Antioxidant activity and protective effects against oxidative damage of human cells induced by X-radiation of phenolic glycosides isolated from pepper fruits Capsicum annuum L.

The antioxidant and radioprotective effects of the phenolic glycosides from Capsicum annuum L. were examined. There were: sinapoyl-E-glucoside, quercetin-3-O-rhamnoside-7-O-glucoside, quercetin-3-O-rhamnoside and luteolin-7-O-(2-apiosyl)-glucoside. To the best of our knowledge, this is the first study to assay these compounds for their radioprotective effect on human cell lymphocytes in response to oxidative damage induced by X radiation and their antioxidant abilities. Investigated compounds showed weaker antiradical activities, but their radioprotective potentials were higher than those of their aglycones. Quercetin-3-O-rhamnoside showed the highest radioprotective activity (50% according to control). Furthermore, quercetin and luteolin derivatives, in contrast to free aglycones, were not cytotoxic against human lymphocytes for all concentrations tested. The best correlation between radioprotective and antiradical activities of the investigated compounds was observed in the relationship to O2− generated using the NADH/PMS method (R2 = 0.859). Thus, we propose that superoxide radical scavenging activity is a useful method for screening for compounds with promising radioprotective potential.