Unveiling the binding landscape of cinnamaldehyde with digestive proteases:An exploration of specific interactions and conformational dynamics.

Cinnamaldehyde (CMA) is a natural compound with health benefits that have demonstrated multiple biological effects in food and pharmacy. Here, the binding mechanism of CMA to trypsin and pepsin in vitro was systematically investigated by multispectral combined with computational simulations. Results showed that CMA with trypsin and pepsin was static quenching mechanism. Thermodynamic parameters, molecular docking and dynamics simulation analyses showed that hydrogen bonding and van der Waals force were the main interaction forces in the CMA-trypsin system, whereas the binding of the CMA-pepsin system was dominated by electrostatic force. The binding affinity of the CMA-pepsin was significantly higher than that of the CMA-trypsin at 310 K. Spectroscopy analyses confirmed the ability of CMA to induce conformational changes in both. The studies have revealed the binding mechanism of CMA to trypsin/pepsin and provided theoretical support at the molecular level for elucidating the potential biological effects of CMA in the digestive system.