Antioxidative Behaviors of 4-Hydroxy-2,5-dimethyl-3(2H)-furanone and 4-Hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone against Lipid Peroxidation

Natural flavor compounds, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) and 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF), were evaluated for antioxidative behaviors against lipid peroxidations. They inhibited hydroperoxidation of methyl linoleate initiated by a lipid-soluble azo compound, 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN), in solution. The antioxidative activities of HDMF and HEMF were less than that of ascorbic acid when the emulsified methyl linoleate oxidized by a water-soluble azo compound, 2,2'-azobis(2-amidinopropane) dihydrochloride, while they were more effective than ascorbic acid when lipid peroxidation was initiated by a lipid-soluble AMVN. These furanones were also more effective than ascorbic acid in the inhibition of the formation of cholesteryl ester hydroperoxides in plasma. HEMF suppressed the oxidation of low-density lipoprotein without any synergistic effect with alpha-tocopherol. In the autoxidation of rat brain homogenate, HDMF and HEMF acted as inhibitors, while ascorbic acid acted as a prooxidant. These results indicate that HDMF and HEMF are potent antioxidants so that they would be important components not only in exhibiting desirable flavor but also in inhibiting oxidative deterioration in foods.