Evaluation of the Antioxidant Properties of Five Mentha Species

The aim of the study was to evaluate the antioxidant and free radical scavenging properties and to determine the phenolic content of the ethanol extract from five Mentha species [M. longifolia (L.) Huds., M. piperita L., M. pulegium L., M. rotundifolia (L.) Huds., and M. spicata L.]. The antioxidant activities of the extracts were investigated with two different methods, 2,2’-diphenyl-1-picrylhydrazyl radical (DPPH•) and 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS•+). M. piperita exhibited the strongest activity as a DPPH• scavenger. On the other hand, all the extracts were active in the ABTS•+ assay and no significant difference was observed in this assay. The total phenolic content (TPC) of the extracts was determined by Folin-Ciocalteu method and M. piperita showed the highest TPC. A high correlation was found between the DPPH• scavenging potency and the total phenolic content of the extracts (r2 > 0.989).