Protective activity of the methanol extract of Usnea longissima against oxidative damage and genotoxicity caused by aflatoxin B1 in vitro

Aim: To investigate the effects of methanol extracts obtained from Usnea longissima (UME) on the genotoxicity and oxidative stress of aflatoxin B1 (AFB1) in cultured human blood cells.Materials and methods: Sister chromatid exchange (SCE) and micronucleus (MN) tests were used for estimation of genotoxic influences. Activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) and the malondialdehyde (MDA) level were also measured to evaluate the antioxidative effect of UME.Results: In the SCE and MN test systems, it was observed that UME suppressed the mutagenic effects of AFB1. Furthermore, an increase of MDA level and a decrease of SOD and GPx activities were observed after AFB1 treatment. UME eliminated the genotoxicity of AFB1 and lipid peroxidation by increasing the level of antioxidant enzymes activities.Conclusion: It was shown here for the first time that UME modulates the adverse effects of AFB1 in human blood cells. The results of the present study have also clearly shown that UME has strong antioxidative and antigenotoxic effects, and the role of these enzymes on the mechanism of antigenotoxic activity may be due to its antioxidant potency.