Flavonoids from Rhamnus alaternus L. (Rhamnaceae): Kaempferol 3-O-β-isorhamninoside and rhamnocitrin 3-O-β-isorhamninoside protect against DNA damage in human lymphoblastoid cell and enhance antioxidant activity

Abstract Kaempferol 3-O-β-isorhamninoside (K3O-ir) and rhamnocitrin 3-O-β-isorhamninoside (R3O-ir), were isolated from Rhamnus alaternus L leaves. The genotoxic and antigenotoxic properties of these compounds were investigated by assessing the induction and inhibition of the genotoxicity induced by the direct-acting mutagen, hydrogen peroxide (H 2 O 2 ), using the “comet assay.” K3O-ir and R3O-ir exhibited a preventive effect against H 2 O 2 induced DNA damages in human lymphoblastoid TK6 cells and its derivative the p53 deficient cell line NH32. These two flavonoids, also investigated for their antioxidant capacities, using different antioxidant tests, such as: Cuprac, Frap and reducing power assays, revealed significant activity through their capacities to transfer electrons.