Toxicological Investigations of Plants Traditionally used for Mosquito Control in Kenya’s South Coast

Background: Mosquito borne diseases affect many people globally and impede economic development. Plants are used for mosquito control since they are cost-effective, readily available and culturally acceptable. Objective: To investigate toxicological effects of plants use for mosquito control in Kenya’s south coast. Methods: Aqueous, acetone and hexane extract of L. camara (leaves), T. minuta (whole plant), A. indica (leaves), A. digitata (leaves), O. suave (whole plant) and P. barbatus (leaves) were tested for genotoxic potential using Allium cepa test. Acute dermal irritation and ocular toxicity were conducted as per OECD test guidelines. Results: There were significant differences among extracts and concentrations p<0.001. A. indica extracts showed a significant difference on root growth; P value for hexane was < 0.001, aqueous, 0.004 and acetone, 0.007. The roots were bent. A. indica showed most mitotic inhibition at concentration of 1mg/ml at 70.36±0.68 which was similar to vincristine sulphate. The least active was A. digitata at 1.42±0.68 at 0.125 mg/ml. Extracts of O. suave caused turgidity on the roots of Allium cepa. A. indica extracts had ghost cells(aqueous) and binucleate cells (acetone) while Aqueous extract of P. barbatus showed high cytoplasm to nucleus ratio. Conclusion: A. indica and P. barbatus extracts caused abnormal cells and it is possible for them to cause the same in human. None of the extracts exhibited dermal irritation or acute ocular toxicity. There was no significant change in weight of the test animals during the treatment period and there were no mortalities. Key words: genotoxic potential, Allium cepa test, mitotic inhibition, acute dermal irritation/corrosion, ocular toxicity