Eugenol--an inhibitor of lipoxygenase-dependent lipid peroxidation.

The effect of eugenol on enzymatic lipid peroxidation catalyzed by soybean lipoxygenase was studied in an in vitro system. Lipid peroxidation was inhibited by eugenol in a concentration-dependent manner. The half-maximal inhibition (IC50) was found to be 380 microM eugenol. Enzyme kinetic studies showed that eugenol non-competitively inhibited lipid peroxidation by altering the maximum velocity (Vmax) and without any change in Michaelis-Menten constant (Km) values. The inhibitory mechanism implies that eugenol does not inactivate the enzyme directly but may interfere with fatty acid radical intermediates due to its hydroxy radical scavenging ability and thus play a role in inhibiting the propagation of lipid peroxidation.