JOURNAL 18


Records of Natural Products
VOLUME & ISSUE
Year: 2008 Issue: 3 July-September
PAGES
p.83 - 93
STATISTICS
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AUTHORS
    Omayma A. Eldahshan, Nahla A. Ayoub, Abdel-Nasser B. Singab and Mohamed M. Al-Azizi
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GRAPHICAL ABSTRACT


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 ( 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]-D-gluco-pyranoside (Rhamnazin 3-O-rutinoside) 8, kaempferol-3-O-[6''-O-α- L-rhamnopyranosyl]- D-glucopyranoside (nicotiflorin) 9, apigenin 10, luteolin 11, tricin 12, quercetin 13 and kaempferol 14.

KEYWORDS
  • doum leaves
  • Hyphaene thebaica (Palmae)
  • phenolics
  • hypoxanthine/xanthine oxidase assay