Abstract
The antioxidant activity of the aqueous ethanolic extract of Doum leaves, Hyphaene thebaica L. (Palmae), was studied. Data obtained showed that the extract scavenged superoxide anion radicals (IC50 = 1602 mu g/ml) in a dose dependant manner using xanthine/hypoxanthine oxidase assay. Four major flvonoidal compounds were identified by LC/SEI as; Quercetin glucoside, Kaempferol rhamnoglucoside, Dimethyoxyquercetin rhamnoglucoside. While, further in-depth phytochemical investigation of this extract lead to the isolation and identification of fourteen compounds; their structures were elucidated based upon the interpretation of their spectral data(UV, H-1, C-13 NMR and ESI/MS) as; 8-C-beta-D-glucopyranosyl-5, 7, 4'-trihydroxyflavone (vitexin) 1, 6-C-beta-D-glucopyranosyl-5, 7, 4'-trihydroxyflavone (iso-vitexin) 2, quercetin 3-O-beta-C-4(1)-D-glucopyranoside 3, gallic acid 4, quercetin 7-O-beta-C-4(1)-D-glucoside 5, luteolin 7-O-beta-C-4(1)-D-glucoside 6, tricin 5 O-beta-C-4(1)-D-glucoside 7, 7, 3' dimethoxy quercetin 3-O-[6 ''-O-alpha-L-rhamnopyranosyl]-beta-D-gluco-pyranoside (Rhamnazin 3-O-rutinoside) 8, kaempferol-3-O-[6 ''-O-alpha-L-rhamnopyranosyl]-beta-D- glucopyranoside (nicotiflorin) 9, apigenin 10, luteolin 11, tricin 12, quercetin 13 and kaempferol 14.