Comparative Cytotoxic and Genotoxic Assessment of Methylparaben and Propylparaben on Allium cepa Root Tips by Comet and Allium cepa Assays

Parabens (PBs) are alkyl esters of para‐hydroxybenzoic acid and are widely used in pharmaceuticals, food and beverages, and cosmetics due to their antimicrobial properties. Parabens are also known as “Endocrine disruptors” and can cause toxicity in different organisms. Parabens, especially methylparaben and propylparaben are also present in many environmental matrices, such as water sources and soil, and can cause cytotoxic and genotoxic effects in different organisms. This study aimed to evaluate the genotoxic and cytotoxic effects of the two most commonly used types of parabens that are methylparaben and propylparaben on meristematic cells in onion root tips by comet assay and cytological anomaly‐based evaluation. Root growth inhibition assay was used to evaluate root growth inhibition. A. cepa assay was used to assess mitotic index (MI) and chromosomal aberrations (CAs). DNA damage was assessed by comet assay. The half maximal effective concentration (EC50) on the growth of A. cepa cells calculated for methylparaben and propylparaben was 75 ug/mL (2.70 ± 0.10 cm) and 25 ug/mL (2.70 ± 0.2 cm), respectively. Similarly, dose‐ and time‐dependent decrease in mitotic index (MI), increase in chromosomal aberrations (CAs) and increase in DNA damage were observed by the exposure of A. cepa root tips to methylparaben and propylparaben upon 24 h and 48 h exposure periods. The findings of the study showed that propylparaben is more cytotoxic and genotoxic than methylparaben as evidenced by a significant reduction in MI, along with an increase in chromosomal aberrations and DNA damage when compared to methylparaben.