Inhibitory effects of chlorogenic acids on linoleic acid peroxidation and haemolysis

Abstract

Antioxidant activities of chlorogenic acid and related catechols were investigated by both the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging system and the superoxide anion-mediated linoleic acid peroxidation system. At 10 μM, chlorogenic acid, 3,5-dicaffeoylquinic acid, caffeic acid and protocatechuic acid showed more scavenging activities on DPPH than dl-α-tocopherol or ascorbic acid. DPPH radical scavenging activities of these compounds increased dose-dependently at concentrations ranging from 1 to 50 μM; 1 mol of chlorogenic acid reacted with ca 4 mol of radical, and 1 mol of 3,5-dicaffeoylquinic acid with ca 6 mol of radical. Chlorogenic acid, 3,5-dicaffeoylquinic acid and caffeic acid inhibited the formation of conjugated diene from linoleic acid. The inhibitory activity of 3,5-dicaffeoylquinic acid was stronger than that of chlorogenic acid or caffeic acid; dl-α-tocopherol was the most inhibitory of the other catechols tested. Effects on the haemolysis and peroxidation of mouse erythrocytes induced by H 2O 2 was also examined. Cafreic acid, chlorogenic acid, 3,5-dicaffeoylquinic acid and dl-α-tocopherol exhibited strong inhibitory activities, but cinnamic acid, p-coumaric acid, ferulic acid, protocatechuic acid and vanillic acid were ineffective. Caffeic acid (25 μM) inhibited the rupture and haemolysis of erythrocytes.