The effect of para-substituted benzaldehyde derivatives with push/pull electron groups on the conformation of bovine serum albumin and its toxicity investigation in Brachionus calyciflorus Pallas (rotifers).

As intermediates widely used in the synthesis of industrial compounds, excessive ingestion of 4-hydroxybenzaldehyde (4-HBzH) and 4-nitrobenzaldehyde (4-NBzH) may induce potentially irreversible damage in organisms. The potential toxicological of 4-HBzH and 4-NBzH were investigated through a multi-disciplinary approach involving density functional theory (DFT), multispectral techniques and molecular docking, with bovine serum albumin (BSA) employed as the model protein of the study. The interaction mechanism between 4-NBzH/4-HBzH and BSA involved static quenching, and the affinity of 4-NBzH for BSA was stronger than that of 4-HBzH as shown by the K value (4-NBzH: 6.30 × 10 M ＞ 4-HBzH: 5.96 × 10 M), which is also confirmed by DFT calculations. The binding of 4-HBzH/4-NBzH to BSA is mainly through hydrogen bonding and hydrophobic interactions, to which van der Waals forces also contribute, as supported by molecular simulations. Furthermore, the toxicity test based on the Brachionus calyciflorus Pallas (Rotifers) showed that the LC of 4-NBzH (8.36 mg/L) was significantly lower than that of 4-HBzH (12.13 mg/L). Interestingly, the electron-withdrawing group-substituted benzaldehyde derivatives may be more hazardous than the electron donor-substituted benzaldehyde derivatives. The findings of this study elucidate toxicological information on the action of 4-HBzH/4-NBzH with BSA and rotifers and offer theoretical foundation for the prevention of the hazards from benzaldehyde derivatives.