Differential sensitivity of Allium cepa L. and Vicia faba L. to aqueous extracts of Cascabela thevetia (L.) Lippold

Abstract

Cascabela thevetia (L.) Lippold, a well-known plant of family Apocynaceae is used as traditional medicine, has pharmacologically active constituents, yet is highly toxic, due to high glycoside content in seeds, leaves and fruits. So, an assessment of cytotoxicity/mutagenicity becomes prerequisite for its therapeutic efficacy. Two in vivo test systems -Allium cepa test and Vicia faba assay were used for genotoxicity monitoring; with the macroscopic parameter of root growth and the microscopic parameters of Mitotic Index (MI), chromosomal aberrations (CA) and Micronuclei (MN) of meristematic cells as reliable indicators of toxicity. The aqueous leaf and fruit extract of the plant were found to be significantly cytotoxic at 3mg/ml with all sorts of CA. Significant reduction in MI, abundance of CA, presence of MN after recovery, supported by statistical analyses indicated high/ sub lethal genotoxicity. However, the sensitivity of the two systems varied, with A. cepa being more sensitive to reduction in MI and V. faba being more sensitive for CA specially MN. Thus cautious, appropriate and minimum requisite of the plant should be used in therapeutic applications.