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Molecules, Volume 15, Issue 7 (July 2010), Pages 4490-5065

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Open AccessArticle Natural Carotenoids as Nanomaterial Precursors for Molecular Photovoltaics: A Computational DFT Study
Molecules 2010, 15(7), 4490-4510; doi:10.3390/molecules15074490
Received: 15 April 2010 / Revised: 13 June 2010 / Accepted: 21 June 2010 / Published: 24 June 2010
Cited by 23 | PDF Full-text (2617 KB)
Abstract
In this work several natural carotenoids were studied as potential nanomaterial precursors for molecular photovoltaics. M05-2X/6-31+G(d,p) level of theory calculations were used to obtain their molecular structures, as well as to predict the infrared (IR) and ultraviolet (UV-Vis) spectra, the dipole moment [...] Read more.
In this work several natural carotenoids were studied as potential nanomaterial precursors for molecular photovoltaics. M05-2X/6-31+G(d,p) level of theory calculations were used to obtain their molecular structures, as well as to predict the infrared (IR) and ultraviolet (UV-Vis) spectra, the dipole moment and polarizability, the pKa, and the chemical reactivity parameters (electronegativity, hardness, electrophilicity and Fukui functions) that arise from Conceptual DFT. The calculated values were compared with the available experimental data for these molecules and discussed in terms of their usefulness in describing photovoltaic properties. Full article
Open AccessArticle Palladium/Zirconium Oxide Nanocomposite as a Highly Recyclable Catalyst for C-C Coupling Reactions in Water
Molecules 2010, 15(7), 4511-4525; doi:10.3390/molecules15074511
Received: 10 May 2010 / Revised: 16 June 2010 / Accepted: 21 June 2010 / Published: 24 June 2010
Cited by 25 | PDF Full-text (808 KB)
Abstract
Palladium nanoparticles have been electrochemically supported on zirconium oxide nanostructured powders and all the nanomaterials have been characterized by several analytical techniques. The Pd/ZrO2 nanocatalyst is demonstrated to be a very efficient catalyst in Heck, Ullmann, and Suzuki reactions of aryl [...] Read more.
Palladium nanoparticles have been electrochemically supported on zirconium oxide nanostructured powders and all the nanomaterials have been characterized by several analytical techniques. The Pd/ZrO2 nanocatalyst is demonstrated to be a very efficient catalyst in Heck, Ullmann, and Suzuki reactions of aryl halides in water. The catalyst efficiency is attributed to the stabilization of Pd nanophases provided by tetra(alkyl)- ammonium hydroxide, which behaves both as base and PTC (phase transfer catalyst) agent. Full article
(This article belongs to the Special Issue Nano-catalysts and Nano-technologies for Green Organic Synthesis)
Open AccessArticle Anti-Oxidative Activity of An Aqueous Suspension of Commercial Preparation of The Mushroom Coprinus comatus
Molecules 2010, 15(7), 4564-4571; doi:10.3390/molecules15074564
Received: 11 May 2010 / Revised: 18 June 2010 / Accepted: 22 June 2010 / Published: 24 June 2010
Cited by 11 | PDF Full-text (485 KB)
Abstract
In this study the effects of an aqueous suspension of a commercial preparation of the mushroom Coprinus comatus on oxidative stress induced in rats by alloxane and carbon tetrachloride was examined. The effects were estimated from changes in the biochemical parameters (xanthine [...] Read more.
In this study the effects of an aqueous suspension of a commercial preparation of the mushroom Coprinus comatus on oxidative stress induced in rats by alloxane and carbon tetrachloride was examined. The effects were estimated from changes in the biochemical parameters (xanthine oxidase, glutathione peroxidase and catalase activity, reduced glutathione content, and extent of lipid peroxidation) of liver homogenate as well as histological changes in the liver of the rats treated with alloxane and carbon tetrachloride. Two screening doses of alloxane sufficient to induce diabetes in rats did not have any significant effect on the examined biochemical parameters of liver homogenate or on the cytoarchitectonics of liver cross-sections. Treatment with carbon tetrachloride resulted in a significant increase in the intensity of lipid peroxidation and peroxydasis activity, as well as with decrease in catalase activity. Certain changes in liver cross sections were detected, such is lymphocyte infiltration of dilated sinusoid capillaries. Administration of Coprinus comatus suspension thus showed antioxidative potential, evidenced by an increase of antioxidative status of liver homogenate and prevention of histological changes in liver cross sections. Full article
Open AccessCommunication Volatiles from a Rare Acer spp. Honey Sample from Croatia
Molecules 2010, 15(7), 4572-4582; doi:10.3390/molecules15074572
Received: 10 June 2010 / Accepted: 23 June 2010 / Published: 24 June 2010
Cited by 12 | PDF Full-text (161 KB)
Abstract
A rare sample of maple (Acer spp.) honey from Croatia was analysed. Ultrasonic solvent extraction (USE) using: 1) pentane, 2) diethyl ether, 3) a mixture of pentane and diethyl ether (1:2 v/v) and 4) dichloromethane as solvents was applied. All the [...] Read more.
A rare sample of maple (Acer spp.) honey from Croatia was analysed. Ultrasonic solvent extraction (USE) using: 1) pentane, 2) diethyl ether, 3) a mixture of pentane and diethyl ether (1:2 v/v) and 4) dichloromethane as solvents was applied. All the extracts were analysed by GC and GC/MS. The most representative extracts were 3) and 4). Syringaldehyde was the most striking compound, being dominant in the extracts 2), 3) and 4) with percentages 34.5%, 33.1% and 35.9%, respectively. In comparison to USE results of other single Croatian tree honey samples (Robinia pseudoacacia L. nectar honey, Salix spp. nectar and honeydew honeys, Quercus frainetto Ten. honeydew as well as Abies alba Mill. and Picea abies L. honeydew) and literature data the presence of syringaldehyde, previously identified in maple sap and syrup, can be pointed out as a distinct characteristic of the Acer spp. honey sample. Headspace solid-phase microextraction (HS-SPME) combined with GC and GC/MS identified benzaldehyde (16.5%), trans-linalool oxide (20.5%) and 2-phenylethanol (14.9%) as the major compounds that are common in different honey headspace compositions. Full article
Open AccessArticle Alkaloids from Fissistigma latifolium (Dunal) Merr.
Molecules 2010, 15(7), 4583-4588; doi:10.3390/molecules15074583
Received: 1 June 2010 / Accepted: 7 June 2010 / Published: 24 June 2010
Cited by 7 | PDF Full-text (167 KB)
Abstract
A phytochemical study of the bark of Fissistigma latifolium (Annonaceae) yielded a new aporphine alkaloid, (-)-N-methylguattescidine (1), and eight known alkaloids: liriodenine (2), oxoxylopine (3), (-)-asimilobine (4), dimethyltryptamine (5), (-)-remerine (6), (-)-anonaine (7), columbamine (8) [...] Read more.
A phytochemical study of the bark of Fissistigma latifolium (Annonaceae) yielded a new aporphine alkaloid, (-)-N-methylguattescidine (1), and eight known alkaloids: liriodenine (2), oxoxylopine (3), (-)-asimilobine (4), dimethyltryptamine (5), (-)-remerine (6), (-)-anonaine (7), columbamine (8) and lysicamine (9). The compounds were isolated using various chromatographic methods and structural elucidation was accomplished by means of spectroscopic methods, notably 1D-NMR (1H, 13C, DEPT), 2D-NMR (COSY, HMQC, HMBC), UV, IR and MS. Full article
Open AccessArticle New Steroidal Glycosides Isolated as CD40L Inhibitors of Activated Platelets
Molecules 2010, 15(7), 4589-4598; doi:10.3390/molecules15074589
Received: 24 April 2010 / Revised: 25 May 2010 / Accepted: 7 June 2010 / Published: 25 June 2010
Cited by 10 | PDF Full-text (301 KB)
Abstract
Three new compounds were isolated from the dried bulbs of Allium macrostemon Bunge. Their structures were elucidated from their spectral data as (25R)-26-O-β-D-glucopyranosyl-5α-furostane-3β,12β,22,26-tetraol-3-O-β-D-glucopyranos-yl (1→2) [β-D-glucopyranosyl (1→3)]-β-D-glucopyranosyl (1→4)-β-D-galactopyranoside (1), (25R)-26-O-β-D-glucopyranosyl-5α-furostane-3β,12α,22,26-tetraol-3-O-β-D-glucopyranosyl (1→2) [β-D-glucopyranosyl (1→3)]-β-D-glucopyranosyl (1→4)-β-D-galacto- pyranoside (2) and (25R)-26-O-β-D-glucopyranosyl-5β-furostane-3β,12α,22,26-tetraol-3-O-β-D-glucopyranosyl (1→2)-β-D-galactopyranoside (3), respectively. The inhibition effect of all compounds on CD40 ligand (CD40L) expression on the membrane of activated platelets stimulated by ADP was tested. Compounds 1 and 2 exhibited significant inhibitory activities in a dose dependent manner (P < 0.05), suggesting their potential application as CD40L inhibitors. Full article
Open AccessArticle Compounds from Viburnum sargentii Koehne and Evaluation of Their Cytotoxic Effects on Human Cancer Cell Lines
Molecules 2010, 15(7), 4599-4609; doi:10.3390/molecules15074599
Received: 2 April 2010 / Revised: 14 May 2010 / Accepted: 9 June 2010 / Published: 25 June 2010
Cited by 3 | PDF Full-text (454 KB)
Abstract
Compounds were isolated from a methanol extract of the dried stem barks of Viburnum sargentii Koehne. The structures of the compounds, namely 9'-O-methylvibsanol (3), furcatoside A (4) and lareciresinol (5) were elucidated by analysis of spectroscopic data and comparison with values for [...] Read more.
Compounds were isolated from a methanol extract of the dried stem barks of Viburnum sargentii Koehne. The structures of the compounds, namely 9'-O-methylvibsanol (3), furcatoside A (4) and lareciresinol (5) were elucidated by analysis of spectroscopic data and comparison with values for previously known analogues. In addition, (+)-catechin (1), (+)-epicatechin (2) were also isolated. This work also examined the cytotoxic effects of three compounds 3-5 (25-100 μM) in MCF-7 and A549 cells after 24, 48 and 72 h of exposure. Our results showed that 9'-O-methylvibsanol (3) exhibited strong concentration-dependent anticancer effects according to the MTT assay and produced morphological changes consistent with apoptosis, as confirmed by Ho3342 staining analysis revealed that more apoptotic cells were observed after 9'-Omethylvibsanol (3) treatment. Full article
Open AccessArticle Variation in Total Polyphenolics Contents of Aerial Parts of Potentilla Species and Their Anticariogenic Activity
Molecules 2010, 15(7), 4639-4651; doi:10.3390/molecules15074639
Received: 10 May 2010 / Revised: 23 June 2010 / Accepted: 28 June 2010 / Published: 29 June 2010
Cited by 26 | PDF Full-text (155 KB)
Abstract
The aerial parts of selected Potentilla species (P. anserina, P. argentea, P. erecta, P. fruticosa, P. grandiflora, P. nepalensis, P. norvegica, P. pensylvanica, P. crantzii and P. thuringiaca) were investigated in order to determine their contents of polyphenolic compounds. The [...] Read more.
The aerial parts of selected Potentilla species (P. anserina, P. argentea, P. erecta, P. fruticosa, P. grandiflora, P. nepalensis, P. norvegica, P. pensylvanica, P. crantzii and P. thuringiaca) were investigated in order to determine their contents of polyphenolic compounds. The results showed that P. fruticosa has relatively high concentrations of tannins (167.3 ± 2.0 mg/g dw), proanthocyanidins (4.6 ± 0.2 mg/g dw) and phenolic acids (16.4 ± 0.8 mg/g dw), as well as flavonoids (7.0 ± 1.1 mg/g dw), calculated as quercetin. Furthermore, we investigated the in vitro inhibitory effects of aqueous extracts from these species against cariogenic Streptococcus spp. strains. It was found that the tested samples moderately inhibit the growth of oral streptococci. However, all the preparations exhibited inhibitory effects on water-insoluble α-(1→3)-, α-(1→6)-linked glucan (mutan) and artificial dental plaque formation. The extract from P. fruticosa showed the highest anti-biofilm activities, with minimum mutan and biofilm inhibition concentrations of 6.25–25 and 50–100 µg/mL, respectively. The results indicate that the studied Potentilla species could be a potential plant material for extracting biologically active compounds, and could become a useful supplement for pharmaceutical products as a new anticariogenic agent in a wide range of oral care products. Full article
Open AccessArticle Supported and Non-Supported Ruthenium(II)/Phosphine/[3-(2-Aminoethyl)aminopropyl]trimethoxysilane Complexes and Their Activities in the Chemoselective Hydrogenation of trans-4-Phenyl-3-butene-2-al
Molecules 2010, 15(7), 4652-4669; doi:10.3390/molecules15074652
Received: 21 May 2010 / Revised: 22 June 2010 / Accepted: 25 June 2010 / Published: 30 June 2010
Cited by 12 | PDF Full-text (763 KB)
Abstract
Syntheses of four new ruthenium(II) complexes of the [RuCl2(P)2(N)2] type using 2-(diphenylphosphino)ethyl methyl ether (P~O) as ether-phosphine and triphenylphosphine (PPh3) as monodentate phosphine ligands in the presence of [3-(2-aminoethyl)aminopropyl]trimethoxysilane as diamine co-ligand are presented [...] Read more.
Syntheses of four new ruthenium(II) complexes of the [RuCl2(P)2(N)2] type using 2-(diphenylphosphino)ethyl methyl ether (P~O) as ether-phosphine and triphenylphosphine (PPh3) as monodentate phosphine ligands in the presence of [3-(2-aminoethyl)aminopropyl]trimethoxysilane as diamine co-ligand are presented for the first time. The reactions were conducted at room temperature and under an inert atmosphere. Due to the presence of the trimethoxysilane group in the backbone of complexes 1 and 2 they were subjected to an immobilization process using the sol-gel technique in the presence of tetraethoxysilane as cross-linker. The structural behavior of the phosphine ligands in the desired complexes during synthesis were monitored by 31P{1H}-NMR. Desired complexes were deduced from elemental analyses, Infrared, FAB-MS and 1H-, 13C- and 31P-NMR spectroscopy, xerogels X1 and X2 were subjected to solid state, 13C-, 29Si- and 31P-NMR spectroscopy, Infrared and EXAF. These complexes served as hydrogenation catalysts in homogenous and heterogeneous phases, and chemoselective hydrogenation of the carbonyl function group in trans-4-phenyl-3-butene-2-al was successfully carried out under mild basic conditions. Full article
Open AccessArticle A General Strategy for the Preparation of Carbon Nanotubes and Graphene Oxide Decorated with PdO Nanoparticles in Water
Molecules 2010, 15(7), 4679-4694; doi:10.3390/molecules15074679
Received: 30 May 2010 / Revised: 11 June 2010 / Accepted: 2 July 2010 / Published: 2 July 2010
Cited by 21 | PDF Full-text (2351 KB)
Abstract
The preparation of carbon nanotube (CNT)/PdO nanoparticles and graphene oxide (GO)/PdO nanoparticle hybrids via a general aqueous solution strategy is reported. The PdO nanoparticles are generated in situ on the CNTs and GO by a one-step “green” synthetic approach in aqueous Pd(NO [...] Read more.
The preparation of carbon nanotube (CNT)/PdO nanoparticles and graphene oxide (GO)/PdO nanoparticle hybrids via a general aqueous solution strategy is reported. The PdO nanoparticles are generated in situ on the CNTs and GO by a one-step “green” synthetic approach in aqueous Pd(NO3)2 solution under ambient conditions without adding any additional chemicals. The production of PdO is confirmed by energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and thermal gravimetric analysis. The morphologies of the resulting CNT/PdO and GO/PdO nanohybrids are characterized by transmission and/or scanning transmission electron microscopy. PdO nanoparticles with an average size of 2–3 nm in diameter are decorated evenly along the surfaces of CNTs and GO. This synthesis strategy is demonstrated to be compatible for 1) CNTs with different modifications, including pristine, oxidized, and polymer-functionalized CNTs; 2) different types of CNTs, including single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), and multiwalled carbon nanotubes (MWCNTs); and 3) different shapes of carbon materials, including tubular CNTs and planar GO. The as-prepared CNT/PdO and GO/PdO nanohybrids can be transformed into CNT/Pd and GO/Pd nanohybrids by reduction with NaBH4, and can then be used as a heterogeneous catalyst in the catalytic reduction of 4-nitrophenol. Full article
(This article belongs to the Special Issue Nano-catalysts and Nano-technologies for Green Organic Synthesis)
Open AccessArticle Antiosteoporotic Effects and Proteomic Characterization of the Target and Mechanism of an Er-Xian Decoction on Osteoblastic UMR-106 and Osteoclasts Induced From RAW264.7
Molecules 2010, 15(7), 4695-4710; doi:10.3390/molecules15074695
Received: 4 May 2010 / Revised: 11 June 2010 / Accepted: 29 June 2010 / Published: 5 July 2010
Cited by 14 | PDF Full-text (818 KB)
Abstract
Er-Xian Decoction (EXD) has been used for the treatment of osteoporosis disorders, menopausal syndrome, and other aging diseases in the Chinese traditional healthcare system. However, the targets and mechanism of action have not been clarified. This study was designed to investigate the [...] Read more.
Er-Xian Decoction (EXD) has been used for the treatment of osteoporosis disorders, menopausal syndrome, and other aging diseases in the Chinese traditional healthcare system. However, the targets and mechanism of action have not been clarified. This study was designed to investigate the effects and possible target proteins of EXD on osteoblastic UMR-106 cells and osteoclasts induced from RAW264.7 cells using the proteomic analysis technique. We found that EXD at a concentration of 50–200 μg/mL significantly enhanced osteoblastic UMR-106 cell proliferation, alkaline phosphatase (ALP) activity and formation of bone nodules, and decreased tartrate-resistant acid phosphatase (TRAP) activity and the bone resorption action of osteoclasts induced from RAW 264.7 cells. In EXD-treated osteoblasts, there were increases in the expression of heat-shock protein 1, high mobility group protein (Hmgb1), acidic ribosomal phosphoprotein P0, histone 2, carbonyl reductase 1, ATP synthase, aldolase A, and Rho GDP dissociation inhibitor (GDI)-alpha; and reduction in the expression of carbonic anhydrase 3, prohibitin, hemiferrin, far upstream element (FUSE)-binding protein. In EXD-treated osteoclasts, there were increases in the expression of vimentin, protein disulfide isomerase associated 3 and alpha-fetoprotein; and reduction in the expression of calnexin. These results indicated that EXD modulates bone metabolism through regulation of osteoblastic proliferation, apoptosis, and cell activation, and osteoclastic protein folding and aggregation. Full article
Open AccessArticle Synthesis of Some New Pyridine-2,6-carboxamide-derived Schiff Bases as Potential Antimicrobial Agents
Molecules 2010, 15(7), 4711-4721; doi:10.3390/molecules15074711
Received: 13 June 2010 / Revised: 30 June 2010 / Accepted: 1 July 2010 / Published: 6 July 2010
Cited by 20 | PDF Full-text (179 KB)
Abstract
A series of pyridine-bridged 2,6-bis-carboxamide Schiff's bases has been prepared starting from 2,6-pyridinedicarbonyl dichloride (1) and L-alanine or 2-methyl-alanine methyl ester.The coupling of acid chloride 1 with L-alanine methyl ester hydrochloride -or 2-methylalanine methyl ester hydrochloride gave the corresponding 2,6-bis-carboxamide [...] Read more.
A series of pyridine-bridged 2,6-bis-carboxamide Schiff's bases has been prepared starting from 2,6-pyridinedicarbonyl dichloride (1) and L-alanine or 2-methyl-alanine methyl ester.The coupling of acid chloride 1 with L-alanine methyl ester hydrochloride -or 2-methylalanine methyl ester hydrochloride gave the corresponding 2,6-bis-carboxamide pyridine methyl esters 2a,b.Hydrazonolysis of 2 with hydrazine hydrate afforded the corresponding bis-hydrazides 3a,b. Treatment of 3a,b with appropriate aromatic or heterocyclic aldehydes afforded the corresponding pyridine- bridged 2,6-bis-carboxamide Schiff's bases 4a-f and 5a-f, respectively. The newly synthesized compounds 2-5 were screened for their bactericidal and fungicidal activities. Many of the obtained compounds exhibited significant antimicrobial activity, comparable to streptomycin and fusidic acid, which were used as reference antibiotic drugs. Full article
Open AccessArticle Regioselective O-Derivatization of Quercetin via Ester Intermediates. An Improved Synthesis of Rhamnetin and Development of a New Mitochondriotropic Derivative
Molecules 2010, 15(7), 4722-4736; doi:10.3390/molecules15074722
Received: 10 June 2010 / Revised: 22 June 2010 / Accepted: 2 July 2010 / Published: 6 July 2010
Cited by 14 | PDF Full-text (328 KB)
Abstract
The regioselective synthesis of several quercetin (3,3’,4’,5,7-pentahydroxy flavone) tetraesters bearing a single free OH on 5-C was achieved in good yield by proper choice of reaction conditions using common esterification procedures. Tetracetylated quercetin with the free OH on 7-C was selectively obtained [...] Read more.
The regioselective synthesis of several quercetin (3,3’,4’,5,7-pentahydroxy flavone) tetraesters bearing a single free OH on 5-C was achieved in good yield by proper choice of reaction conditions using common esterification procedures. Tetracetylated quercetin with the free OH on 7-C was selectively obtained instead via imidazole-promoted deacylation of the corresponding pentaester. Unambiguous structural characterization of the two isomeric tetraacetyl quercetin derivatives was obtained by combined HSQC and HMBC 2D-NMR analysis. These molecules can be used as starting materials for the regioselective synthesis of other derivatives. High yield syntheses of the natural polyphenol rhamnetin (7-O-methylquercetin) and of the new mitochondriotropic compound 7-(4-triphenylphosphoniumbutyl) quercetin iodide are reported as examples. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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Open AccessArticle Synthesis and Preliminary Evaluation of the Antimicrobial Activity of Selected 3-Benzofurancarboxylic Acid Derivatives
Molecules 2010, 15(7), 4737-4749; doi:10.3390/molecules15074737
Received: 1 June 2010 / Revised: 29 June 2010 / Accepted: 1 July 2010 / Published: 6 July 2010
Cited by 11 | PDF Full-text (332 KB)
Abstract
Halogen derivatives of selected 3-benzofurancarboxylic acids were prepared using 6-acetyl-5-hydroxy-2-methyl-3-benzofuranocarboxylic acid as starting material. 1H-NMR spectra were obtained for all of the synthesized structures, and for compound VI, an X-ray crystal structure was also obtained. All derivatives were tested for [...] Read more.
Halogen derivatives of selected 3-benzofurancarboxylic acids were prepared using 6-acetyl-5-hydroxy-2-methyl-3-benzofuranocarboxylic acid as starting material. 1H-NMR spectra were obtained for all of the synthesized structures, and for compound VI, an X-ray crystal structure was also obtained. All derivatives were tested for antimicrobial activity against a selection of Gram-positive cocci, Gram-negative rods and yeasts. Three compounds, III, IV, and VI, showed antimicrobial activity against Gram-positive bacteria (MIC 50 to 200 mg/mL). Compounds VI and III exhibited antifungal activity against the Candida strains C. albicans and C. parapsilosis (MIC – 100 mg/mL). Full article
Open AccessArticle Synthesis, Characterization and Reactivity Ratio Study of Poly(di(tri-n-butyltin) citraconate-co-N-vinylimidazole)
Molecules 2010, 15(7), 4750-4756; doi:10.3390/molecules15074750
Received: 13 June 2010 / Revised: 28 June 2010 / Accepted: 30 June 2010 / Published: 7 July 2010
Cited by 2 | PDF Full-text (127 KB)
Abstract
The organotin monomer di(tri-n-butyltin) citraconate (DTBTC, I) was synthesized. Subsequently this monomer was copolymerized with N-vinylimidazole (VI) using a free radical technique. The overall conversion was kept low (≤14% wt/wt) for all studied samples and the copolymer composition [...] Read more.
The organotin monomer di(tri-n-butyltin) citraconate (DTBTC, I) was synthesized. Subsequently this monomer was copolymerized with N-vinylimidazole (VI) using a free radical technique. The overall conversion was kept low (≤14% wt/wt) for all studied samples and the copolymer composition was determined from tin analysis using the Gilman and Rosenberg method. The synthesized monomer and copolymer were further characterized by elemental analysis, 1H- and 13C-NMR, and FTIR spectroscopy. Full article
Open AccessArticle Inhibition of HIV-1 Replication and Dimerization Interference by Dual Inhibitory RNAs
Molecules 2010, 15(7), 4757-4772; doi:10.3390/molecules15074757
Received: 31 May 2010 / Revised: 28 June 2010 / Accepted: 1 July 2010 / Published: 7 July 2010
Cited by 7 | PDF Full-text (616 KB)
Abstract
The 5’-untranslated region (5’UTR) of the HIV-1 RNA is an attractive target for engineered ribozymes due to its high sequence and structural conservation. This region encodes several conserved structural RNA domains essential in key processes of the viral replication and infection cycles. [...] Read more.
The 5’-untranslated region (5’UTR) of the HIV-1 RNA is an attractive target for engineered ribozymes due to its high sequence and structural conservation. This region encodes several conserved structural RNA domains essential in key processes of the viral replication and infection cycles. This paper reports the inhibitory effects of catalytic antisense RNAs composed of two inhibitory RNA domains: an engineered ribozyme targeting the 5’ UTR and a decoy or antisense domain of the dimerization initiation site (DIS). These chimeric molecules are able to cleave the HIV-1 5’UTR efficiently and prevent viral genome dimerization in vitro. Furthermore, catalytic antisense RNAs inhibited viral production up to 90% measured as p24 antigen levels in ex vivo assays. The use of chimeric RNA molecules targeting different domains represents an attractive antiviral strategy to be explored for the prevention of side effects from current drugs and of the rapid emergence of escape variants of HIV-1. Full article
(This article belongs to the Special Issue Catalytic Nucleic Acids)
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Open AccessArticle Solid-Phase Synthesis of the Lipopeptide Myr-HBVpreS/2-78, a Hepatitis B Virus Entry Inhibitor
Molecules 2010, 15(7), 4773-4783; doi:10.3390/molecules15074773
Received: 20 May 2010 / Revised: 2 July 2010 / Accepted: 5 July 2010 / Published: 7 July 2010
Cited by 8 | PDF Full-text (306 KB)
Abstract
Chronic HBV infection is the leading cause of liver cirrhosis and hepatocellular carcinoma (HCC). Synthetic peptides derived from the N-terminus of the large HBV envelope protein (L-protein) have been shown to efficiently block HBV entry. Myr-HBVpreS/2-78, the parent compound of these [...] Read more.
Chronic HBV infection is the leading cause of liver cirrhosis and hepatocellular carcinoma (HCC). Synthetic peptides derived from the N-terminus of the large HBV envelope protein (L-protein) have been shown to efficiently block HBV entry. Myr-HBVpreS/2-78, the parent compound of these drugs, inhibits human HBV infection in vitro and in vivo. An efficient synthesis is required, as these peptides constitute a novel class of anti HBV drugs. Consequently, the solid phase synthesis of the N-terminal 77 amino acids of the viral L-protein was studied in detail. The peptide was N-terminally myristoylated to resemble the natural, postranslationally modified protein. The synthesis was monitored using the Fmoc cleavage pattern of the solid phase synthesis on a standard peptide synthesizer and by LC-MS analyses of the arising side products. “Difficult sequences” in the positions 42-47 of the peptide sequence complicate the efficient synthesis of the 77-mer peptide HBVpreS/2-78. Attempts were undertaken to optimize the synthesis by heating, double coupling or the use of pseudoproline dipeptides. HPLC-MS analyses showed that the efficiency of the synthesis could be increased best by temperature elevation. This resulted in a higher purity of the crude product after solid phase synthesis. It was possible to minimize the occurrence of side products due to the positive effects related to higher reaction temperature. In conclusion, the peptide is accessible by stepwise SPPS without the necessity of segment coupling. Full article
(This article belongs to the Special Issue Solid Phase Synthesis)
Open AccessCommunication Palladium(II) Complexes of NS Donor Ligands Derived from Steroidal Thiosemicarbazones as Antibacterial Agents
Molecules 2010, 15(7), 4784-4791; doi:10.3390/molecules15074784
Received: 13 May 2010 / Revised: 28 May 2010 / Accepted: 9 June 2010 / Published: 8 July 2010
Cited by 20 | PDF Full-text (161 KB)
Abstract
We have investigated the antibacterial activity of some new steroidal thiosemicarbazones and their Pd(II) metal complexes were prepared by the reaction of the thiosemicarbazones with [Pd(DMSO)2Cl2]. The steroidal thiosemicarbazones were prepared by the reaction of thiosemicarbazides with a [...] Read more.
We have investigated the antibacterial activity of some new steroidal thiosemicarbazones and their Pd(II) metal complexes were prepared by the reaction of the thiosemicarbazones with [Pd(DMSO)2Cl2]. The steroidal thiosemicarbazones were prepared by the reaction of thiosemicarbazides with a steroidal ketone. The structures of these compounds were elucidated by IR, 1H-NMR, 13C-NMR, FAB mass spectroscopic methods, elemental analyses and TGA analysis. The antibacterial activity of these compounds were tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria. The results showed that steroidal complexes are better inhibitors of both types of the bacteria (Gram-positive and Gram-negative) as compared to steroidal thiosemicarbazones. Compound Ia displays remarkable antibacterial activity as compared to amoxicillin. Full article
Open AccessArticle Machine Learning Techniques for Single Nucleotide Polymorphism—Disease Classification Models in Schizophrenia
Molecules 2010, 15(7), 4875-4889; doi:10.3390/molecules15074875
Received: 4 June 2010 / Revised: 8 July 2010 / Accepted: 9 July 2010 / Published: 12 July 2010
Cited by 10 | PDF Full-text (614 KB)
Abstract
Single nucleotide polymorphisms (SNPs) can be used as inputs in disease computational studies such as pattern searching and classification models. Schizophrenia is an example of a complex disease with an important social impact. The multiple causes of this disease create the need [...] Read more.
Single nucleotide polymorphisms (SNPs) can be used as inputs in disease computational studies such as pattern searching and classification models. Schizophrenia is an example of a complex disease with an important social impact. The multiple causes of this disease create the need of new genetic or proteomic patterns that can diagnose patients using biological information. This work presents a computational study of disease machine learning classification models using only single nucleotide polymorphisms at the HTR2A and DRD3 genes from Galician (Northwest Spain) schizophrenic patients. These classification models establish for the first time, to the best knowledge of the authors, a relationship between the sequence of the nucleic acid molecule and schizophrenia (Quantitative Genotype – Disease Relationships) that can automatically recognize schizophrenia DNA sequences and correctly classify between 78.3–93.8% of schizophrenia subjects when using datasets which include simulated negative subjects and a linear artificial neural network. Full article
(This article belongs to the Special Issue From Computational Chemistry to Complex Networks)
Open AccessArticle A New High-Performance Liquid Chromatographic Method for the Determination and Distribution of Linalool in Michelia alba
Molecules 2010, 15(7), 4890-4897; doi:10.3390/molecules15074890
Received: 23 June 2010 / Revised: 7 July 2010 / Accepted: 8 July 2010 / Published: 12 July 2010
Cited by 10 | PDF Full-text (186 KB)
Abstract
A new high-performance liquid chromatographic method with photodiode array detection was established for the determination of linalool in the plant Michelia alba. Linalool was extracted from the plant sample with the aid of ultrasound, and was analyzed on a Waters RP [...] Read more.
A new high-performance liquid chromatographic method with photodiode array detection was established for the determination of linalool in the plant Michelia alba. Linalool was extracted from the plant sample with the aid of ultrasound, and was analyzed on a Waters RP C18 column (4.6 × 150 mm, 5 μm) using an acetonitrile and water (55:45, v/v) mobile phase at a flow rate of 1.0 mL/min. The column temperature was set at 25 ºC, and the detection wavelength was 210 nm. The linear range of the method was 5–200 μg/mL with a correlation coefficient of 0.9975. The recovery was 92–112%, and the relative standard deviation was 1.85% (n = 9). The present method has been used to study the distribution of linalool in the plant Michelia alba. The plant samples include flowers, leaves and tender twigs. Furthermore, leaves included samples in their tender, grown-up and fallen phases, and flowers included samples in their juvenile, middle and whitening phases. The concentrations of linalool in different parts of the plant were 0.21–0.65%, 1.63–4.89% and 0.43% for leaves, flowers and tender twigs, respectively. The results showed that all the plant materials contained relative high concentration of linalool, and juvenile phase flowers contained the highest concentration of linalool. Notably, the fallen leaves also contained high concentrations of linalool, which could be a potential resource of this compound. The results obtained are very helpful for the potential full utilization of this plant. Full article
Open AccessArticle Antifungal Activity of Extracts and Prenylated Coumarins Isolated from Baccharis darwinii Hook & Arn. (Asteraceae)
Molecules 2010, 15(7), 4898-4907; doi:10.3390/molecules15074898
Received: 17 June 2010 / Revised: 1 July 2010 / Accepted: 7 July 2010 / Published: 13 July 2010
Cited by 15 | PDF Full-text (119 KB)
Abstract
The petroleum ether extract of Baccharis darwinii showed activity against Cryptococcus neoformans and dermatophytes. Bioactivity-guided fractionation of Baccharis darwinii has resulted in the isolation of three coumarins: 5’-hydroxy aurapten (anisocoumarin H, 1), aurapten (7-geranyloxycoumarin, 2) and 5’-oxoaurapten (diversinin, 3). [...] Read more.
The petroleum ether extract of Baccharis darwinii showed activity against Cryptococcus neoformans and dermatophytes. Bioactivity-guided fractionation of Baccharis darwinii has resulted in the isolation of three coumarins: 5’-hydroxy aurapten (anisocoumarin H, 1), aurapten (7-geranyloxycoumarin, 2) and 5’-oxoaurapten (diversinin, 3). The structures of these compounds were characterized by spectroscopic methods. These compounds were evaluated for their antimicrobialactivity against a panel of each, bacteria and fungi. Compound 3 showed the best activities against Microsporum gypseum, Trichophyton rubrum and Trichophyton mentagrophytes with MICs = 15.6 µg/mL, followed by compound 1 whose MICs against the same fungi were 62.5 µg/mL. In addition they showed fungicidal rather than fungistatic activity. Both compounds showed moderate activity (MICs = 125 µg/mL) against Cryptococcus neoformans. This is the first report of the presence of compound 1 in B. darwinii. Full article
Open AccessArticle Syntheses, Characterization, and Photo-Hydrogen-Evolving Properties of Tris(2,2'-bipyridine)ruthenium(II) Derivatives Tethered to an H2-Evolving (2-phenylpyridinato)platinum(II) Unit
Molecules 2010, 15(7), 4908-4923; doi:10.3390/molecules15074908
Received: 25 May 2010 / Revised: 1 July 2010 / Accepted: 14 July 2010 / Published: 14 July 2010
Cited by 17 | PDF Full-text (800 KB)
Abstract
With the aim of developing new molecular devices having higher photo-hydrogen-evolving activity, Pt(ppy)ClX units (ppy = 2-phenylpyridinate, X = Cl- or DMSO; DMSO = dimethylsulfoxide) have been employed as an H2-evolving site, as the catalytic activity of [Pt(ppy)Cl2 [...] Read more.
With the aim of developing new molecular devices having higher photo-hydrogen-evolving activity, Pt(ppy)ClX units (ppy = 2-phenylpyridinate, X = Cl- or DMSO; DMSO = dimethylsulfoxide) have been employed as an H2-evolving site, as the catalytic activity of [Pt(ppy)Cl2]- was confirmed to be higher than those of other mononuclear platinum(II) complexes. In the present study, two new heterodinuclear Ru(II)Pt(II) complexes, produced by condensation of [Ru(bpy)2(5-amino-phen)]2+ (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) with [Pt(cppy)Cl2]- and Pt(cppy)(DMSO)Cl (cppy = 9-carboxy-phenylpyridinate), respectively, have been prepared and their photo-hydrogen-evolving activities have been evaluated in detail. The ineffectiveness of these systems as photo-hydrogen-evolving molecular devices are interpreted in terms of their negative driving forces for the photoinduced electron transfer from the triplet MLCT excited state of the Ru chromophore to the p*(ppy) orbital of the catalyst moiety. Full article
(This article belongs to the Special Issue Photochemistry in Organic Synthesis)
Open AccessArticle Solid-Phase Synthesis of New Trp(Nps)-Containing Dipeptide Derivatives as TRPV1 Channel Blockers
Molecules 2010, 15(7), 4924-4933; doi:10.3390/molecules15074924
Received: 11 June 2010 / Revised: 14 July 2010 / Accepted: 15 July 2010 / Published: 15 July 2010
Cited by 2 | PDF Full-text (248 KB)
Abstract Trp(Nps)-Lys-NH2 derivatives, bearing alkyl or guanidine groups either at the N–terminus or on the Lys side-chain or at both positions were conveniently prepared on solid-phase and evaluated as TRPV1 channel antagonists. Full article
(This article belongs to the Special Issue Solid Phase Synthesis)
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Open AccessArticle Antioxidant Activities of Various Extracts from Artemisisa selengensis Turcz (LuHao)
Molecules 2010, 15(7), 4934-4946; doi:10.3390/molecules15074934
Received: 20 May 2010 / Revised: 30 June 2010 / Accepted: 14 July 2010 / Published: 16 July 2010
Cited by 13 | PDF Full-text (184 KB)
Abstract
The antioxidant activities of the various extracts and fractions from the herbs of Artemisia selegensis Turcz (AST) were investigated by in vitro and in vivo assays. FRAP, DPPH and ABTS assays were used to evaluate the antioxidant activities of the extracts/fractions in vitro. The effect of water extract (WE) in reducing oxidative stress in male mice was evaluated. Phenolic acid compounds contribute significantly to the antioxidant activity. From the results of three in vitro antioxidant assays, WE was found to have the highest antioxidant activity, and among the WE subfractions, the water soluble fraction has a significant antioxidant activity. The in vivo antioxidant assay results showed that high doses of WE significantly decrease the MDA level compared to normal diet and D-(+) galactose group (p < 0.05), and the SOD activity of mice given a high dose of WE was the highest. These in vitro and in vivo studies demonstrated that the extracts, especially the WE from AST, have significant antioxidant and free radical scavenging activities. In summary, we propose that AST could be potentially used as a rich source of natural antioxidants. Full article
Open AccessArticle Solid-Phase Synthetic Route to Multiple Derivatives of a Fundamental Peptide Unit
Molecules 2010, 15(7), 4961-4983; doi:10.3390/molecules15074961
Received: 7 June 2010 / Revised: 23 June 2010 / Accepted: 12 July 2010 / Published: 20 July 2010
Cited by 4 | PDF Full-text (357 KB)
Abstract
Amino acids are Nature’s combinatorial building blocks. When substituted on both the amino and carboxyl sides they become the basic scaffold present in all peptides and proteins. We report a solid-phase synthetic route to large combinatorial variations of this fundamental scaffold, extending [...] Read more.
Amino acids are Nature’s combinatorial building blocks. When substituted on both the amino and carboxyl sides they become the basic scaffold present in all peptides and proteins. We report a solid-phase synthetic route to large combinatorial variations of this fundamental scaffold, extending the variety of substituted biomimetic molecules available to successfully implement the Distributed Drug Discovery (D3) project. In a single solid-phase sequence, compatible with basic amine substituents, three-point variation is performed at the amino acid a-carbon and the amino and carboxyl functionalities. Full article
(This article belongs to the Special Issue Solid Phase Synthesis)
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Open AccessArticle Anethole Isomerization and Dimerization Induced by Acid Sites or UV Irradiation
Molecules 2010, 15(7), 5012-5030; doi:10.3390/molecules15075012
Received: 21 May 2010 / Revised: 21 June 2010 / Accepted: 25 June 2010 / Published: 22 July 2010
Cited by 7 | PDF Full-text (429 KB)
Abstract
The formation of cis-anethole and various dimers as a result of the exposure of trans-anethole to microporous solid acids (dealuminated HY zeolites), or UV-Vis irradiation was established by means of high resolution gas chromatography coupled to mass spectrometry. 3,4-bis-(4-Methoxyphenyl)-(E [...] Read more.
The formation of cis-anethole and various dimers as a result of the exposure of trans-anethole to microporous solid acids (dealuminated HY zeolites), or UV-Vis irradiation was established by means of high resolution gas chromatography coupled to mass spectrometry. 3,4-bis-(4-Methoxyphenyl)-(E)-hex-2-ene was the most abundant compound among eight different methoxyphenyl-disubstituted hexenes produced by electrophilic addition and elimination reactions induced by HY zeolites. (1a,2a,3b,4b)-1,2-bis(4-Methoxyphenyl)-3,4-dimethylcyclobutane was the principal component in the mixture of 5 methoxyphenyl-disubstituted cyclobutanes found, together with cis-anethole, after UV-Vis irradiation of a trans-anethole solution in toluene. Full article
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Open AccessArticle Selecting Diversified Compounds to Build a Tangible Library for Biological and Biochemical Assays
Molecules 2010, 15(7), 5031-5044; doi:10.3390/molecules15075031
Received: 2 July 2010 / Revised: 14 July 2010 / Accepted: 19 July 2010 / Published: 23 July 2010
Cited by 11 | PDF Full-text (963 KB)
Abstract
The quality of diverse compound selection mainly depends on cluster algorithms, descriptors, the combinations of the descriptors, and similarity metrics. The Jarvis-Patrick algorithm, MDL search keys, and Daylight fingerprints are a well accepted algorithm and structure descriptors for compound library diversity analysis. [...] Read more.
The quality of diverse compound selection mainly depends on cluster algorithms, descriptors, the combinations of the descriptors, and similarity metrics. The Jarvis-Patrick algorithm, MDL search keys, and Daylight fingerprints are a well accepted algorithm and structure descriptors for compound library diversity analysis. Based upon our 288 experiments on selecting compounds from various descriptor combinations, we have found (1) hybrid Daylight and MDL structural descriptors for diversity analyses can produce worse results; (2) selections based purely on 2,048-bit Daylight fingerprints yield better results than the ones based purely on MDL 166-bit search keys; (3) when Daylight fingerprints and MDL search keys are combined, it is better to compute the similarities independently, then to take the smaller value for the outcome. This will yield better average separation of clusters; (4) regarding the consistency of different clustering approaches, the Daylight fingerprints based clustering is more consistent with the SCA approach than it does with the MDL search keys based approach; (5) The MDL search keys based selection approach tends to select a greater number of compounds from larger clusters. As the Daylight fingerprint is folded two and three times, respectively, information is lost, and this approach tends to select a greater number of compounds from larger clusters as well. These results have not been reported before to our knowledge. Full article
Open AccessArticle Platinum-Catalyzed Hydrative Cyclization of 1,6-Diynes for the Synthesis of 3,5-Substituted Conjugated Cyclohexenones
Molecules 2010, 15(7), 5045-5052; doi:10.3390/molecules15075045
Received: 4 June 2010 / Revised: 24 June 2010 / Accepted: 5 July 2010 / Published: 23 July 2010
Cited by 2 | PDF Full-text (183 KB)
Abstract We have developed a Pt(COD)Cl2-catalyzed hydrative cyclization of 1,6-diynes leading to the formation of functionalized cyclohexenones in good yields. Full article
(This article belongs to the Special Issue Ring-Closing Metathesis)
Open AccessArticle An Amperometric Immunosensor Based on a Polyelectrolyte/ Gold Magnetic Nanoparticle Supramolecular Assembly—Modified Electrode for the Determination of HIV p24 in Serum
Molecules 2010, 15(7), 5053-5065; doi:10.3390/molecules15075053
Received: 10 April 2010 / Accepted: 19 July 2010 / Published: 23 July 2010
Cited by 17 | PDF Full-text (450 KB)
Abstract
Unmanaged sudden withdrawal from the excessive consumption of alcohol (ethanol) adversely alters neuronal integrity in vulnerable brain regions such as the cerebellum, hippocampus, or cortex. In addition to well known hyperexcitatory neurotransmissions, ethanol withdrawal (EW) provokes the intense generation of reactive oxygen [...] Read more.
Unmanaged sudden withdrawal from the excessive consumption of alcohol (ethanol) adversely alters neuronal integrity in vulnerable brain regions such as the cerebellum, hippocampus, or cortex. In addition to well known hyperexcitatory neurotransmissions, ethanol withdrawal (EW) provokes the intense generation of reactive oxygen species (ROS) and the activation of stress-responding protein kinases, which are the focus of this review article. EW also inflicts mitochondrial membranes/membrane potential, perturbs redox balance, and suppresses mitochondrial enzymes, all of which impair a fundamental function of mitochondria. Moreover, EW acts as an age-provoking stressor. The vulnerable age to EW stress is not necessarily the oldest age and varies depending upon the target molecule of EW. A major female sex steroid, 17β-estradiol (E2), interferes with the EW-induced alteration of oxidative signaling pathways and thereby protects neurons, mitochondria, and behaviors. The current review attempts to provide integrated information at the levels of oxidative signaling mechanisms by which EW provokes brain injuries and E2 protects against it. Full article
(This article belongs to the Special Issue Supramolecular Assembly)

Review

Jump to: Research

Open AccessReview High Throughput Extraction of Plant, Marine and Fungal Specimens for Preservation of Biologically Active Molecules
Molecules 2010, 15(7), 4526-4563; doi:10.3390/molecules15074526
Received: 6 May 2010 / Revised: 17 June 2010 / Accepted: 21 June 2010 / Published: 24 June 2010
Cited by 45 | PDF Full-text (917 KB)
Abstract
The Developmental Therapeutics Program (DTP) of the U.S. National Cancer Institute (NCI), at its NCI-Frederick facility, has built perhaps the largest and most diverse natural products screening library in the world for drug discovery. Composed of plant, marine organism and microbial extracts, [...] Read more.
The Developmental Therapeutics Program (DTP) of the U.S. National Cancer Institute (NCI), at its NCI-Frederick facility, has built perhaps the largest and most diverse natural products screening library in the world for drug discovery. Composed of plant, marine organism and microbial extracts, it currently contains in excess of 230,000 unique materials. From the inception of this program to identify new anticancer chemotherapeutics from natural products sources in 1987, two extracts have been sequentially prepared from each specimen: one produced by organic solvent extraction, which yields a complex material that contains non- to moderately polar small molecules, and a water-soluble extract, a milieu largely unexplored for useful drugs in earlier years, which contains polar small to medium-sized molecules. Plant specimens and microbial ferments are extracted by modified traditional methods, while the method developed to produce extracts from marine organisms is unique and very different from that used by marine natural products chemists previously, but again yields both an organic solvent soluble and a water soluble material for inclusion into the screening library. Details of high throughput extract production for preservation of biologically active molecules are presented. Full article
Open AccessReview In Vitro and Ex Vivo Selection Procedures for Identifying Potentially Therapeutic DNA and RNA Molecules
Molecules 2010, 15(7), 4610-4638; doi:10.3390/molecules15074610
Received: 26 May 2010 / Revised: 17 June 2010 / Accepted: 24 June 2010 / Published: 28 June 2010
Cited by 13 | PDF Full-text (695 KB)
Abstract
It was only relatively recently discovered that nucleic acids participate in a variety of biological functions, besides the storage and transmission of genetic information. Quite apart from the nucleotide sequence, it is now clear that the structure of a nucleic acid plays [...] Read more.
It was only relatively recently discovered that nucleic acids participate in a variety of biological functions, besides the storage and transmission of genetic information. Quite apart from the nucleotide sequence, it is now clear that the structure of a nucleic acid plays an essential role in its functionality, enabling catalysis and specific binding reactions. In vitro selection and evolution strategies have been extremely useful in the analysis of functional RNA and DNA molecules, helping to expand our knowledge of their functional repertoire and to identify and optimize DNA and RNA molecules with potential therapeutic and diagnostic applications. The great progress made in this field has prompted the development of ex vivo methods for selecting functional nucleic acids in the cellular environment. This review summarizes the most important and most recent applications of in vitro and ex vivo selection strategies aimed at exploring the therapeutic potential of nucleic acids. Full article
(This article belongs to the Special Issue Catalytic Nucleic Acids)
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Open AccessReview Ribozyme-Mediated Inhibition of 801-bp Deletion-Mutant Epidermal Growth Factor Receptor mRNA Expression in Glioblastoma Multiforme
Molecules 2010, 15(7), 4670-4678; doi:10.3390/molecules15074670
Received: 8 June 2010 / Revised: 28 June 2010 / Accepted: 29 June 2010 / Published: 30 June 2010
Cited by 2 | PDF Full-text (234 KB)
Abstract
The epidermal growth factor receptor (HER1/EGFR) is known to be disregulated in a large subgroup of glioblastoma multiforme cases. Disregulation of HER1/EGFR is related to malignant transformation and tumor growth in various human cancers, including malignant glioma. One mechanism that may lead [...] Read more.
The epidermal growth factor receptor (HER1/EGFR) is known to be disregulated in a large subgroup of glioblastoma multiforme cases. Disregulation of HER1/EGFR is related to malignant transformation and tumor growth in various human cancers, including malignant glioma. One mechanism that may lead to disregulated HER1/EGFR signaling is the intrinsic alteration of the receptor structure due to mutational changes. The most common mutant form of HER1/EGFR, named variant III (EGFRvIII), results from an 801 bp in-frame deletion in the DNA sequence encoding the extracellular ligand-binding domain. Independent of ligand–binding, EGFRvIII is constitutively activated and beyond external control. Since its cellular expression was shown to relate enhanced tumorigenicity, various therapeutic strategies were developed to target EGFRvIII, including monoclonal antibodies, vaccination therapies and small-molecule tyrosine kinase inhibitors. In this review, we focus on ribozyme-mediated inhibition of EGFRvIII messenger RNA expression as a gene therapeutic approach for EGFRvIII-expressing glioblastoma multiforme. Full article
(This article belongs to the Special Issue Catalytic Nucleic Acids)
Open AccessReview Recyclable Nanostructured Catalytic Systems in Modern Environmentally Friendly Organic Synthesis
Molecules 2010, 15(7), 4792-4814; doi:10.3390/molecules15074792
Received: 25 May 2010 / Revised: 30 June 2010 / Accepted: 5 July 2010 / Published: 8 July 2010
Cited by 19 | PDF Full-text (882 KB)
Abstract
Modern chemical synthesis makes heavy use of different types of catalytic systems: homogeneous, heterogeneous and nano-sized. The latter – nano-sized catalysts – have given rise in the 21st century to a rapidly developing area of research encompassing several prospects and opportunities for [...] Read more.
Modern chemical synthesis makes heavy use of different types of catalytic systems: homogeneous, heterogeneous and nano-sized. The latter – nano-sized catalysts – have given rise in the 21st century to a rapidly developing area of research encompassing several prospects and opportunities for new technologies. Catalytic reactions ensure high regio- and stereoselectivity of chemical transformations, as well as better yields and milder reaction conditions. In recent years several novel catalytic systems were developed for selective formation of carbon-heteroatom and carbon-carbon bonds. This review presents the achievements of our team in our studies on various types of catalysts containing metal nanoparticles: palladium-containing diblock copolymer micelles; soluble palladium-containing polymers; metallides on a support; polymeric metal salts and oxides; and, in addition, metal-free organic catalysts based on soluble polymers acting as nanoreactors. Representative examples are given and discussed in light of possible applications to solve important problems in modern organic synthesis. Full article
(This article belongs to the Special Issue Nano-catalysts and Nano-technologies for Green Organic Synthesis)
Open AccessReview Microheterogeneous Catalysis
Molecules 2010, 15(7), 4815-4874; doi:10.3390/molecules15074815
Received: 1 June 2010 / Revised: 23 June 2010 / Accepted: 5 July 2010 / Published: 9 July 2010
Cited by 5 | PDF Full-text (481 KB)
Abstract
The catalytic effect of micelles, polymers (such as DNA, polypeptides) and nanoparticles, saturable receptors (cyclodextrins and calixarenes) and more complex systems (mixing some of the above mentioned catalysts) have been reviewed. In these microheterogeneous systems the observed changes in the rate constants [...] Read more.
The catalytic effect of micelles, polymers (such as DNA, polypeptides) and nanoparticles, saturable receptors (cyclodextrins and calixarenes) and more complex systems (mixing some of the above mentioned catalysts) have been reviewed. In these microheterogeneous systems the observed changes in the rate constants have been rationalized using the Pseudophase Model. This model produces equations that can be derived from the Brönsted equation, which is the basis for a more general formulation of catalytic effects, including electrocatalysis. When, in the catalyzed reaction one of the reactants is in the excited state, the applicability (at least formally) of the Pseudophase Model occurs only in two limiting situations: the lifetime of the fluorophore and the distributions of the quencher and the probe are the main properties that define the different situations. Full article
(This article belongs to the Special Issue Heterogeneous Catalysis)
Open AccessReview Extremely Efficient Catalysis of Carbon-Carbon Bond Formation Using "Click" Dendrimer-Stabilized Palladium Nanoparticles
Molecules 2010, 15(7), 4947-4960; doi:10.3390/molecules15074947
Received: 24 June 2010 / Revised: 8 July 2010 / Accepted: 12 July 2010 / Published: 20 July 2010
Cited by 21 | PDF Full-text (632 KB)
Abstract
This article is an account of the work carried out in the authors’ laboratory illustrating the usefulness of dendrimer design for nanoparticle palladium catalysis. The “click” synthesis of dendrimers constructed generation by generation by 1à3 C connectivity, introduces 1,2,3-triazolyl ligands insides the [...] Read more.
This article is an account of the work carried out in the authors’ laboratory illustrating the usefulness of dendrimer design for nanoparticle palladium catalysis. The “click” synthesis of dendrimers constructed generation by generation by 1à3 C connectivity, introduces 1,2,3-triazolyl ligands insides the dendrimers at each generation. Complexation of the ligands by PdII followed by reduction to Pd0 forms dendrimer-stabilized Pd nanoparticles (PdNPs) that are extremely reactive in the catalysis of olefin hydrogenation and C-C bond coupling reactions. The stabilization can be outer-dendritic for the small zeroth-generation dendrimer or intra-dendritic for the larger first- and second-generation dendrimers. The example of the Miyaura-Suzuki reaction that can be catalyzed by down to 1 ppm of PdNPs with a “homeopathic” mechanism (the less, the better) is illustrated here, including catalysis in aqueous solvents. Full article
(This article belongs to the Special Issue Nano-catalysts and Nano-technologies for Green Organic Synthesis)
Open AccessReview Alcohol Withdrawal and Brain Injuries: Beyond Classical Mechanisms
Molecules 2010, 15(7), 4984-5011; doi:10.3390/molecules15074984
Received: 30 April 2010 / Revised: 15 July 2010 / Accepted: 19 July 2010 / Published: 20 July 2010
Cited by 11 | PDF Full-text (616 KB)
Abstract
Unmanaged sudden withdrawal from the excessive consumption of alcohol (ethanol) adversely alters neuronal integrity in vulnerable brain regions such as the cerebellum, hippocampus, or cortex. In addition to well known hyperexcitatory neurotransmissions, ethanol withdrawal (EW) provokes the intense generation of reactive oxygen [...] Read more.
Unmanaged sudden withdrawal from the excessive consumption of alcohol (ethanol) adversely alters neuronal integrity in vulnerable brain regions such as the cerebellum, hippocampus, or cortex. In addition to well known hyperexcitatory neurotransmissions, ethanol withdrawal (EW) provokes the intense generation of reactive oxygen species (ROS) and the activation of stress-responding protein kinases, which are the focus of this review article. EW also inflicts mitochondrial membranes/membrane potential, perturbs redox balance, and suppresses mitochondrial enzymes, all of which impair a fundamental function of mitochondria. Moreover, EW acts as an age-provoking stressor. The vulnerable age to EW stress is not necessarily the oldest age and varies depending upon the target molecule of EW. A major female sex steroid, 17β-estradiol (E2), interferes with the EW-induced alteration of oxidative signaling pathways and thereby protects neurons, mitochondria, and behaviors. The current review attempts to provide integrated information at the levels of oxidative signaling mechanisms by which EW provokes brain injuries and E2 protects against it. Full article
(This article belongs to the Special Issue Neuroprotective Strategies)

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