title: Decorosides A and B, cytotoxic flavonoid glycosides from the leaves of Rhododendron decorum.
abstract: Bioassay and NMR-guided fractionation of the methanolic extract of Rhododendron decorum leaves resulted in the isolation of two new flavonoid glycosides, 5,7-dihydroxy-6,8-dimethyldihydroflavanone-7-O-alpha-L-arabinopyranosyl(1-->6)-beta-D-glucopyranoside (decoroside A, 1) and its 3-hydroxy congener (decoroside B, 2), along with five known compounds myricitrin (3), afzelin (4), (-)-epicatechin (5), (+)-catechin (6), and ampeloptin (7). The structures of the isolated compounds were elucidated by extensive interpretation of their spectral data. Biological evaluation using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed promising cytotoxic activities of these compounds against different cancer cell lines.
authors.forename: Mostafa E
authors.initials: ME
authors.lastname: Rateb
authors.forename: Hossam M
authors.initials: HM
authors.lastname: Hassan
authors.forename: El-Shaimaa A
authors.initials: el-SA
authors.lastname: Arafa
authors.forename: Marcel
authors.initials: M
authors.lastname: Jaspars
authors.forename: Rainer
authors.initials: R
authors.lastname: Ebel
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry* / Q000494:pharmacology; D045744:Cell Line, Tumor; D005419:Flavonoids / Q000737:chemistry* / Q000494:pharmacology; D006027:Glycosides / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry*; D029793:Rhododendron / Q000737:chemistry*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D005419:Flavonoids; D006027:Glycosides; C000589050:decoroside A; C000589051:decoroside B