Investigation of the antioxidant and synergistic activity of lycopene and other natural antioxidants using LAME and AMVN model systems

The antioxidant activity of lycopene and its cooperative interaction with vitamin E were studied in a homogenous solution of linoleic acid methyl ester (LAME). Antioxidant property of lycopene, β-carotene, vitamins C and E, individually or in combination, were assayed by measuring the inhibiting effect of individual or combination of antioxidants on the production of diene hydroperoxides from LAME oxidation induced by azo-initiator 2,2′-azobis (2,4-dimethylvaleronitrile) (AMVN). The lipophilic tomato extracts were also determined by the same assay. The lipophilic tomato extracts displayed greater inhibition on LAME oxidation compared to pure lycopene. The observed enhancement of inhibition on LAME oxidation by tomato lipophilic extracts might have results from the additive effect of individual antioxidants in the mixture and/or cooperative interaction between structurally different antioxidant. Combination of lycopene and vitamin E exhibited a greater inhibitory effect, in a concentration-dependent manner, than the additive effect of individual antioxidants, while the combination of β-carotene and vitamin E did not produce a similar synergistic effect. This study investigated the interaction between structurally different antioxidants.