Antioxidant activity and protection of human umbilical vein endothelial cells from hydrogen peroxide-induced injury by DMC, a chalcone from buds of Cleistocalyx operculatus

The aim of this work was to study the antioxidant activity and the protective effect of 2 ',4 '-dihydroxy-6 ' methoxy-3',5'-dimethylchalcone (DMC), the main compound from the buds of Cleistocalyx operculatus, on human umbilical vein endothelial cells against cytotoxicity induced by H2O2. The antioxidant activities of DMC were measured by ABTS assay, ferric reducing antioxidant power (FRAP) and hydroxyl radical scavenging activity, and protective effects of DMC on human umbilical vein endothelial cells against cytotoxicity induced by H2O2 were tested. DMC was found to have high ABTS radical scavenging activity (176.5 +/- 52 mu mol trolox equivalents/500 mu mol DMC) and strong ferric reducing antioxidant power (2133 +/- 5.8 mu mol trolox equivalents/500 mu mol DMC). In addition, DMC scavenged the hydroxyl radicals, with IC50 values of 243.7 +/- 6.3 mu M, slightly lower than the reference antioxidant ascorbic acid (ASC). Moreover, DMC could protect the human umbilical vein endothelial cells against H2O2-induced cytotoxicity by decrease intracellular and extracellular ROS levels, reduction in catalase (CAT) activity and increment in malondialdehyde (MDA) level. These results suggested that DMC has the potential to be used in the therapy of oxidative damage. (C) 2013 SAAB. Published by Elsevier B.V. All rights reserved.