MORPHOLOGICAL TRANSFORMATION OF SYRIAN-HAMSTER EMBRYO CELLS IN PRIMARY CULTURE BY MALACHITE GREEN CORRELATES WELL WITH THE EVIDENCE FOR FORMATION OF REACTIVE FREE-RADICALS

Malachite green (MG) (green crystals with metallic luster and very soluble in water) is highly cytotoxic to mammalian cells and also acts as a liver tumor promoter. In view of its industrial importance and possible exposure to individuals, MG poses a potential environmental health hazard. We have studied the effect of MG on the formation of morphologically transformed colonies using Syrian hamster embryo (SHE) cell transformation assay. MG induced a dose-related increase in the formation of transformed foci, the optimum concentration being 0.05 mu g/ml. Electron spin resonance (ESR) analysis using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin-trapping agent showed the formation of reactive free radicals during the in vitro metabolism of MG. The present study suggests a close relationship between the morphological transformation of SHE cells by MG and the possible involvement of reactive free radical formation.