title: Antioxidant activity of prenylated flavonoids from the West African medicinal plant Dorstenia mannii.
abstract: The antioxidant activities of three prenylated flavonoids from Dorstenia mannii (6,8-diprenyleriodictyol, dorsmanin C and dorsmanin F) were compared to the common, non-prenylated flavonoid, quercetin. The prenylated flavonoids were found to be potent scavengers of the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), and are more potent than butylated hydroxy toluene (BHT), a common antioxidant used as a food additive. The prenylated flavonoids also inhibited Cu(2+)-mediated oxidation of human low density lipoprotein (LDL). Dose-response studies indicated that the prenylated flavonoids were effective inhibitors of lipoprotein oxidation with IC50 values <1 microM and had similar inhibitory potency compared to quercetin, but was not directly related to Cu binding. Unlike quercetin, they did not show any pro-oxidant activity at high doses in the Cu(2+)-mediated lipoprotein oxidation system. The medicinal action of Dorstenia mannii may be related to the high concentration of potent antioxidant prenylated flavonoids in this species.
authors.affiliation: Department of Medicine, University of Western Australia, P.O. Box X2213 GPO, Perth 6847, Australia.
authors.forename: K G
authors.initials: KG
authors.lastname: Dufall
authors.forename: B T
authors.initials: BT
authors.lastname: Ngadjui
authors.forename: K F
authors.initials: KF
authors.lastname: Simeon
authors.forename: B M
authors.initials: BM
authors.lastname: Abegaz
authors.forename: K D
authors.initials: KD
authors.lastname: Croft
mesh_terms: D000349:Africa; D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification; D001713:Biphenyl Compounds; D002084:Butylated Hydroxytoluene / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification; D016166:Free Radical Scavengers / Q000737:chemistry; D029586:Moraceae / Q000737:chemistry*; D010851:Picrates / Q000737:chemistry; D011794:Quercetin / Q000737:chemistry; D013997:Time Factors
chemical_list: C478607:6,8-diprenyleriodictyol; D000975:Antioxidants; D001713:Biphenyl Compounds; D005419:Flavonoids; D016166:Free Radical Scavengers; D010851:Picrates; C478608:dorsmanin C; C478609:dorsmanin F; D002084:Butylated Hydroxytoluene; D011794:Quercetin; C004931:1,1-diphenyl-2-picrylhydrazyl