COMPARATIVE PROTECTION AGAINST OXYRADICALS BY 3 FLAVONOIDS ON CULTURED ENDOTHELIAL-CELLS

Oxygen-derived foe radicals are known to injure the endothelium of aor ta in diverse disorders. In this study we compared the cytoprotective effects of three flavonoids against oxyradical damage to porcine aorti c endothelial cells in vitro. Cultured porcine aortic endothelial cell s were exposed to oxyradicals generated by xanthine oxidase-hypoxanthi ne (XO-HP). The cytoprotective activities of morin, quercetin, and cat echin on these systems were compared using established morphologic cri teria. The results in the XO-HP system showed that morin at 0.125, 0.2 5, and 0.5 mM delayed cell necrosis to 27.4 +/- 1.3, 46.8 +/- 1.8, and longer than 70 min, respectively, compared with 12.0 +/- 1.3 min in t he control group. These degrees of protection were significantly stron ger than those provided by quercetin and catechin at corresponding con centrations (p < 0.01). Morin and quercetin were moderate inhibitors o f xanthine oxidase on the basis of the oxygen consumption rate, wherea s catechin at the same concentrations had little inhibitory effect. Th e data from uric acid formation and cytochrome c reduction were consis tent with the oxygen consumption measurement for the three flavonoids.