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Molecules, Volume 13, Issue 9 (September 2008), Pages 2039-2339

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Research

Jump to: Review

Open AccessArticle Synthesis, IR Spectra, Crystal Structure and DFT Studies on 1-Acetyl-3-(4-Chlorophenyl)-5-(4-Methylphenyl)-2-Pyrazoline
Molecules 2008, 13(9), 2039-2048; doi:10.3390/molecules13092039
Received: 31 July 2008 / Revised: 19 August 2008 / Accepted: 25 August 2008 / Published: 1 September 2008
Cited by 5 | PDF Full-text (335 KB) | HTML Full-text | XML Full-text
Abstract
1-Acetyl-3-(4-chlorophenyl)-5-(4-methylphenyl)-2-pyrazoline has been synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction. Density functional (DFT) calculations have been carried out for the title compound by using the B3LYP method at the 6-311G** basis set level. The calculated results show that
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1-Acetyl-3-(4-chlorophenyl)-5-(4-methylphenyl)-2-pyrazoline has been synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction. Density functional (DFT) calculations have been carried out for the title compound by using the B3LYP method at the 6-311G** basis set level. The calculated results show that the predicted geometry can reproduce well the structural parameters. Predicted vibrational frequencies have been assigned and compared with experimental IR spectra and they are supported each other. On the basis of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated, revealing the correlations between C0p, m, S0m, H0m and temperatures. Full article
Open AccessArticle New secoiridoid Glycosides from the Roots of Picrorhiza Scrophulariiflora
Molecules 2008, 13(9), 2049-2057; doi:10.3390/molecules13092049
Received: 30 June 2008 / Revised: 27 August 2008 / Accepted: 28 August 2008 / Published: 1 September 2008
Cited by 14 | PDF Full-text (288 KB) | HTML Full-text | XML Full-text
Abstract
Three new secoiridoid glycosides, named picrogentiosides A (1), B (2) and C (3), have been isolated from the underground parts of Picrorhiza Scrophulariiflora, together with the two known compounds plantamajoside (4) and plantainoside D (5). Their structures were established by spectroscopic analyses
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Three new secoiridoid glycosides, named picrogentiosides A (1), B (2) and C (3), have been isolated from the underground parts of Picrorhiza Scrophulariiflora, together with the two known compounds plantamajoside (4) and plantainoside D (5). Their structures were established by spectroscopic analyses and comparisons with data from related compounds. A pilot pharmacological study showed that picrogentiosides A (1) and B (2) have an immunomodulatory effect in vitro. Full article
Open AccessArticle Chemical Composition, Antioxidant and Antibacterial Properties of Achillea collina Becker ex Heimerl s.l. and A. pannonica Scheele Essential oils
Molecules 2008, 13(9), 2058-2068; doi:10.3390/molecules13092058
Received: 14 July 2008 / Revised: 5 August 2008 / Accepted: 12 August 2008 / Published: 2 September 2008
Cited by 36 | PDF Full-text (532 KB) | HTML Full-text | XML Full-text
Abstract
The in vitro antioxidant and antimicrobial activities of two Achillea millefolium (Adanson) Koch s.l species essential oils (A. collina Becker ex Heimerl s.l. and A. pannonica Scheele, Asteraceae) originating from the Golija and Radan mountains (Serbia) were investigated. The chemical profiles of
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The in vitro antioxidant and antimicrobial activities of two Achillea millefolium (Adanson) Koch s.l species essential oils (A. collina Becker ex Heimerl s.l. and A. pannonica Scheele, Asteraceae) originating from the Golija and Radan mountains (Serbia) were investigated. The chemical profiles of the essential oils were evaluated by GC-MS. Antioxidant activity was assessed as free radical scavenging capacity (RSC) towards 2,2-diphenyl-1-picrylhydrazil (DPPH) radicals, together with effects on lipid peroxidation (LP). Antibacterial activity was examined on 21 bacterial strains. Based on the chemical composition of the essential oil, A. collina s.l. from Mount Golija was classified as a chamazulene chemotype (tetraploid). The high percentage of oxygenated monoterpenes and absence of azulene in the essential oil obtained from A. pannonica from Radan pointing that this population is octaploid. Essential oil of A. pannonica expressed stronger antimicrobial activity on almost all tested bacteria. Furthermore, this essential oil expressed higher scavenging effects on DPPH radical (IC50 = 0.52 comparing to 0.62 μg/mL). Only in the LP evaluation, essential oil of A. collina s.l. from Golija exhibited stronger antioxidant activity (IC50 = 0.75 comparing to 2.12 μg/mL). Full article
Open AccessArticle Microwave Synthesis of Quaternary Ammonium Salts
Molecules 2008, 13(9), 2107-2113; doi:10.3390/molecules13092107
Received: 12 August 2008 / Revised: 27 August 2008 / Accepted: 1 September 2008 / Published: 3 September 2008
Cited by 6 | PDF Full-text (184 KB) | HTML Full-text | XML Full-text
Abstract The microwave synthesis of several quaternary ammonium salts is described. The synthesis provides comparable or better yields than published methods with reduced reaction times and in the absence of solvent. Full article
Open AccessCommunication Chemical Composition, Antifungal and Antitumor Properties of Ether Extracts of Scapania verrucosa Heeg. and its Endophytic Fungus Chaetomium fusiforme
Molecules 2008, 13(9), 2114-2125; doi:10.3390/molecules13092114
Received: 19 June 2008 / Revised: 15 August 2008 / Accepted: 3 September 2008 / Published: 4 September 2008
Cited by 36 | PDF Full-text (203 KB) | HTML Full-text | XML Full-text
Abstract
An endophytic fungus Chaetomium fusiforme was obtained from a liverwort, Scapania verrucosa. A comparison of the constituents of the ether extracts between S. verrucosa and the C. fusiforme culture was investigated by gas chromatography-mass spectrometry (GC/MS). The yield of ether extract based
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An endophytic fungus Chaetomium fusiforme was obtained from a liverwort, Scapania verrucosa. A comparison of the constituents of the ether extracts between S. verrucosa and the C. fusiforme culture was investigated by gas chromatography-mass spectrometry (GC/MS). The yield of ether extract based on dried plant material was 0.6% and 59 compounds were found in S. verrucosa. (+)-Aromadendrene (9.12%), hexadecanoic acid (6.92%), 6-isopropenyl-4,8a-dimethyl-1,2,3,5,6,7,8,8a-octahydro-naphthalen-2-ol (5.97%), s-tetrachloroethane (5.61%) and acetic acid (5.30%) were found to be the most abundant components among the 49 characterized compounds in S. verrucosa, which represented 84.64% of the total extract. However, the constituents of the cultured endophyte extract contained mainly acetic acid (35.05%), valeric acid, 3-methyl-, methyl ester (21.25%), and butane-2, 3-diol (12.24%). Although the extracts of S. verrucosa and its endophyte showed little chemical composition correlation, both of them demonstrated antifungal and antitumor activities. Furthermore, C. fusiforme has displayed a wider range of antimicrobial and antitumor activities, which were better than the host plant. These results could support the suggestion of endophytes as an alternative of the host for medicinal activity. Full article
Open AccessArticle Synthesis of Schiff and Mannich Bases of Isatin Derivatives with 4-Amino-4,5-Dihydro-1H-1,2,4-Triazole-5-Ones
Molecules 2008, 13(9), 2126-2135; doi:10.3390/molecules13092126
Received: 15 August 2008 / Revised: 28 August 2008 / Accepted: 1 September 2008 / Published: 10 September 2008
Cited by 36 | PDF Full-text (188 KB) | HTML Full-text | XML Full-text
Abstract
Ethyl imidate hydrochlorides 1 were prepared by passing HCl gas through solutions of substituted benzyl cyanides and absolute ethanol. Ethoxycarbonylhydrazones 2 were synthesized from the reaction of compounds 1 with ethyl carbazate. Treatment of 2 with hydrazine hydrate leads to the formation of
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Ethyl imidate hydrochlorides 1 were prepared by passing HCl gas through solutions of substituted benzyl cyanides and absolute ethanol. Ethoxycarbonylhydrazones 2 were synthesized from the reaction of compounds 1 with ethyl carbazate. Treatment of 2 with hydrazine hydrate leads to the formation of substituted 4-amino-4,5-dihydro-1H-1,2,4-triazole-5-ones 3. Isatin and 5-chloroisatin were added to 3 to form Schiff bases 4 and N-Mannich bases 5 of these compounds were synthesized by reacting with formaldehyde and piperidine. Their chemical structures were confirmed by means of IR, 1H- and 13C-NMR data and by elemental analysis. Full article
Open AccessArticle Antifilarial Lead Molecules Isolated from Trachyspermum ammi
Molecules 2008, 13(9), 2156-2168; doi:10.3390/molecules13092156
Received: 8 August 2008 / Revised: 1 September 2008 / Accepted: 3 September 2008 / Published: 11 September 2008
Cited by 38 | PDF Full-text (199 KB) | HTML Full-text | XML Full-text
Abstract
Lymphatic filariasis is caused by infection with the parasitic filarial nematodes Wuchereria bancrofti, Brugia malayi and B. timori, transmitted by mosquitoes. The lack of an adulticidal drug poses a challenge to filariasis elimination, hence it is essential to develop an effective
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Lymphatic filariasis is caused by infection with the parasitic filarial nematodes Wuchereria bancrofti, Brugia malayi and B. timori, transmitted by mosquitoes. The lack of an adulticidal drug poses a challenge to filariasis elimination, hence it is essential to develop an effective antifilarial drug which could either kill or permanently sterilize the adult worms. In the reported work the in vitro activity of a methanolic extract of fruits of Trachyspermum ammi (Apiaceae) against adult bovine filarial Setaria digitata worms has been investigated. A bioassay-guided fractionation was carried out by subjecting the crude extract to flash chromatography. HPLC analysis was done for the crude extract and active fraction. The crude extract and the active fraction showed significant activity against the adult S. digitata by both a worm motility and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] reduction assays. The isolated active principle was chemically characterized by IR, 1H-NMR and MS analysis and identified as a phenolic monoterpene. It was screened for in vivo antifilarial activity against the human filarial worm B. malayi in Mastomys coucha, showing macrofilaricidal activity and female worm sterility in vivo against B. malayi. The findings thus provide a new lead for development of a macrofilaricidal drug from natural products Full article
Open AccessArticle Phytochemical Contents and Antioxidant Capacities of Two Aloe greatheadii var. davyana Extracts
Molecules 2008, 13(9), 2169-2180; doi:10.3390/molecules13092169
Received: 10 June 2008 / Revised: 22 August 2008 / Accepted: 23 August 2008 / Published: 12 September 2008
Cited by 34 | PDF Full-text (190 KB) | HTML Full-text | XML Full-text
Abstract
Aloe greatheadii var. davyana (Asphodelaceae) is used among rural South African communities to treat arthritis, skin cancer, burns, eczema, psoriasis, digestive problems, high blood pressure and diabetes, despite very little supporting scientific evidence. Due to increased interest by both the scientific community and
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Aloe greatheadii var. davyana (Asphodelaceae) is used among rural South African communities to treat arthritis, skin cancer, burns, eczema, psoriasis, digestive problems, high blood pressure and diabetes, despite very little supporting scientific evidence. Due to increased interest by both the scientific community and industry regarding the medicinal uses of this plant species, we identified, quantified and compared the phytochemical contents and antioxidant capacities of two extracts of A. greatheadii; a leaf gel extract (LGE) and a 95 % aqueous ethanol leaf gel extract (ELGE), using various modified extraction procedures, GC-MS and spectrophotometry. Apart from extensively characterizing this medicinal plant with regards to its organic acid, polyphenols/phenolic acid, alcohol, aldehyde, ketone, alkane, pyrimidine, indole, alkaloid, phytosterol, fatty acid and dicarboxylic acid contents and antioxidant capacities, we describe a modified extraction procedure for the purpose of general phytochemical characterization, and compare this to a 95 % aqueous ethanol extraction technique. From the results it is clear that A. greatheadii contains a variety of compounds with confirmed antioxidant capacity and other putative health benefits (such as blood glucose, cholesterol and cortisol lowering properties) relating to the prevention or treatment of diabetes, cardiovascular disease, cancer and hypertension. The results also indicate that separate ethyl acetate/diethyl ether and hexane extractions of the LGE, better serve for general phytochemical characterization purposes, and 95 % aqueous ethanol extraction for concentrating selective groups of health related compounds, hence justifying its use for biological in vivo efficacy studies. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Phytochemical Analysis of the Essential Oil from Botanically Certified Oleogum Resin of Boswellia sacra (Omani Luban)
Molecules 2008, 13(9), 2181-2189; doi:10.3390/molecules13092181
Received: 27 August 2008 / Revised: 10 September 2008 / Accepted: 10 September 2008 / Published: 16 September 2008
Cited by 24 | PDF Full-text (178 KB) | HTML Full-text | XML Full-text
Abstract
The yield of hydrodistillation of a botanically certified Oleogum Resin of Boswellia sacra essential oil (5.5%); and its chemical constituents were determined. The GC/MS technique was used for the analysis of the oil. Several oil components were identified based upon comparison of their
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The yield of hydrodistillation of a botanically certified Oleogum Resin of Boswellia sacra essential oil (5.5%); and its chemical constituents were determined. The GC/MS technique was used for the analysis of the oil. Several oil components were identified based upon comparison of their mass spectral data with those of reference compounds published in literature or stored in a computer library. The oil was characterized by the high content of the monoterpenes (34) which constituted 97.3% in which E-β-ocimene and limonene were the major constituents. The remaining 2.7% was accounted for the sesquiterpenes (16) in which the E-caryophyllene was the major constituent. The analysis proved the complete absence of the diterpenes. Full article
Open AccessArticle Evaluation of Flavonoids and Furanocoumarins from Citrus bergamia (Bergamot) Juice and Identification of New Compounds
Molecules 2008, 13(9), 2220-2228; doi:10.3390/molecules13092220
Received: 1 August 2008 / Revised: 1 September 2008 / Accepted: 9 September 2008 / Published: 18 September 2008
Cited by 20 | PDF Full-text (326 KB) | HTML Full-text | XML Full-text
Abstract
Bergamot juice (BJ) contains different classes of flavonoids (e.g. flavanones and flavones) that can exert beneficial effects on human health. The aim of this study was to evaluate the qualitative and quantitative composition of a BJ obtained from fruits harvested in Southern Italy
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Bergamot juice (BJ) contains different classes of flavonoids (e.g. flavanones and flavones) that can exert beneficial effects on human health. The aim of this study was to evaluate the qualitative and quantitative composition of a BJ obtained from fruits harvested in Southern Italy (Calabria) at the end of their maturation period. The identity of several flavonoids and furanocoumarins was assessed by co-chromatography, UV spectra and molecular weight comparison. The unknown compounds were dissociated by induced collision (CID-MS) and their identity established through the characteristic ions product. By this approach a complete profile of about twenty compounds (furano-coumarins, flavonoids C- and O-glycosides) present in BJ was obtained. Furthermore, three acylated flavanones, present in amounts of 20.1±1.1, 89.3±2.2 and 190.1±3.1 mg/L, respectively, and which seem to correspond to di-oxalate derivatives of neoeriocitrin, naringin and neohesperidin, were identified for the first time in BJ. The other main flavanones were naringin, neohesperidin and neoeriocitrin, and their content was 167.5±1.8, 123.9±1.7 and 73.3±1.6 mg/L, respectively. Concerning flavones, the total amount in BJ was about 160 mg/L and the main ones were vicenin-2, stellarin-2, rhoifolin and neodiosmin. Bergapten and bergamottin were the primary furanocoumarins in BJ and their amounts were 9.0±0.4 and 18.2±0.5 mg/L, respectively. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle New Triterpene Glucosides from the Roots of Rosa laevigata Michx
Molecules 2008, 13(9), 2229-2237; doi:10.3390/molecules13092229
Received: 18 August 2008 / Revised: 11 September 2008 / Accepted: 12 September 2008 / Published: 22 September 2008
Cited by 11 | PDF Full-text (288 KB) | HTML Full-text | XML Full-text
Abstract
Two new ursane-type triterpene glucosides, 2α,3α,24-trihydroxyurs-12,18-dien-28-oic acid β-D-glucopyranosyl ester (1) and 2α,3α,23-trihydroxyurs-12,19(29)-dien-28-oic acid β-D-glucopyranosyl ester (2), were isolated from the roots of Rosa laevigata, together with three known compounds: 2α,3β,19α-trihydroxyurs-12-en-28-oic acid β-Dglucopyranosyl ester (3), 2α,3α,19α-trihydroxyurs-12-en-28-oic acid β-D-glucopyranosyl ester (4) and 2α,3β,19α,23-tetrahydroxyurs-12-en-28-oic acid
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Two new ursane-type triterpene glucosides, 2α,3α,24-trihydroxyurs-12,18-dien-28-oic acid β-D-glucopyranosyl ester (1) and 2α,3α,23-trihydroxyurs-12,19(29)-dien-28-oic acid β-D-glucopyranosyl ester (2), were isolated from the roots of Rosa laevigata, together with three known compounds: 2α,3β,19α-trihydroxyurs-12-en-28-oic acid β-Dglucopyranosyl ester (3), 2α,3α,19α-trihydroxyurs-12-en-28-oic acid β-D-glucopyranosyl ester (4) and 2α,3β,19α,23-tetrahydroxyurs-12-en-28-oic acid β-D-glucopyranosyl ester (5). The structures of new compounds were established on the basis of detailed 1D and 2D NMR spectroscopic analyses. Compounds 2 and 5 exhibited modest in vitro antifungal activities against Candida albicans and C. krusei. Full article
Open AccessArticle Design and Synthesis of Immunoconjugates and Development of an Indirect ELISA for Rapid Detection of 3, 5-Dinitrosalicyclic Acid Hydrazide
Molecules 2008, 13(9), 2238-2248; doi:10.3390/molecules13092238
Received: 22 August 2008 / Revised: 14 September 2008 / Accepted: 16 September 2008 / Published: 23 September 2008
Cited by 12 | PDF Full-text (227 KB) | HTML Full-text | XML Full-text
Abstract
In this study novel immunoconjugates were designed, synthesized and then used to develop a rapid, specific and sensitive indirect ELISA method to directly detect residues of 3,5-dinitrosalicyclic acid hydrazide (DNSH), a toxic metabolite of nifursol present in chicken tissues. The hapten DNSHA was
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In this study novel immunoconjugates were designed, synthesized and then used to develop a rapid, specific and sensitive indirect ELISA method to directly detect residues of 3,5-dinitrosalicyclic acid hydrazide (DNSH), a toxic metabolite of nifursol present in chicken tissues. The hapten DNSHA was first designed and used to covalently couple to BSA to form an immunogen which was immunized to rabbits to produce a polyclonal antibody against DNSH. Furthermore, a novel 3,5-dinitrosalicylic acidovalbumin (DNSA-OVA) immunoconjugate structurally different from DNSHA-OVA was designed and used as a “substructural coating antigen” to improve the sensitivity of an indirect ELISA analysis for a direct DNSH detection. Based on the “substructural coating antigen” concept, an optimized indirect ELISA method was established that exhibited good specificity and high sensitivity for detecting DNSH, with a cross-reactivity of less than 0.1% (excluding the parent compound nifursol), IC50 of 0.217 nmol/mL and detection limit of 0.018 nmol/mL. Finally, a simple and efficient analysis of DNSH samples in chicken tissues showed that the average recovery rate of the indirect ELISA analysis was 82.3%, with the average coefficient of variation 15.9%. Thus, the developed indirect ELISA method exhibited the potential for a rapid detection of DNSH residues in tissue. Full article
Open AccessArticle Effects of Various Drugs on Alcohol-induced Oxidative Stress in the Liver
Molecules 2008, 13(9), 2249-2259; doi:10.3390/molecules13092249
Received: 11 August 2008 / Revised: 8 September 2008 / Accepted: 12 September 2008 / Published: 23 September 2008
Cited by 9 | PDF Full-text (200 KB) | HTML Full-text | XML Full-text
Abstract
The major aim of this work was to investigate how alcohol-induced oxidative stress in combined chemotherapy changes the metabolic function of the liver in experimental animals. This research was conducted to establish how bromocriptine, haloperidol and azithromycin, applied to the experimental model, affected
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The major aim of this work was to investigate how alcohol-induced oxidative stress in combined chemotherapy changes the metabolic function of the liver in experimental animals. This research was conducted to establish how bromocriptine, haloperidol and azithromycin, applied to the experimental model, affected the antioxidative status of the liver. The following parameters were determined: reduced glutathione, activities of glutathione peroxidase, glutathione reductase, peroxidase, catalase, xanthine oxidase and lipid peroxidation intensity. Alanine transaminase was measured in serum. Alcohol stress (AO group) reduced glutathione and the activity of xanthine oxidase and glutathione peroxidase, but increased catalase and alanine transaminase activity. The best protective effect was achieved with the bromocriptine (AB1 group), while other groups had similar effects on the studied parameters. Full article
Open AccessCommunication Isoquinoline Alkaloids Isolated from Corydalis yanhusuo and Their Binding Affinities at the Dopamine D1 Receptor
Molecules 2008, 13(9), 2303-2312; doi:10.3390/molecules13092303
Received: 29 August 2008 / Revised: 15 September 2008 / Accepted: 16 September 2008 / Published: 25 September 2008
Cited by 33 | PDF Full-text (231 KB) | HTML Full-text | XML Full-text
Abstract
Bioactivity-guided fractionation of Corydalis yanhusuo has resulted in the isolation of eight known isoquinoline alkaloids - tetrahydropalmatine, isocorypalmine, stylopine, corydaline, columbamine, coptisin, 13-methylpalmatine, and dehydrocorybulbine. The tertiary alkaloids were further analyzed by chiral HPLC to determine the ratios of d-and l-isomers.
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Bioactivity-guided fractionation of Corydalis yanhusuo has resulted in the isolation of eight known isoquinoline alkaloids - tetrahydropalmatine, isocorypalmine, stylopine, corydaline, columbamine, coptisin, 13-methylpalmatine, and dehydrocorybulbine. The tertiary alkaloids were further analyzed by chiral HPLC to determine the ratios of d-and l-isomers. The isolated compounds were screened for their binding affinities at the dopamine D1 receptor. Isocorypalmine had the highest affinity (Ki = 83 nM). The structure-affinity relationships of these alkaloids are discussed. Full article
Open AccessArticle Efficient TCT-catalyzed Synthesis of 1,5-Benzodiazepine Derivatives under Mild Conditions
Molecules 2008, 13(9), 2313-2325; doi:10.3390/molecules13092313
Received: 22 August 2008 / Revised: 10 September 2008 / Accepted: 10 September 2008 / Published: 25 September 2008
Cited by 21 | PDF Full-text (304 KB) | HTML Full-text | XML Full-text
Abstract
2,4,6-Trichloro-1,3,5-triazine (TCT) efficiently catalyzed the condensation reactions between 1,2-diamines and various enolizable ketones to afford 1,5-benzodiazepines in good to excellent yields. Simple and mild reaction conditions, the use of a cheap catalyst and easy workup and isolation are notable features of this method.
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2,4,6-Trichloro-1,3,5-triazine (TCT) efficiently catalyzed the condensation reactions between 1,2-diamines and various enolizable ketones to afford 1,5-benzodiazepines in good to excellent yields. Simple and mild reaction conditions, the use of a cheap catalyst and easy workup and isolation are notable features of this method. Full article
Open AccessArticle Imidazole-based Potential Bi- and Tridentate Nitrogen Ligands: Synthesis, Characterization and Application in Asymmetric Catalysis
Molecules 2008, 13(9), 2326-2339; doi:10.3390/molecules13092326
Received: 2 September 2008 / Revised: 10 September 2008 / Accepted: 12 September 2008 / Published: 25 September 2008
Cited by 9 | PDF Full-text (591 KB) | HTML Full-text | XML Full-text
Abstract
Twelve new imidazole-based potential bi- and tridentate ligands were synthesized and characterized. Whereas in the first series the α-amino acid and imidazole moieties were linked by an amino bond, in the second series the tridentate ligands, containing two imidazole groups, were separated by
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Twelve new imidazole-based potential bi- and tridentate ligands were synthesized and characterized. Whereas in the first series the α-amino acid and imidazole moieties were linked by an amino bond, in the second series the tridentate ligands, containing two imidazole groups, were separated by an amide bond. The first series was obtained by the reductive amination of 2-phenylimidazole-4-carboxaldehyde with α-amino acid esters. The tridentate ligands were prepared from 2-phenylimidazole-4-carboxylic acid and chiral amines. In the Henry reaction, the amines were revealed as a more reactive species than the less nucleophilic amides, however the enantiomeric excesses were generally poor. Full article

Review

Jump to: Research

Open AccessReview Marine Derived Polysaccharides for Biomedical Applications: Chemical Modification Approaches
Molecules 2008, 13(9), 2069-2106; doi:10.3390/molecules13092069
Received: 26 May 2008 / Revised: 2 July 2008 / Accepted: 25 July 2008 / Published: 3 September 2008
Cited by 148 | PDF Full-text (1479 KB) | HTML Full-text | XML Full-text
Abstract
Polysaccharide-based biomaterials are an emerging class in several biomedical fields such as tissue regeneration, particularly for cartilage, drug delivery devices and gelentrapment systems for the immobilization of cells. Important properties of the polysaccharides include controllable biological activity, biodegradability, and their ability to form
[...] Read more.
Polysaccharide-based biomaterials are an emerging class in several biomedical fields such as tissue regeneration, particularly for cartilage, drug delivery devices and gelentrapment systems for the immobilization of cells. Important properties of the polysaccharides include controllable biological activity, biodegradability, and their ability to form hydrogels. Most of the polysaccharides used derive from natural sources; particularly, alginate and chitin, two polysaccharides which have an extensive history of use in medicine, pharmacy and basic sciences, and can be easily extracted from marine plants (algae kelp) and crab shells, respectively. The recent rediscovery of poly-saccharidebased materials is also attributable to new synthetic routes for their chemical modification, with the aim of promoting new biological activities and/or to modify the final properties of the biomaterials for specific purposes. These synthetic strategies also involve the combination of polysaccharides with other polymers. A review of the more recent research in the field of chemical modification of alginate, chitin and its derivative chitosan is presented. Moreover, we report as case studies the results of our recent work concerning various different approaches and applications of polysaccharide-based biomaterials, such as the realization of novel composites based on calcium sulphate blended with alginate and with a chemically modified chitosan, the synthesis of novel alginate-poly(ethylene glycol) copolymers and the development of a family of materials based on alginate and acrylic polymers of potential interest as drug delivery systems. Full article
Open AccessReview In Vitro and In Vivo Evaluation of Microparticulate Drug Delivery Systems Composed of Macromolecular Prodrugs
Molecules 2008, 13(9), 2136-2155; doi:10.3390/molecules13092136
Received: 21 June 2008 / Revised: 25 August 2008 / Accepted: 27 August 2008 / Published: 10 August 2008
Cited by 12 | PDF Full-text (585 KB) | HTML Full-text | XML Full-text
Abstract
Macromolecular prodrugs are very useful systems for achieving controlled drug release and drug targeting. In particular, various macromolecule-antitumor drug conjugates enhance the effectiveness and improve the toxic side effects. Also, polymeric micro- and nanoparticles have been actively examined and their in vivo behaviors
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Macromolecular prodrugs are very useful systems for achieving controlled drug release and drug targeting. In particular, various macromolecule-antitumor drug conjugates enhance the effectiveness and improve the toxic side effects. Also, polymeric micro- and nanoparticles have been actively examined and their in vivo behaviors elucidated, and it has been realized that their particle characteristics are very useful to control drug behavior. Recently, researches based on the combination of the concepts of macromolecular prodrugs and micro- or nanoparticles have been reported, although they are limited. Macromolecular prodrugs enable drugs to be released at a certain controlled release rate based on the features of the macromolecule-drug linkage. Micro- and nanoparticles can control in vivo behavior based on their size, surface charge and surface structure. These merits are expected for systems produced by the combination of each concept. In this review, several micro- or nanoparticles composed of macromolecule-drug conjugates are described for their preparation, in vitro properties and/or in vivo behavior. Full article
Open AccessReview Polyphenols in Cocoa and Cocoa Products: Is There a Link between Antioxidant Properties and Health?
Molecules 2008, 13(9), 2190-2219; doi:10.3390/molecules13092190
Received: 16 August 2008 / Revised: 29 August 2008 / Accepted: 2 September 2008 / Published: 16 September 2008
Cited by 52 | PDF Full-text (272 KB) | HTML Full-text | XML Full-text
Abstract
Cocoa and cocoa products have received much attention due to their significant polyphenol contents. Cocoa and cocoa products, namely cocoa liquor, cocoa powder and chocolates (milk and dark chocolates) may present varied polyphenol contents and possess different levels of antioxidant potentials. For the
[...] Read more.
Cocoa and cocoa products have received much attention due to their significant polyphenol contents. Cocoa and cocoa products, namely cocoa liquor, cocoa powder and chocolates (milk and dark chocolates) may present varied polyphenol contents and possess different levels of antioxidant potentials. For the past ten years, at least 28 human studies have been conducted utilizing one of these cocoa products. However, questions arise on which of these products would deliver the best polyphenol contents and antioxidant effects. Moreover, the presence of methylxanthines, peptides, and minerals could synergistically enhance or reduce antioxidant properties of cocoa and cocoa products. To a greater extent, cocoa beans from different countries of origins and the methods of preparation (primary and secondary) could also partially influence the antioxidant polyphenols of cocoa products. Hence, comprehensive studies on the aforementioned factors could provide the understanding of health-promoting activities of cocoa or cocoa products components. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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Open AccessReview Useful Spectrokinetic Methods for the Investigation of Photochromic and Thermo-Photochromic Spiropyrans
Molecules 2008, 13(9), 2260-2302; doi:10.3390/molecules13092260
Received: 14 August 2008 / Revised: 19 September 2008 / Accepted: 19 September 2008 / Published: 25 September 2008
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Abstract
This review reports on the main results of a set of kinetic elucidation methods developed by our team over the last few years. Formalisms, procedures and examples to solve all possible AB photochromic and thermophotochromic kinetics are presented. Also, discussions of the operating
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This review reports on the main results of a set of kinetic elucidation methods developed by our team over the last few years. Formalisms, procedures and examples to solve all possible AB photochromic and thermophotochromic kinetics are presented. Also, discussions of the operating conditions, the continuous irradiation experiment, the spectrokinetic methods testing with numerical integration methods, and the identifiability/distinguishability problems, are included. Full article
(This article belongs to the Special Issue Spiro Compounds)

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