DOSE-RESPONSE EFFECTS OF MALACHITE GREEN ON FREE-RADICAL FORMATION, LIPID-PEROXIDATION AND DNA-DAMAGE IN SYRIAN-HAMSTER EMBRYO CELLS AND THEIR MODULATION BY ANTIOXIDANTS

Malachite green (MG), consisting of green crystals with a metallic lustre, is very soluble in water and is highly cytotoxic to mammalian cells and also acts as a liver tumour promoter. In view of its industrial importance and possible exposure to human beings, MG poses a potential environmental health hazard. We have earlier reported the possible involvement of reactive free radicals in morphological transformation of Syrian hamster embryo (SHE) cells by MG. In this study we have studied the dose-response effects of MG on free radical formation, lipid peroxidation and DNA damage in SHE cells. Electron spin resonance analysis with 5,5-dimethyl-1-pyrroline-N-oxide as a spin-trapping agent was used to study the production of free radicals from MG. Exposure of SHE cells to MG demonstrated a dose-dependent increase in the generation of free radicals, lipid peroxidation and DNA damage. Treatment of SHE cells with antioxidant enzymes such as catalase (CAT) and glutathione peroxidase (GPx) prior to MG exposure decreased lipid peroxidation and DNA damage, with CAT being more effective than GPx. Since metabolism of MG leads to the generation of free radicals, and CAT and GPx decreased MG-induced lipid peroxidation and DNA damage, the present study confirms the possible relationship between the genotoxicity of SHE cells by MG and the involvement of reactive free radical formation.