Isolation of soluble epoxide hydrolase inhibitor of capsaicin analogs from Capsicum chinense Jacq. cv. Habanero.

Capsaicin (1) and dihydrocapsaicin (2) were isolated from the aerial parts of Capsicum chinense Jacq. cv. Habanero. In in vitro studies, the exhibited potent inhibitory activity against soluble epoxide hydrolase (sEH), with IC₅₀ values of 5.6 ± 1.2 and 7.3 ± 0.7 μM. Enzyme kinetics suggested that the two compounds (1 and 2) were competitive inhibitors with K_i values of 2.5 ± 1.0 and 4.7 ± 2.3 μM, respectively. Molecular docking and molecular dynamic studies showed that capsaicin analogs (1 and 2) bound strongly with Asp335, Tyr383, and Tyr466 residues in the active site. These results suggest that the two inhibitors (1 and 2) represent potentially therapeutic inhibitors of sEH.