Potential Superoxide Anion Radical Scavenging Activity of Doum Palm ( Hyphaene thebaica L.) Leaves Extract

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 ( IC 50=1602 µg/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, 1H, 13C NMR and ESI/MS )as; 8-C-β-D-glucopyranosyl-5, 7, 4`-trihydroxyflavone (vitexin) 1, 6-C-β-D-glucopyranosyl-5, 7, 4`-trihydroxyflavone (iso-vitexin) 2, quercetin 3-O-β- 4C 1-D-glucopyranoside 3, gallic acid 4, quercetin 7-O-β- 4C 1-D-glucoside 5, luteolin 7-O-β- 4C 1-D-glucoside 6, tricin 5 O-β- 4C 1-D-glucoside 7, 7, 3` dimethoxy quercetin 3-O-[6''-O-α-L-rhamnopyranosyl]-β-D-gluco-pyranoside (Rhamnazin 3-O-rutinoside) 8, kaempferol-3-O-[6''-O-α- L-rhamnopyranosyl]-β- D-glucopyranoside (nicotiflorin) 9, apigenin 10, luteolin 11, tricin 12, quercetin 13 and kaempferol 14.