
Molecules 2011, 16(1), 28-37; doi:10.3390/molecules16010028
Received: 24 November 2010 / Revised: 20 December 2010 / Accepted: 22 December 2010 / Published: 24 December 2010
Cited by 33 | PDF Full-text (105 KB)
Abstract
In the present study, we investigated the anti-fatigue activity in male Kunming mice of extracts of stem bark from Acanthopanax senticosus (ASSE) using a forced swimming test. Mice were divided into four groups (three ASSE administered groups and the control group). The control
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In the present study, we investigated the anti-fatigue activity in male Kunming mice of extracts of stem bark from Acanthopanax senticosus (ASSE) using a forced swimming test. Mice were divided into four groups (three ASSE administered groups and the control group). The control group were gavaged with distilled water and ASSE administered groups were gavaged with ASSE (100, 200 and 400 mg/kg). After four weeks, a forced swimming test was performed and the biochemical parameters related to fatigue were examined. The results suggested that ASSE could extend the swimming time to exhaustion of the mice, as well as increase the tissue glycogen contents, while decreasing the blood lactate and serum urea nitrogen contents. This indicated that ASSE had anti-fatigue activity and could elevate the exercise tolerance. Full article
Open AccessArticle Enhancement in the Catalytic Activity of Pd/USY in the Heck Reaction Induced by H2 Bubbling
Molecules 2011, 16(1), 38-51; doi:10.3390/molecules16010038
Received: 17 November 2010 / Revised: 13 December 2010 / Accepted: 24 December 2010 / Published: 24 December 2010
Cited by 7 | PDF Full-text (756 KB)
Abstract
Pd was loaded on ultra stable Y (USY) zeolites prepared by steaming NH4-Y zeolite under different conditions. Heck reactions were carried out over the prepared Pd/USY. We found that H2 bubbling was effective in improving not only the catalytic activity
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Pd was loaded on ultra stable Y (USY) zeolites prepared by steaming NH4-Y zeolite under different conditions. Heck reactions were carried out over the prepared Pd/USY. We found that H2 bubbling was effective in improving not only the catalytic activity of Pd/USY, but also that of other supported Pd catalysts and Pd(OAc)2. Moreover, the catalytic activity of Pd/USY could be optimized by choosing appropriate steaming conditions for the preparation of the USY zeolites; Pd loaded on USY prepared at 873 K with 100% H2O gave the highest activity (TOF = 61,000 h−1), which was higher than that of Pd loaded on other kinds of supports. The prepared Pd/USY catalysts were applicable to the Heck reactions using various kinds of substrates including bromo- and chloro-substituted aromatic and heteroaromatic compounds. Characterization of the acid properties of the USY zeolites revealed that the strong acid site (OHstrong) generated as a result of steaming had a profound effect on the catalytic activity of Pd. Full article
(This article belongs to the Special Issue Cross-Coupling Reactions in Organic Synthesis)
Open AccessArticle Novel Synthesis and Antitumor Evaluation of Polyfunctionally Substituted Heterocyclic Compounds Derived from 2-Cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide
Molecules 2011, 16(1), 52-73; doi:10.3390/molecules16010052
Received: 10 November 2010 / Revised: 20 December 2010 / Accepted: 22 December 2010 / Published: 27 December 2010
Cited by 21 | PDF Full-text (219 KB)
Abstract
The reaction of 2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene with ethyl cyanoacetate gave 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide. The latter was used to synthesize different heterocyclic derivatives comprising thiophene, thiazole, pyrazole, pyridine, pyrimidine, and coumarin rings. The mechanistic and synthetic pathways depended on regioselective attack and/or
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The reaction of 2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene with ethyl cyanoacetate gave 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide. The latter was used to synthesize different heterocyclic derivatives comprising thiophene, thiazole, pyrazole, pyridine, pyrimidine, and coumarin rings. The mechanistic and synthetic pathways depended on regioselective attack and/or cyclization by the cyanoacetamido moiety in the key precursor on various chemical reagents. The competition of the reaction pathways including dipolar cyclization, dinucleophilic-bielectrophilic attack, β-attack, Gewald-type attack, and condensation reactions led to the diversity of the synthesized products. The antitumor activities of the synthesized products were studied and evaluated. Most of the compounds revealed high inhibitory effects when screened in vitro for their antiproliferative activity. Three human cancer cell lines, namely, breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and CNS cancer (SF-268) were used in the screening tests. The simplicity of the synthetic procedures which mainly involved one-pot reactions under mild reaction conditions, the convenience of yield production and the diversity of the reactive sites in the produced systems play a valuable role for further heterocyclic transformations and further biological investigations. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessArticle Effect of Five Different Stages of Ripening on Chemical Compounds in Medlar (Mespilus germanica L.)
Molecules 2011, 16(1), 74-91; doi:10.3390/molecules16010074
Received: 11 November 2010 / Revised: 23 December 2010 / Accepted: 24 December 2010 / Published: 28 December 2010
Cited by 25 | PDF Full-text (604 KB)
Abstract
The study of changes of nutritional value of fruit during the ripening process can help estimate the optimal date for fruit harvesting to achieve the best quality for direct consumption and further utilization. The aim of this study was to monitor the changes
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The study of changes of nutritional value of fruit during the ripening process can help estimate the optimal date for fruit harvesting to achieve the best quality for direct consumption and further utilization. The aim of this study was to monitor the changes of chemical composition of medlar fruit (Mespilus germanica L.) measured at five various ripening stages including 134, 144, 154, 164 and 174 days after full bloom (DAFB). Fruits were analyzed and ascorbic acid (AA) and total phenolic compound content with respect to the total antioxidant activity were determined. In addition, selected micronutrients and macronutrients were monitored. The results of our experiments demonstrate that ascorbic acid, total phenolic compound content and total antioxidant activity decreased significantly with increasing time of ripeness. The decreasing tendency in potassium, calcium and magnesium contents during the ripening stages was also determined. During the ripening period, the content of all micronutrients as well as phosphorus and sodium was balanced, with no statistically significant differences between the monitored ripening stages, which can be considered as a positive fact with respect to ideal consumption quality of fruit. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Synthesis of Substituted 1,4-Diazepines and 1,5-Benzodiazepines Using an Efficient Heteropolyacid-Catalyzed Procedure
Molecules 2011, 16(1), 92-99; doi:10.3390/molecules16010092
Received: 19 November 2010 / Accepted: 11 December 2010 / Published: 28 December 2010
Cited by 12 | PDF Full-text (118 KB)
Abstract
An efficient and improved procedure for the synthesis of 1,4-diazepine and 1,5-benzodiazepine derivatives via the reaction of ketimine intermediates with aldehydes in the presence of Keggin-type heteropolyacids (HPAs) was developed. High yields and short reaction times were obtained for both electron-releasing and
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An efficient and improved procedure for the synthesis of 1,4-diazepine and 1,5-benzodiazepine derivatives via the reaction of ketimine intermediates with aldehydes in the presence of Keggin-type heteropolyacids (HPAs) was developed. High yields and short reaction times were obtained for both electron-releasing and electron-withdrawing substituted 1,4-diazepine  and 1,5-benzodiazepines derivatives. Full article
Open AccessArticle Synthesis of a Dehydroabietyl Derivative Bearing a 2-(2′-Hydroxyphenyl) Benzimidazole Unit and Its Selective Cu2+ Chemosensing
Molecules 2011, 16(1), 100-106; doi:10.3390/molecules16010100
Received: 17 November 2010 / Revised: 9 December 2010 / Accepted: 16 December 2010 / Published: 28 December 2010
Cited by 5 | PDF Full-text (299 KB) | Supplementary Files
Abstract
A dehydroabietyl derivative 2 bearing a 2-(2′-hydroxyphenyl)benzimidazole unit was synthesized and its sensing behaviors toward metal ions were investigated by UV-Vis and fluorescence spectroscopy methods. In THF solution, compound 2 exhibited excellent selectivity for Cu(II) over miscellaneous other metal ions including Cr(II), Mn(II),
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A dehydroabietyl derivative 2 bearing a 2-(2′-hydroxyphenyl)benzimidazole unit was synthesized and its sensing behaviors toward metal ions were investigated by UV-Vis and fluorescence spectroscopy methods. In THF solution, compound 2 exhibited excellent selectivity for Cu(II) over miscellaneous other metal ions including Cr(II), Mn(II), Co(II), Ni(II), Zn(II), Cd(II), Al(III), Mg(II), Pb(II), Hg(II), Na(I), Li(I) and K(I) evidenced through the quenching of the fluorescence of the benzimidazole fragment. The reaction between 2 and Cu2+ was found to be stoichiometric with the formation of a 1:1 complex. Full article
Open AccessArticle Antimalarial Activity of Methanolic Leaf Extract of Piper betle L.
Molecules 2011, 16(1), 107-118; doi:10.3390/molecules16010107
Received: 25 November 2010 / Revised: 18 December 2010 / Accepted: 21 December 2010 / Published: 28 December 2010
Cited by 27 | PDF Full-text (384 KB)
Abstract
The need for new compounds active against malaria parasites is made more urgent by the rapid spread of drug-resistance to available antimalarial drugs. The crude methanol extract of Piper betle leaves (50–400 mg/kg) was investigated for its antimalarial activity against Plasmodium berghei (NK65)
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The need for new compounds active against malaria parasites is made more urgent by the rapid spread of drug-resistance to available antimalarial drugs. The crude methanol extract of Piper betle leaves (50–400 mg/kg) was investigated for its antimalarial activity against Plasmodium berghei (NK65) during early and established infections. The phytochemical and antioxidant potentials of the crude extract were evaluated to elucidate the possibilities of its antimalarial effects. The safety of the extract was also investigated in ICR mice of both sexes by the acute oral toxicity limit test. The leaf extract demonstrated significant (P < 0.05) schizonticidal activity in all three antimalarial evaluation models. Phytochemical screening showed that the leaf extract contains some vital antiplasmodial chemical constituents. The extract also exhibited a potent ability to scavenge the free radicals. The results of acute toxicity showed that the methanol extract of Piper betle leaves is toxicologically safe by oral administration. The results suggest that the Malaysian folklorical medicinal application of the extract of Piper betle leaf has a pharmacological basis. Full article
Open AccessArticle Magnetically Recoverable Magnetite/Gold Catalyst Stabilized by Poly(N-vinyl-2-pyrrolidone) for Aerobic Oxidation of Alcohols
Molecules 2011, 16(1), 149-161; doi:10.3390/molecules16010149
Received: 1 December 2010 / Revised: 16 December 2010 / Accepted: 28 December 2010 / Published: 29 December 2010
Cited by 11 | PDF Full-text (376 KB)
Abstract
Fe3O4:PVP/Au nanocomposite synthesized via a two-step procedure was tested as a quasi-homogenous alcohol oxidation catalyst. It was found that the nanocomposite was able to carry out aerobic oxidation of alcohols in water at room temperature. Studies show rapid magnetic
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Fe3O4:PVP/Au nanocomposite synthesized via a two-step procedure was tested as a quasi-homogenous alcohol oxidation catalyst. It was found that the nanocomposite was able to carry out aerobic oxidation of alcohols in water at room temperature. Studies show rapid magnetic recoverability and reusability characteristics. Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
Open AccessArticle The Relationship between Phenolics and Flavonoids Production with Total Non Structural Carbohydrate and Photosynthetic Rate in Labisia pumila Benth. under High CO2 and Nitrogen Fertilization
Molecules 2011, 16(1), 162-174; doi:10.3390/molecules16010162
Received: 24 November 2010 / Revised: 15 December 2010 / Accepted: 21 December 2010 / Published: 29 December 2010
Cited by 34 | PDF Full-text (130 KB)
Abstract
A factorial split plot 4 × 3 experiment was designed to examine and characterize the relationship among production of secondary metabolites (total phenolics, TP; total flavonoids, TF), carbohydrate content and photosynthesis of three varieties of the Malaysian medicinal herb Labisia pumila Benth. namely
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A factorial split plot 4 × 3 experiment was designed to examine and characterize the relationship among production of secondary metabolites (total phenolics, TP; total flavonoids, TF), carbohydrate content and photosynthesis of three varieties of the Malaysian medicinal herb Labisia pumila Benth. namely the varieties alata, pumila and lanceolata under CO2 enrichment (1,200 µmol mol-1) combined with four levels of nitrogen fertilization (0, 90, 180 and 270 kg N ha-1). No varietal differences were observed, however, as the levels of nitrogen increased from 0 to 270 kg N ha-1, the production of TP and TF decreased in the order leaves>roots>stems. The production of TP and TF was related to increased total non structural carbohydrate (TNC), where the increase in starch content was larger than that in sugar concentration. Nevertheless, the regression analysis exhibited a higher influence of soluble sugar concentration (r2 = 0.88) than starch on TP and TF biosynthesis. Photosynthesis, on the other hand, displayed a significant negative relationship with TP and TF production (r2 = -0.87). A decrease in photosynthetic rate with increasing secondary metabolites might be due to an increase in the shikimic acid pathway that results in enhanced production of TP and TF. Chlorophyll content exhibited very significant negative relationships with total soluble sugar, starch and total non structural carbohydrate. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Design and Synthesis of Anti-MRSA Benzimidazolylbenzene-sulfonamides. QSAR Studies for Prediction of Antibacterial Activity
Molecules 2011, 16(1), 175-189; doi:10.3390/molecules16010175
Received: 22 November 2010 / Revised: 24 December 2010 / Accepted: 28 December 2010 / Published: 29 December 2010
Cited by 6 | PDF Full-text (147 KB)
Abstract
A series of benzimidazolylbenzenesulfonamide compounds containing electron-releasing and electron-withdrawing substituents were synthesized and tested for their in vitro antibacterial activity. Two BZS compounds showed strong antibacterial activity against methicillin-resistant Staphylococcus aureus and Bacillus subtilis. Quantitative studies of their structure-activity relationship using a
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A series of benzimidazolylbenzenesulfonamide compounds containing electron-releasing and electron-withdrawing substituents were synthesized and tested for their in vitro antibacterial activity. Two BZS compounds showed strong antibacterial activity against methicillin-resistant Staphylococcus aureus and Bacillus subtilis. Quantitative studies of their structure-activity relationship using a simple linear regression analysis were applied to explore the correlation between the biological activity and the charges on acidic hydrogen atoms in the synthesized compounds. Full article
(This article belongs to the Special Issue Prodrugs)
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Open AccessArticle Casbane Diterpene as a Promising Natural Antimicrobial Agent against Biofilm-Associated Infections
Molecules 2011, 16(1), 190-201; doi:10.3390/molecules16010190
Received: 17 November 2010 / Revised: 29 November 2010 / Accepted: 20 December 2010 / Published: 30 December 2010
Cited by 42 | PDF Full-text (685 KB) | Supplementary Files
Abstract
Croton nepetaefolius is a native plant from northeastern Brazil that belongs to the Euphorbiaceae family. The biological action of this plant has been extensively explored, being the secondary metabolites responsible for its properties alkaloids, diterpenes, and triterpenes. This study aimed to evaluate the
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Croton nepetaefolius is a native plant from northeastern Brazil that belongs to the Euphorbiaceae family. The biological action of this plant has been extensively explored, being the secondary metabolites responsible for its properties alkaloids, diterpenes, and triterpenes. This study aimed to evaluate the ability of casbane diterpene (CD), isolated from the ethanolic extract of C. nepetaefolius, to inhibit microbial growth and biofilm formation of several clinical relevant species (bacteria and yeasts). It was found that CD possessed biocidal and biostatic activity against the majority of the species screened, with minimal active concentrations ranging between 125 and 500 µg/mL. In addition, it was observed that biofilm formation was inhibited even when the planktonic growth was not significantly affected. In conclusion, CD showed potential to be a natural tool for the treatment of diseases caused by different infectious microorganisms. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle An Efficient New Route to Dihydropyranobenzimidazole Inhibitors of HCV Replication
Molecules 2011, 16(1), 281-290; doi:10.3390/molecules16010281
Received: 15 November 2010 / Revised: 24 December 2010 / Accepted: 28 December 2010 / Published: 30 December 2010
Cited by 10 | PDF Full-text (172 KB)
Abstract
A class of dihydropyranobenzimidazole inhibitors was recently discovered that acts against the hepatitis C virus (HCV) in a new way, binding to the IRES-IIa subdomain of the highly conserved 5' untranslated region of the viral RNA and thus preventing the ribosome from initiating
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A class of dihydropyranobenzimidazole inhibitors was recently discovered that acts against the hepatitis C virus (HCV) in a new way, binding to the IRES-IIa subdomain of the highly conserved 5' untranslated region of the viral RNA and thus preventing the ribosome from initiating translation. However, the reported synthesis of these compounds is lengthy and low-yielding, the intermediates are troublesome to purify, and the route is poorly structured for the creation of libraries. We report a streamlined route to this class of inhibitors in which yields are far higher and most intermediates are crystalline. In addition, a key variable side chain is introduced late in the synthesis, allowing analogs to be easily synthesized for optimization of antiviral activity. Full article
Open AccessCommunication Relationship between Oversulfation and Conformation of Low and High Molecular Weight Fucoidans and Evaluation of Their in Vitro Anticancer Activity
Molecules 2011, 16(1), 291-297; doi:10.3390/molecules16010291
Received: 30 November 2010 / Revised: 24 December 2010 / Accepted: 28 December 2010 / Published: 30 December 2010
Cited by 42 | PDF Full-text (247 KB)
Abstract
Low and high molecular weight fucoidans (F5-30K and F>30K) were chemically modified through the addition of sulfate groups, and the effect of oversulfation on the in vitro anticancer activity was investigated. After the addition of sulfate groups, a considerable increase
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Low and high molecular weight fucoidans (F5-30K and F>30K) were chemically modified through the addition of sulfate groups, and the effect of oversulfation on the in vitro anticancer activity was investigated. After the addition of sulfate groups, a considerable increase of 35.5 to 56.8% was observed in the sulfate content of the F5-30K fraction, while the sulfate content of the F>30K fraction increased to a lesser extent (from 31.7 to 41.2%). Significant differences in anticancer activity were observed between the oversulfated F5–30K and F>30K fractions, with activities of 37.3–68.0% and 20.6–35.8%, respectively. This variation in the anticancer activity of oversulfated fucoidan derivatives was likely due to differences in their sulfate content. The results suggest that the molecular conformation of these molecules is closely related to the extent of sulfation in the fucan backbones and that the sulfates are preferably substituted when the fucoidan polymers are in a loose molecular conformation. Full article
Open AccessArticle A Route to Dicyanomethylene Pyridines and Substituted Benzonitriles Utilizing Malononitrile Dimer as a Precursor
Molecules 2011, 16(1), 298-306; doi:10.3390/molecules16010298
Received: 12 October 2010 / Revised: 20 December 2010 / Accepted: 22 December 2010 / Published: 4 January 2011
Cited by 7 | PDF Full-text (167 KB)
Abstract
The conditions of the reaction of malononitrile dimer with enaminones and arylidenemalononitrile could be adapted to yield either pyridines or benzene derivatives. A new synthesis of pyrido[1,2-a]pyrimidines from the reaction of malononitrile dimer 1 and 2-phenyl-3-piperidin-1-yl-acrylonitrile (11) is described. Compound
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The conditions of the reaction of malononitrile dimer with enaminones and arylidenemalononitrile could be adapted to yield either pyridines or benzene derivatives. A new synthesis of pyrido[1,2-a]pyrimidines from the reaction of malononitrile dimer 1 and 2-phenyl-3-piperidin-1-yl-acrylonitrile (11) is described. Compound 1 condensed with DMFDMA to yield an enaminonitrile that reacted with hydrazine hydrate to yield N',4,6-triamino-2H-pyrazolo[3,4-b]pyridine-5-carboxamidine (17). Full article
Open AccessArticle Synthesis, Reactions and Biological Evaluation of Some New Naphtho[2,1-b]furan Derivatives Bearing a Pyrazole Nucleus
Molecules 2011, 16(1), 307-318; doi:10.3390/molecules16010307
Received: 14 November 2010 / Revised: 14 December 2010 / Accepted: 15 December 2010 / Published: 5 January 2011
Cited by 13 | PDF Full-text (166 KB)
Abstract
Vilsmeier formylation of 2-(1-phenylhydrazonoethyl)naphtho[2,1-b]furan (2) gave 3-naphtho[2,1-b]furan-2-yl-1-phenyl-1H-pyrazole-4-carbaldehyde (3), which was reacted with C- and N-nucleophiles to afford naphthofuranpyrazol derivatives 4-8. Treatment of 2-[(3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl)methylene]-malononitrile (4a) with
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Vilsmeier formylation of 2-(1-phenylhydrazonoethyl)naphtho[2,1-b]furan (2) gave 3-naphtho[2,1-b]furan-2-yl-1-phenyl-1H-pyrazole-4-carbaldehyde (3), which was reacted with C- and N-nucleophiles to afford naphthofuranpyrazol derivatives 4-8. Treatment of 2-[(3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl)methylene]-malononitrile (4a) with reactants having active hydrogen and Et3N gave the corresponding pyrazoline, pyran and chromene addition product derivatives 10, 12 and 13, consisting of three different connected heterocyclic moieties. Reaction of 1-((3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl) methylene)-2-phenylhydrazone (6b) with AcONa and ethyl bromoacetate or chloroacetone afforded the thiazolidinone and methylthiazole derivatives 14 and 15, respectively. In addition, intramolecular cyclization of 6d with Ac2O afford the corresponding 1,3,4-thiadiazol-2-yl acetamide derivative 16. The structures of the synthesized compounds were confirmed by IR, 1H-NMR/13C-NMR and mass spectral studies. Compound 14 showed promising effects against the tested Gram positive and negative bacteria and fungi. Full article
Open AccessArticle Synthesis, Molecular Structure, Spectral Properties and Antifungal Activity of Polymethylene-α,ω-bis(N,N- dimethyl-N-dodecyloammonium Bromides)
Molecules 2011, 16(1), 319-335; doi:10.3390/molecules16010319
Received: 22 December 2010 / Revised: 27 December 2010 / Accepted: 4 January 2011 / Published: 5 January 2011
Cited by 18 | PDF Full-text (425 KB)
Abstract
Hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (1), pentamethylene-1,5-bis(N,N-dimethyl-N-dodecylammonium bromide) (2), tetramethylene-1,4-bis(N,N-dimethyl-N-dodecylammonium bromide) (3), trimethylene-1,3-bis(N,N-dimethyl-N-dodecylammonium bromide) (4) and ethylene-1,2-bis(N,N-dimethyl-N-dodecylammonium bromide)
[...] Read more.
Hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (1), pentamethylene-1,5-bis(N,N-dimethyl-N-dodecylammonium bromide) (2), tetramethylene-1,4-bis(N,N-dimethyl-N-dodecylammonium bromide) (3), trimethylene-1,3-bis(N,N-dimethyl-N-dodecylammonium bromide) (4) and ethylene-1,2-bis(N,N-dimethyl-N-dodecylammonium bromide) (5) have been obtained and characterized by FTIR and NMR spectroscopy. DFT calculations have also been carried out. The optimized bond lengths, bond angles and torsion angles calculated by Hartree-Fock/3-21G(d,p) approach have been presented. MIC values for A. niger, P. chrysogenum, C. albicans have been determined and the relationship between MIC and spacer length has been discussed. Full article
Open AccessArticle The Relationships between Phenolic Content, Pollen Diversity, Physicochemical Information and Radical Scavenging Activity in Honey
Molecules 2011, 16(1), 336-347; doi:10.3390/molecules16010336
Received: 30 November 2010 / Accepted: 29 December 2010 / Published: 7 January 2011
Cited by 16 | PDF Full-text (166 KB)
Abstract
Honey is rich in different secondary plant metabolites acting as natural antioxidants and contributing to human health. Radical scavenging activity (RSA) is related to antioxidant activity, while the correlation between the phenolic content and RSA is often weak. Consequently, exclusive information on phenolics
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Honey is rich in different secondary plant metabolites acting as natural antioxidants and contributing to human health. Radical scavenging activity (RSA) is related to antioxidant activity, while the correlation between the phenolic content and RSA is often weak. Consequently, exclusive information on phenolics is often insufficient to qualify the RSA and the health promoting effects of honey. The paper deals with a case study of honey samples originating from the alpine areas of Italy’s Lombardia and Veneto regions and realized by standard physicochemical and statistical analytical methods. In pure honey, the total phenolic content and the RSA were measured in spectrophotometric tests with the 2,2-diphenyl-1-picrylhydrazyl (DPPH·) free radical and Folin-Ciocalteu assays, respectively. Melissopalynological data was used to qualify pollen diversity through rank-frequency curves separating the samples into two groups. On the basis of physicochemical data, the samples were analyzed through multivariate classification and ranking procedures resulting in the identification of an outlier. Elimination of the outlier produced a high correlation between the total phenolic content and RSA in the two pollen diversity groups. The case study suggests that, after disregarding outliers, the RSA activity can be satisfactorily qualified on the basis of phenolics with pollen diversity as a covariate. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Hydrogen Generation Using a CuO/ZnO-ZrO2 Nanocatalyst for Autothermal Reforming of Methanol in a Microchannel Reactor
Molecules 2011, 16(1), 348-366; doi:10.3390/molecules16010348
Received: 25 December 2010 / Revised: 6 January 2011 / Accepted: 7 January 2011 / Published: 7 January 2011
Cited by 9 | PDF Full-text (1430 KB)
Abstract
In the present work, a microchannel reactor for autothermal reforming of methanol using a synthesized catalyst porous alumina support-CuO/ZnO mixed with ZrO2 sol washcoat has been developed and its fine structure and inner surface characterized. Experimentally, CuO/ZnO and alumina support with ZrO
[...] Read more.
In the present work, a microchannel reactor for autothermal reforming of methanol using a synthesized catalyst porous alumina support-CuO/ZnO mixed with ZrO2 sol washcoat has been developed and its fine structure and inner surface characterized. Experimentally, CuO/ZnO and alumina support with ZrO2 sol washcoat catalyst (catalyst slurries) nanoparticles is the catalytically active component of the microreactor. Catalyst slurries have been dried at 298 K for 5 h and then calcined at 623 K for 2 h to increase the surface area and specific pore structures of the washcoat catalyst. The surface area of BET N2 adsorption isotherms for the as-synthesized catalyst and catalyst/ZrO2 sol washcoat samples are 62 and 108 ± 2 m2g−1, respectively. The intensities of Cu content from XRD and XPS data indicate that Al2O3 with Cu species to form CuAl2O4. The EXAFS data reveals that the Cu species in washcoat samples have Cu-O bonding with a bond distance of 1.88 ± 0.02 Å and the coordination number is 3.46 ± 0.05, respectively. Moreover, a hydrogen production rate of 2.16 L h−1 is obtained and the corresponding methanol conversion is 98% at 543 K using the CuO/ZnO with ZrO2 sol washcoat catalyst. Full article
(This article belongs to the Special Issue Nano-catalysts and Nano-technologies for Green Organic Synthesis)
Open AccessCommunication Ni(0)-CMC-Na Nickel Colloids in Sodium Carboxymethyl-Cellulose: Catalytic Evaluation in Hydrogenation Reactions
Molecules 2011, 16(1), 367-372; doi:10.3390/molecules16010367
Received: 29 November 2010 / Revised: 22 December 2010 / Accepted: 5 January 2011 / Published: 7 January 2011
Cited by 2 | PDF Full-text (140 KB)
Abstract A recyclable catalyst, Ni(0)-CMC-Na, composed of nickel colloids dispersed in a water soluble bioorganic polymer, sodium carboxymethylcellulose (CMC-Na), was synthesized by a simple procedure from readily available reagents. The catalyst thus obtained is stable and highly active in alkene hydrogenations. Full article
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Open AccessArticle Observation of Different Catalytic Activity of Various 1-Olefins during Ethylene/1-Olefin Copolymerization with Homogeneous Metallocene Catalysts
Molecules 2011, 16(1), 373-383; doi:10.3390/molecules16010373
Received: 18 November 2010 / Revised: 28 December 2010 / Accepted: 5 January 2011 / Published: 7 January 2011
Cited by 11 | PDF Full-text (548 KB)
Abstract
This research aimed to investigate the copolymerization of ethylene and various 1-olefins. The comonomer lengths were varied from 1-hexene (1-C6) up to 1-octadecene (1-C18) in order to study the effect of comonomer chain length on the activity and properties
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This research aimed to investigate the copolymerization of ethylene and various 1-olefins. The comonomer lengths were varied from 1-hexene (1-C6) up to 1-octadecene (1-C18) in order to study the effect of comonomer chain length on the activity and properties of the polymer in the metallocene/MAO catalyst system. The results indicated that two distinct cases can be described for the effect of 1-olefin chain length on the activity. Considering the short chain length comonomers, such as 1-hexene, 1-octene and 1-decene, it is obvious that the polymerization activity decreased when the length of comonomer was higher, which is probably due to increased steric hindrance at the catalytic center hindering the insertion of ethylene monomer to the active sites, hence, the polymerization rate decreased. On the contrary, for the longer chain 1-olefins, namely 1-dodecene, 1-tetradecene and 1-octadecene, an increase in the comonomer chain length resulted in better activity due to the opening of the gap aperture between Cp(centroid)-M-Cp-(centroid), which forced the coordination site to open more. This effect facilitated the polymerization of the ethylene monomer at the catalytic sites, and thus, the activity increased. The copolymers obtained were further characterized using thermal analysis, X-ray diffraction spectroscopy and 13C-NMR techniques. It could be seen that the melting temperature and comonomer distribution were not affected by the 1-olefin chain length. The polymer crystallinity decreased slightly with increasing comonomer chain length. Moreover, all the synthesized polymers were typical LLDPE having random comonomer distribution. Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
Open AccessArticle Functionalized 4-Hydroxy Coumarins: Novel Synthesis, Crystal Structure and DFT Calculations
Molecules 2011, 16(1), 384-402; doi:10.3390/molecules16010384
Received: 22 November 2010 / Revised: 20 December 2010 / Accepted: 27 December 2010 / Published: 7 January 2011
Cited by 11 | PDF Full-text (435 KB)
Abstract
A novel short-step methodology for the synthesis in good yields of functionalized coumarins has been developed starting from an activated precursor, the N-hydroxysuccinimide ester of O-acetylsalicylic acid. The procedure is based on a tandem C-acylation-cyclization process under mild reaction conditions.
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A novel short-step methodology for the synthesis in good yields of functionalized coumarins has been developed starting from an activated precursor, the N-hydroxysuccinimide ester of O-acetylsalicylic acid. The procedure is based on a tandem C-acylation-cyclization process under mild reaction conditions. The structure of 3-methoxycarbonyl-4-hydroxy coumarin has been established by X-ray diffraction analysis and its geometry was compared with optimized parameters by means of DFT calculations. Full article
Open AccessArticle Herbicidal Activity of Peumus boldus and Drimys winterii Essential Oils from Chile
Molecules 2011, 16(1), 403-411; doi:10.3390/molecules16010403
Received: 29 November 2010 / Revised: 17 December 2010 / Accepted: 7 January 2011 / Published: 10 January 2011
Cited by 10 | PDF Full-text (231 KB)
Abstract
The essential oil composition of Peumus boldus and Drimys winterii was analyzed by means of capillary GC-FID and GC-MS. More than 96% of the total oil components (43 and 54 compounds, respectively) were identified, with ascaridole (51.17 ± 9.51), p-cymene (16.31 ±
[...] Read more.
The essential oil composition of Peumus boldus and Drimys winterii was analyzed by means of capillary GC-FID and GC-MS. More than 96% of the total oil components (43 and 54 compounds, respectively) were identified, with ascaridole (51.17 ± 9.51), p-cymene (16.31 ± 2.52) and 1,8-cineole (14.45 ± 2.99) as the main compounds in P. boldus and g-eudesmol (21.65 ± 0.41), followed of elemol (12.03 ± 0.34) and terpinen-4-ol (11.56 ± 1.06) in D. winterii. The herbicidal activity was tested against Amaranthus hybridus and Portulaca oleracea. P. boldus essential oil was the most phytotoxic against both weeds, inhibiting seed germination and seedling growth at all concentrations assayed (0.125–1 µL/mL). D. winterii essential oil did not show any effect on A. hybridus germination and only affected P. oleracea germination at the highest concentration. The results suggest the possible use of the essential oil from P. boldus as a natural herbicide. Full article
(This article belongs to the Section Natural Products)
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Open AccessArticle Palladium(0) Deposited on PAMAM Dendrimers as a Catalyst for C–C Cross Coupling Reactions
Molecules 2011, 16(1), 427-441; doi:10.3390/molecules16010427
Received: 2 December 2010 / Revised: 4 January 2011 / Accepted: 7 January 2011 / Published: 10 January 2011
Cited by 11 | PDF Full-text (817 KB)
Abstract
PAMAM dendrimers of generations G2–G3 as well as a partially substituted derivative of generation G4 and a low-molecular-weight tricyclic ligand 4 were used to bind Pd(0) nanoparticles. The obtained adducts were tested as catalysts for C–C cross-coupling reactions, such as the Suzuki-Miyaura, Hiyama,
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PAMAM dendrimers of generations G2–G3 as well as a partially substituted derivative of generation G4 and a low-molecular-weight tricyclic ligand 4 were used to bind Pd(0) nanoparticles. The obtained adducts were tested as catalysts for C–C cross-coupling reactions, such as the Suzuki-Miyaura, Hiyama, Heck and Sonogashira reaction. The highest yields of the coupling product, diphenylacetylene, were obtained with all the catalysts studied in the Sonogashira coupling performed in ethanol with K2CO3 as base. Very good results, 85–100%, were also found in the Suzuki-Miyaura cross-coupling, while the efficiency of the Hiyama coupling appeared lower, with 38–52% of 2-Methylbiphenyl formed. In all reactions, the G2–Pd(0) catalyst, containing an unmodified dendrimer, afforded the highest yields of the cross-coupling products. Full article
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Open AccessArticle Feeding Deterrents against Two Grain Storage Insects from Euphorbia fischeriana
Molecules 2011, 16(1), 466-476; doi:10.3390/molecules16010466
Received: 17 November 2010 / Revised: 5 January 2011 / Accepted: 7 January 2011 / Published: 10 January 2011
Cited by 8 | PDF Full-text (221 KB)
Abstract
The screening of several Chinese medicinal herbs for insecticidal principles showed that Euphorbia fischeriana roots possessed significant feeding deterrent activity against two stored-product insects (Tribolium castaneum and Sitophilus zeamais). From ethanol extract, four feeding deterrents were isolated by bioassay-guided fractionation. The
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The screening of several Chinese medicinal herbs for insecticidal principles showed that Euphorbia fischeriana roots possessed significant feeding deterrent activity against two stored-product insects (Tribolium castaneum and Sitophilus zeamais). From ethanol extract, four feeding deterrents were isolated by bioassay-guided fractionation. The compounds were identified as jolkinolide B, 12-deoxyphorbol 13-(9Z)-octadecenoate 20-acetate, 17-hydroxyjolkinolide A and B on the basis of their phytochemical and spectral data. Jolkinolide B and 17-hydroxyjolkinolide B possessed strong feeding deterrent activities against S. zeamais (EC50 = 342.1 and 543.9 ppm, respectively) and T. castaneum adults (EC50 = 361.4 and 551.5 ppm, respectively). 17-Hydroxyjolkinolide A and 12-deoxyphorbol 13-(9Z)-octadecenoate 20-acetate A also exhibited feeding deterrent activity against the two grain storage insects with EC50 values of 631.9 and 884.3 ppm for S. zeamais and 656.5 and 1058.4 ppm for T. castaneum adults. Full article
Open AccessArticle A Quantified Ginseng (Panax ginseng C.A. Meyer) Extract Influences Lipid Acquisition and Increases Adiponectin Expression in 3T3-L1 Cells
Molecules 2011, 16(1), 477-492; doi:10.3390/molecules16010477
Received: 8 November 2010 / Revised: 21 December 2010 / Accepted: 7 January 2011 / Published: 10 January 2011
Cited by 12 | PDF Full-text (606 KB)
Abstract
A Panax ginseng extract (PGE) with a quantified amount of ginsenosides was utilized to investigate its potential to inhibit proliferation, influence lipid acquisition and adiponectin expression in 3T3-L1 cells. Seven fingerprint ginsenosides were quantified using high performance liquid chromatography and their respective molecular
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A Panax ginseng extract (PGE) with a quantified amount of ginsenosides was utilized to investigate its potential to inhibit proliferation, influence lipid acquisition and adiponectin expression in 3T3-L1 cells. Seven fingerprint ginsenosides were quantified using high performance liquid chromatography and their respective molecular weights were further confirmed via LC-ESI-MS analysis from four different extraction methods. Extraction using methanol under reflux produced significantly higher amounts of ginsenosides. The methanol extract consisted of Rg1 (47.40 ± 4.28 mg/g, dry weight of extract), Re (61.62 ± 5.10 mg/g), Rf (6.14 ± 0.28 mg/g), Rb1 (21.73 ± 1.29 mg/g), Rc (78.79 ± 4.15 mg/g), Rb2 (56.80 ± 3.79 mg/g), Rd (5.90 ± 0.41 mg/g). MTT analysis showed that PGE had a concentrationdependent cytotoxic effect on 3T3-L1 preadipocyte and the LC50 value was calculated to be 18.2 ± 5 μg/mL. Cell cycle analysis showed minimal changes in all four phases. Differentiating adipocytes treated with ginseng extract had a visible decrease in lipid droplets formation measured by Oil red O staining. Consequently, triglycerides levels in media significantly (P < 0.05) decreased by 39.5% and 46.1% when treated at concentrations of 1 μg/mL and 10 μg/mL compared to untreated control cells. Western blot analysis showed that the adiponectin protein expression was significantly (P < 0.05) increased at 10 μg/mL, but not at 1 μg/mL. A quantified PGE reduced the growth of 3T3-L1 cells, down-regulated lipid accumulation and up-regulated adiponectin expression in the 3T3-L1 adipocyte cell model. Full article
(This article belongs to the Special Issue Glycosides)
Open AccessArticle Tomato Polyphenol Oxidase B Is Spatially and Temporally Regulated during Development and in Response to Ethylene
Molecules 2011, 16(1), 493-517; doi:10.3390/molecules16010493
Received: 22 December 2010 / Accepted: 7 January 2011 / Published: 11 January 2011
Cited by 14 | PDF Full-text (264 KB)
Abstract
Plant polyphenol oxidases (PPOs) are ubiquitous plastid-localized enzymes. A precise analysis of PPO function in plants has been complicated by the presence of several family members with immunological cross reactivity. Previously we reported the isolation of genomic clones coding for the seven members
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Plant polyphenol oxidases (PPOs) are ubiquitous plastid-localized enzymes. A precise analysis of PPO function in plants has been complicated by the presence of several family members with immunological cross reactivity. Previously we reported the isolation of genomic clones coding for the seven members of the tomato (Solanum lycopersicum) PPO family (A, A’, B, C, D, E, and F). Here we report the complex spatial and temporal expression of one of the members, PPO B. The PPO B promoter was sequenced and subjected to homology analysis. Sequence similarities were found to nucleotide sequences of genes encoding enzymes/proteins active in the following systems: phenylpropanoid biosynthesis, signal transduction and responsiveness to hormones and stresses, fruit and seed proteins/enzymes, and photosynthesis. Chimeric gene fusions were constructed linking PPO B 5' flanking regions to the reporter gene, b-glucuronidase (GUS). The resultant transgenic plants were histochemically analyzed for GUS activity in various vegetative and reproductive tissues, and evaluated for PPO B responsiveness to ethylene induction. It was shown that PPO B expression was tissue specific, developmentally regulated, ethylene induced, and localized predominantly to mitotic or apoptotic tissues. Full article
(This article belongs to the Section Metabolites)
Open AccessArticle A New Sesquiterpene with a Novel 1β, 8β-Oxygen Bridge from Heteropappus altaicus (willd.) Novopokr.
Molecules 2011, 16(1), 518-522; doi:10.3390/molecules16010518
Received: 29 November 2010 / Revised: 30 December 2010 / Accepted: 6 January 2011 / Published: 11 January 2011
Cited by 2 | PDF Full-text (168 KB)
Abstract A new guaiane-type sesquiterpene, 4α,7β-dihydroxy-10βH-guai-5-en-1β,8β-endoxide (1), was isolated from Heteropappus altaicus (Compositea). The structure of compound 1, which contains exhibited a rare 1,8-oxide bridge, was established on the basis of spectroscopic data. Full article
(This article belongs to the Section Natural Products)
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Open AccessCommunication Synthesis and Anti-Bacterial Activities of a Bis-Chalcone Derived from Thiophene and Its Bis-Cyclized Products
Molecules 2011, 16(1), 523-531; doi:10.3390/molecules16010523
Received: 26 December 2010 / Accepted: 10 January 2011 / Published: 12 January 2011
Cited by 33 | PDF Full-text (251 KB)
Abstract
A chalcone was prepared by the reaction of terephthalaldehyde with 3-acetyl-2,5-dimethylthiophene. Treatment of this chalcone with thiosemicarbazide/phenyl hydrazine/guanidine hydrochloride/thiourea afforded the corresponding pyrazoline,  pyrazole, and pyrimidine in good yields. All the new compounds have been characterized by IR, 1H-NMR, 13C-NMR, GC-MS
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A chalcone was prepared by the reaction of terephthalaldehyde with 3-acetyl-2,5-dimethylthiophene. Treatment of this chalcone with thiosemicarbazide/phenyl hydrazine/guanidine hydrochloride/thiourea afforded the corresponding pyrazoline,  pyrazole, and pyrimidine in good yields. All the new compounds have been characterized by IR, 1H-NMR, 13C-NMR, GC-MS and elemental analyses. The anti-bacterial activity of these compounds were first tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined with the reference of standard drug chloramphenicol. The results showed that the pyrazoline derivative is better at inhibiting growth of both types of bacteria (Gram-positive and Gram-negative) compared to chloramphenicol. Full article
Open AccessArticle White Spot Syndrome Virus Orf514 Encodes a Bona Fide DNA Polymerase
Molecules 2011, 16(1), 532-542; doi:10.3390/molecules16010532
Received: 16 November 2010 / Revised: 19 December 2010 / Accepted: 11 January 2011 / Published: 12 January 2011
Cited by 5 | PDF Full-text (445 KB)
Abstract
White spot syndrome virus (WSSV) is the causative agent of white spot syndrome, one of the most devastating diseases in shrimp aquaculture. The genome of WSSV includes a gene that encodes a putative family B DNA polymerase (ORF514), which is 16% identical in
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White spot syndrome virus (WSSV) is the causative agent of white spot syndrome, one of the most devastating diseases in shrimp aquaculture. The genome of WSSV includes a gene that encodes a putative family B DNA polymerase (ORF514), which is 16% identical in amino acid sequence to the Herpes virus 1 DNA polymerase. The aim of this work was to demonstrate the activity of the WSSV ORF514-encoded protein as a DNA polymerase and hence a putative antiviral target. A 3.5 kbp fragment encoding the conserved polymerase and exonuclease domains of ORF514 was overexpressed in bacteria. The recombinant protein showed polymerase activity but with very low level of processivity. Molecular modeling of the catalytic protein core encoded in ORF514 revealed a canonical polymerase fold. Amino acid sequence alignments of ORF514 indicate the presence of a putative PIP box, suggesting that the encoded putative DNA polymerase may use a host processivity factor for optimal activity. We postulate that WSSV ORF514 encodes a bona fide DNA polymerase that requires accessory proteins for activity and maybe target for drugs or compounds that inhibit viral DNA replication. Full article
(This article belongs to the Special Issue Enzyme-Catalyzed Reactions)
Open AccessArticle Antimicrobial Activity of Diterpenes from Viguiera arenaria against Endodontic Bacteria
Molecules 2011, 16(1), 543-551; doi:10.3390/molecules160100543
Received: 17 December 2010 / Revised: 28 December 2010 / Accepted: 5 January 2011 / Published: 13 January 2011
Cited by 24 | PDF Full-text (176 KB)
Abstract
Six pimarane-type diterpenes isolated from Viguiera arenaria Baker and two semi-synthetic derivatives were evaluated in vitro against a panel of representative microorganisms responsible for dental root canal infections. The microdilution method was used for the determination of the minimum inhibitory concentration (MIC) and
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Six pimarane-type diterpenes isolated from Viguiera arenaria Baker and two semi-synthetic derivatives were evaluated in vitro against a panel of representative microorganisms responsible for dental root canal infections. The microdilution method was used for the determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Porphyromonas gingivalis, Prevotella nigrescens, Prevotella intermedia, Prevotella buccae, Fusobacterium nucleatum, Bacteroides fragilis, Actinomyces naeslundii, Actinomyces viscosus, Peptostreptococcus micros, Enterococcus faecalis and Aggregatibacter actinomycetemcomitans. The compounds ent-pimara-8(14),15-dien-19-oic acid, its sodium salt and ent-8(14),15-pimaradien-3β-ol were the most active, displaying MIC values ranging from 1 to 10 μg mL-1. The results also allow us to conclude that minor structural differences among these diterpenes significantly influence their antimicrobial activity, bringing new perspectives to the discovery of new chemicals for use as a complement to instrumental endodontic procedures. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle 3-Acetyloxy-2-cyano-2-(alkylaminocarbamoyl)propyl Groups as Biodegradable Protecting Groups of Nucleoside 5´-mono-Phosphates
Molecules 2011, 16(1), 552-566; doi:10.3390/molecules16010552
Received: 22 November 2010 / Revised: 30 December 2010 / Accepted: 13 January 2011 / Published: 14 January 2011
Cited by 3 | PDF Full-text (533 KB)
Abstract
Thymidine 5´-bis[3-acetyloxy-2-cyano-2-(2-phenylethylcarbamoyl)propyl]phosphate (1) has been prepared and the removal of phosphate protecting groups by hog liver carboxyesterase (HLE) at pH 7.5 and 37 °C has been followed by HPLC. The first detectable intermediates are the (RP)- and (
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Thymidine 5´-bis[3-acetyloxy-2-cyano-2-(2-phenylethylcarbamoyl)propyl]phosphate (1) has been prepared and the removal of phosphate protecting groups by hog liver carboxyesterase (HLE) at pH 7.5 and 37 °C has been followed by HPLC. The first detectable intermediates are the (RP)- and (SP)-diastereomers of the monodeacetylated triester 14, which subsequently undergo concurrent retro-aldol condensation to diester 4 and enzyme-catalyzed hydrolysis to the fully deacetylated triester 15. The former pathway predominates, representing 90% of the overall breakdown of 14. The diester 4 undergoes the enzymatic deacetylation 700 times less readily than the triester, but gives finally thymidine 5´-monophosphate as the desired main product. To elucidate the potential toxicity of the electrophilic 2-cyano-N-(2-phenylethyl)acrylamideby-product 17 released upon the deprotection, the hydrolysis of 1 has also been studied in the presence of glutathione (GSH). Full article
(This article belongs to the Special Issue Prodrugs)
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Open AccessArticle Homopolymerization of Ethylene, 1-Hexene, Styrene and Copolymerization of Styrene With 1,3-Cyclohexadiene Using (h5-Tetramethylcyclopentadienyl)dimethylsilyl(N-Ar’)amido-TiCl2/MAO (Ar’=6-(2-(Diethylboryl)phenyl)pyrid-2-yl, Biphen-3-yl)
Molecules 2011, 16(1), 567-582; doi:10.3390/molecules16010567
Received: 1 December 2010 / Revised: 9 January 2011 / Accepted: 13 January 2011 / Published: 14 January 2011
Cited by 8 | PDF Full-text (519 KB)
Abstract
The propensity of a half-sandwich (η5-tetramethylcyclopentadienyl) dimethylsilylamido TiIV-based catalyst bearing an auxiliary diethylboryl-protected pyridyl moiety (Ti-8), activated by methylaluminoxane (MAO) to homopolymerize α-olefins such as ethylene, 1-hexene and styrene as well as to copolymerize styrene with 1,3-cyclo-hexadiene is described.
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The propensity of a half-sandwich (η5-tetramethylcyclopentadienyl) dimethylsilylamido TiIV-based catalyst bearing an auxiliary diethylboryl-protected pyridyl moiety (Ti-8), activated by methylaluminoxane (MAO) to homopolymerize α-olefins such as ethylene, 1-hexene and styrene as well as to copolymerize styrene with 1,3-cyclo-hexadiene is described. The reactivity of Ti-8 was investigated in comparison to a 6-(2-(diethylboryl)phenyl)pyrid-2-yl-free analogue (Ti-3). Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
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Open AccessArticle Phytochemical and Cytotoxic Investigations of Alpinia mutica Rhizomes
Molecules 2011, 16(1), 583-589; doi:10.3390/molecules16010583
Received: 2 December 2010 / Revised: 31 December 2010 / Accepted: 7 January 2011 / Published: 14 January 2011
Cited by 29 | PDF Full-text (112 KB)
Abstract
The methanol and fractionated extracts (hexane, ethyl acetate and water) of Alpinia mutica (Zingiberaceae) rhizomes were investigated for their cytotoxic effect against six human carcinoma cell lines, namely KB, MCF7, A549, Caski, HCT116, HT29 and non-human fibroblast cell line (MRC 5) using an
[...] Read more.
The methanol and fractionated extracts (hexane, ethyl acetate and water) of Alpinia mutica (Zingiberaceae) rhizomes were investigated for their cytotoxic effect against six human carcinoma cell lines, namely KB, MCF7, A549, Caski, HCT116, HT29 and non-human fibroblast cell line (MRC 5) using an in vitro cytotoxicity assay. The ethyl acetate extract possessed high inhibitory effect against KB, MCF7 and Caski cells (IC50 values of 9.4, 19.7 and 19.8 µg/mL, respectively). Flavokawin B (1), 5,6-dehydrokawain (2), pinostrobin chalcone (3) and alpinetin (4), isolated from the active ethyl acetate extract were also evaluated for their cytotoxic activity. Of these, pinostrobin chalcone (3) and alpinetin (4) were isolated from this plant for the first time. Pinostrobin chalcone (3) displayed very remarkable cytotoxic activity against the tested human cancer cells, such as KB, MCF7 and Caski cells (IC50 values of 6.2, 7.3 and 7.7 µg/mL, respectively). This is the first report of the cytotoxic activity of Alpinia mutica. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Chemistry of the Enaminone of 1-Acetylnaphthalene under Microwave Irradiation Using Chitosan as a Green Catalyst
Molecules 2011, 16(1), 609-623; doi:10.3390/molecules16010609
Received: 9 November 2010 / Revised: 4 January 2011 / Accepted: 6 January 2011 / Published: 17 January 2011
Cited by 9 | PDF Full-text (158 KB)
Abstract
Enaminone 1 was reacted with hydrazonoyl halides 2a-d to yield 3,4-disubstituted pyrazoles 6a-d. Coupling with arenediazonium chlorides afforded the 2-(arylhydrazono)-3-(1-naphthalenyl)-3-oxopropionaldehydes 13a-c. Compounds 13 could be utilized for the synthesis of a variety of arylpyrazoles, arylazolopyrimidines, and pyridazinones via reaction with hydrazines,
[...] Read more.
Enaminone 1 was reacted with hydrazonoyl halides 2a-d to yield 3,4-disubstituted pyrazoles 6a-d. Coupling with arenediazonium chlorides afforded the 2-(arylhydrazono)-3-(1-naphthalenyl)-3-oxopropionaldehydes 13a-c. Compounds 13 could be utilized for the synthesis of a variety of arylpyrazoles, arylazolopyrimidines, and pyridazinones via reaction with hydrazines, aminoazoles, and active methylene derivatives, respectively. A comparative study of aforementioned reactions was carried out with chitosan as a basic ecofriendly catalyst under conventional heating as well as under pressurized microwave irradiation conditions. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
Open AccessArticle Carotenoids in Fruits of Different Persimmon Cultivars
Molecules 2011, 16(1), 624-636; doi:10.3390/molecules16010624
Received: 9 November 2010 / Revised: 21 December 2010 / Accepted: 11 January 2011 / Published: 17 January 2011
Cited by 14 | PDF Full-text (266 KB)
Abstract
Carotenoids in the peel and the flesh of persimmon fruit were identified, and the contents of carotenoids in the fleshes of 46 different persimmon cultivars were analyzed. The results indicated that 31 specific carotenoids were detected in both cultivars of persimmons, among which
[...] Read more.
Carotenoids in the peel and the flesh of persimmon fruit were identified, and the contents of carotenoids in the fleshes of 46 different persimmon cultivars were analyzed. The results indicated that 31 specific carotenoids were detected in both cultivars of persimmons, among which nine specific carotenoids were characterized. β-Cryptoxanthin was the most abundant carotenoid among all individual components in both the peel and the flesh, accounting for about 20-30% of the total carotenoids in both cultivars. The contents of total carotenoids in the fleshes of different persimmon cultivars were between 194.61 µg/100g FW and 1,566.30 µg/100g FW. Zeaxanthin was also the most abundant in all persimmon fleshes besides β-Cryptoxanthin, and the total amount of these two components accounted for 37.84-85.11% of the total carotenoids. The RE values in the fleshes of different cultivars also differed greatly. Besides, the stage of maturation was also important factor which could influence the carotenoid content and RE value in the fleshes. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Synthesis, Inhibitory Effects on Nitric Oxide and Structure-Activity Relationships of a Glycosphingolipid from the Marine Sponge Aplysinella rhax and Its Analogues
Molecules 2011, 16(1), 637-651; doi:10.3390/molecules16010637
Received: 9 December 2010 / Revised: 29 December 2010 / Accepted: 14 January 2011 / Published: 17 January 2011
Cited by 3 | PDF Full-text (564 KB)
Abstract
The novel glycosphingolipid, b-D-GalNAcp(1®4)[a-D-Fucp(1®3)]-b-D-GlcNAcp(1®)Cer (A), isolated from the marine sponge Aplysinella rhax has a unique structure, with D-fucose and N-acetyl-D-galactosamine moieties attached to a reducing-end N-acetyl-D-glucosamine through an a1®3 and b1®4 linkage, respectively.
[...] Read more.
The novel glycosphingolipid, b-D-GalNAcp(1®4)[a-D-Fucp(1®3)]-b-D-GlcNAcp(1®)Cer (A), isolated from the marine sponge Aplysinella rhax has a unique structure, with D-fucose and N-acetyl-D-galactosamine moieties attached to a reducing-end N-acetyl-D-glucosamine through an a1®3 and b1®4 linkage, respectively. We synthesized glycolipid 1 and some non-natural di- and trisaccharide analogues 2-6 containing a D-fucose residue. Among these compounds, the natural type showed the most potent nitric oxide (NO) production inhibitory activity against LPS-induced J774.1 cells. Our results indicate that both the presence of a D-Fuca1-3GlcNAc-linkage and the ceramide aglycon portion are crucial for optimal NO inhibition. Full article
Open AccessArticle Monosaccharide-NAIM Derivatives for D-, L-Configurational Analysis
Molecules 2011, 16(1), 652-664; doi:10.3390/molecules16010652
Received: 15 December 2010 / Revised: 28 December 2010 / Accepted: 13 January 2011 / Published: 17 January 2011
Cited by 8 | PDF Full-text (459 KB)
Abstract
The D-, L-enantiomeric pairs of common monosaccharides (xylose, ribose, rhamnose, arabinose, fucose, glucose, mannose, galactose, N-acetylgalactosamine, glucuronic acid and galacturonic acid) were derivatized with 2,3-naphthalenediamine to form the corresponding D-, L-aldo-NAIM derivatives. A simple and facile capillary electrophoretic method was established for
[...] Read more.
The D-, L-enantiomeric pairs of common monosaccharides (xylose, ribose, rhamnose, arabinose, fucose, glucose, mannose, galactose, N-acetylgalactosamine, glucuronic acid and galacturonic acid) were derivatized with 2,3-naphthalenediamine to form the corresponding D-, L-aldo-NAIM derivatives. A simple and facile capillary electrophoretic method was established for sugar composition analysis by simultaneously determining the migration times of these aldo-NAIMs using borate buffer at high pH (100 mM, pH 9.0). The methodology is also applicable to sialic acid (ketose monosaccharides). The quantitation level of the proposed method was in the 10~500 ppm range and the LOD was 1 ppm. The enantioseparation of D, L pairs of aldo-NAIMs were also achieved by using modified sulfated-a-cyclodextrin as the chiral selector in phosphate buffer (300 mM, pH 3.0). In addition, the combination by reductive amination of amino-aldo-NAIM agent and D-, L-enantiomeric pairs of monosaccharides formed a diastereomeric pair for saccharide configuration analysis. Aldo-NAIM derivatives are thus shown to be rapid and efficient agents for analyzing saccharide compositions and configurations with good linearity and short analysis times via capillary electrophoresis. Full article
(This article belongs to the Special Issue Glycosides)
Open AccessArticle Bioassay-Guided Isolation of an Anti-Ulcer Compound, Tagitinin C, from Tithonia diversifolia: Role of Nitric Oxide, Prostaglandins and Sulfhydryls
Molecules 2011, 16(1), 665-674; doi:10.3390/molecules16010665
Received: 16 December 2010 / Revised: 6 January 2011 / Accepted: 13 January 2011 / Published: 17 January 2011
Cited by 20 | PDF Full-text (69 KB)
Abstract
Tithonia diversifolia is a medicinal plant from the Municipality of Suchiapa, Chiapas, Mexico, that according to local folk medicine is considered useful in the treatment of gastric ulcers. The aim of the present study was to investigate the gastroprotective activity of T. diversifolia
[...] Read more.
Tithonia diversifolia is a medicinal plant from the Municipality of Suchiapa, Chiapas, Mexico, that according to local folk medicine is considered useful in the treatment of gastric ulcers. The aim of the present study was to investigate the gastroprotective activity of T. diversifolia by using an ethanol-induced gastric ulcer experimental model in male Wistar rats. The results showed that T. diversifolia had gastroprotective activity, and that the dichloromethane extract had the highest protective activity (close to 90% when using doses between 10 to 100 mg/kg), and that further the compound tagitinin C isolated from this extract was the main active gastroprotective agent. Rats treated with tagitinin C suspended in Tween 80 at 1, 3, 10 and 30 mg/kg showed 37.7, 70.1, 100, and 100% gastroprotection, respectively. The effect elicited by tagitinin C (30 mg/kg) was not attenuated by pretreatment with either NG-nitro-L-arginine methyl ester (70 mg/kg, i.p.), a nitric oxide (NO) synthase inhibitor, N-ethylmaleimide (10 mg/kg, s.c.), a blocker of sulfhydryl groups, or indomethacin (10 mg/kg, s.c.), a blocker of prostaglandin synthesis, which suggests that the gastroprotective mechanism of action of this sesquiterpene lactone does not involve NO, sulfhydryl groups or prostaglandins. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Two New Chroman Derivations from the Endophytic Penicillium sp. DCS523
Molecules 2011, 16(1), 686-693; doi:10.3390/molecules16010686
Received: 2 December 2010 / Revised: 24 December 2010 / Accepted: 28 December 2010 / Published: 18 January 2011
Cited by 3 | PDF Full-text (221 KB)
Abstract
Strain DCS523 was isolated from the branch tissue of Daphniphyllum longeracemosum and determined to be a Penicillium sp. according to the ITS sequence analysis. The extracts from the PDA solid fermentation media of Penicillium sp. DCS523 were purified to give two new chroman
[...] Read more.
Strain DCS523 was isolated from the branch tissue of Daphniphyllum longeracemosum and determined to be a Penicillium sp. according to the ITS sequence analysis. The extracts from the PDA solid fermentation media of Penicillium sp. DCS523 were purified to give two new chroman derivatives as well as six known compounds. Based on their spectral data the new compounds were identified as (Z)-6-acetyl- 3-(1,2-dihydroxypropylidene)-5-hydroxy-8-methylchroman-2-one (1) and 6-acetyl-2α,5- dihydroxy-2-(2-hydroxypropyl)- 3α,8-dimethylchroman (2), respectively. Full article
Open AccessArticle Emodin-8-O-β-D-Glucoside from Polygonum Amplexicaule D. Don var. Sinense Forb. Promotes Proliferation and Differentiation of Osteoblastic MC3T3-E1 Cells
Molecules 2011, 16(1), 728-737; doi:10.3390/molecules16010728
Received: 26 November 2010 / Revised: 7 January 2011 / Accepted: 17 January 2011 / Published: 18 January 2011
Cited by 13 | PDF Full-text (279 KB)
Abstract
Polygonum amplexicaule D. Don var. sinense Forb. (Polygonaceae) (PAF) is a famous traditional herb used to treat fractures, rheumatoid arthritis, muscle injury and pain. The present study was designed to investigate a PAF derived-chemical compound emodin-8-O-β-D-glucoside (EG) on the proliferation
[...] Read more.
Polygonum amplexicaule D. Don var. sinense Forb. (Polygonaceae) (PAF) is a famous traditional herb used to treat fractures, rheumatoid arthritis, muscle injury and pain. The present study was designed to investigate a PAF derived-chemical compound emodin-8-O-β-D-glucoside (EG) on the proliferation and differentiation of osteoblastic MC3T3-E1 cell in vitro. A compound was isolated from PAF extract by HPLC and identified as emodin-8-O-β-D-glucoside (EG) by spectroscopic methods. EG significantly promoted cell proliferation at 0.1–100 ng/mL, and increased the cell proportion in S-phase from 16.34% to 32.16%. Moreover, EG increased alkaline phosphatase (ALP) expression in MC3T3-E1 cells at the concentration from 0.1 to 100 ng/mL and inhibited PGE2 production induced by TNF-α in osteoblasts at the concentrations ranging from 10–100 ng/mL, suggesting that cell differentiation was induced in MC3T3-E1 osteoblasts. Taken together, these results indicated compound EG directly stimulated cell proliferation and differentiation of osteoblasts, therefore this study preliminarily explored the pharmacological mechanism of PAF to promote the healing of bone rheumatism and various fractures. Full article
Open AccessArticle Modulation of the Pharmacological Activities of Secretory Phospholipase A2 from Crotalus durissus cascavella Induced by Naringin
Molecules 2011, 16(1), 738-761; doi:10.3390/molecules16010738
Received: 10 December 2010 / Revised: 4 January 2011 / Accepted: 13 January 2011 / Published: 18 January 2011
PDF Full-text (795 KB)
Abstract
In this work we have characterized the action of the naringin, a flavonoid found in grapefruit and known for its various pharmacological effects, which include antioxidant blood lipid lowering and anticancer activity, on the structure and biochemical activities of a secretory phospholipase A
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In this work we have characterized the action of the naringin, a flavonoid found in grapefruit and known for its various pharmacological effects, which include antioxidant blood lipid lowering and anticancer activity, on the structure and biochemical activities of a secretory phospholipase A (sPLA2) from Crotalus durissus cascavella, an important protein involved in the releasinge of arachidonic acid in phospholipid membranes. sPLA2 was incubated with naringin (mol:mol) at 37 °C and a discrete reduction in the UV scanning signal and a modification of the circular dichroism spectra were observed after treatment with naringin, suggesting modifications of the secondary structure of the protein. This flavonoid was able to decrease enzymatic activity and some pharmacological effects, such as myonecrosis, platelet aggregation, and neurotoxic activity caused by sPLA2, however, the inflammatory effect was not affected by naringin. In addition, small angle X-ray scattering (SAXS) data were collected for sPLA2 and naringin-treated sPLA2 to evaluate possible modifications of the protein structure. These structural investigations have shown that sPLA2 is an elongated dimer in solution and after treatment with naringin a conformational change in the dimeric configuration was observed. Our results suggest that structural modification may be correlated with the loss of enzymatic activity and alterations in pharmacological properties. Full article
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Open AccessCommunication Schistosomicidal Activity of the Essential Oil of Ageratum conyzoides L. (Asteraceae) against Adult Schistosoma mansoni Worms
Molecules 2011, 16(1), 762-773; doi:10.3390/molecules16010762
Received: 19 November 2010 / Revised: 11 January 2011 / Accepted: 17 January 2011 / Published: 18 January 2011
Cited by 30 | PDF Full-text (148 KB)
Abstract
The in vitro schistosomicidal effects of the essential oil of Ageratum conyzoides L. (Ac-EO) against adult worms of Schistosoma mansoni is reported in this paper. Concerning this activity, Ac-EO was considered to be active, but less effective than the positive control (praziquantel, PZQ)
[...] Read more.
The in vitro schistosomicidal effects of the essential oil of Ageratum conyzoides L. (Ac-EO) against adult worms of Schistosoma mansoni is reported in this paper. Concerning this activity, Ac-EO was considered to be active, but less effective than the positive control (praziquantel, PZQ) in terms of separation of coupled pairs, mortality, decrease in motor activity, and tegumental alterations. However, Ac-EO caused an interesting dose-dependent reduction in the number of eggs of S. mansoni. Precocene I (74.30%) and (E)-caryophyllene (14.23%) were identified as the two major constituents of Ac-EO. These compounds were tested individually and were found to be much less effective than Ac-EO and PZQ. A mixture of the two major compounds in a ratio similar to that found in the Ac-EO was also less effective than Ac-EO, thus revealing that there are no synergistic effects between these components. These results suggest that the essential oil of A. conyzoides is very promising for the development of new schistosomicidal agents. Full article
(This article belongs to the Section Natural Products)
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Open AccessArticle Specific Radioactivity of Neutron Induced Radioisotopes: Assessment Methods and Application for Medically Useful 177Lu Production as a Case
Molecules 2011, 16(1), 818-846; doi:10.3390/molecules16010818
Received: 25 November 2010 / Revised: 10 January 2011 / Accepted: 17 January 2011 / Published: 19 January 2011
Cited by 8 | PDF Full-text (868 KB)
Abstract
The conventional reaction yield evaluation for radioisotope production is not sufficient to set up the optimal conditions for producing radionuclide products of the desired radiochemical quality. Alternatively, the specific radioactivity (SA) assessment, dealing with the relationship between the affecting factors and the inherent
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The conventional reaction yield evaluation for radioisotope production is not sufficient to set up the optimal conditions for producing radionuclide products of the desired radiochemical quality. Alternatively, the specific radioactivity (SA) assessment, dealing with the relationship between the affecting factors and the inherent properties of the target and impurities, offers a way to optimally perform the irradiation for production of the best quality radioisotopes for various applications, especially for targeting radiopharmaceutical preparation. Neutron-capture characteristics, target impurity, side nuclear reactions, target burn-up and post-irradiation processing/cooling time are the main parameters affecting the SA of the radioisotope product. These parameters have been incorporated into the format of mathematical equations for the reaction yield and SA assessment. As a method demonstration, the SA assessment of 177Lu produced based on two different reactions, 176Lu (n,γ)177Lu and 176Yb (n,γ) 177Yb (β- decay) 177Lu, were performed. The irradiation time required for achieving a maximum yield and maximum SA value was evaluated for production based on the 176Lu (n,γ)177Lu reaction. The effect of several factors (such as elemental Lu and isotopic impurities) on the 177Lu SA degradation was evaluated for production based on the 176Yb (n,γ) 177Yb (β- decay) 177Lu reaction. The method of SA assessment of a mixture of several radioactive sources was developed for the radioisotope produced in a reactor from different targets. Full article
(This article belongs to the Special Issue Radiochemistry)
Open AccessArticle Enhancement of Diepoxin ζ Production by Yeast Extract and Its Fractions in Liquid Culture of Berkleasmium-Like Endophytic Fungus Dzf12 from Dioscorea zingiberensis
Molecules 2011, 16(1), 847-856; doi:10.3390/molecules16010847
Received: 14 December 2010 / Revised: 7 January 2011 / Accepted: 18 January 2011 / Published: 19 January 2011
Cited by 14 | PDF Full-text (358 KB)
Abstract
This study was to examine the effects of yeast extract (YE) and its fractions (YE1 and YE2) on the growth and diepoxin ζ (a spirobisnaphthalene with a diversity of bioactivities) production in liquid culture of Berkleasmium-like endophytic fungus Dzf12 from Dioscorea zingiberensis
[...] Read more.
This study was to examine the effects of yeast extract (YE) and its fractions (YE1 and YE2) on the growth and diepoxin ζ (a spirobisnaphthalene with a diversity of bioactivities) production in liquid culture of Berkleasmium-like endophytic fungus Dzf12 from Dioscorea zingiberensis. When YE was applied to the liquid medium at 10 g/L on day 3 of culture, the diepoxin ζ production was most effectively enhanced 3.2-fold (378.70 mg/L versus 120.09 mg/L in control) after another 10 days culture. Feeding with 15 g/L of YE on day 9, the mycelia biomass reached 16.44 g/L, about 2.3-fold in comparison with the control (7.15 g/L). The polysaccharide fraction (YE1) was mainly responsible for stimulating diepoxin ζ accumulation, and the non-polysaccharide fraction (YE2) was mainly responsible for promoting mycelia growth. The results showed that the diepoxin ζ production in liquid culture of endophyte Dzf12 could be effectively enhanced by YE and its fractions. Full article
Open AccessArticle Lipophilic Toxin Profile in Mytilus galloprovincialis during Episodes of Diarrhetic Shellfish Poisoning (DSP) in the N.E. Adriatic Sea in 2006
Molecules 2011, 16(1), 888-899; doi:10.3390/molecules16010888
Received: 22 November 2010 / Revised: 31 December 2010 / Accepted: 18 January 2011 / Published: 21 January 2011
Cited by 11 | PDF Full-text (274 KB)
Abstract
Dinophysis spp. blooms and related shellfish toxicity events of diarrhetic shellfish poisoning (DSP) have been the most reported toxicity event through the Croatian National monitoring program. With the aim to characterize the DSP toxin profile in shellfish farmed in Croatia, for the first
[...] Read more.
Dinophysis spp. blooms and related shellfish toxicity events of diarrhetic shellfish poisoning (DSP) have been the most reported toxicity event through the Croatian National monitoring program. With the aim to characterize the DSP toxin profile in shellfish farmed in Croatia, for the first time a complete analysis of the toxin profile of Croatian mussels has been carried out using the LC-MS/MS technique. The obtained results showed okadaic acid (OA) as the main toxin contaminating Croatian mussels at that time. The maximum concentration of OA in shellfish tissue was recorded 12 days after the Dinophysis fortii bloom, thus suggesting that rapid growth of the toxin level in the shellfish occurred in the first week after the bloom while it was slower in the second week. Furthermore, the presence of only OA at concentrations which could endanger human health suggests D. fortii as the main organism responsible for the toxic event that occurred in Lim Bay. The presence of gymnodimine and spirolides in Croatian mussel has been detected for the first time, while the presence of yessotoxin and pectenotoxin-2 is confirmed. Full article
(This article belongs to the Special Issue Toxins - Organic and Analytical Chemistry)
Open AccessArticle Efficient In Vivo Selection of a Novel Tumor-Associated Peptide from a Phage Display Library
Molecules 2011, 16(1), 900-914; doi:10.3390/molecules16010900
Received: 15 December 2010 / Revised: 14 January 2011 / Accepted: 18 January 2011 / Published: 21 January 2011
Cited by 8 | PDF Full-text (450 KB)
Abstract
We developed a screening procedure to identify ligands from a phage display random peptide library that are selective for circulating bone marrow derived cells homing to angiogenic tumors. Panning the library on blood outgrowth endothelial cell suspension in vitro followed by in vivo
[...] Read more.
We developed a screening procedure to identify ligands from a phage display random peptide library that are selective for circulating bone marrow derived cells homing to angiogenic tumors. Panning the library on blood outgrowth endothelial cell suspension in vitro followed by in vivo selection based on homing of bone marrow-bound phage to angiogenic tumors, yielded the peptide QFPPKLTNNSML. Upon intravenous injection phage displaying this peptide homed to Lewis lung carcinoma (LLC) tumors in vivo whereas control phage did not localize to tumor tissue. Phage carrying the QFPPKLTNNSML peptide labeled with 64Cu radionuclide when administered intravenously into a tumor bearing mouse was detected noninvasively with positron emission tomography (PET) around the tumor. These proof-of-principle experiments demonstrate the ability of the QFPPKLTNNSML peptide to deliver payload (radiolabeled phage conjugates) in vivo to sites of ongoing angiogenesis and point to its potential clinical utility in a variety of physiologic and pathologic processes where neovascular growth is a critical component. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
Open AccessArticle X-Ray Supramolecular Structure, NMR Spectroscopy and Synthesis of 3-Methyl-1-phenyl-1H-chromeno[4,3-c]pyrazol-4-ones Formed by the Unexpected Cyclization of 3-[1-(Phenyl-hydrazono)ethyl]-chromen-2-ones
Molecules 2011, 16(1), 915-932; doi:10.3390/molecules16010915
Received: 16 December 2010 / Revised: 8 January 2011 / Accepted: 18 January 2011 / Published: 21 January 2011
Cited by 6 | PDF Full-text (428 KB)
Abstract
The molecular structures of nine 3-methyl-1-phenyl-1H-chromeno[4,3-c]pyrazol-4-one isomers, obtained by the oxidative cyclization of the corresponding 1-phenylhydrazono chromen-2-ones with copper acetate as catalyst, are reported. The molecular and supramolecular structures of the 8-chloro, 8-bromo- and 8-nitro isomers 2b-d, were established by
[...] Read more.
The molecular structures of nine 3-methyl-1-phenyl-1H-chromeno[4,3-c]pyrazol-4-one isomers, obtained by the oxidative cyclization of the corresponding 1-phenylhydrazono chromen-2-ones with copper acetate as catalyst, are reported. The molecular and supramolecular structures of the 8-chloro, 8-bromo- and 8-nitro isomers 2b-d, were established by X-ray diffraction. The halogenated isomers 2b and 2c are isomorphs, they crystallize as a triclinic system, space group P-1 with two molecules in the asymmetric unit. Compound 2d crystallizes as a monoclinic system, space group P21/m with two molecules in the unit cell. The 1-phenyl ring [Cg(4)] is almost perpendicularly positioned to the chromene-pyrazole ring system. This conformation is in agreement with the anisotropic NMR shielding effect exerted by the phenyl ring over H-9 in solution. The supramolecular architecture is almost controlled by C―H···A (A = O, p) and face to face p-stacking interactions. The observed p-stacking trend between chromene and pyrazole rings is given by the overlapping between the best donor and acceptor rings in each compound. Full article
(This article belongs to the Section Molecular Diversity)
Open AccessArticle Preparation of Polyester-Based Metal-Cross Linked Polymeric Composites as Novel Materials Resistant to Bacterial Adhesion and Biofilm Formation
Molecules 2011, 16(1), 933-950; doi:10.3390/molecules16010933
Received: 27 November 2010 / Revised: 25 December 2010 / Accepted: 17 January 2011 / Published: 21 January 2011
Cited by 4 | PDF Full-text (211 KB)
Abstract
Bacterial biofilms constitute an extremely resistant form of bacterial colonization with dire health and economical implications. Towards achieving polymeric composites capable of resisting bacterial adhesion and biofilm formation, we prepared five 2,6-pyridinedicarboxylate-based polyesters employing five different diol monomers. The resulting polyesters were complexed
[...] Read more.
Bacterial biofilms constitute an extremely resistant form of bacterial colonization with dire health and economical implications. Towards achieving polymeric composites capable of resisting bacterial adhesion and biofilm formation, we prepared five 2,6-pyridinedicarboxylate-based polyesters employing five different diol monomers. The resulting polyesters were complexed with copper (II) or silver (I). The new polymers were characterized by proton and carbon nuclear magnetic resonance spectroscopy, inherent viscosity, infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The corresponding metal complexes were characterized by differential scanning calorimery and infrared spectroscopy. The amounts of complexed copper and silver were determined by atomic absorption spectrophotometry. Finally, the resulting composites were tested for their antibacterial potential and were found to effectively resist bacterial attachment and growth. Full article
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Review

Jump to: Research

Open AccessReview Solid-State [2+2] Photodimerization and Photopolymerization of α,ω-Diarylpolyene Monomers: Effective Utilization of Noncovalent Intermolecular Interactions in Crystals
Molecules 2011, 16(1), 119-148; doi:10.3390/molecules16010119
Received: 25 November 2010 / Revised: 17 December 2010 / Accepted: 24 December 2010 / Published: 28 December 2010
Cited by 54 | PDF Full-text (918 KB)
Abstract
[2+2] Photocycloaddition of olefins is a very useful reaction in synthetic organic chemistry to obtain cyclobutane-containing molecules, which are almost inaccessible by other methods. The reaction, when performed in the crystalline state, occurs more efficiently and selectively than in homogeneous solution due to
[...] Read more.
[2+2] Photocycloaddition of olefins is a very useful reaction in synthetic organic chemistry to obtain cyclobutane-containing molecules, which are almost inaccessible by other methods. The reaction, when performed in the crystalline state, occurs more efficiently and selectively than in homogeneous solution due to tight and regular molecular arrangement in the crystal state. Despite numerous examples for the solid-state [2+2] photodimerization of monoenes, however, it is still a challenge to prepare not only dimers but also higher oligomers and polymers from conjugated polyenes, which have multiple reactive double bonds in a molecule. In our recent studies of the solid-state photoreactions of α,ω-diarylpolyenes, noncovalent intermolecular interactions in crystals were effectively utilized to prealign molecules in stacking arrangements, suitable for the [2+2] reaction. With appropriate ring-substituents, [2+2] photodimerization and photopolymerization of the polyenes took place, although the degree of polymerization was relatively low. This review will describe the details of these reactions. Full article
(This article belongs to the Special Issue Cycloaddition Reactions in Organic Synthesis)
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Open AccessReview Small Molecule Inhibitors as Countermeasures for Botulinum Neurotoxin Intoxication
Molecules 2011, 16(1), 202-220; doi:10.3390/molecules16010202
Received: 30 November 2010 / Revised: 20 December 2010 / Accepted: 29 December 2010 / Published: 30 December 2010
Cited by 19 | PDF Full-text (3737 KB)
Abstract
Botulinum neurotoxins (BoNTs) are the most potent of known toxins and are listed as category A biothreat agents by the U.S. CDC. The BoNT-mediated proteolysis of SNARE proteins inhibits the exocytosis of acetylcholine into neuromuscular junctions, leading to life-threatening flaccid paralysis. Currently, the
[...] Read more.
Botulinum neurotoxins (BoNTs) are the most potent of known toxins and are listed as category A biothreat agents by the U.S. CDC. The BoNT-mediated proteolysis of SNARE proteins inhibits the exocytosis of acetylcholine into neuromuscular junctions, leading to life-threatening flaccid paralysis. Currently, the only therapy for BoNT intoxication (which results in the disease state botulism) includes experimental preventative antibodies and long-term supportive care. Therefore, there is an urgent need to identify and develop inhibitors that will serve as both prophylactic agents and post-exposure ‘rescue’ therapeutics. This review focuses on recent progress to discover and develop small molecule inhibitors as therapeutic countermeasures for BoNT intoxication. Full article
(This article belongs to the Special Issue Toxins - Organic and Analytical Chemistry)
Open AccessReview Targeting Cell Entry of Enveloped Viruses as an Antiviral Strategy
Molecules 2011, 16(1), 221-250; doi:10.3390/molecules16010221
Received: 6 October 2010 / Revised: 16 December 2010 / Accepted: 24 December 2010 / Published: 30 December 2010
Cited by 34 | PDF Full-text (1381 KB)
Abstract
The entry of enveloped viruses into their host cells involves several successive steps, each one being amenable to therapeutic intervention. Entry inhibitors act by targeting viral and/or cellular components, through either the inhibition of protein-protein interactions within the viral envelope proteins or between
[...] Read more.
The entry of enveloped viruses into their host cells involves several successive steps, each one being amenable to therapeutic intervention. Entry inhibitors act by targeting viral and/or cellular components, through either the inhibition of protein-protein interactions within the viral envelope proteins or between viral proteins and host cell receptors, or through the inhibition of protein-lipid interactions. Interestingly, inhibitors that concentrate into/onto the membrane in order to target a protein involved in the entry process, such as arbidol or peptide inhibitors of the human immunodeficiency virus (HIV), could allow the use of doses compatible with therapeutic requirements. The efficacy of these drugs validates entry as a point of intervention in viral life cycles. Strategies based upon small molecule antiviral agents, peptides, proteins or nucleic acids, would most likely prove efficient in multidrug combinations, in order to inhibit several steps of virus life cycle and prevent disease progression. Full article
(This article belongs to the Special Issue Antivirals)
Open AccessReview Phenolic Compounds in Brassica Vegetables
Molecules 2011, 16(1), 251-280; doi:10.3390/molecules16010251
Received: 19 October 2010 / Revised: 6 December 2010 / Accepted: 28 December 2010 / Published: 30 December 2010
Cited by 169 | PDF Full-text (313 KB)
Abstract
Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against
[...] Read more.
Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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Open AccessReview Phage Display for the Generation of Antibodies for Proteome Research, Diagnostics and Therapy
Molecules 2011, 16(1), 412-426; doi:10.3390/molecules16010412
Received: 10 November 2010 / Revised: 4 January 2011 / Accepted: 7 January 2011 / Published: 10 January 2011
Cited by 42 | PDF Full-text (251 KB)
Abstract
Twenty years after its development, antibody phage display using filamentous bacteriophage represents the most successful in vitro antibody selection technology. Initially, its development was encouraged by the unique possibility of directly generating recombinant human antibodies for therapy. Today, antibody phage display has been
[...] Read more.
Twenty years after its development, antibody phage display using filamentous bacteriophage represents the most successful in vitro antibody selection technology. Initially, its development was encouraged by the unique possibility of directly generating recombinant human antibodies for therapy. Today, antibody phage display has been developed as a robust technology offering great potential for automation. Generation of monospecific binders provides a valuable tool for proteome research, leading to highly enhanced throughput and reduced costs. This review presents the phage display technology, application areas of antibodies in research, diagnostics and therapy and the use of antibody phage display for these applications. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
Open AccessReview Theoretical Studies of Homogeneous Catalysts Mimicking Nitrogenase
Molecules 2011, 16(1), 442-465; doi:10.3390/molecules16010442
Received: 1 December 2010 / Revised: 27 December 2010 / Accepted: 5 January 2011 / Published: 10 January 2011
Cited by 11 | PDF Full-text (949 KB)
Abstract
The conversion of molecular nitrogen to ammonia is a key biological and chemical process and represents one of the most challenging topics in chemistry and biology. In Nature the Mo-containing nitrogenase enzymes perform nitrogen ‘fixation’ via an iron molybdenum cofactor (FeMo-co) under ambient
[...] Read more.
The conversion of molecular nitrogen to ammonia is a key biological and chemical process and represents one of the most challenging topics in chemistry and biology. In Nature the Mo-containing nitrogenase enzymes perform nitrogen ‘fixation’ via an iron molybdenum cofactor (FeMo-co) under ambient conditions. In contrast, industrially, the Haber-Bosch process reduces molecular nitrogen and hydrogen to ammonia with a heterogeneous iron catalyst under drastic conditions of temperature and pressure. This process accounts for the production of millions of tons of nitrogen compounds used for agricultural and industrial purposes, but the high temperature and pressure required result in a large energy loss, leading to several economic and environmental issues. During the last 40 years many attempts have been made to synthesize simple homogeneous catalysts that can activate dinitrogen under the same mild conditions of the nitrogenase enzymes. Several compounds, almost all containing transition metals, have been shown to bind and activate N2 to various degrees. However, to date Mo(N2)(HIPTN)3N with (HIPTN)3N= hexaisopropyl-terphenyl-triamidoamine is the only compound performing this process catalytically. In this review we describe how Density Functional Theory calculations have been of help in elucidating the reaction mechanisms of the inorganic compounds that activate or fix N2. These studies provided important insights that rationalize and complement the experimental findings about the reaction mechanisms of known catalysts, predicting the reactivity of new potential catalysts and helping in tailoring new efficient catalytic compounds. Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
Open AccessReview Transition Metal Catalyzed Synthesis of Aryl Sulfides
Molecules 2011, 16(1), 590-608; doi:10.3390/molecules16010590
Received: 17 December 2010 / Revised: 10 January 2011 / Accepted: 14 January 2011 / Published: 17 January 2011
Cited by 102 | PDF Full-text (238 KB)
Abstract
The presence of aryl sulfides in biologically active compounds has resulted in the development of new methods to form carbon-sulfur bonds. The synthesis of aryl sulfides via metal catalysis has significantly increased in recent years. Historically, thiolates and sulfides have been thought to
[...] Read more.
The presence of aryl sulfides in biologically active compounds has resulted in the development of new methods to form carbon-sulfur bonds. The synthesis of aryl sulfides via metal catalysis has significantly increased in recent years. Historically, thiolates and sulfides have been thought to plague catalyst activity in the presence of transition metals. Indeed, strong coordination of thiolates and thioethers to transition metals can often hinder catalytic activity; however, various catalysts are able to withstand catalyst deactivation and form aryl carbon-sulfur bonds in high-yielding transformations. This review discusses the metal-catalyzed arylation of thiols and the use of disulfides as metal-thiolate precursors for the formation of C-S bonds. Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
Open AccessReview The Role of Adenosine Receptor Agonists in Regulation of Hematopoiesis
Molecules 2011, 16(1), 675-685; doi:10.3390/molecules16010675
Received: 20 December 2010 / Revised: 4 January 2011 / Accepted: 17 January 2011 / Published: 17 January 2011
Cited by 12 | PDF Full-text (121 KB)
Abstract
The review summarizes data evaluating the role of adenosine receptor signaling in murine hematopoietic functions. The studies carried out utilized either non-selective activation of adenosine receptors induced by elevation of extracellular adenosine or by administration of synthetic adenosine analogs having various proportions of
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The review summarizes data evaluating the role of adenosine receptor signaling in murine hematopoietic functions. The studies carried out utilized either non-selective activation of adenosine receptors induced by elevation of extracellular adenosine or by administration of synthetic adenosine analogs having various proportions of selectivity for a particular receptor. Numerous studies have described stimulatory effects of non-selective activation of adenosine receptors, manifested as enhancement of proliferation of cells at various levels of the hematopoietic hierarchy. Subsequent experimental approaches, considering the hematopoiesis-modulating action of adenosine receptor agonists with a high level of selectivity to individual adenosine receptor subtypes, have revealed differential effects of various adenosine analogs. Whereas selective activation of A1 receptors has resulted in suppression of proliferation of hematopoietic progenitor and precursor cells, that of A3 receptors has led to stimulated cell proliferation in these cell compartments. Thus, A1 and A3 receptors have been found to play a homeostatic role in suppressed and regenerating hematopoiesis. Selective activation of adenosine A3 receptors has been found to act curatively under conditions of drug- and radiation-induced myelosuppression. The findings in these and further research areas will be summarized and mechanisms of hematopoiesis-modulating action of adenosine receptor agonists will be discussed. Full article
(This article belongs to the Special Issue Nucleoside Analogues)
Open AccessReview Bioinformatics Resources and Tools for Phage Display
Molecules 2011, 16(1), 694-709; doi:10.3390/molecules16010694
Received: 20 December 2010 / Revised: 1 January 2011 / Accepted: 17 January 2011 / Published: 18 January 2011
Cited by 23 | PDF Full-text (140 KB)
Abstract
Databases and computational tools for mimotopes have been an important part of phage display study. Five special databases and eighteen algorithms, programs and web servers and their applications are reviewed in this paper. Although these bioinformatics resources have been widely used to exclude
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Databases and computational tools for mimotopes have been an important part of phage display study. Five special databases and eighteen algorithms, programs and web servers and their applications are reviewed in this paper. Although these bioinformatics resources have been widely used to exclude target-unrelated peptides, characterize small molecules-protein interactions and map protein-protein interactions, a lot of problems are still waiting to be solved. With the improvement of these tools, they are expected to serve the phage display community better. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
Open AccessReview Sequestration and Transport of Lignin Monomeric Precursors
Molecules 2011, 16(1), 710-727; doi:10.3390/molecules16010710
Received: 23 November 2010 / Revised: 13 January 2011 / Accepted: 17 January 2011 / Published: 18 January 2011
Cited by 28 | PDF Full-text (202 KB)
Abstract
Lignin is the second most abundant terrestrial biopolymer after cellulose. It is essential for the viability of vascular plants. Lignin precursors, the monolignols, are synthesized within the cytosol of the cell. Thereafter, these monomeric precursors are exported into the cell wall, where they
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Lignin is the second most abundant terrestrial biopolymer after cellulose. It is essential for the viability of vascular plants. Lignin precursors, the monolignols, are synthesized within the cytosol of the cell. Thereafter, these monomeric precursors are exported into the cell wall, where they are polymerized and integrated into the wall matrix. Accordingly, transport of monolignols across cell membranes is a critical step affecting deposition of lignin in the secondarily thickened cell wall. While the biosynthesis of monolignols is relatively well understood, our knowledge of sequestration and transport of these monomers is sketchy. In this article, we review different hypotheses on monolignol transport and summarize the recent progresses toward the understanding of the molecular mechanisms underlying monolignol sequestration and transport across membranes. Deciphering molecular mechanisms for lignin precursor transport will support a better biotechnological solution to manipulate plant lignification for more efficient agricultural and industrial applications of cell wall biomass. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessReview The Discovery of Small-Molecule Mimicking Peptides through Phage Display
Molecules 2011, 16(1), 774-789; doi:10.3390/molecules16010774
Received: 16 December 2010 / Revised: 12 January 2011 / Accepted: 18 January 2011 / Published: 19 January 2011
Cited by 4 | PDF Full-text (376 KB)
Abstract
Using peptides to achieve the functional and structural mimicry of small-molecules, especially those with biological activity or clear biotechnological applications, has great potential in overcoming difficulties associated with synthesis, or unfavorable physical properties. Combinatorial techniques like phage display can aid in the discovery
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Using peptides to achieve the functional and structural mimicry of small-molecules, especially those with biological activity or clear biotechnological applications, has great potential in overcoming difficulties associated with synthesis, or unfavorable physical properties. Combinatorial techniques like phage display can aid in the discovery of these peptides even if their mechanism of mimicry is not rationally obvious.The major focus of this field has been limited to developing biotin and sugar mimetics. However, the full “mimicry” of these peptides has not yet been fully established as some bind to the target with a different mechanism than that of the natural ligand and some do not share all of the natural ligand’s binding partners. In this article, mimicry of small-molecules by phage display-discovered peptides is reviewed and their potential in biochemical and medical applications is analyzed. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
Open AccessReview Phage Display: Selecting Straws Instead of a Needle from a Haystack
Molecules 2011, 16(1), 790-817; doi:10.3390/molecules16010790
Received: 9 December 2010 / Revised: 12 January 2011 / Accepted: 17 January 2011 / Published: 19 January 2011
Cited by 58 | PDF Full-text (195 KB)
Abstract
An increasing number of peptides with specific binding affinity to various protein and even non-protein targets are being discovered from phage display libraries. The power of this method lies in its ability to efficiently and rapidly identify ligands with a desired target property
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An increasing number of peptides with specific binding affinity to various protein and even non-protein targets are being discovered from phage display libraries. The power of this method lies in its ability to efficiently and rapidly identify ligands with a desired target property from a large population of phage clones displaying diverse surface peptides. However, the search for the needle in the haystack does not always end successfully. False positive results may appear. Thus instead of specific binders phage with no actual affinity toward the target are recovered due to their propagation advantages or binding to other components of the screening system, such as the solid phase, capturing reagents, contaminants in the target sample or blocking agents, rather than the target. Biopanning experiments on different targets performed in our laboratory revealed some previously identified and many new target-unrelated peptide sequences, which have already been frequently described and published, but not yet recognized as target-unrelated. Distinguishing true binders from false positives is an important step toward phage display selections of greater integrity. This article thoroughly reviews and discusses already identified and new target-unrelated peptides and suggests strategies to avoid their isolation. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
Open AccessReview Peptide Phage Display as a Tool for Drug Discovery: Targeting Membrane Receptors
Molecules 2011, 16(1), 857-887; doi:10.3390/molecules16010857
Received: 7 December 2010 / Revised: 14 January 2011 / Accepted: 19 January 2011 / Published: 21 January 2011
Cited by 74 | PDF Full-text (338 KB)
Abstract
Ligands selected from phage-displayed random peptide libraries tend to be directed to biologically relevant sites on the surface of the target protein. Consequently, peptides derived from library screenings often modulate the target protein’s activity in vitro and in vivo and can be used
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Ligands selected from phage-displayed random peptide libraries tend to be directed to biologically relevant sites on the surface of the target protein. Consequently, peptides derived from library screenings often modulate the target protein’s activity in vitro and in vivo and can be used as lead compounds in drug design and as alternatives to antibodies for target validation in both genomics and drug discovery. This review discusses the use of phage display to identify membrane receptor modulators with agonistic or antagonistic activities. Because isolating or producing recombinant membrane proteins for use as target molecules in library screening is often impossible, innovative selection strategies such as panning against whole cells or tissues, recombinant receptor ectodomains, or neutralizing antibodies to endogenous binding partners were devised. Prominent examples from a two-decade history of peptide phage display will be presented, focusing on the design of affinity selection experiments, methods for improving the initial hits, and applications of the identified peptides. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
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Open AccessReview Palladium Catalyzed Allylic C-H Alkylation: A Mechanistic Perspective
Molecules 2011, 16(1), 951-969; doi:10.3390/molecules16010951
Received: 30 November 2010 / Revised: 13 January 2011 / Accepted: 18 January 2011 / Published: 21 January 2011
Cited by 33 | PDF Full-text (622 KB)
Abstract
The atom-efficiency of one of the most widely used catalytic reactions for forging C-C bonds, the Tsuji-Trost reaction, is limited by the need of preoxidized reagents. This limitation can be overcome by utilization of the recently discovered palladium-catalyzed C-H activation, the allylic C-H
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The atom-efficiency of one of the most widely used catalytic reactions for forging C-C bonds, the Tsuji-Trost reaction, is limited by the need of preoxidized reagents. This limitation can be overcome by utilization of the recently discovered palladium-catalyzed C-H activation, the allylic C-H alkylation reaction which is the topic of the current review. Particular emphasis is put on current mechanistic proposals for the three reaction types comprising the overall transformation: C-H activation, nucleophillic addition, and re-oxidation of the active catalyst. Recent advances in C-H bond activation are highlighted with emphasis on those leading to C-C bond formation, but where it was deemed necessary for the general understanding of the process closely related C-H oxidations and aminations are also included. It is found that C-H cleavage is most likely achieved by ligand participation which could involve an acetate ion coordinated to Pd. Several of the reported systems rely on benzoquinone for re-oxidation of the active catalyst. The scope for nucleophilic addition in allylic C-H alkylation is currently limited, due to demands on pKa of the nucleophile. This limitation could be due to the pH dependence of the benzoquinone/hydroquinone redox couple. Alternative methods for re-oxidation that does not rely on benzoquinone could be able to alleviate this limitation. Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
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Open AccessReview Recent Advances in the Application of Chiral Phosphine Ligands in Pd-Catalysed Asymmetric Allylic Alkylation
Molecules 2011, 16(1), 970-1010; doi:10.3390/molecules16010970
Received: 20 December 2010 / Revised: 18 January 2011 / Accepted: 19 January 2011 / Published: 21 January 2011
Cited by 40 | PDF Full-text (1797 KB)
Abstract
One of the most powerful approaches for the formation of simple and complex chiral molecules is the metal-catalysed asymmetric allylic alkylation. This reaction has been broadly studied with a great variety of substrates and nucleophiles under different reaction conditions and it has promoted
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One of the most powerful approaches for the formation of simple and complex chiral molecules is the metal-catalysed asymmetric allylic alkylation. This reaction has been broadly studied with a great variety of substrates and nucleophiles under different reaction conditions and it has promoted the synthesis of new chiral ligands to be evaluated as asymmetric inductors. Although the mechanism as well as the active species equilibria are known, the performance of the catalytic system depends on the fine tuning of factors such as type of substrate, nucleophile nature, reaction medium, catalytic precursor and type of ligand used. Particularly interesting are chiral phosphines which have proved to be effective asymmetric inductors in several such reactions. The present review covers the application of phosphine-donor ligands in Pd-catalysed asymmetric allylic alkylation in the last decade. Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
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