Antioxidant Activity of some Medicinal Plant Extracts: Implications for Neuroprotection

Abstract

Background and Objective:This study was conducted in order to evaluate the effect of aqueous and ethanolic extracts of Phyllanthus niruri, Uncaria tomentosa and Mentha pulegium against Lipid Peroxidation (LP). Additionally, it was determined the ability of these plants to scavenge specific free radicals and the interaction with iron ions. Methodology: The LP, scavenging activity, total phenolics and flavonoids were determined by colorimetric methods, whereas HPLC analysis was used to characterize the phytoconstituents. Results: Extracts significantly prevented both basal or induced (by Fe 2+ , malonate, sodium nitroprusside or ferrocyanide) LP. Accordingly, the extracts were better antioxidants at higher used concentrations, the effect of aqueous seems to be higher than ethanolic; the effect of plants were found to be P. niruri>M. pulegium>U. tomentosa; extracts were better antioxidants when used in rat brain homogenates, as compared to yolk phospholipids. Extracts also presented significant scavenging activity, prevented deoxyribose degradation and chelate Fe 2+. The HPLC analysis revealed that the extracts have different types and quantities of phytoconstituents. Conclusion: Altogether, presented results support the idea that antioxidant activities of extracts are related to the ability to scavenge specific free radicals and/or interaction with redox chemistry of iron ions. Thus, the broad range of antioxidant activity of these plants indicates the use with potential application to reduce LP associated to neurodegenerative disorders.