Role of Ocimum sanctum as a Genoprotective Agent on Chlorpyrifos-Induced Genotoxicity

Abstract

Protective effect of Ocimum sanctum was evaluated on chlorpyrifos-induced genotoxicity in in vivo and in vitro models. Two different concentrations of pesticide were taken, i.e., 1/5 and 1/15 of LD(50) of chlorpyrifos for the in vivo study. Rats were pre-treated orally with O. sanctum extract (OE) at 50 mg/kg b.wt. For the in vitro studies, human lymphocyte cultures were exposed to 75 μg/ml chlorpyrifos with and without OE. Structural and numerical (both aneuploidy and euploidy types) chromosomal aberrations (CAs) were scored for the assessment of induced genotoxic effects, while the variation in mitotic index (MI) was considered as a monitor for induced cellular toxicity. The same concentration of the pesticide (75 μg/ml) was taken to study the DNA damage by comet assay. Results showed that lymphocytes treated with the pesticide exhibited increased DNA damage but the increase was statistically insignificant (P>0.05). In rats pretreated with OE, a significant (P<0.01) increase in MI was observed and there was a significant decrease in the frequency of aberrant cells as compared to the rats treated with chlorpyrifos alone. A significant (P<0.05) increase in CA was observed in cultures treated with 75 μg/ml chlorpyrifos as compared to controls, which decreased significantly (P<0.05) with OE pretreatment.

Keywords: Chlorpyrifos; Ocimum sanctum; chromosomal aberration; comet assay.