Genotoxic Effect of Paraben and Oxybenzone on Root Tips of Allium cepa

Paraben is widely used as preservative in foodstuffs, cosmetics and pharmaceutical drugs. Oxybenzone is the most popular UV filter in skin protecting formulations or sunscreens. When washed into the water bodies both paraben and oxybenzone act as environmental contaminants. Though there are reports on cytotoxicity of Paraben and Oxybenzone on aquatic animals, studies on genotoxic and cytotoxic behavior of these on plant cells are few. This study aims to investigate cytotoxic and genotoxic impacts of Oxybenzone, Methyl paraben and Propyl paraben on root tip cells of Allium cepa, using it as an indicator organism, exposing the onion root tips to different concentrations of Oxybenzone (0.1, 0.2, 0.3, 0.4, 0.5, 0.6%), Methyl paraben and Propyl paraben (0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30%) that are usually used as per FDA guidelines. The maximum root length (28.6±0.3mm) was observed in 0.01% concentration of MP after 24 h, then (28.9±0.3mm) in 0.01% concentration of MP after 48 h and then (18.5±0.7mm)in 0.1% concentration of OB after 72 h. respectively. The average decrease in root length was far more prominent in MP concentrations than in OB and PP. The mitotic index of the control was found to be 32.4±0.7, 36.9±0.6 and 40.5±0.7 after 24, 48 and 72 h respectively. Mitotic index reduced to 8.9±0.5, 8.2±0.3 and 7.5±0.6 in 0.6% OB and 6.5±0.3, 5.9±0.9 and 5.1±0.8 in 0.30% MP 9.2±0.3, 8.8 ±0.4 and 8.1±0.6 in 0.30 PP after 24, 48 and 72 h of exposure. A high negative correlation was observed between Mitotic index and concentrations of OB, MP and PP. Higher concentrations OB, MP and PP disturb stages of cell division causing chromatin bridge formation, stickiness, disturbed metaphase, multiple chromosomal breaks and cell disintegration. The present study also suggests that plants being an important component of the ecosystems need to be included in evaluating the overall toxicological impact of the parabens and oxybenzone in the environment.