Toxicity of food additive sodyum benzoat on human erythrocytes in vitro and protective effect of catechin and quercetin

Food preservatives are commonly used as antimicrobial agents in many kinds of foods. A number of toxicological studies of sodium benzoate (SB) have been reported in humans and various animal species. The aim of this study was to evaluate the protective effect of catechin and quercetin in adversing SB-induced oxidative stress in human erythrocytes in vitro. For this purpose, the effects of various doses of SB (6.25, 12.5, 25, 50, 100 µg/ml), catechin (10 µM) and quercetin (10 µM) on level of malondialdehit (MDA) and the activities of enzymes of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) in erythrocytes were studied. No chemicals were administered for control group. The experimental groups were divided into five groups: catechin, quercetin, SB, SB + catechin, SB + quercetin. Each SB dose was incubated with a previously prepared erythrocyte sample at 37 oC for 60 min. After incubation, antioxidant enzymes activities and MDA levels were detected. Significantly higher MDA and lower activities of SOD, CAT, GPx and GST were observed with the increasing concentrations of SB treatment (p<0.05). Treatment of catechin or quercetin protected the erythrocytes exposed to low concentrations of SB against oxidative stress. But these effects were seen only at extremely low concentrations of SB (12.5, 25, 50 µg/ml). The presence of catechin or quercetin at 10 µM concentrations have no effect on SB-induced toxicity in erythrocytes at a high concentrations of SB (50 and 100 µg/ml).