Effect of polyphenolic compounds from Coriandrum sativum on H2O2-induced oxidative stress in human lymphocytes

Polyphenolic compounds are widely distributed in plants and known to be excellent antioxidants in vitro. They have the capacity to reduce free-radical formation by scavenging free radicals and protecting antioxidant defences. The present study evaluated the antioxidant potencies of polyphenolic compounds from a spice, Coriandrum sativum against hydrogen peroxide-induced oxidative damage in human lymphocytes. Pretreatment with polyphenolic rich fractions protected human lymphocytes against H2O2-induced oxidative damage. H2O2 treatment significantly decreased the activities of antioxidant enzymes, such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and caused decreased glutathione content and increased thiobarbituric acid-reacting substances (TBARS). Treatment with polyphenolic fractions (50 μg/ml) increased the activities of antioxidant enzymes and glutathione content and reduced the levels of TBARS significantly. Observed reduction in the level of lipid peroxides showed a decreased tendency of peroxidative damage. We conclude that, under these experimental conditions, polyphenolic compounds effectively suppress hydrogen peroxide-induced oxidative stress.