Comparison of tea and sesame seed oils as two natural antioxidants in a fish oil model system by radical scavenging activity.

Tea and sesame seed oils, two natural antioxidants at 5% and 10% levels, were added to carp (Cyprinus caprio) and common kilka (Clupeonella cultiventris caspia) oils, and the peroxide value and thiobarbituric acid were evaluated after 13 days at 60 degrees C (oven test). The results showed that the antioxidant effects of tea and sesame seed oils in the two aforementioned fish oils were statistically similar. In addition, the radical scavenging activity (RSA) of tea and sesame seed oils (extracted with two solvents:n-hexane and benzene) and their methanolic extract (methanol-soluble phase), ethanolic extract (ethanol-soluble phase) and lipid fraction (non-soluble in methanol or ethanol) were evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical method. The results revealed that the RSA of sesame seed oil was higher than that of tea seed oil (IC(50) = 52 mg and 45 mg, respectively). In addition, among ethanolic and methanolic extracts, the RSA of the ethanolic extract of sesame seed oil (IC(50) = 65 ml and 68 ml in n-hexane and benzene solvents, respectively) and of the ethanolic extract of tea seed oil in benzene solvent (IC(50) = 73 ml) were the highest. Also, the RSA in the lipid fraction, non-soluble phase of sesame seed oil was the highest (IC(50) = 74 mg and 81 mg in n-hexane and benzene solvents, respectively). Furthermore, after 6 days at 60 degrees C the RSA values of tea and sesame seed oils were the same.