Genotoxic and antigenotoxic potential of the Lagenandra toxicaria Dalz. rhizome methanol extract using Allium cepa assay.

Abstract

This study is the first ever approach to evaluate the possible genotoxic effect of the Lagenandra toxicaria rhizome methanol extract and its antigenotoxic potency against 3% H2O2 induced genetic damage on Allium cepa root tip model. The assay revealed a significant decrease in mitotic index (MI) and an increase in the percentage of clastogenicity in a time and dose-dependent manner in the roots exposed to Lagenandra toxicaria extract at 0.2 mg/ml, 0.5 mg/ml, 1 mg/ml, 5 mg/ml and 10 mg/ml concentration for 1, 2 and 4hour. The ultra structures of cell surface and biochemical changes of the cells were assessed in four hour treated roots using Field emission scanning electron microscopy (FESEM) and Fourier-transform infrared spectroscopy (FTIR). The higher dose of 10 mg/ml treated roots showed an evident morphological as well as biochemical changes compared to the control. The agarose gel electrophoresis showed the loss of DNA integrity in the roots that were treated with 10 mg/ml extract for four hours, where as the control showed comparatively intact DNA bands. The in situ histochemical staining by Schiff’s reagent and nitroblueterasolium (NBT) confirmed the increased lipid peroxidation and free radical generation in four hour treated samples. Subsequently, the possible antigenotoxic potential of the plant extract was explored at its lower doses using H2O2 standard assays. The H2O2 treatment induced nuclear lesions in 93.45 ± 2.33% cells and it was seen to be reduced significantly (50.99 ±7.59 % and 37.13 ± 2.66 %) after the treatment with lower concentration of 0.01 mg/ml and 0.02 mg/ml extract respectively. This suggest that the Lagenandra toxicaria rhizome methanol extract acts as antigenotoxic agent at lower doses but at higher doses the extract induces clastogenic effects and thus acts like a janus-faced compound.