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Abstract: Exposure to ultraviolet B (UVB, 280–320) radiation induces the formation of reactive oxygen species (ROS) in the biological system. In this study, we examined the protective effect of ursolic acid on UVB-induced lipid peroxidation and oxidative DNA damage with reference to alterations in cellular antioxidant status in human lymphocytes. Series of in vitro tests (hydroxyl radical, superoxide, nitric oxide, DPPH and ABTS radical scavenging assays) demonstrates antioxidant property of ursolic acid in our study. Treatment of lymphocytes with ursolic acid alone (at 10μg/mL) gave no significant change in cell viability, thiobarbituric acid reactive substances (TBARSs), lipid hydroperoxides (LHPs), % tail DNA and tail moment when compared with normal lymphocytes. UVB-exposure significantly increased TBARS, LHP and % tail DNA, tail moment; decreased % cell viability and antioxidant status in irradiated lymphocytes. Treatment with ursolic acid 30min prior to UVB-exposure resulted in a significant decline of TBARS, LHP, % tail DNA and tail moment and increased % cell viability as ursolic acid concentration increased. Based on our results we conclude that ursolic acid, a dietary antioxidant, mediates its protective effect through modulation of UVB-induced reactive oxygen species. [Copyright &y& Elsevier]

Abstract: UV-B induces lipid peroxidation and oxidative stress in mammalian cells by producing reactive oxygen species. In this present study, we report the protective effect of ferulic acid (FA; 3-methoxy-4-hydroxycinnamic acid), a dietary antioxidant, on UV-B–induced oxidative stress and lipid peroxidation using normal human lymphocytes. Treatment of the human peripheral lymphocytes with UV-B irradiation caused a significant (P < .05) depletion of reduced glutathione (GSH) levels, superoxide dismutase, catalase, and GSH peroxidase activities, and increased the levels of thiobarbituric acid–reactive substances. Treatment of human lymphocytes with FA before 30 minutes of irradiation inhibited UV-B–induced lipid peroxidation. Ferulic acid also inhibited UV-B–induced depletion of antioxidant defense components, such as GSH peroxidase, catalase, superoxide dismutase, and GSH. The maximum dose of FA (10 μg/mL) normalized the UV-B–induced oxidative stress, indicating the protective effect of FA in human peripheral lymphocytes under in vitro conditions against UV-B exposure. Our observations suggest that FA reduces UV-B–induced lipid peroxidation and enhances antioxidant status in human lymphocytes exposed to UV-B radiation, and therefore, FA could serve as a protector against the UV-B–induced pathologic changes. [Copyright &y& Elsevier]

Abstract: In this study we examined radioprotective effect of ferulic acid (FA) on gamma radiation-induced dicentric aberration and lipid peroxidation with reference to alterations in cellular antioxidant status in cultured lymphocytes. To establish most effective protective support we used three different concentrations of FA (1, 5 and 10μg/ml) and three different doses of γ-radiation (1, 2 and 4Gy). Treatment of lymphocytes with FA alone (at 10μg/ml) gave no significant change in micronuclei (MN), dicentric aberration (DC), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) or glutathione peroxidase (GPx) activities when compared with normal lymphocytes; irradiation at 1, 2 and 4Gy increased the MN and DC frequencies in a dose-dependent manner. Treatment with FA for 30min before radiation exposure resulted in a significant decline of MN and DC yields as FA concentration increased. Compared to 1Gy exposure alone, the extent to which FA (1μg/ml) reduced the MN and DC yields was 75% and 50%, respectively. With 4Gy irradiation, FA (10μg/ml) decreased 45% MN and 25% DC frequencies. FA-pretreated lymphocytes (1, 5 and 10μg/ml) showed progressively decreased TBARS levels after irradiation. Irradiation (1, 2 and 4Gy) significantly decreased GSH levels, SOD, CAT and GPx activities in a dose-dependent manner. Pretreatment with 10μg/ml of FA significantly (p <0.05) prevented the decreases in the radiation-induced GSH, SOD, CAT and GPx activities. These findings suggest potential use and benefit of FA as a radioprotector. [Copyright &y& Elsevier]