Separation and evaluation of antioxidant constituents from Carthamus tinctorius

Bio-active components from Carthamus tinctorius were separated on the basis of antioxidant capacities in vitro. The antioxidant capacity was investigated on the basis of the ability to scavenge DPPH radical, ABTS radical and reduce Fe3+ of different polar fractions. Furthermore, the chemical compounds were isolated from bio-active fraction, and were evaluated for the antioxidative effects. Five major components were isolated and identified from water extract as 6-hydroxykaempferol 3,6,7-tri-O-β-D-glucoside(1), 6-hydroxykaempferol 3-O-β-rutinoside-6-O-β-D-glucoside (2), 6-hydroxykaempferol 3-O-β-D-glucoside (3), hydroxysafflor yellow A (4) and anhydrosafflor yellow B (5). By evaluating and comparing the antioxidative effects of different fractions and obtained compounds, the results showed that water extract displayed significantly high antioxidative activities and 6-hydroxykaempferol glycosides and quinochalcone C-glycosides were found as main contribution for antioxidant property.