Abstract: AIM: To investigate the protective effects of onychin on oxidative injured endothelial cells and its protective mechanism. METHODS: The injured model was established by endothelial cell treated with oxLDL. Protective effect of onychin on growth inhibition of endothelial cells injured by oxLDL was determined by MTT assay;NO concentrations in the medium were determined by nitrate reductase assay.The damage degree of endothelial cells was assessed by showing the TBARS and LDH levels in conditioned media. RESULTS: Onychin with various concentrations, given 24 hours, could decrease the growth inhibitory rates of endothelial cells injured by oxLDL, increase NO concentration and decrease the TBARS and LDH levels in the medium. CONCLUSION: Onychin can protect endothelial cells against oxidative damage.

Key words: oxidative stree, onychin, endothelial cell, thiobarbituric acid-reactive substances, NO, lactate dehydrogenase