Inhibition of lipid oxidation in foods and feeds and hydroxyl radical-treated fish erythrocytes: A comparative study of Ginkgo biloba leaves extracts and synthetic antioxidants

摘要

Abstract This study explored the effects of butylated hydroxytoluene (BHT) and ethoxyquin (EQ) and ethyl ether extracts, ethyl acetate extracts (EAE), acetone extracts, ethanol extracts and aqueous extracts of Ginkgo biloba leaves (EGbs) on lipid oxidation in a linoleic acid emulsion, fish flesh and fish feed and in hydroxyl radical (·OH)-treated carp erythrocytes. The linoleic acid, fish flesh and fish feed were incubated with BHT, {EQ} and {EGbs} at 45°C for 8?d, respectively, except for the control group. The lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed was then measured by the ferric thiocyanate method or thiobarbituric acid method. The carp erythrocytes were treated with BHT, {EQ} or {EGbs} in the presence of 40?μmol/L FeSO4 and 20?μmol/L {H2O2} at 37°C for 6?h, except for the control group. Oxidative stress and apoptosis parameters in carp erythrocytes were then evaluated by the commercial kit. The results showed that BHT, {EQ} and {EGbs} inhibited lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed and ·OH-induced phosphatidylserine exposure and {DNA} fragmentation (the biomarkers of apoptosis) in carp erythrocytes. Furthermore, BHT, {EQ} and {EGbs} decreased the generation of reactive oxygen species (ROS), inhibited the oxidation of cellular components and restored the activities of enzymatic antioxidants in ·OH-treated carp erythrocytes. Of all examined EGbs, {EAE} showed the strongest effects. The effects of {EAE} on lipid oxidation in the linoleic acid emulsion and on superoxide anion and malonaldehyde levels, catalase activity and apoptosis in ·OH-treated carp erythrocytes were equivalent to or stronger than those of BHT. Moreover, these results indicated that the inhibition order of {EGbs} on the generation of {ROS} and oxidation of cellular components in fish erythrocytes approximately agreed with that for the food and feed materials tested above. And, the antioxidative and anti-apoptotic effects of {EGbs} were positively correlated with their flavonoid content. Taken together, these results revealed that the fish erythrocyte system can be used as an experimental model to evaluate lipid oxidation in food and feed ingredients. The {EAE} can be used as a potential natural antioxidant or apoptosis inhibitor. The inhibition effects of {EGbs} on lipid oxidation and apoptosis may be due to the presence of flavonoid compounds.