Search

Abstract: The aim of the present study was to assess the protective effect of apigenin, a dietary flavone, against cytogenetic alterations in human peripheral blood lymphocytes (HPBL) induced by Cobalt-60 radiation (3Gy). Results of MTT [3-(4, 5-dimethyl-2-thiaozolyl)-2,5-diphenyl-2H tetrazolium bromide] assay revealed that 37.2μM of apigenin was found to be non-toxic in HPBL. At this dose (37.2μM) of apigenin, the LD50 radiation dose of HPBL increased from 2.9Gy to 3.4Gy, which resulted in a DMF of 1.17. Apigenin (37.2μM) treatment 1h before irradiation significantly (p <0.05) reduced DNA damage in irradiated HPBL as measured by comet assay (% tail DNA, tail length, tail moment, and olive tail moment). Moreover, apigenin treatment significantly decreased the frequencies of dicentric (DC), acentric fragments (AF), and acentric rings (AR) in irradiated HPBL. Apigenin pretreatment also reduced the radiation-induced CBMN (cytokinesis blocked micronuclei) anomalies such as micronuclei (MNi), nucleoplasmic bridges (NPB) and nuclear buds (NBUD) in HPBL. These results also showed that there was a significant correlation between NPB and DC frequencies and MNi and AF+AR. Treatment with apigenin alone had no significant effect on DNA damage and chromosomal aberrations in HPBL. Thus, the current studies indicate that apigenin protects HPBL from radiation-induced cytogenetic alterations. [Copyright &y& Elsevier]

Abstract: The present study was aimed to explore the antioxidant potential of apigenin and its preventive effect on radiation-induced oxidative damage in human peripheral blood lymphocytes (HPBL). Apigenin (4′, 5, 7-trihydroxy flavone) effectively scavenges hydroxyl (OH•), superoxide anion (O2 •–), 1, 1-diphenyl- 2-picrylhydrazyl (DPPH•) and 2, 2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid radical cation (ABTS•+) in a concentration-dependent manner (37.2–186μM). Gamma-radiation (3Gy) exposure increased the levels of reactive oxygen species (ROS), % apoptotic cells and decreased the mitochondrial membrane potential (ΔΨm) in HPBL. On the other hand, apigenin treatment (37.2μM) 60min prior to irradiation significantly decreased ROS generation in HPBL. It has also been observed that apigenin treatment significantly reduced γ-radiation-induced apoptotic incidence and modulates loss of ΔΨm in HPBL. Furthermore, apigenin treatment significantly maintains cellular antioxidant status (superoxide dismutase, catalase, glutathione peroxidase activities and reduced glutathione level) and protects cellular milieu from γ-radiation-induced lipid peroxidation and micronuclei formation in irradiated HPBL. Radiation exposure increased p53, p21, Bax and NF-kB expressions and decreased Bcl-2 expression in HPBL. Conversely, an increase in Bcl-2 along with a decrease in p53, p21, Bax and NF-kB expression was observed in apigenin plus irradiated HPBL. Taken together, the present study indicates that apigenin showed strong antioxidant property in free radical scavenging systems and protects HPBL from radiation-induced oxidative damages at cellular and molecular level. [Copyright &y& Elsevier]

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]

Abstract: Sesamol pretreated (1, 5 and 10μg/ml) lymphocytes were exposed to different doses of γ-radiation, i.e., 1, 2 and 4Gray (Gy) and the cellular changes were estimated by using cytokinesis blocked micronucleus assay (MN), dicentric aberration (DC), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Radiation significantly increased MN, DC frequencies, TBARS levels and decreased GSH and antioxidant enzyme levels in a dose dependent manner. The highest damage to lymphocytes was observed at 4Gy irradiation. On the other hand, sesamol pretreatment significantly decreased MN, DC frequencies, TBARS levels and increased GSH levels and SOD, CAT and GPx activities in a concentration dependent manner. At 1Gy irradiation all concentrations of sesamol (1, 5 and 10μg/ml) significantly protects the lymphocytes from radiation damage. At 2Gy irradiation 5 and 10μg/ml of sesamol shows significant radioprotection. Since the highest damage was observed at 4Gy irradiation both 1 and 5μg/ml of sesamol pretreatment were not sufficient to protect the lymphocytes from radiation damage but 10μg/ml of sesamol significantly (p &#60;0.05) protects the lymphocytes from radiation effect. Thus, sesamol pretreatment gives significant protection to cultured human lymphocytes against γ-radiation induced cellular damage. The possible mechanism involved in the radioprotective influence of sesamol is discussed. [Copyright &y& Elsevier]

Highlights: [•] Antioxidant potential of Jatropha curcas. [•] UVB-radiation-induced DNA damage in cultured human blood lymphocytes. [•] RB4 fraction and L1 fraction protect UVB-radiation-induced DNA damage in HPBL. [ABSTRACT FROM AUTHOR]