Constituents of the seeds of Cassia tora with inhibitory activity on soluble expoxide hydrolease

Efforts to extract soluble epoxide hydrolase (sEH) inhibitors from food sources through bioactivity-guided fractionation of Cassia tora seed extracts led to the isolation of one new compound, 1, and 15 known compounds, 2-16. Structural elucidations were performed using 1D/2D NMR spectroscopy and mass spectrometry. Compounds 1, 3, 4, 6, 10, 11, and 13-16 exhibited inhibitory activities on sEH with IC50 values of 2.2 +/- 2.1-40.6 +/- 3.4 mu M. Compound 13 was particularly active and exhibited a reversible-uncompetitive behavior in enzyme kinetic studies. A binding site on the enzyme for compound 13 was also predicted by Autodock 4.2 simulations. (C) 2015 Elsevier Ltd. All rights reserved.