Free-radical Scavenging Flavonol 3-O-glycosides from the Leaves of Ribes biebersteinii Berl.

 Ribes biebersteinii Berl. (Grossulariaceae), commonly known as ‘reddish-black berry’, is an Iranian medicinal plant found mainly in the region of the Arasbaran forests in Iran. Reversed-phase preparative HPLC analyses of the methanol extract of the leaves of this plant afforded four flavonol glycosides, e.g. quercetin 3-O-sophoroside (1), quercetin 3-O-sambubioside (2), kaempferol 3-O-sophoroside (3) and kaempferol 3,5-di-O-b-D-glucopyranoside (4). The free-radical-scavenging properties of the n-hexane, DCM and MeOH extracts, as well as the isolated compounds 1-4 were evaluated by the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay.