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 lus tre, is very soluble in water and is highly cytotoxic to mammalian cel ls and also acts as a liver tumour promoter. In view of its industrial importance and possible exposure to human beings, MG poses a potentia l environmental health hazard. We have earlier reported the possible i nvolvement of reactive free radicals in morphological transformation o f Syrian hamster embryo (SHE) cells by MG. In this study we have studi ed the dose-response effects of MG on free radical formation, lipid pe roxidation and DNA damage in SHE cells. Electron spin resonance analys is 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 decrea sed MG-induced lipid peroxidation and DNA damage, the present study co nfirms the possible relationship between the genotoxicity of SHE cells by MG and the involvement of reactive free radical formation.