Modulation of UVB-induced Oxidative Stress by Ursolic Acid in Human Blood Lymphocytes

UV radiation-induced damages may result in pre-cancerous and cancerous lesions and acceleration of skin aging. It involves an imbalance of the endogenous antioxidant system that leads to the increase of free radical levels. Antioxidant pretreatment might inhibit such imbalance. In the present study, the photoprotective effect of ursolic acid (UA; 3 beta -hydroxy-urs-12-en-28-oic acid), a dietary polyphenolic phytochemical, has been examined in the UVB-(280-320 nm) irradiated human blood lymphocytes. Lymphocytes pretreated with increasing concentrations of ursolic acid (1, 5 and 10 mu g mL super(-1)) for 30 min, were irradiated and lipid peroxidation and antioxidant defense were examined. UVB-irradiated lymphocytes exhibited increased levels of lipid peroxidation and disturbances in antioxidant status. Ursolic acid pretreatment resulted in significant reduction in thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LPH) levels. Further, antioxidants like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), vitamin-C (Vit-C) and vitamin-E (Vit-E) were normalised in ursolic acid pretreated plus UVB-treated lymphocytes. The maximum dose of ursolic acid (10 mu g mL super(-1)) normalized the UVB induced lipid peroxidation, indicating the photoprotective effect of ursolic acid in human peripheral lymphocytes under in vitro condition.