Effect of diastereoisomeric epoxyrotenones on hepatic epoxide hydrase activity

The effect on epoxide hydrase activity of the two diastereomeric (6′R) and (6′S)-6′,7′-epoxyrotenones formed during the oxidative metabolism of rotenone on the isopropenyl side chain is reported. The activity of microsomal epoxide hydrase was determined using styrene oxide as substrate. The results indicate that the two diastereomeric 6′,7′-epoxyrotenones are good substrates for epoxide hydrase and are noncompetitive inhibitors for the hydration of styrene oxide. The more polar of the two isomers is more active as inhibitor of this enzyme.