Molecules

845 KiB

Open AccessReview

Asymmetric Synthesis of Naturally Occuring Spiroketals

by B. Rama Raju and Anil K. Saikia

Molecules 2008, 13(8), 1942-2038; https://doi.org/10.3390/molecules13081942 - 28 Aug 2008

Cited by 81 | Viewed by 16095

Spiroketals are widely found as substructures of many naturally occurring compounds from diverse sources including plants, animals as well as microbes. Naturally occurring spiroketals are biologically active and most of them are chiral molecules. This article aims at reviewing the asymmetric synthesis of [...] Read more.

Spiroketals are widely found as substructures of many naturally occurring compounds from diverse sources including plants, animals as well as microbes. Naturally occurring spiroketals are biologically active and most of them are chiral molecules. This article aims at reviewing the asymmetric synthesis of biologically active spiroketals for last 10 years (1998-2007). Full article

(This article belongs to the Special Issue Spiro Compounds)

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226 KiB

Open AccessArticle

Flavonoids and a New Polyacetylene from Bidens parviflora Willd

by Yu-Lan Li, Jun Li, Nai-Li Wang and Xin-Sheng Yao

Molecules 2008, 13(8), 1931-1941; https://doi.org/10.3390/molecules13081931 - 28 Aug 2008

Cited by 186 | Viewed by 16651

Abstract

Fifteen flavonoids, 1-7 and 9-16, and a polyacetylene, 8, were isolated from the ethanol extract of the dried whole plant of Bidens parviflora Willd. by various chromatographic techniques. Their structures have been elucidated on the basis of spectroscopic analyses and chemical studies. Compound [...] Read more.

Fifteen flavonoids, 1-7 and 9-16, and a polyacetylene, 8, were isolated from the ethanol extract of the dried whole plant of Bidens parviflora Willd. by various chromatographic techniques. Their structures have been elucidated on the basis of spectroscopic analyses and chemical studies. Compound 8 is new and was identified as 3-(R),8(E)-decene-4,6-diyne-1,3,10-triol. All the flavonoid compounds were isolated for the first time from this plant species. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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264 KiB

Open AccessCommunication

A New 3-Benzylchroman Derivative from Sappan Lignum (Caesalpinia sappan)

by Lin-chun Fu, Xin-an Huang, Zhen-yuan Lai, Ying-jie Hu, Hong-jiao Liu and Xiao-ling Cai

Molecules 2008, 13(8), 1923-1930; https://doi.org/10.3390/molecules13081923 - 28 Aug 2008

Cited by 63 | Viewed by 15265

Abstract

3'-Deoxy-4-O-methylepisappanol, a new 3-benzylchroman derivative, was isolated from Sappan Lignum, together with thirteen known chemical compounds identified as protosappanin A, sappanchalcone, sappanone B, palmitic acid, (+)-(8S,8'S)-bisdihydrosiringenin, brazilein, 3-deoxysappanchalcone, (+)-lyoniresinol, 3-deoxysappanone B, protosappanin B, isoprotosappanin B, 3'-O-methylbrazilin and brazilin, respectively. Among these known compounds, [...] Read more.

3'-Deoxy-4-O-methylepisappanol, a new 3-benzylchroman derivative, was isolated from Sappan Lignum, together with thirteen known chemical compounds identified as protosappanin A, sappanchalcone, sappanone B, palmitic acid, (+)-(8S,8'S)-bisdihydrosiringenin, brazilein, 3-deoxysappanchalcone, (+)-lyoniresinol, 3-deoxysappanone B, protosappanin B, isoprotosappanin B, 3'-O-methylbrazilin and brazilin, respectively. Among these known compounds, this is the first time that (+)-(8S,8'S)-bisdihydrosiringenin was obtained from the family Caesalpiniaceae. Full article

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289 KiB

Open AccessReview

Efficacy of the Oral Fluorouracil Pro-drug Capecitabine in Cancer Treatment: a Review

by Georgios V. Koukourakis, Vassilios Kouloulias, Michael J. Koukourakis, Georgios A. Zacharias, Haralabos Zabatis and John Kouvaris

Molecules 2008, 13(8), 1897-1922; https://doi.org/10.3390/molecules13081897 - 27 Aug 2008

Cited by 72 | Viewed by 15701

Abstract

Capecitabine (Xeloda®) was developed as a pro-drug of fluorouracil (FU), with the aim of improving tolerability and intratumor drug concentrations through its tumorspecific conversion to the active drug. The purpose of this paper is to review the available information on capecitabine, focusing on [...] Read more.

Capecitabine (Xeloda®) was developed as a pro-drug of fluorouracil (FU), with the aim of improving tolerability and intratumor drug concentrations through its tumorspecific conversion to the active drug. The purpose of this paper is to review the available information on capecitabine, focusing on its clinical effectiveness against various carcinomas. Identification of all eligible English trails was made by searching the PubMed and Cochrane databases from 1980 to 2007. Search terms included capecitabine, Xeloda and cancer treatment. Nowadays, FDA has approved the use of capecitabine as a first line therapy in patients with metastatic colorectal cancer when single-agent fluoropyrimidine is preferred. The drug is also approved for use as a single agent in metastatic breast cancer patients who are resistant to both anthracycline and paclitaxel-based regimens or when further anthracycline treatment is contraindicated. It is also approved in combination with docetaxel after failure of prior anthracycline-based chemotherapy. In patients with prostate, pancreatic, renal cell and ovarian carcinomas, capecitabine as a single-agent or in combination with other drugs has also shown benefits. Improved tolerability and comparable efficacy, compared with the intravenous FU/LV combination, in addition to its oral administration, make capecitabine an attractive option for the treatment of several types of carcinomas. Full article

(This article belongs to the Special Issue 5-Fluorouracil)

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410 KiB

Open AccessReview

Rigorous Biogenetic Network for a Group of Indole Alkaloids Derived from Strictosidine

by László F. Szabó

Molecules 2008, 13(8), 1875-1896; https://doi.org/10.3390/molecules13081875 - 27 Aug 2008

Cited by 86 | Viewed by 16604

Abstract

Strictosidine, the precursor of more than 2,500 indole alkaloids, was isolated from four species of three plant families. By searching the Dictionary of Natural Products on DVD it was found that about 150 indole alkaloids were obtained from the same species (coalkaloids), which [...] Read more.

Strictosidine, the precursor of more than 2,500 indole alkaloids, was isolated from four species of three plant families. By searching the Dictionary of Natural Products on DVD it was found that about 150 indole alkaloids were obtained from the same species (coalkaloids), which is a direct proof of their common origin. On the base of their threedimensional structure, taxonomic properties and standard reaction mechanisms an extended network was established which involved the four fundamental skeletons, the three types of carbon framework in the secologanin subunit and all major groups of indole alkaloids derived from secologanin and tryptamine (except a few minor groups, in which only less then 10 alkaloids were known). The system was extended to the heterodimer indole alkaloids and the quinoindole alkaloids as well. Full article

(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)

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224 KiB

Open AccessArticle

Evaluation of the Chemical Composition of Brazilian Commercial Cymbopogon citratus (D.C.) Stapf Samples

by Luiz Cláudio Almeida Barbosa, Ulisses Alves Pereira, Ana Paula Martinazzo, Célia Regina Álvares Maltha, Róbson Ricardo Teixeira and Evandro De Castro Melo

Molecules 2008, 13(8), 1864-1874; https://doi.org/10.3390/molecules13081864 - 27 Aug 2008

Cited by 100 | Viewed by 13856

Abstract

The concentration and the chemical composition of the essential oils obtained from different samples of Cymbopogon citratus were evaluated. Among the 12 samples investigated (11 dried leaf samples and fresh plant leaves), seven presented essential oil concentrations within the threshold established by the [...] Read more.

The concentration and the chemical composition of the essential oils obtained from different samples of Cymbopogon citratus were evaluated. Among the 12 samples investigated (11 dried leaf samples and fresh plant leaves), seven presented essential oil concentrations within the threshold established by the Brazilian legislation. The moisture content was also determined and the majority of the samples presented humidity contents near 12%. The GC and GC/MS analyses of the essential oils led to identification of 22 compounds, with neral and geranial as the two major components. The total percentage of these two compounds varied within the investigated sample oils from 40.7% to 75.4%. In addition, a considerable variation in the chemical composition of the analyzed samples was observed. The process of grinding the leaves significantly decreased (by up to 68%) the essential oil content, as well as the percentage of myrcene in the oils. Full article

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424 KiB

Open AccessArticle

Oligomerization of Indole Derivatives with Incorporation of Thiols

by Felikss Mutulis, Adolf Gogoll, Ilze Mutule, Sviatlana Yahorava, Aleh Yahorau, Edvards Liepinsh and Jarl E.S. Wikberg

Molecules 2008, 13(8), 1846-1863; https://doi.org/10.3390/molecules13081846 - 26 Aug 2008

Cited by 1 | Viewed by 11295

Abstract

Two molecules of indole derivative, e.g. indole-5-carboxylic acid, reacted with one molecule of thiol, e.g. 1,2-ethanedithiol, in the presence of trifluoroacetic acid to yield adducts such as 3-[2-(2-amino-5-carboxyphenyl)-1-(2-mercaptoethylthio)ethyl]-1Hindole-5-carboxylic acid. Parallel formation of dimers, such as 2,3-dihydro-1H,1'H-2,3'-biindole-5,5'-dicarboxylic acid and trimers, such as 3,3'-[2-(2-amino-5-carboxyphenyl) ethane-1,1-diyl]bis(1H-indole-5-carboxylic [...] Read more.

Two molecules of indole derivative, e.g. indole-5-carboxylic acid, reacted with one molecule of thiol, e.g. 1,2-ethanedithiol, in the presence of trifluoroacetic acid to yield adducts such as 3-[2-(2-amino-5-carboxyphenyl)-1-(2-mercaptoethylthio)ethyl]-1Hindole-5-carboxylic acid. Parallel formation of dimers, such as 2,3-dihydro-1H,1'H-2,3'-biindole-5,5'-dicarboxylic acid and trimers, such as 3,3'-[2-(2-amino-5-carboxyphenyl) ethane-1,1-diyl]bis(1H-indole-5-carboxylic acid) of the indole derivatives was also observed. Reaction of a mixture of indole and indole-5-carboxylic acid with 2-phenylethanethiol proceeded in a regioselective way, affording 3-[2-(2-aminophenyl)-1-(phenethylthio)ethyl]-1H-indole-5-carboxylic acid. An additional product of this reaction was 3-[2-(2-aminophenyl)-1-(phenethylthio)ethyl]-2,3-dihydro-1H,1'H-2,3'-biindole-5'-carboxylic acid, which upon standing in DMSO-d6 solution gave 3-[2-(2-aminophenyl)-1-(phenethylthio)ethyl]-1H,1'H-2,3'-biindole-5'-carboxylic acid. Structures of all compounds were elucidated by NMR, and a mechanism for their formation was suggested. Full article

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203 KiB

Open AccessArticle

Synthesis of a Novel D-Glucose-Conjugated 15-Crown-5 Ether with a Spiro Ketal Structure

by Takashi Yamanoi, Yoshiki Oda, Hitomi Muraishi and Sho Matsuda

Molecules 2008, 13(8), 1840-1845; https://doi.org/10.3390/molecules13081840 - 22 Aug 2008

Cited by 7 | Viewed by 9029

Abstract

This paper describes a synthetic approach to a novel D-glucose-conjugated 15-crown-5 ether having a spiroketal structure starting from a 1-C-vinylated glucose derivative. The approach consists of the glycosylation of the vinylated glucose derivative to give an ethyleneoxy spacer derivative using bismuth(III) triflate, the [...] Read more.

This paper describes a synthetic approach to a novel D-glucose-conjugated 15-crown-5 ether having a spiroketal structure starting from a 1-C-vinylated glucose derivative. The approach consists of the glycosylation of the vinylated glucose derivative to give an ethyleneoxy spacer derivative using bismuth(III) triflate, the conversion of the 1-C-vinyl group of the glucoside produced into a carboxylic acid group, and the intramolecular condensation between the carboxyl group and the terminal hydroxyl group in the ethyleneoxy spacer. A D-glucose-conjugated 15-crown-5 ether having a unique spiroketal structure was thus successfully synthesized. Full article

(This article belongs to the Special Issue Spiro Compounds)

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1424 KiB

Open AccessArticle

CoMFA, CoMSIA and Eigenvalue Analysis on Dibenzodioxepinone and Dibenzodioxocinone Derivatives as Cholesteryl Ester Transfer Protein Inhibitors

by Xu-qiong Xiong, Dong-mei Zhao, Peng-fei Bu, Yang Liu, Jin-hong Ren, Jian Wang and Mao-sheng Cheng

Molecules 2008, 13(8), 1822-1839; https://doi.org/10.3390/molecules13081822 - 22 Aug 2008

Cited by 5 | Viewed by 14416

Abstract

CoMFA, CoMSIA and eigenvalue analysis (EVA) were performed to study the structural features of 61 diverse dibenzodioxepinone and dibenzodioxocinone analogues to probe cholesteryl ester transfer protein (CETP) inhibitory activity. Three methods yielded statistically significant models upon assessment of cross-validation, bootstrapping, and progressive scrambling. [...] Read more.

CoMFA, CoMSIA and eigenvalue analysis (EVA) were performed to study the structural features of 61 diverse dibenzodioxepinone and dibenzodioxocinone analogues to probe cholesteryl ester transfer protein (CETP) inhibitory activity. Three methods yielded statistically significant models upon assessment of cross-validation, bootstrapping, and progressive scrambling. This was further validated by an external set of 13 derivatives. Our results demonstrate that three models have a good interpolation as well as extrapolation. The hydrophobic features were confirmed to contribute significantly to inhibitor potencies, while a pre-oriented hydrogen bond provided by the hydroxyl group at the 3-position indicated a good correlation with previous SAR, and a hydrogen bond acceptor may play a crucial role in CETP inhibition. These derived models may help us to gain a deeper understanding of the binding interaction of these lactone-based compounds and aid in the design of new potent compounds against CETP. Full article

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161 KiB

Open AccessCommunication

Synthesis of RP 48497, an Impurity of Eszopiclone

by Yu Sharov, Lei Zhang, Gui-Jie Du, Jian Ren and Mao-Sheng Cheng

Molecules 2008, 13(8), 1817-1821; https://doi.org/10.3390/molecules13081817 - 22 Aug 2008

Cited by 3 | Viewed by 11462

Abstract

RP 48497 is a photodegradation product of eszopiclone, a non-benzodiazepine sedative-hypnotic used in the treatment of insomnia. We report herein the first synthesis of RP 48497 via reduction, chlorination, and recyclization of 6-(5-chloropyridin-2-yl)-7-hydroxy-6,7-dihydropyrrolo[3,4-b]pyrazin-5-one (3), a key intermediate in the synthesis of eszopiclone. The [...] Read more.

RP 48497 is a photodegradation product of eszopiclone, a non-benzodiazepine sedative-hypnotic used in the treatment of insomnia. We report herein the first synthesis of RP 48497 via reduction, chlorination, and recyclization of 6-(5-chloropyridin-2-yl)-7-hydroxy-6,7-dihydropyrrolo[3,4-b]pyrazin-5-one (3), a key intermediate in the synthesis of eszopiclone. The structure of RP 48497 was confirmed by its ¹H-NMR and MS data. The mechanism of the reduction step in the synthesis of RP 48497 was also studied and the key parameters were determined. These findings should be important for quality control purposes in the manufacture of eszopiclone. Full article

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1744 KiB

Open AccessReview

Trehalose and Trehalose-based Polymers for Environmentally Benign, Biocompatible and Bioactive Materials

by Naozumi Teramoto, Navzer D. Sachinvala and Mitsuhiro Shibata

Molecules 2008, 13(8), 1773-1816; https://doi.org/10.3390/molecules13081773 - 21 Aug 2008

Cited by 115 | Viewed by 30384

Abstract

Trehalose is a non-reducing disaccharide that is found in many organisms but not in mammals. This sugar plays important roles in cryptobiosis of selaginella mosses, tardigrades (water bears), and other animals which revive with water from a state of suspended animation induced by [...] Read more.

Trehalose is a non-reducing disaccharide that is found in many organisms but not in mammals. This sugar plays important roles in cryptobiosis of selaginella mosses, tardigrades (water bears), and other animals which revive with water from a state of suspended animation induced by desiccation. The interesting properties of trehalose are due to its unique symmetrical low-energy structure, wherein two glucose units are bonded face-to-face by 1→1-glucoside links. The Hayashibara Co. Ltd., is credited for developing an inexpensive, environmentally benign and industrial-scale process for the enzymatic conversion of α-1,4-linked polyhexoses to α,α-D-trehalose, which made it easy to explore novel food, industrial, and medicinal uses for trehalose and its derivatives. Trehalosechemistry is a relatively new and emerging field, and polymers of trehalose derivatives appear environmentally benign, biocompatible, and biodegradable. The discriminating properties of trehalose are attributed to its structure, symmetry, solubility, kinetic and thermodynamic stability and versatility. While syntheses of trehalose-based polymer networks can be straightforward, syntheses and characterization of well defined linear polymers with tailored properties using trehalose-based monomers is challenging, and typically involves protection and deprotection of hydroxyl groups to attain desired structural, morphological, biological, and physical and chemical properties in the resulting products. In this review, we will overview known literature on trehalose’s fascinating involvement in cryptobiology; highlight its applications in many fields; and then discuss methods we used to prepare new trehalose-based monomers and polymers and explain their properties. Full article

(This article belongs to the Special Issue Polysaccharides: Organic Chemistry, Bioactivity and Analysis, including Those from Medicinal Plants and Fungi)

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226 KiB

Open AccessArticle

Amifostine Protection Against Mitomycin-induced Chromosomal Breakage in Fanconi Anaemia Lymphocytes

by Ricardo M. Camelo, Fernanda S. G. Kehdy, Carlos E. Salas and Miriam T. P. Lopes

Molecules 2008, 13(8), 1759-1772; https://doi.org/10.3390/molecules13081759 - 21 Aug 2008

Cited by 10 | Viewed by 10613

Abstract

Fanconi anaemia (FA) is a rare genetic chromosomal instability syndrome caused by impairment of DNA repair and reactive oxygen species (ROS) imbalance. This disease is also related to bone marrow failure and cancer. Treatment of these complications with radiation and alkylating agents may [...] Read more.

Fanconi anaemia (FA) is a rare genetic chromosomal instability syndrome caused by impairment of DNA repair and reactive oxygen species (ROS) imbalance. This disease is also related to bone marrow failure and cancer. Treatment of these complications with radiation and alkylating agents may enhance chromosomal breakage. We have evaluated the effect of amifostine (AMF) on basal and mitomycin C (MMC)-induced chromosomal breakage in FA blood cells using the micronucleus assay. The basal micronuclei count was higher among FA patients than healthy subjects. Pre-treatment with AMF significantly inhibited micronucleation induced by MMC in healthy subjects (23.4 ± 4.0 – MMC vs 12.3 ± 2.9 – AMF →MMC) MN/1000CB, p < 0.01, one way ANOVA) as well as in FA patients (80.0 ± 5.8 – MMC vs 40.1 ± 5.8 – AMF →MMC) MN/1000CB, p < 0.01, ANOVA). Release of ROS by peripheral blood mononuclear cells treated with AMF →MMC and measured by chemoluminometry showed that AMF-protection was statistically higher among FA patients than in healthy individuals. Based on these results we suggest that AMF prevents chromosomal breakage induced by MMC, probably by its antioxidant effect. Full article

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759 KiB

Open AccessArticle

1,2,5,10,11,14-Hexaoxadispiro[5.2.5.2]hexadecanes: Novel Spirofused Bis-Trioxane Peroxides

by Axel G. Griesbeck, Lars-Oliver Höinck, Johann Lex, Jörg Neudörfl, Dirk Blunk and Tamer T. El-Idreesy

Molecules 2008, 13(8), 1743-1758; https://doi.org/10.3390/molecules13081743 - 19 Aug 2008

Cited by 7 | Viewed by 10995

Abstract

A set of new bis-spirofused 1,2,4-trioxanes 4a-d was obtained from the reaction of cyclohexane-1,4-dione with allylic hydroperoxides 2a-d, bearing an additional hydroxy group in the homoallylic position, by diastereoselective photooxygenation of allylic alcohols 1a-d and subsequent BF₃-catalyzed peroxyacetalization with the diketone. [...] Read more.

A set of new bis-spirofused 1,2,4-trioxanes 4a-d was obtained from the reaction of cyclohexane-1,4-dione with allylic hydroperoxides 2a-d, bearing an additional hydroxy group in the homoallylic position, by diastereoselective photooxygenation of allylic alcohols 1a-d and subsequent BF₃-catalyzed peroxyacetalization with the diketone. From the reaction of a monoprotected cyclohexane-1,4-dione 5 with the allylic hydroperoxide 6 derived from the singlet oxygenation of methyl hydroxytiglate, one monospiro compound was obtained, the 1,2,4-trioxane ketone 7, as well as a mixture of the diastereoisomeric syn- and anti bis-1,2,4-trioxanes 8. The structures of bis-1,2,4-trioxanes were examined theoretically by DFT methods and compared with X-ray structural data in order to evaluate the preferential trioxane ring conformational orientation. Full article

(This article belongs to the Special Issue Spiro Compounds)

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1422 KiB

Open AccessReview

Application of Metabolic Engineering to the Production of Scopolamine

by Javier Palazón, Arturo Navarro-Ocaña, Liliana Hernandez-Vazquez and Mohammad Hossein Mirjalili

Molecules 2008, 13(8), 1722-1742; https://doi.org/10.3390/molecules13081722 - 18 Aug 2008

Cited by 80 | Viewed by 19684

Abstract

Scopolamine is an alkaloid widely used in medicine for its anticholinergic activity. The aim of this review is to show that metabolic engineering techniques constitute a suitable tool to improve the production of tropane alkaloids, focusing in particular on scopolamine. We present an [...] Read more.

Scopolamine is an alkaloid widely used in medicine for its anticholinergic activity. The aim of this review is to show that metabolic engineering techniques constitute a suitable tool to improve the production of tropane alkaloids, focusing in particular on scopolamine. We present an overview of results obtained by various research groups, including our own, who have studied the overexpression of genes involved in the biosynthesis of scopolamine in different plant species that produce tropane alkaloids. Experiments carried out to improve production in hairy root cultures will also be described, as well as those attempting to biotransform hyoscyamine into scopolamine in roots and transgenic tobacco cells. Full article

(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)

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269 KiB

Open AccessArticle

New Triterpene Diglycosides from the Rhizome of Cimifuga foetida

by Lirong Sun, Jian Yan, Yin Nian, Lin Zhou, Hongjie Zhang and Minghua Qiu

Molecules 2008, 13(8), 1712-1721; https://doi.org/10.3390/molecules13081712 - 13 Aug 2008

Cited by 14 | Viewed by 10115

Abstract

Five new 9,19-cycloartane triterpene diglycosides, which have been named cimiaceroside C (1), and cimifosides A-D (2-5) together with the known compounds cimiracemoside D (6), cimidahurine (7) and α-D-glucopyranosyl-l-β-D-fructofuranoside (8) were isolated from the rhizome of Cimicifuga foetida. The new triterpene diglycosides 1-5 were [...] Read more.

Five new 9,19-cycloartane triterpene diglycosides, which have been named cimiaceroside C (1), and cimifosides A-D (2-5) together with the known compounds cimiracemoside D (6), cimidahurine (7) and α-D-glucopyranosyl-l-β-D-fructofuranoside (8) were isolated from the rhizome of Cimicifuga foetida. The new triterpene diglycosides 1-5 were identified as cimiacerol-3-O-β-D-xylopyranosyl-(1''→3')-β-D-xylopyranoside, 12β-hydroxycimigenol-3-O-β-D-xylopyranosyl-(1''→3')-β-D-xylopyranoside, 25-Oacetylcimig- enol-3-O-β-D-xylopyranosyl-(1''→3')-β-D-xylopyranoside, 24- acetylhydroshengmanol-3-O-β-D-xylopyranosyl-(1''→3')-β-D-xylopyranoside and 26- deoxyacetylacteol-3-O-β-D-xylo- pyranosyl-(1''→3')-β-D-xylopyranoside, respectively, based on analysis of their spectral data and chemical reactions. Full article

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172 KiB

Open AccessArticle

Extraction and Separation of Volatile and Fixed Oils from Berries of Laurus nobilis L. by Supercritical CO₂

by Hanen Marzouki, Alessandra Piras, Bruno Marongiu, Antonella Rosa and M. Assunta Dessì

Molecules 2008, 13(8), 1702-1711; https://doi.org/10.3390/molecules13081702 - 13 Aug 2008

Cited by 52 | Viewed by 12111

Abstract

Isolation of volatile and fixed oils from dried berries of Laurus nobilis L. from Tunisia have been obtained by supercritical fractioned extraction with carbon dioxide. Extraction experiments were carried out at a temperature of 40 °C and pressures of 90 and 250 bar. [...] Read more.

Isolation of volatile and fixed oils from dried berries of Laurus nobilis L. from Tunisia have been obtained by supercritical fractioned extraction with carbon dioxide. Extraction experiments were carried out at a temperature of 40 °C and pressures of 90 and 250 bar. The extraction step performed at 90 bar produced a volatile fraction mainly composed of (E)-β-ocimene (20.9%), 1,8-cineole (8.8%), α-pinene (8.0%), β-longipinene (7.1%), linalool acetate (4.5%), cadinene (4.7%), β-pinene (4.2%), α-terpinyl acetate (3.8%) and α-bulnesene (3.5%). The oil yield in this step of the process was 0.9 % by weight charged. The last extraction step at 250 bar produced an odorless liquid fraction, in which a very small percentage of fragrance compounds was found, whereas triacylglycerols were dominant. The yield of this step was 15.0 % by weight. The most represented fatty acids of the whole berry fixed oil were 12:0 (27.6%), 18:1 n-9 (27.1%), 18:2 n-6 (21.4%), and 16:0 (17,1%), with the 18:1 n-9 and 18:2 n-6 unsaturated fatty acids in particular averaging 329 μg/mg of oil. Full article

190 KiB

Open AccessArticle

New Acetylenic Norlignan Compounds from Rhizomes of Curculigo crassifolia

by Kai-jin Wang, Ning Li and Hu Wang

Molecules 2008, 13(8), 1696-1701; https://doi.org/10.3390/molecules13081696 - 13 Aug 2008

Cited by 14 | Viewed by 8442

Abstract

Two pairs of diastereoisomeric acetylenic norlignan compounds with PhCH(OR₁)CH(OR₂)CH₂C≡CPh skeleta: (1R, 2R)-1-O-methylnyasicoside (1) and (1S, 2R)-1-O-methylnyasicoside (2), and (1R, 2R)-crassifogenin D (3) and (1S, 2R)- crassifogenin D (4), were isolated from the ethanolic extract of rhizomes of [...] Read more.

Two pairs of diastereoisomeric acetylenic norlignan compounds with PhCH(OR₁)CH(OR₂)CH₂C≡CPh skeleta: (1R, 2R)-1-O-methylnyasicoside (1) and (1S, 2R)-1-O-methylnyasicoside (2), and (1R, 2R)-crassifogenin D (3) and (1S, 2R)- crassifogenin D (4), were isolated from the ethanolic extract of rhizomes of Curculigo crassifolia. Compounds 3 and 4 are new and their structures were elucidated on the basis of spectroscopic evidence and comparisons with literature data. Full article

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301 KiB

Open AccessReview

Fucoidan: Structure and Bioactivity

by Bo Li, Fei Lu, Xinjun Wei and Ruixiang Zhao

Molecules 2008, 13(8), 1671-1695; https://doi.org/10.3390/molecules13081671 - 12 Aug 2008

Cited by 1106 | Viewed by 54023

Abstract

Fucoidan refers to a type of polysaccharide which contains substantial percentages of L-fucose and sulfate ester groups, mainly derived from brown seaweed. For the past decade fucoidan has been extensively studied due to its numerous interesting biological activities. Recently the search for new [...] Read more.

Fucoidan refers to a type of polysaccharide which contains substantial percentages of L-fucose and sulfate ester groups, mainly derived from brown seaweed. For the past decade fucoidan has been extensively studied due to its numerous interesting biological activities. Recently the search for new drugs has raised interest in fucoidans. In the past few years, several fucoidans’ structures have been solved, and many aspects of their biological activity have been elucidated. This review summarizes the research progress on the structure and bioactivity of fucoidan and the relationships between structure and bioactivity. Full article

(This article belongs to the Special Issue Polysaccharides: Organic Chemistry, Bioactivity and Analysis, including Those from Medicinal Plants and Fungi)

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512 KiB

Open AccessReview

Chemical and Enzymatic Approaches to Carbohydrate-Derived Spiroketals: Di-D-Fructose Dianhydrides (DFAs)

by M. Isabel García-Moreno, Juan M. Benito, Carmen Ortiz Mellet and José M. García Fernández

Molecules 2008, 13(8), 1640-1670; https://doi.org/10.3390/molecules13081640 - 12 Aug 2008

Cited by 31 | Viewed by 16986

Abstract

Di-D-fructose dianhydrides (DFAs) comprise a unique family of stereoisomeric spiro-tricyclic disaccharides formed upon thermal and/or acidic activation of sucroseand/ or D-fructose-rich materials. The recent discovery of the presence of DFAs in food products and their remarkable nutritional features has attracted considerable interest from [...] Read more.

Di-D-fructose dianhydrides (DFAs) comprise a unique family of stereoisomeric spiro-tricyclic disaccharides formed upon thermal and/or acidic activation of sucroseand/ or D-fructose-rich materials. The recent discovery of the presence of DFAs in food products and their remarkable nutritional features has attracted considerable interest from the food industry. DFAs behave as low-caloric sweeteners and have proven to exert beneficial prebiotic nutritional functions, favouring the growth of Bifidobacterium spp. In the era of functional foods, investigation of the beneficial properties of DFAs has become an important issue. However, the complexity of the DFA mixtures formed during caramelization or roasting of carbohydrates by traditional procedures (up to 14 diastereomeric spiroketal cores) makes evaluation of their individual properties a difficult challenge. Great effort has gone into the development of efficient procedures to obtain DFAs in pure form at laboratory and industrial scale. This paper is devoted to review the recent advances in the stereoselective synthesis of DFAs by means of chemical and enzymatic approaches, their scope, limitations, and complementarities. Full article

(This article belongs to the Special Issue Spiro Compounds)

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238 KiB

Open AccessArticle

Statistical Assessment of Solvent Mixture Models Used for Separation of Biological Active Compounds

by Sorana D. Bolboacă, Elena M. Pică, Claudia V. Cimpoiu and Lorentz Jäntschi

Molecules 2008, 13(8), 1617-1639; https://doi.org/10.3390/molecules13081617 - 11 Aug 2008

Cited by 5 | Viewed by 11407

Abstract

Two mathematical models with seven and six parameters have been created for use as methods for identification of the optimum mobile phase in chromatographic separations. A series of chromatographic response functions were proposed and implemented in order to assess and validate the models. [...] Read more.

Two mathematical models with seven and six parameters have been created for use as methods for identification of the optimum mobile phase in chromatographic separations. A series of chromatographic response functions were proposed and implemented in order to assess and validate the models. The assessment was performed on a set of androstane isomers. Pearson, Spearman, Kendall tau-a,b,c and Goodman-Kruskal correlation coefficients were used in order to identify and to quantify the link and its nature (quantitative, categorical, semi-quantitative, both quantitative and categorical) between experimental values and the values estimated by the mathematical models. The study revealed that the six parameter model is valid and reliable for five chromatographic response factors (retardation factor, retardation factor ordered ascending by the chromatographic peak, resolution of pairs of compound, resolution matrix of successive chromatographic peaks, and quality factor). Furthermore, the model could be used as an instrument in analysis of the quality of experimental data. The results obtained by applying the model with six parameters for deviations of rank sums suggest that the data of the experiment no. 8 are questionable. Full article

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230 KiB

Open AccessReview

Composition and Applications of Aloe vera Leaf Gel

by Josias H. Hamman

Molecules 2008, 13(8), 1599-1616; https://doi.org/10.3390/molecules13081599 - 8 Aug 2008

Cited by 787 | Viewed by 101186

Abstract

Many of the health benefits associated with Aloe vera have been attributed to the polysaccharides contained in the gel of the leaves. These biological activities include promotion of wound healing, antifungal activity, hypoglycemic or antidiabetic effects antiinflammatory, anticancer, immunomodulatory and gastroprotective properties. While [...] Read more.

Many of the health benefits associated with Aloe vera have been attributed to the polysaccharides contained in the gel of the leaves. These biological activities include promotion of wound healing, antifungal activity, hypoglycemic or antidiabetic effects antiinflammatory, anticancer, immunomodulatory and gastroprotective properties. While the known biological activities of A. vera will be briefly discussed, it is the aim of this review to further highlight recently discovered effects and applications of the leaf gel. These effects include the potential of whole leaf or inner fillet gel liquid preparations of A. vera to enhance the intestinal absorption and bioavailability of co-administered compounds as well as enhancement of skin permeation. In addition, important pharmaceutical applications such as the use of the dried A. vera gel powder as an excipient in sustained release pharmaceutical dosage forms will be outlined. Full article

(This article belongs to the Special Issue Polysaccharides: Organic Chemistry, Bioactivity and Analysis, including Those from Medicinal Plants and Fungi)

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221 KiB

Open AccessArticle

A Simple, Rapid and Mild One Pot Synthesis of Benzene Ring Acylated and Demethylated Analogues of Harmine under Solvent-free Conditions

by Sabira Begum, Syed Nawazish Ali, Farhat Farhat, Syed Imran Hassan and Bina S. Siddiqui

Molecules 2008, 13(8), 1584-1598; https://doi.org/10.3390/molecules1301584 - 6 Aug 2008

Cited by 3 | Viewed by 12100

Abstract

A simple, rapid, solvent-free, room temperature one pot synthesis of benzene ring acylated and demethylated analogues of harmine using acyl halides/acid anhydrides and AlCl₃ has been developed. Eight different acyl halides/acid anhydrides were used in the synthesis. The resulting mixture of products [...] Read more.

A simple, rapid, solvent-free, room temperature one pot synthesis of benzene ring acylated and demethylated analogues of harmine using acyl halides/acid anhydrides and AlCl₃ has been developed. Eight different acyl halides/acid anhydrides were used in the synthesis. The resulting mixture of products was separated by column chromatography to afford 10- and 12-monoacyl analogues, along with 10,12-diacyl-11-hydroxy products. In five cases the corresponding 10-acyl-11-hydroxy analogues were also obtained. Yields from the eight syntheses (29 products in total) were in the 6-34% range and all compounds were fully characterized. Full article

(This article belongs to the Section Natural Products Chemistry)

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297 KiB

Open AccessArticle

4-Azatricyclo[5.2.2.02,6]undecane-3,5,8-triones as Potential Pharmacological Agents

by Jerzy Kossakowski, Anna Bielenica, Barbara Mirosław, Anna E. Kozioł, Izabela Dybała and Marta Struga

Molecules 2008, 13(8), 1570-1583; https://doi.org/10.3390/molecules13081570 - 6 Aug 2008

Cited by 27 | Viewed by 8357

Abstract

A series of twenty six arylpiperazine and aminoalkanol derivatives of 4-azatricyclo[ 5.2.2.0^2,6]undecane-3,5,8-trione have been prepared. The synthesized compounds were evaluated for their cytotoxicity and anti-HIV-1 activity in MT-4 cells. Full article

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214 KiB

Open AccessReview

5-Fluorouracil: Mechanisms of Resistance and Reversal Strategies

by Ning Zhang, Ying Yin, Sheng-Jie Xu and Wei-Shan Chen

Molecules 2008, 13(8), 1551-1569; https://doi.org/10.3390/molecules13081551 - 5 Aug 2008

Cited by 562 | Viewed by 30980

Abstract

The purpose of this work is to review the published studies on the mechanisms of action and resistance of 5-fluorouracil. The review is divided into three main sections: mechanisms of anti-tumor action, studies of the resistance to the drug, and procedures for the [...] Read more.

The purpose of this work is to review the published studies on the mechanisms of action and resistance of 5-fluorouracil. The review is divided into three main sections: mechanisms of anti-tumor action, studies of the resistance to the drug, and procedures for the identification of new genes involved in resistance with microarray techniques. The details of the induction and reversal of the drug resistance are also described. Full article

(This article belongs to the Special Issue 5-Fluorouracil)

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481 KiB

Open AccessArticle

Structure Determination of β-Glucans from Ganoderma lucidum with Matrix-assisted Laser Desorption/ionization (MALDI) Mass Spectrometry

by Wei-Ting Hung, Shwu-Huey Wang, Chung-Hsuan Chen and Wen-Bin Yang

Molecules 2008, 13(8), 1538-1550; https://doi.org/10.3390/molecules13081538 - 3 Aug 2008

Cited by 55 | Viewed by 16546

Abstract

A novel method that uses matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to analyze molecular weight and sequencing of glucan in Ganoderma lucidum is presented. Thus, β-glucan, which was isolated from fruiting bodies of G. lucidum, was measured in a direct and fast [...] Read more.

A novel method that uses matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to analyze molecular weight and sequencing of glucan in Ganoderma lucidum is presented. Thus, β-glucan, which was isolated from fruiting bodies of G. lucidum, was measured in a direct and fast way using MALDI mass spectrometry. In addition, tandem mass spectrometry of permethylated glucans of G. lucidum, dextran, curdlan and maltohexaose were also pursued and different fragment patterns were obtained. The G. lucidum glucan structure was determined and this method for linkage analysis of permethylated glucan has been proven feasible. Full article

(This article belongs to the Special Issue Polysaccharides: Organic Chemistry, Bioactivity and Analysis, including Those from Medicinal Plants and Fungi)

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194 KiB

Open AccessArticle

Isolation and Characterization of Phenolic Compounds from the Leaves of Salix matsudana

by Xiang Li, Zhi Liu, Xin-feng Zhang, Li-juan Wang, Yi-nan Zheng, Chang-chun Yuan and Guang-zhi Sun

Molecules 2008, 13(8), 1530-1537; https://doi.org/10.3390/molecules13081530 - 3 Aug 2008

Cited by 39 | Viewed by 15335

Abstract

A bioassay-guided in vitro screen has revealed that a 70% methanol extract of the leaves of Salix matsudana shows considerable inhibitory activity against cyclooxygenases (COX-1 and COX-2). A subsequent phytochemical study led to the isolation of a new flavonoid, matsudone A (1), together [...] Read more.

A bioassay-guided in vitro screen has revealed that a 70% methanol extract of the leaves of Salix matsudana shows considerable inhibitory activity against cyclooxygenases (COX-1 and COX-2). A subsequent phytochemical study led to the isolation of a new flavonoid, matsudone A (1), together with five known flavonoids – luteolin (2), isoquercitrin (3), 7-methoxyflavone (4), luteolin 7-O-glucoside (5), 4',7-dihydroxyflavone (6) – and two phenolic glycosides, leonuriside A (7) and piceoside (8). Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies, high resolution ESI mass spectroscopic analyses and comparisons with literature data. The isolated compounds 1-8 were tested for their inhibitory activities against COX-1 and COX-2. Compounds 1, 5 and 6 were found to have potent inhibitory effect on COX-2 and compounds 3-5 exhibited moderate inhibition against COX-1. Full article

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Molecules, Volume 13, Issue 8 (August 2008) – 26 articles , Pages 1530-2038

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