1 University of Sao Paulo, Brazil.
Conjugated fatty acids is the general term for isomers of polyunsaturated fatty acids with conjugated double bounds, which has been associated with many health benefits effects, include antioxidant activity. Actually, researches focused in isomers from a-linolenic acid (from Linseed, LSO), like conjugated linolenic acid (CLNA) that includes multiples isomers from specific seeds, a-eleostearic (bitter melon, MSO) and punicic acid (pomegranate, PSO). CLNAs could be metabolized into conjugated linoleic acid (CLA), which have been shown the same benefits. The aim of this study was investigated in vitro and in vivo antioxidant capacity of vegetable oils containing polyunsaturated fatty acids, conjugated and non-conjugated. Different oils: CLA, LSO, PSO and MSO, were analyzed and administrated to Wistar rats by gavage for 6 weeks. Oils, serum and liver antioxidant capacity were measured by Peroxyl Radical Assay (ORAC) a nd Thiobarbituric Acid Reactive Substance (TBARS). The results from oils by ORAC, showed that CLA was more potent scavenging oxygen, probably by free fatty acids form. Similarly the results of MSO were higher than PSO, but, both equal to LSO. TBA values in oils were lower in sequence: LSO>PSO>MSO>CLA. The animals supplemented with MSO showed lower TBARS values, in accordance to results from high levels ORAC in serum too. Even PSO presented reduced production of TBARS, the antioxidant capacity in serum weren’t different in relation to control group. Overall results of ORAC in hepatic tissue showed that animals supplemented with CLA and LSO had higher antioxidant capacity compared to control group. The in vivo results show that the supplementation with oils containing different conjugated and non-conjugated isomers of polyunsaturated fatty acids, have different effects in relation to the antioxidant capacity, emphasizing the MSO that showed better plasma antioxidant capacity.