Inhibitory effect of Emblica officinalis on the in vivo clastogenicity of benzo[a]pyrene and cyclophosphamide in mice

Benzo[a]pyrene (B[a]P) and cyclophosphamide (CP) are potent carcinogens/mut agens. Effect of Emblica officinalis extract administration on the in vivo genotoxicity of B[a]P and CP was studied using bone marrow chromosomal aber ration and micronucleus induction tests in mice. Three doses (50, 250 and 500 mg/kg body weight) of the plant extract were a dministered orally for 7 consecutive days prior to the administration of si ngle dose of mutagens (B[a]P 125 mg/kg oral; CP 40 mg/kg i.p.). It was found that administration of 250 and 500 mg/kg of E. officinalis ext ract significantly inhibited the genotoxicity of B[a]P as well as CP in bot h the assay systems. Administration of 50 mg/kg of the plant extract had no inhibitory effect. Vitamin C, a major constituent of E. officinalis when administered at dose level of 9 mg/kg b.w. (the approximate estimated amount present in the high est dose of plant extract, i.e. 500 mg) for 7 days did inhibit chromosomal aberrations and micronuclei induction, but not in a significant manner. Effect of administration of the abovementioned effective doses (250 and 500 mg/kg oral for 7 days) of plant extract and Vitamin C (9 mg/kg oral for 7 days) on the hepatic activation and detoxification enzymes was also studied . Significant induction in the levels of glutathione content (GSH) and of a ntioxidant and detoxification enzymes viz., glutathione peroxidase (GPx), g lutathione reductase (GR) and glutathione-S transferase (GST) resulted from plant extract treatment to animals. On the other hand, cytochrome P 450 le vel was significantly decreased in the plant-extract-treated animals. There was no significant change in cytochrome P 450, GSH contents and activities of enzymes on treatment with vitamin C. The data indicate that the possible mechanism of inhibition by plant extrac t is mediated hy its modulatory effect on hepatic activation and dispositio n processes.