Cytotoxicity and genotoxicity effects of some medicinal plants on root growth and root tip meristem of Allium cepa

Cytotoxic and genotoxic effects of extract and essential oil of medicinal plants are evaluated by cytogenetic experiments and parameters like mitotic index and chromosomal aberrations. Evaluation of cytotoxicity and genotoxicity of aqueous extracts of Securigera cecuridaca seeds, Adiantum capillus-veneris leaves, and Trachyspermum ammi fruits on meristem cells of Allium cepa root and its growth was the aims of this study. Twenty gram of powdered samples were poured in to separate Erlenmeyer flask and 100 ml of distillated water were added. The flasks were covered by aluminum foil and shacked for 24 hours. Then extracts were filtered and centrifuged. In order to determine percentage of mitotic index and chromosomal aberrations 3000 cells were countered for each treatment and by division of mitotic cells and chromosomal aberrations numbers to total cells multiply to 100 were calculated. The results showed that the reduction of mitotic index and root growth of onion are related to extract concentration. The highest cytotoxicity and genotoxicity are related to aqueous extracts of A. capillus-veneris leaves and S. securodaca seeds, respectively. The extracts of three plants induced chromosomal aberrations such as C-mitosis, chromosomal stickiness, loss and laggard chromosome, chromosomal bridge, micronucleus and also cell death in the root meristematic cells of onion. The extract of S. cecuridaca seeds had the highest genotoxicity. Root of Allium cepa test is a rapid and efficient method for evaluation of cytotoxicity and genotoxicity of aqueous extracts of medicinal plants. This study shows that consumption of medicinal plants must be with precaution.