Inhibitory activity of lignanamides isolated from hemp seed hulls(Cannabis sativa L.) against soluble epoxide...

Soluble epoxide hydrolase (sEH) is a therapeutic target for inflammation. In the present study, we isolated one new (1) and four known (2-5) compounds from the ethyl acetate fraction of hemp seed hulls. Their structures were elucidated as lignanamides via nuclear magnetic resonance and mass spectral analyses. All five compounds inhibited sEH activity, with half-maximal inhibitory concentrations of 2.7 ± 0.3 to 18.3 ± 1.0 μM. These lignanamides showed a competitive mechanism of inhibition via binding to sEH, with k_i values below 10 μmol. Molecular simulations revealed that compounds 1-5 fit stably into the active site of sEH, and the key amino acid residues participating in their bonds were identified. It was confirmed that the potential inhibitors 4 and 5 continuously maintained a distance of 3.5 Å from one (Tyr383) and four amino (Asp335, Tyr383, Asn472, tyr516) residues, respectively. These findings provide a framework for the development of naturally derived sEH inhibitors.