Novel epicatechin derivatives with antioxidant activity modulate interleukin-1β release in lipopolysaccharide-stimulated human blood

Abstract

We examine the potential antioxidant activity and the immune function of new epicatechin conjugates obtained by depolymerization of grape polymeric flavanols in the presence of cysteamine or cysteine. When incubated with an erythrocyte suspension, flavanols protected the erythrocyte membrane from hemolysis induced by 2,2′-azo-bis(2-amidinopropane)dihydrochloride (AAPH), an azo free radical initiator. The inhibitory effect was concentration-dependent and the IC50 was 119.8 μM for epicatechin, and 74.9 and 89.4 μM for the cysteine and cysteamine derivatives, respectively. These compounds were tested for their antioxidant activity and their capacity to modulate interleukin-1β (IL-1β), which is currently considered to be the major cytokine factor influencing the acute phase of the inflammatory response. At concentrations up to 20 μM, epicatechin and its derivatives inhibited the production of IL-1β in whole blood incubated in the presence of E. coli lipopolysaccharide (LPS), in a concentration-dependent manner. The most active compound was the cysteamine derivative.