Molecular docking and spectral shift supported toxicity profile of metaldehyde mollucide and the toxicity-reducing effects of bitter melon extract

Abstract

Excessive use of metaldehyde to combat mollusks directly or indirectly endangers non-targeted organisms. The present study aimed to reveal the antitoxic potential of bitter melon (Momordica charantia L.) extract (BME) against metaldehyde-related toxicity in Allium cepa L. The experimental groups formed using A. cepa bulbs were exposed to aqueous solutions containing 350 mg/L BME, 700 mg/L BME, 200 mg/L metaldehyde, 200 mg/L metaldehyde +350 mg/L BME and 200 mg/L metaldehyde +700 mg/L BME, respectively. The bulbs in the control group dipped in tap water. Metaldehyde suppressed growth with respect to germination ratio, root elongation and weight gain parameters. In metaldehyde-administered group, mitotic index (MI) was reduced, while the frequencies of micronucleus (MN) and chromosomal aberrations (CAs) increased. Metaldehyde promoted CAs such as sticky chromosomes, vagrant chromosome, fragment, unequal distribution of chromatin, reverse polarization, bridge and multipolar anaphase in root tip meristem cells. Spectral shift and molecular docking confirmed the genotoxic effect of metaldehyde resulting from DNA-metaldehyde interaction. The DNA damage in root meristems was revealed using the Comet Assay. Metaldehyde stress provoked oxidative stress. Activities superoxide dismutase (SOD) and catalase (CAT) enzymes along with level of malondialdehyde (MDA) accumulation accelerated. In roots treated with metaldehyde, epidermis cell damage, flattened cell nucleus, cortex cell damage and cortex cell wall thickening were observed as meristematic cell damage. BME attenuated metaldehyde-induced toxicity in a dose-dependent manner. This study demonstrated the mitigative potential of plant derived BME with no-to-low side effects against hazardous chemicals including metaldehyde. Nature is the most valuable weapon against toxicity from pollutants. Therefore, the protective potential of BME against other harmful agents should be screened.