Cytotoxicity, genotoxicity, and enzyme activity effects of UV filters and their chlorinated by-products in human lung epithelial cells (A549).

UV filters, commonly found in personal care products, undergo chlorination in swimming pools, forming disinfection by-products (DBPs) with potential toxicological and health impacts. This study aimed to evaluate the cytotoxic, genotoxic, and biochemical effects of three UV filters - 2-hydroxy-4-methoxybenzo-phenone (benzophenone-3 or BP3), diethylamino hydroxybenzoyl hexyl benzoate (DHHB), and 4-tert-butyl-4'-methoxydibenzoylmethane (avobenzone) - and their chlorinated by-products in human lung epithelial (A549) cells and investigate their interaction with lipid membranes under visible and UV light conditions. Parent UV filters exhibited moderate cytotoxicity at higher concentrations (BP-3: 167 μM; DHHB and avobenzone: 16.7 μM), whereas their chlorinated derivatives demonstrated enhanced cytotoxic effects, particularly 3,5-dichloro BP3 (BP3-Cl: 16.7 μM; BP3-diCl: 33.3 μM) and 2-chloro avobenzone (16.67 μM). Significant increases in glutathion-S-transferase (GST) activity were observed for 3,5-dichloro BP3 at concentrations of 74.5 μM and 166.67 μM, indicating possible oxidative stress responses, but no genotoxic effects were observed suggesting other mechanism of toxicity. Membrane interaction studies showed that 3,5-dichloro BP3 caused vesicle deformation under UVA exposure (385-400 nm), highlighting the potential of chlorinated by-products to alter membrane stability. Chlorination enhances the cytotoxic potential of UV filters, likely through oxidative stress and membrane disruption. These findings emphasize the need for further research on the environmental and health implications of UV filter DBPs, particularly in contexts of prolonged UV exposure such as swimming pool environments.