Enantioselective toxicological effects of chiral profenofos and 2-Bromo-4-chlorophenol on bovine serum albumin: Molecular-cellular-biological multilevel evaluation

As a typical chiral organophosphate insecticide, the enantiomer of profenofos exhibits significant bioselective toxicity in the environment. This study investigates the enantioselective effects of chiral profenofos and 2-Bromo-4-chlorophenol on BSA. Multispectral analysis confirmed that S/R-profenofos and 2-Bromo-4-chlorophenol alterd the microenvironment of BSA, decreasing the α-helices content from 53.6 % to 52.9 %, 53.0 %, and 52.8 %. The binding constants K_a for the interaction of S/R-profenofos and 2-Bromo-4-chlorophenol with BSA were 4.70, 4.66 and 4.23 × 10⁴ M⁻¹, respectively. The LC₅₀ of S/R-profenofos and 2-Bromo-4-chlorophenol for zebrafish were about 0.670, 0.739 and 0.954 mg/L, while the acetylcholinesterase inhibition rate were 86.64 %, 81.21 % and 73.64 %, respectively. The toxicity levels follows the pattern of S-profenofos>R-profenofos>2-Bromo-4-chlorophenol, which was also confirmed by the molecular docking and cell experiments. This study evaluated the interaction mechanism between chiral pesticides and model proteins at the molecular level, providing a new perspective on the food safety risk of chiral pesticides.