Resolution and determination of enantiomeric purity of new chiral derivatives of xanthones using polysaccharide-based stationary phases.

Posted on by

Related Articles

Resolution and determination of enantiomeric purity of new chiral derivatives of xanthones using polysaccharide-based stationary phases.

J Chromatogr A. 2012 Jul 25;

Authors: Fernandes C, Brandão P, Santos A, Tiritan ME, Afonso C, Cass QB, Pinto MM

Abstract

The enantioresolution and determination of the enantiomeric purity of 24 new chiral derivatives of xanthones (CDXs) were investigated on polysaccharide-based chiral stationary phases (CSPs). The tris-3,5-dimethylphenylcarbamates of cellulose and amylose and tris-3,5-dimethoxyphenylcarbamate of amylose were selected as CSPs for this work. The separation of enantiomeric mixtures of CDXs was explored under multimodal elution conditions. All the enantiomeric mixtures of CDXs were enantioseparated with very high enantioselectivity and resolution with ? and R(S) ranging from 1.43 to 12.41 and from 1.48 to 10.29, respectively. The best performances were achieved on amylose tris-3,5-dimethylphenylcarbamate stationary phase under polar organic elution conditions. Furthermore the enantiomeric purity for all the CDXs was measured, achieving values higher than 99%. Based on the obtained results, the influence of the mobile phases and structural features of the CSPs and CDXs on chiral discrimination are also discussed.

PMID: 22889602 [PubMed - as supplied by publisher]

pubmed: xanthones research

Chemistry and biology of genus Vismia.

Posted on by
Related Articles

Chemistry and biology of genus Vismia.

Pharm Biol. 2012 Aug 13;

Authors: Hussain H, Al-Harrasi A, Saleem M, Green IR, van Ree T, Ghulam A

Abstract

Context: Many herbal remedies have been employed in the treatment and management of various human ailments since the beginning of human civilization. Vismia is an extensive genus of the family Hypericaceae and consists of small trees inhabiting the tropical and subtropical regions of South and Central America. Within the framework of an International Cooperative Biodiversity Groups project, three Vismia species were studied for their potential anticancer activity. Objectives: This review is an extensive study of the available scientific literature published and comprises of the ethnopharmacological, phytochemical and therapeutic potential of genus of plants under the umbrella Vismia. Methods: The present review includes 134 natural products with 47 references compiled from the major databases, viz., Chemical Abstracts, Science Direct, SciFinder, PubMed, Dr. Dukes Phytochemical and Ethnobotany, CIMER, and InteliHealth. Results: An exhaustive survey of the accessed literature revealed that flavonoids, flavanols, xanthones, anthraones, anthraquinones, benzophenones, lignans, steroids, monoterpenes and triterpenes constituted the major classes of phytoconstituents of this genus. Pharmacological reports revealed that it is used for skin diseases such as dermatitis, leprosy, syphilis, herpes, scabies and eczemas, and as an anticancer for human breast, CNS, and lung cancer cell lines. Conclusion: Genus Vismia plants seem to hold great potential for an in-depth investigation towards discovering biological activities, especially for the treatment of cancers affecting our society. Through this review, the authors hope to attract the attention of natural product researchers throughout the world to focus on the unexplored potential of Vismia plants, with the view of developing new formulations with an improved therapeutic value.

PMID: 22881063 [PubMed - as supplied by publisher]

pubmed: xanthones research

Bioassay-Guided Isolation of Prenylated Xanthones and Polycyclic Acylphloroglucinols from the Leaves of Garcinia nujiangensis.

Posted on by
Related Articles

Bioassay-Guided Isolation of Prenylated Xanthones and Polycyclic Acylphloroglucinols from the Leaves of Garcinia nujiangensis.

J Nat Prod. 2012 Aug 7;

Authors: Xia ZX, Zhang DD, Liang S, Lao YZ, Zhang H, Tan HS, Chen SL, Wang XH, Xu HX

Abstract

Bioassay-guided fractionation of the acetone extract of the leaves of Garcinia nujiangensis resulted in the isolation of two new prenylated xanthones, nujiangexanthones A (1) and B (2), three new polycyclic polyprenylated acylphloroglucinols, nujiangefolins A-C (3-5), and 10 known related analogues. The structures of compounds 1-5 were elucidated by interpretation of their spectroscopic data. Compounds 3 and 4 are unusual polycyclic polyprenylated acylphloroglucinols in which the enol hydroxy group forms a six-membered ring with a benzene ring carbon. The compounds isolated were evaluated for their cytotoxic effects against 11 cancer cell lines and immortalized MIHA normal liver cells, and the test substances demonstrated selectivity toward the cancer cells. Isojacareubin (6) was found to be the most potent cytotoxic compound of those tested.

PMID: 22871217 [PubMed - as supplied by publisher]

pubmed: xanthones research

Xanthones from the stems of Cratoxylum cochinchinense.

Posted on by

Xanthones from the stems of Cratoxylum cochinchinense.

Magn Reson Chem. 2012 Aug 1;

Authors: Duan Y, Dai Y, Chen L, Liu M, Li Y, Yao X

Abstract

Four new xanthones, 1-methoxy-3,7,8-trihydroxyxanthone (1), 1-methoxy-4,7,8-trihydroxyxanthone (2), 1-methoxy-4,7-dihydroxyxanthone (3), and 1,4-dimethoxy-2,7-dihydroxyxanthone (4) were isolated from the stems of Cratoxylum cochinchinense along with four known xanthones (5-8). The structures of new compounds were determined by extensive spectroscopic analyses, mainly 1D and 2D NMR and HRESIMS data. Copyright © 2012 John Wiley & Sons, Ltd.

PMID: 22865675 [PubMed - as supplied by publisher]

pubmed: xanthones research

Bioguided fractionation and isolation of natural inhibitors of advanced glycation end-products (AGEs) from Calophyllum flavoramulum.

Posted on by
Related Articles

Bioguided fractionation and isolation of natural inhibitors of advanced glycation end-products (AGEs) from Calophyllum flavoramulum.

Phytochemistry. 2012 Jun;78:98-106

Authors: Ferchichi L, Derbré S, Mahmood K, Touré K, Guilet D, Litaudon M, Awang K, Hadi AH, Le Ray AM, Richomme P

Abstract

Advanced glycation end-products (AGEs) are associated with many pathogenic disorders such as Alzheimer’s disease, pathogenesis of diabetes, atherosclerosis or endothelial dysfunction leading to cardiovascular events. Clusiaceae and Calophyllaceae families are rich in compounds like polyphenols which are able to inhibit their formation and are therefore of great interest. Calophyllum flavoramulum Hend. & Wyatt-Sm., a native Malaysian plant, was selected after an anti-AGEs screening conducted on DCM and MeOH extracts from plants belonging to these aforementioned families. In a first study, bioguided fractionation of the MeOH leaf extract of C. flavoramulum afforded amentoflavone, 3-methoxy-2-hydroxyxanthone, 3,4-dihydroxy-tetrahydrofuran-3-carboxylic acid, quercitrin, 3,4-dihydroxybenzoic acid, canophyllol and apetalactone. Amentoflavone and 3-methoxy-2-hydroxyxanthone were found to be very potent (IC(50)=0.05 and 0.06 mM respectively), while anti-AGEs activities of quercitrin and 3,4-dihydroxybenzoic acid appeared as moderately strong (IC(50)=0.5 mM). In a second study, a systematic phytochemical study of the cyclohexane, DCM and EtOAc extracts obtained from the same plant was conducted to isolate the following products: flavoramulone, 6-deoxyjacareubin, rheediachromenoxanthone, 2,3-dihydroamentoflavone and benzoic acid. 3,4-Dihydroxy-tetrahydrofuran-3-carboxylic acid and flavoramulone were isolated for the first time and their structures were identified by means of IR, MS and NMR spectrometries.

PMID: 22445651 [PubMed - indexed for MEDLINE]

pubmed: xanthones research