Characterization of polyphenolic constituents and radical scavenging ability of ripe tomato and red pepper fruits

Objective: Characterization of polyphenolic contents and the inhibitory effects of aqueous extracts of ripe tomato (Lycopersicon esculentum) and red pepper (Capsicum annuum) fruits on the sodium nitroprusside (SNP) and iron(II) (Fe2+)-induced lipid peroxidation in rat liver were examined in this study. Materials and Methods: Various experimental models such as the ABTS• (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) scavenging ability and ferric reducing power were used to characterize the antioxidant activity of the extracts. High-performance liquid chromatography (HPLC) was used to determine the phenolic content of the extracts. Malondialdehyde (MDA) was used as a measure of oxidative stress in the rat’s liver tissue. Results: The ABTS• scavenging ability and ferric reducing power of the aqueous extract of ripe red pepper were significantly higher than that of ripe tomato. Ripe red pepper and tomato fruits extracts inhibited NO• in a concentration dependent manner. Furthermore, the introduction of extracts of ripe red pepper and tomato caused a significant concentration-dependent decrease in the MDA content of the SNP and Fe2+-stressed liver homogenates. In addition, HPLC analyses of the extracts revealed the presence of different phenolic compounds. Conclusion: With respect to the results of the current study, ripe tomato, and red pepper could be considered to be potential sources of natural antioxidants.