Isolation and identification of a new flavonoid glycoside from Carrichtera annua L. seeds

Background: Flavonoids are a major group of constituents and are assumed to be among the beneficial components. Recently, they have also received considerable interest as components of foodstuffs and nutraceuticals because of their antioxidant and anticancer properties. Materials and Methods: About 500 g of air-dried powdered seeds of C. annua were defatted seeds and extracted with 70% methanol. The combined methanol extract was partitioned with chloroform and n-butanol. The butanol extract was concentrated and subjected to column chromatography on polyamide. Results: The fraction eluted with aqueous methanol (40% and 50%) was found to contain three main flavonoids (1, 2, and 3). Repeated column chromatography on polyamide and Sephadex LH-20 gave compound 1. Compounds 2 and 3 were further purified using preparative paper chromatography with 20% HOAc and Sephadex LH-20 column. Conclusions: Reinvestigation of the flavonoidal constituents of the butanol fraction of the aqueous methanolic extract of Carrichteraannua seeds led to isolation and identification of a new flavonoidal glycosidenamed as quercetin 3-O-[(6-sinapoyl-b-glucopyranosyl)-(1;2)-b-arabinopyranosyl]-7-O-b-glucopyranoside 1, in addition to, quarecetin-3-O-glucoside 2, isorhamnetin-3-O-b-runtinoside3, and isorhamnetin4.Structures of the isolated compounds were established by UV, MS, and (1) H and (13) C NMR.