title: A prenylated xanthone from Allanblackia floribunda.
abstract: A new prenylated xanthone, named allanxanthone A, was isolated from the stem bark of Allanblackia floribunda in addition to known compounds, 1,5-dihydoxyxanthone, 1,5,6-trihydroxy-3,7-dimethoxyxanthone, stigmasterol and stigmasteryl-3-O-beta-D-glucopyranoside. The structure of the new compound was assigned as 1,3,5-trihydroxy-2-(3-methylbut-2-enyl)-4-(1,1-dimethylprop-2-enyl) xanthone, by means of spectroscopic analysis. The 13C NMR spectral data of 1,5-dihydroxyxanthone is reported here for the first time as well as the in vitro cytotoxic activity of xanthone metabolites against the KB cell line.
authors.affiliation: Department of Organic Chemistry, Faculty of Science, University of Yaounde I, PO Box 812, Yaounde, Cameroon. ankengf@uycdc.uninet.cm
authors.forename: Augustin E
authors.initials: AE
authors.lastname: Nkengfack
authors.forename: Guy A
authors.initials: GA
authors.lastname: Azebaze
authors.forename: Juliette C
authors.initials: JC
authors.lastname: Vardamides
authors.forename: Zacharias T
authors.initials: ZT
authors.lastname: Fomum
authors.forename: Fanie R
authors.initials: FR
authors.lastname: van Heerden
mesh_terms: D002163:Cameroon; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D007624:KB Cells / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D017368:Protein Prenylation; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D014966:Xanthenes / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D044004:Xanthones
chemical_list: D010936:Plant Extracts; D014966:Xanthenes; D044004:Xanthones; C009689:xanthone