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Molecules, Volume 12, Issue 7 (July 2007), Pages 1259-1547

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Editorial

Jump to: Research, Review, Other

Open AccessEditorial Non-Open Access and Its Adverse Impact on Molecules
Molecules 2007, 12(7), 1436-1437; doi:10.3390/12071436
Received: 10 July 2007 / Accepted: 16 July 2007 / Published: 16 July 2007
Cited by 8 | PDF Full-text (21 KB) | HTML Full-text | XML Full-text

Research

Jump to: Editorial, Review, Other

Open AccessArticle Synthesis of Novel Nitro-substituted Triaryl Pyrazole Derivatives as Potential Estrogen Receptor Ligands
Molecules 2007, 12(7), 1259-1273; doi:10.3390/12071259
Received: 11 June 2007 / Revised: 29 June 2007 / Accepted: 29 June 2007 / Published: 2 July 2007
Cited by 15 | PDF Full-text (152 KB) | HTML Full-text | XML Full-text
Abstract
Novel tetrasubstituted pyrazole derivatives bearing a nitro substituent on their A-phenol ring were synthesized and their binding affinity towards the estrogen receptor (ER) subtypes ERα and ERβ was determined. Among compounds tested, the 2-nitrophenol derivative 5c was found to bind satisfactorily to [...] Read more.
Novel tetrasubstituted pyrazole derivatives bearing a nitro substituent on their A-phenol ring were synthesized and their binding affinity towards the estrogen receptor (ER) subtypes ERα and ERβ was determined. Among compounds tested, the 2-nitrophenol derivative 5c was found to bind satisfactorily to both estrogen receptor subtypes (RBAα=5.17 and RBAβ=3.27). In general, the introduction of a nitro group into the A ring of these compounds was found to benefit their ERβ binding abilities. Full article
Open AccessArticle (-)-Catechin in Cocoa and Chocolate: Occurence and Analysis of an Atypical Flavan-3-ol Enantiomer
Molecules 2007, 12(7), 1274-1288; doi:10.3390/12071274
Received: 30 May 2007 / Revised: 2 July 2007 / Accepted: 2 July 2007 / Published: 4 July 2007
Cited by 50 | PDF Full-text (155 KB) | HTML Full-text | XML Full-text
Abstract
Cocoa contains high levels of different flavonoids. In the present study, the enantioseparation of catechin and epicatechin in cocoa and cocoa products by chiral capillary electrophoresis (CCE) was performed. A baseline separation of the catechin and epicatechin enantiomers was achieved by using [...] Read more.
Cocoa contains high levels of different flavonoids. In the present study, the enantioseparation of catechin and epicatechin in cocoa and cocoa products by chiral capillary electrophoresis (CCE) was performed. A baseline separation of the catechin and epicatechin enantiomers was achieved by using 0.1 mol·L−1 borate buffer (pH 8.5) with 12 mmol·L-1 (2-hydroxypropyl)-γ-cyclodextrin as chiral selector, a fused-silica capillary with 50 cm effective length (75 μm I.D.), +18 kV applied voltage, a temperature of 20°C and direct UV detection at 280 nm. To avoid comigration or coelution of other similar substances, the flavan-3-ols were isolated and purified using polyamide-solid-phase-extraction and LC-MS analysis. As expected, we found (-)-epicatechin and (+)-catechin inunfermented, dried, unroasted cocoa beans. In contrast, roasted cocoa beans and cocoa products additionally contained the atypical flavan-3-ol (-)-catechin. This is generally formed during the manufacturing process by an epimerization which converts (-)-epicatechin to its epimer (-)-catechin. High temperatures during the cocoa bean roasting process and particularly the alkalization of the cocoa powder are the main factors inducing the epimerization reaction. In addition to the analysis of cocoa and cocoa products, peak ratios were calculated for a better differentiation of the cocoa products. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle A Simplified Procedure for Indole Alkaloid Extraction from Catharanthus roseus Combined with a Semi-synthetic Production Process for Vinblastine
Molecules 2007, 12(7), 1307-1315; doi:10.3390/12071307
Received: 30 May 2007 / Revised: 1 July 2007 / Accepted: 4 July 2007 / Published: 5 July 2007
Cited by 15 | PDF Full-text (75 KB) | HTML Full-text | XML Full-text
Abstract
Dried leaves of Catharanthus roseus were extracted with aqueous acidic 0.1 M solution of HCl. Alkaloid-embonate complexes were obtained as precipitates by treating the extract with an alkaline (NaOH) solution of embonic acid (4,4-methylene-bis-3-hydroxynaphtalenecarboxylic acid). The precipitate mainly consisted of catharanthine and [...] Read more.
Dried leaves of Catharanthus roseus were extracted with aqueous acidic 0.1 M solution of HCl. Alkaloid-embonate complexes were obtained as precipitates by treating the extract with an alkaline (NaOH) solution of embonic acid (4,4-methylene-bis-3-hydroxynaphtalenecarboxylic acid). The precipitate mainly consisted of catharanthine and vindoline embonates and it was directly used as the starting material for a semi-synthesis of the anti-cancer bisindole alkaloid vinblastine. The coupling reaction involved oxidation of catharanthine in aqueous acidic medium by singlet oxygen (1O2), continuously produced in situ by the reaction between H2O2 with NaClO. An excess of NaBH4 was used for the reduction step. Analysis of the reaction mixture indicated a maximum yield of 20% for vinblastine at pH 8.3, based on the initial amount of catharanthine concentration. Direct-injection electrospray ionization mass spectrometry in positive ion mode was used for the identification of vinblastine. The mass spectra of vinblastine were dominated by the corresponding protonated molecular ion [M+H]+ at m/z 811 and the characteristic fragment ions matched with those of the standard compound. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Design and Synthesis of a Coumarin-based Acidichromic Colorant
Molecules 2007, 12(7), 1316-1324; doi:10.3390/12071316
Received: 6 June 2007 / Revised: 1 July 2007 / Accepted: 1 July 2007 / Published: 6 July 2007
Cited by 12 | PDF Full-text (114 KB) | HTML Full-text | XML Full-text
Abstract
This paper describes the fine-tuning of the acidichromic properties of a coumarin-containing colorant 1 by incorporation of electron-donating and electron-withdrawing substituents on the coumarin moiety. Colorant 1 can undergo two distinct and reversible color changes under both strongly acidic and basic conditions, [...] Read more.
This paper describes the fine-tuning of the acidichromic properties of a coumarin-containing colorant 1 by incorporation of electron-donating and electron-withdrawing substituents on the coumarin moiety. Colorant 1 can undergo two distinct and reversible color changes under both strongly acidic and basic conditions, but not in the presence of gaseous ammonia. The results indicated that the bromo-substituted compound 5b changes from red to yellow when exposed to gaseous ammonia, both in solution and on polycarbonate film, suggesting that an electron-withdrawing group at the 7-position of the coumarin moiety made the enolic hydrogen on 5b more susceptible to deprotonation by a base than in the unsubstituted compound 1. Full article
Open AccessArticle Chlorine Anion Encapsulation by Molecular Capsules Based on Cucurbit[5]uril and Decamethylcucurbit[5]uril
Molecules 2007, 12(7), 1325-1333; doi:10.3390/12071325
Received: 2 June 2007 / Revised: 3 July 2007 / Accepted: 3 July 2007 / Published: 6 June 2007
Cited by 21 | PDF Full-text (165 KB) | HTML Full-text | XML Full-text
Abstract
Three barrel-shaped artificial molecular capsules 1-3, based on normal cucurbit[5]uril (Q[5]) and decamethylcucurbit[5]uril (Me10Q[5]), were synthesized and structurally characterized by single-crystal X-ray diffraction. Encapsulation of a chlorine anion in the cavity of a Q[5] or Me10Q[5] to form closed a molecular capsule [...] Read more.
Three barrel-shaped artificial molecular capsules 1-3, based on normal cucurbit[5]uril (Q[5]) and decamethylcucurbit[5]uril (Me10Q[5]), were synthesized and structurally characterized by single-crystal X-ray diffraction. Encapsulation of a chlorine anion in the cavity of a Q[5] or Me10Q[5] to form closed a molecular capsule with the coordinated metal ions or coordinated metal ions and water molecules in the crystal structures of these compounds is common. The three complexes [Pr2(C30H30N20O10)Cl3(H2O)13]3+3Cl-·5H2O (1), [Sr2(C40H50N20O10)(H2O)4Cl]3+3Cl-·2(HCl) 19H2O (2) and [K(C40H50N20O10)(H2O)Cl]·[Zn(H2O)2Cl2]·[ZnCl4]2-·2(H3O)+·8H2O (3) all crystallize as isolated molecular capsules. Full article
Open AccessArticle A Novel and Efficient Synthesis of N,N-Dialkylaminoisopropyl- and O-alkylisopropyl-2-(1-alkyl-2-oxopropylidene)phosphonohydrazido Oximes - Potential Marine Fish Toxin Analogues. Part 1
Molecules 2007, 12(7), 1334-1340; doi:10.3390/12071334
Received: 16 April 2007 / Revised: 16 May 2007 / Accepted: 16 July 2007 / Published: 9 July 2007
Cited by 3 | PDF Full-text (61 KB) | HTML Full-text | XML Full-text
Abstract
A novel and efficient method for the synthesis of N,N-dialkylaminoisopropyl- and O-alkylisopropyl-2-(1-alkyl-2-oxopropylidene)phosphonohydrazido oximes (4) using activated silica as dehydrating agent has been developed. The reaction involves the condensation of substituted diacetyl monoxime and N,N-dialkylaminoisopropyl-phosphono hydrazide or O-alkylisopropylphosphono hydrazides and gave the corresponding [...] Read more.
A novel and efficient method for the synthesis of N,N-dialkylaminoisopropyl- and O-alkylisopropyl-2-(1-alkyl-2-oxopropylidene)phosphonohydrazido oximes (4) using activated silica as dehydrating agent has been developed. The reaction involves the condensation of substituted diacetyl monoxime and N,N-dialkylaminoisopropyl-phosphono hydrazide or O-alkylisopropylphosphono hydrazides and gave the corresponding analogues of a naturally occurring fish toxin in excellent yields under mild conditions. Full article
Open AccessArticle Synthesis of 4-Aryl Substituted 3,4-Dihydropyrimidinones Using Silica-chloride Under Solvent Free Conditions
Molecules 2007, 12(7), 1341-1351; doi:10.3390/12071341
Received: 21 May 2007 / Revised: 20 June 2007 / Accepted: 2 July 2007 / Published: 9 July 2007
Cited by 60 | PDF Full-text (85 KB) | HTML Full-text | XML Full-text
Abstract This paper describes an improved procedure for the efficient and facile synthesis of 4-aryl substituted 3, 4-dihydropyrimidinones under mild reaction conditions with excellent yields using inexpensive silica chloride under solvent free conditions. Full article
Open AccessArticle Synthesis and Characterization of a Metal Complex Containing Naringin and Cu, and its Antioxidant, Antimicrobial, Antiinflammatory and Tumor Cell Cytotoxicity
Molecules 2007, 12(7), 1352-1366; doi:10.3390/12071352
Received: 15 May 2007 / Revised: 20 June 2007 / Accepted: 3 July 2007 / Published: 9 July 2007
Cited by 69 | PDF Full-text (98 KB) | HTML Full-text | XML Full-text
Abstract
The antioxidant activity of flavonoids is believed to increase when they are coordinated with transition metal ions. However, the literature on this subject is contradictory and the outcome seems to largely depend on the experimental conditions. In order to understand the contribution [...] Read more.
The antioxidant activity of flavonoids is believed to increase when they are coordinated with transition metal ions. However, the literature on this subject is contradictory and the outcome seems to largely depend on the experimental conditions. In order to understand the contribution of the metal coordination and the type of interaction between a flavonoid and the metal ion, in this study a new metal complex of Cu (II) with naringin was synthesized and characterized by FT-IR, UV-VIS, mass spectrometry (ESI-MS/MS), elemental analysis and 1H-NMR. The results of these analyses indicate that the complex has a Cu (II) ion coordinated via positions 4 and 5 of the flavonoid. The antioxidant, anti-inflammatory and antimicrobial activities of this complex were studied and compared with the activity of free naringin. The Naringin–Cu (II) complex 1 showed higher antioxidant, anti-inflammatory and tumor cell cytoxicity activities than free naringin without reducing cell viability. Full article
Open AccessArticle Structural Characterisation by ESI-MS of Feruloylated Arabino-oligosaccharides Synthesised by Chemoenzymatic Esterification
Molecules 2007, 12(7), 1367-1375; doi:10.3390/12071367
Received: 12 June 2007 / Revised: 3 July 2007 / Accepted: 3 July 2007 / Published: 9 July 2007
Cited by 12 | PDF Full-text (229 KB) | HTML Full-text | XML Full-text
Abstract The chemoenzymatic synthesis of feruloylated arabino-oligosaccharides has been achieved, using a feruloyl esterase type C from Sporotrichum thermophile (StFaeC).The structure of the feruloylated products was confirmed by ESI-MSn. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Comparison of the Biological Properties of Several Marine Sponge-Derived Sesquiterpenoid Quinones
Molecules 2007, 12(7), 1376-1388; doi:10.3390/12071376
Received: 18 June 2007 / Revised: 6 July 2007 / Accepted: 9 July 2007 / Published: 11 July 2007
Cited by 13 | PDF Full-text (102 KB) | HTML Full-text | XML Full-text
Abstract
Eight naturally occurring marine-sponge derived sesquiterpenoid quinones wereevaluated as potential inhibitors of pyruvate phosphate dikinase (PPDK), a C4 plantregulatory enzyme. Of these, the hydroxyquinones ilimaquinone, ethylsmenoquinone andsmenoquinone inhibited PPDK activity with IC50’s (reported with 95% confidenceintervals) of 285.4 (256.4 [...] Read more.
Eight naturally occurring marine-sponge derived sesquiterpenoid quinones wereevaluated as potential inhibitors of pyruvate phosphate dikinase (PPDK), a C4 plantregulatory enzyme. Of these, the hydroxyquinones ilimaquinone, ethylsmenoquinone andsmenoquinone inhibited PPDK activity with IC50’s (reported with 95% confidenceintervals) of 285.4 (256.4 – 317.7), 316.2 (279.2 – 358.1) and 556.0 (505.9 – 611.0) μM,respectively, as well as being phytotoxic to the C4 plant Digitaria ciliaris. The potentialanti-inflammatory activity of these compounds, using bee venom phospholipase A2(PLA2), was also evaluated. Ethylsmenoquinone, smenospongiarine, smenospongidine andilimaquinone inhibited PLA2 activity (% inhibition of 73.2 + 4.8 at 269 μM, 61.5 + 6.1 at242 μM, 41.0 + 0.6 at 224 μM and 36.4 + 8.2 at 279 μM, respectively). SAR analysesindicate that a hydroxyquinone functionality and a short, hydroxide/alkoxide side-chain atC-20 is preferred for inhibition of PPDK activity, and that a larger amine side-chain at C-20 is tolerated for PLA2 inhibitory activity. Full article
Open AccessArticle Synthesis and Characterization of 5,10,15,20-Tetra[3-(3-trifluoromethyl)phenoxy] Porphyrin
Molecules 2007, 12(7), 1389-1398; doi:10.3390/12071389
Received: 30 May 2007 / Revised: 8 July 2007 / Accepted: 9 July 2007 / Published: 11 July 2007
Cited by 5 | PDF Full-text (80 KB)
Abstract
The newly synthesized 5,10,15,20-tetra[3-(3-trifluoromethyl)phenoxy]porphyrin, TTFMPP, has been characterized using mass spectroscopy, 1H-, 13C- and 19F-NMR, MALDI-TOF mass spectrometry, UV-Vis and fluorescence spectrophotometry, andcyclic voltammetry. The NMR confirmed the structure of the compound and the massspectrum was in agreement with [...] Read more.
The newly synthesized 5,10,15,20-tetra[3-(3-trifluoromethyl)phenoxy]porphyrin, TTFMPP, has been characterized using mass spectroscopy, 1H-, 13C- and 19F-NMR, MALDI-TOF mass spectrometry, UV-Vis and fluorescence spectrophotometry, andcyclic voltammetry. The NMR confirmed the structure of the compound and the massspectrum was in agreement with the proposed molecular formula. The UV-Vis absorptionspectrum of TTFMPP shows characteristic spectral patterns similar to those of tetraphenylporphryin, with a Soret band at 419 nm and four Q bands at 515, 550, 590, and 648 nm.Protonation of the porphyrin with TFA resulted in the expected red shift of the Soret band.Excitation at 419 nm gave an emission at 650 nm. The quantum yield of the porphyrin wasdetermined to be 0.08. Cyclic voltammetry was used to determine the oxidation andreduction potentials of the new porphyrin. Two quasi-reversible one-electron reductions at–1.00 and –1.32 V and a quasi-reversible oxidation at 1.20 V versus the silver/silverchloride reference electrode with tetrabutylammonium tetrafluoroborate as the supportingelectrolyte in methylene chloride were observed. Full article
(This article belongs to the Special Issue Heterocycles)
Open AccessArticle Atmospheric Pressure Microwave Assisted Heterogeneous Catalytic Reactions
Molecules 2007, 12(7), 1399-1409; doi:10.3390/12071399
Received: 15 June 2007 / Revised: 8 July 2007 / Accepted: 9 July 2007 / Published: 11 July 2007
Cited by 21 | PDF Full-text (115 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of the study was to investigate microwave selective heatingphenomena and their impact on heterogeneous chemical reactions. We also present a toolwhich will help microwave chemists to answer to such questions as “My reaction yields90% after 7 days at reflux; is [...] Read more.
The purpose of the study was to investigate microwave selective heatingphenomena and their impact on heterogeneous chemical reactions. We also present a toolwhich will help microwave chemists to answer to such questions as “My reaction yields90% after 7 days at reflux; is it possible to obtain the same yield after a few minutes undermicrowaves?” and to have an approximation of their reactions when conducted undermicrowaves with different heterogeneous procedures. This model predicting reactionkinetics and yields under microwave heating is based on the Arrhenius equation, inagreement with experimental data and procedures. Full article
Open AccessArticle Electrochemical Synthesis and Structural Characterization of a Novel Mixed-valence Copper (I)-copper (II) Complex: {[Bis(ethylenediamine) Copper (II)] Bis[diiodocuprate (I)]}
Molecules 2007, 12(7), 1410-1419; doi:10.3390/12071410
Received: 6 June 2007 / Revised: 9 July 2007 / Accepted: 10 July 2007 / Published: 12 July 2007
Cited by 2 | PDF Full-text (172 KB) | HTML Full-text | XML Full-text
Abstract
A novel, mixed-valent copper(I)-copper(II) complex, {[bis(ethylene-diamine)copper(II)] bis[diiodocuprate(I)]} (1), has been prepared by electrochemicaldissolution of a sacrificial copper anode in a solution of ethylenediamine (en), I2 andtetraethylammoniumperchlorate (TEAP) as supporting electrolyte in acetonitrile (AcN)and characterized by single-crystal X-ray structure determination. The crystal [...] Read more.
A novel, mixed-valent copper(I)-copper(II) complex, {[bis(ethylene-diamine)copper(II)] bis[diiodocuprate(I)]} (1), has been prepared by electrochemicaldissolution of a sacrificial copper anode in a solution of ethylenediamine (en), I2 andtetraethylammoniumperchlorate (TEAP) as supporting electrolyte in acetonitrile (AcN)and characterized by single-crystal X-ray structure determination. The crystal structure ofthe complex 1 shows that it consists of a CuI2 polymer formed from I- ligands bridgingCu(I) ions, with a nearly square planar geometry of bivalente Cu(II) atoms chelated by twoethylenediamine ligands. The results also show that direct electrosynthesis of the complexhad high current efficiency, purity and electrolysis yield. Full article
Open AccessArticle An Efficient and Rapid Synthetic Route to Biologically Interesting Pyranochalcone Natural Products
Molecules 2007, 12(7), 1420-1429; doi:10.3390/12071420
Received: 29 June 2007 / Revised: 10 July 2007 / Accepted: 10 July 2007 / Published: 12 July 2007
Cited by 11 | PDF Full-text (100 KB) | HTML Full-text | XML Full-text
Abstract An efficient and concise total synthesis of naturally occurring pyranochalcones was achieved from readily available 2,4-dihydroxyacetophenone and 2,4-dihydroxy-6- methoxyacetophenone. The key steps in the synthetic strategy were ethylenediamine diacetate-catalyzed benzopyran formation and aldol reactions. Full article
Open AccessCommunication Revised NMR data for Incartine: an Alkaloid from Galanthus elwesii
Molecules 2007, 12(7), 1430-1435; doi:10.3390/12071430
Received: 18 June 2007 / Revised: 10 July 2007 / Accepted: 10 July 2007 / Published: 12 July 2007
Cited by 17 | PDF Full-text (72 KB) | HTML Full-text | XML Full-text
Abstract
Phytochemical studies on Galanthus elwesii resulted in the isolation of five alkaloids: incartine, hordenine, hippeastrine, 8-O-demethylhomolycorine and lycorine. The NMR data given previously for incartine were revised and completed by two-dimensional 1H-1H and 1H-13C chemical shift [...] Read more.
Phytochemical studies on Galanthus elwesii resulted in the isolation of five alkaloids: incartine, hordenine, hippeastrine, 8-O-demethylhomolycorine and lycorine. The NMR data given previously for incartine were revised and completed by two-dimensional 1H-1H and 1H-13C chemical shift correlation experiments. In vitro studies on the bioactivity of incartine were carried out. Full article
Open AccessCommunication A Facile, Mild And Efficient One-Pot Synthesis of 2-Substituted Indole Derivatives Catalyzed By Pd(PPh3)2Cl2
Molecules 2007, 12(7), 1438-1446; doi:10.3390/12071438
Received: 8 March 2007 / Revised: 1 July 2007 / Accepted: 2 July 2007 / Published: 19 June 2007
Cited by 30 | PDF Full-text (64 KB) | HTML Full-text | XML Full-text
Abstract 2-Phenylindoles were prepared by heteroannulation of 2-haloaniline derivatives and phenylacetylene under mild conditions in a one-pot reaction catalyzed by Pd(PPh3)2Cl2. Full article
Open AccessArticle Leufolins A and B, Potent Butyrylcholinesterase-inhibiting Flavonoid Glucosides from Leucas urticifolia
Molecules 2007, 12(7), 1447-1454; doi:10.3390/12071447
Received: 2 July 2007 / Revised: 12 July 2007 / Accepted: 12 July 2007 / Published: 19 July 2007
Cited by 21 | PDF Full-text (91 KB) | HTML Full-text | XML Full-text
Abstract
New flavonoidal glucosides leufolins A (1) and B (2), have been isolated from the ethyl acetate soluble fraction of the whole plants of Leucas urticifolia. Their structures were elucidated on the basis of extensive analysis of nuclear magnetic resonance (1D and [...] Read more.
New flavonoidal glucosides leufolins A (1) and B (2), have been isolated from the ethyl acetate soluble fraction of the whole plants of Leucas urticifolia. Their structures were elucidated on the basis of extensive analysis of nuclear magnetic resonance (1D and 2D NMR) spectral data. Both of these compounds exhiited significant inhibitory potential against the enzyme butyrylcholinesterase. Full article
Open AccessArticle The Anti-apoptosis Effects of Daidzein in the Brain of D-Galactose Treated Mice
Molecules 2007, 12(7), 1455-1470; doi:10.3390/12071455
Received: 30 May 2007 / Revised: 3 July 2007 / Accepted: 13 July 2007 / Published: 19 July 2007
Cited by 12 | PDF Full-text (309 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of this study was to explore the neuroprotective effects of daidzein on the apoptotic pathway in the hippocampus and cortex of D-galactose treated mice. For this purpose we have examined the expression of bcl-2 mRNA, bax mRNA and caspase-3 in [...] Read more.
The purpose of this study was to explore the neuroprotective effects of daidzein on the apoptotic pathway in the hippocampus and cortex of D-galactose treated mice. For this purpose we have examined the expression of bcl-2 mRNA, bax mRNA and caspase-3 in the hippocampus and cortex of D-galactose-treated mice after fed with 10 or 5 mg/kg of daidzein. The results of in situ hybridization experiments indicate that daidzein could help increase the transcriptions of bcl-2 and decrease the transcriptions of bax in those brain regions of D-galactose-treated mice. Furthermore, immunohistochemical studies showed that daidzein could reduce the expression of caspase-3 in both brain regions. These results suggest that daidzein in soybean can inhibit the D-gal induced apoptosis via Bcl-2/Bax apoptotic pathway and be a potential medical candidate for neurodegeneration therapy. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Unusual Reactivity Patterns of 1,3,6,8-Tetraazatricyclo-[4.4.1.13,8]-dodecane (TATD) Towards Some Reducing Agents: Synthesis of TMEDA
Molecules 2007, 12(7), 1471-1481; doi:10.3390/12071471
Received: 10 May 2007 / Revised: 29 June 2007 / Accepted: 29 June 2007 / Published: 19 July 2007
Cited by 2 | PDF Full-text (82 KB) | HTML Full-text | XML Full-text
Abstract
N,N,N ́,N ́-Tetramethylethylenediamine (TMEDA) can be synthesized by simple reduction of 1,3,6,8-tetraazatricyclo-[4.4.1.1.3,8]dodecane (TATD), an aminal cage type amine, with formic acid. The aminal can be converted to TMEDA in high yield very easily and in a very short time. We [...] Read more.
N,N,N ́,N ́-Tetramethylethylenediamine (TMEDA) can be synthesized by simple reduction of 1,3,6,8-tetraazatricyclo-[4.4.1.1.3,8]dodecane (TATD), an aminal cage type amine, with formic acid. The aminal can be converted to TMEDA in high yield very easily and in a very short time. We comment on the scope and limitations of the reduction of thisaminal and propose a possible reaction mechanism. Full article
Open AccessArticle New “Green” Approaches to the Synthesis of Pyrazole Derivatives
Molecules 2007, 12(7), 1482-1495; doi:10.3390/12071482
Received: 31 May 2007 / Revised: 16 July 2007 / Accepted: 16 July 2007 / Published: 19 July 2007
Cited by 28 | PDF Full-text (199 KB) | HTML Full-text | XML Full-text
Abstract
A novel approach to the synthesis of pyrazole derivatives from tosylhydrazones of α,β-unsaturated carbonyl compounds possessing a β-hydrogen is proposed, exploiting microwave (MW) activation coupled with solvent free reaction conditions. The cycloaddition was studied on three ketones (trans-4-phenyl-3-buten-2-one, β-ionone and trans-chalcone). The [...] Read more.
A novel approach to the synthesis of pyrazole derivatives from tosylhydrazones of α,β-unsaturated carbonyl compounds possessing a β-hydrogen is proposed, exploiting microwave (MW) activation coupled with solvent free reaction conditions. The cycloaddition was studied on three ketones (trans-4-phenyl-3-buten-2-one, β-ionone and trans-chalcone). The corresponding 3,5-disubstitued-1H-pyrazoles were obtained in high yields and after short reaction times. In order to simplify and point out the green chemistry features of the method, a further improvement was achieved under the same catalytic conditions with a “one pot” synthesis of these heterocyclic compounds, starting directly from their carbonyl precursors via tosylhydrazones generated in situ. For an exhaustive study, the dielectric properties of the solid reaction mixtures were also measured, in order to obtain input data for the numerical simulation of their heating behaviour in the single mode MW cavity which was used for experimental work. In order to supply a valid methodology and tool for measuring the environmental impact, a comparative study between the synthetic route proposed and the classical synthetic route has been carried out. Full article
(This article belongs to the Special Issue Heterocycles)

Review

Jump to: Editorial, Research, Other

Open AccessReview Flavonoids and Strigolactones in Root Exudates as Signals in Symbiotic and Pathogenic Plant-Fungus Interactions
Molecules 2007, 12(7), 1290-1306; doi:10.3390/12071290
Received: 29 May 2007 / Revised: 20 June 2007 / Accepted: 3 July 2007 / Published: 5 July 2007
Cited by 105 | PDF Full-text (123 KB) | HTML Full-text | XML Full-text
Abstract
Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are [...] Read more.
Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungalinteractions such as the arbuscular mycorrhizal (AM) association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF), are provided. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessReview Comparative Evaluation of Various Total Antioxidant Capacity Assays Applied to Phenolic Compounds with the CUPRAC Assay
Molecules 2007, 12(7), 1496-1547; doi:10.3390/12071496
Received: 30 June 2007 / Revised: 17 July 2007 / Accepted: 18 July 2007 / Published: 19 July 2007
Cited by 313 | PDF Full-text (266 KB) | HTML Full-text | XML Full-text
Abstract
It would be desirable to establish and standardize methods that can measure the total antioxidant capacity level directly from vegetable extracts containing phenolics. Antioxidant capacity assays may be broadly classified as electron transfer (ET)− and hydrogen atom transfer (HAT)−based assays. The majority [...] Read more.
It would be desirable to establish and standardize methods that can measure the total antioxidant capacity level directly from vegetable extracts containing phenolics. Antioxidant capacity assays may be broadly classified as electron transfer (ET)− and hydrogen atom transfer (HAT)−based assays. The majority of HAT assays are kinetics-based, and involve a competitive reaction scheme in which antioxidant and substrate compete for peroxyl radicals thermally generated through the decomposition of azo compounds. ET−based assays measure the capacity of an antioxidant in the reduction of an oxidant, which changes colour when reduced. ET assays include the ABTS/TEAC, CUPRAC, DPPH, Folin-Ciocalteu and FRAP methods, each using different chromogenic redox reagents with different standard potentials. This review intends to offer a critical evaluation of existing antioxidant assays applied to phenolics, and reports the development by our research group of a simple and low-cost antioxidant capacity assay for dietary polyphenols, vitamins C and E, and human serum antioxidants, utilizing the copper(II)-neocuproine reagent as the chromogenic oxidizing agent, which we haved named the CUPRAC (cupric ion reducing antioxidant capacity) method. This method offers distinct advantages over other ET−based assays, namely the selection of working pH at physiological pH (as opposed to the Folin and FRAP methods, which work at alkaline and acidic pHs, respectively), applicability to both hydrophilic and lipophilic antioxidants (unlike Folin and DPPH), completion of the redox reactions for most common flavonoids (unlike FRAP), selective oxidation of antioxidant compounds without affecting sugars and citric acid commonly contained in foodstuffs and the capability to assay –SH bearing antioxidants (unlike FRAP). Other similar ET–based antioxidant assays that we have developed or modified for phenolics are the Fe(III)− and Ce(IV)−reducing capacity methods. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessRetraction Withdrawn Paper: Molecules 2005, 10, 1126-1134
Molecules 2007, 12(7), 1289; doi:10.3390/12071289
Published: 4 July 2007
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