NOVEL PROPENYL FLAVONOIDS GLYCOSIDE AND ANTIOXIDANT ACTIVITY OF EGYPTIAN BAUHINIA RETUSAAbstract
Column chromatography of ethyl acetate of Bauhinia retusa afforded a novel flavonoid identified as [ rhamnetin-3-O-α- L-rhamnopyranosyl-3’-O-(prop-1-enyl)], in addition to kaempferol, isorhamnetin-3-α-rhamnoside, qurcitrin, quercetin 3-O-β-D-glucopyranosyl-β-D-glucopyranoside, and quercetin 3,7-di-o- β-D-glucoside have been isolated for the first time. Their structures were established from extensive spectroscopic techniques (UV, MS, 1H and 13C-NMR), chemical studies in addition to comparison with literature data and /or authentic samples. More over,qurcitrin, quercetin 3-O-β-D-glucopyranosyl-β-D-glucopyranoside and ethyl acetate fraction exerted pronounced antioxidant activities (SC50 µg/ml ,13.5 , 14.7 and 18.7 ) respectively, compared with vitamin C (SC50,,13.9 µg/ml ) by DPPH radical scavenging assay.
Zeinab I.A. El Sayed, Wafaa H. B. Hassan and Abdel-Monem Ateya
Department of Pharmacogonosy, Faculty of Pharmacy, University of Zagazig, Zagazig, B.O Box 44519, Egypt
02 June 2014
12 August, 2014
28 December, 2014
01 January, 2015