Evaluation of genotoxic and cytotoxic activities of Solenostemon monostachyus (P. Beauv.) Brig. (Lamiaceae) using Allium cepa test

Background: Solenostemon monostachyus (P. Beauv.) Brig. (Lamiaceae), a medicinal plant used traditionally in the treatment of diseases, was investigated for genotoxic and cytotoxic effects using the Allium cepa test. Methods: The effect of the leaf extract on the root meristem cells of Allium cepa was investigated using onion bulbs exposed to 2.5 mg/mL, 5 mg/mL, and 10 mg/mL concentrations of the extract for macroscopic and microscopic analysis. Tap water was used as a negative control and Methotrexate (0.1 mg/mL) was used as a positive control. Results: There was statistically significant (p< 0.05) inhibition of root growth depending on concentration by the extract when compared with the negative control group. All the tested concentrations of the extract were observed to exert cytotoxic effects on cell division in A. cepa. The mitotic indices were 8.20±3.56%, 4.80±0.86&% and 3.60±0.56% for 2.5mg/mL, 5.0 mg/mL and 10.0 mg/mL of the extract. The extract-induced chromosomal aberrations and micronuclei (MNC) formations (2.33±0.65% for the 2.5 mg/mL of the extract) in A. cepa root tip cells were significant (p<0.05) when compared with control group. The leaf extract treatment further induced cell death, ghost cells, cell membrane damages, and binucleated cells. . Conclusion: These results suggest that the leaf extract of S. monostachyus possesses cytotoxic and genotoxic effects on A. cepa.