Genoprotective potential of Brassica juncea (L.) Czern. against mercury-induced genotoxicity in Allium cepa L.

Brassica juncea (L.) Czern. is an important species of the family Brassicaceae with immense medicinal value.The main goal of this study was to investigate the antigenotoxic effects of different concentrations (0.1%-1.0%) of chloroform extract of B. juncea seeds on mercury-induced (0.75 ppm) genotoxic effects in root cells of Allium cepa. Three different modes of treatment were performed: pretreatment, posttreatment, and simultaneous treatment. For pretreatment, freshly emerged root tips were first treated with different concentrations of seed extract for 3 h and then treated with Hg for 3 h. For posttreatment, the roots were first treated with Hg and then with extract concentrations. For simultaneous treatment, different concentrations of extract were added along with the Hg. The study revealed that chloroform extract was neither toxic nor in possession of genotoxic activity. Treatment with Hg caused a decrease in mitotic index and induction of chromosomal aberrations as compared to the negative control. This effect was reversed by treatment with different concentrations of chloroform extract of seeds of B. juncea. Maximum percentage inhibition (95.3%) of genotoxic effects was observed with 1% chloroform extract (post- and simultaneous treatment). This study clearly indicates that the chloroform extract of B. juncea seeds has antigenotoxic potential against mercury-induced genotoxicity in a dose-dependent manner by evaluating A. cepa root chromosomal aberration assay.