Antioxidant actions of olive leaf extract (Olea europaea L.) on reactive species scavengers

Abstract

This study aimed to evaluate in vitro antioxidant action of olive leaf extract (Olea europaea L.) by: i) Trolox equivalent antioxidant capacity (TEAC) by ABTS•+, DPPH and Ferric reducing antioxidant power (FRAP) assays; ii) scavenging of superoxide anion (O2•-), hypochlorous acid (HOCl) and nitric oxide (NO), compared to ascorbic acid. Results showed TEAC values as 0.148±0.015, 0.215±0.076 and 0.282±0.023 gram of trolox equivalent per gram of dry extract weight, to respective ABTS•+, DPPH• and FRAP. Olive leaf extract was better antioxidant than ascorbic acid on O2•- scavenging, at concentrations over 50 µg/mL; similar effects on NO scavenging for both was seen and on HOCl inhibition, the extract showed lower antioxidant action than ascorbic acid at all concentrations. Olive leaf extract showed potentiality to be used as antioxidant in biological systems.