Genotoxic effects of Ocimum basilicum L and Leucas zeylanica L in root tip cells of Allium cepa L

The present paper mainly deals with the effect of aqueous leaf extract of two plant species Ocimum basilicum L and Leucas zeylanica L on the mitotic index and chromosomal abnormalities in the root tip cells of Allium cepa L. About 50 g of fresh leaves were grinded separately to get the mother solution of the leaf extract which was further diluted to different concentrations by adding required quantity of double distilled water. The root tips of Allium cepa L were treated with different concentrations viz 10%, 25%, 50%, 75% and 100% of the extract of Ocimum basilicum L and Leucas zeylanica L separately and also with double distilled water for the control for four hours at room temperature. The treated and controlled root tips were fixed in freshly prepared 1:3 acetobutanol and squashed in freshly prepared 2% acetocarmine solution. The frequency of cell division (mitotic index) and chromosomal abnormalities were noted in different mitotic stages of mitotic cell division of each treatment. The result showed that both Ocimum basilicum and Leucas zeylanica Loaf extracts are mito-depressive and inducing chromosomal abnormalities such as stickiness, fragments, bridges, laggards, micronuclei, disturbed metaphase/anaphase and micronuclei. The chromosomal abnormalities showed a linear correlation with the doses of the leaf extracts. It was also noted that the leaf extract of Ocimum basilicum L is more mitodepressive than Leucas zeylanica L, hence Ocimum basilicum may be considered as a potential antitumor promoting agent.