Comparison of total phenolic and antioxidant activity of different Mentha spicata and M. longifolia accessions

This study investigated total phenolic and antioxidant activity of five Iranian mint accessions from two different species, Mentha spicata L. (Mzin1, Mzin3 and Mzin8) and M. longifolia L. (Mzin5 and Mzin6). The content of total phenolics (mg tannic acid equivalent per g dry weight of the sample) differed from 50.1 in Mzin3 to 67.2 in Mzin6. The highest percent radical scavenging activity was observed with Mzin6 at all concentrations studied (50, 100, 250, and 500 ppm). Peroxide value of sunflower oil containing Mzin5 and Mzin6 was the lowest among the mint accessions and almost equivalent to that of butylated hydroxytoluene at 200 ppm concentration. In overall, M. longifolia was superior to M. spicata, as determined by two model systems, indicating its potential use as a natural source of dietary antioxidant.