Comparison of total phenolic contents and antioxidant capacities in mint genotypes used as spices

Objective: Mint (Mentha spp.) genotypes used as spices are cultivated in Turkey and used for different purposes including herbal tea, spices, the cosmetics industry, and are used in folk medicine. While mint species have been used in traditional practices during humanity's long history, there is limited research on the comparison of their antioxidant capacity and phenolic contents. This aim of the research is to compare antioxidant capacity and phenolic contents in mint clones to determine superior genotypes for herbal and spice usage and cultivation. Methods: Antioxidant capacity was evaluated by ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC). Total phenolic content in clones were determined by Folin-Ciocalteu method. Results: Maximum total phenolic content [28.27 +/- 3.95 mu g gallic acid equivalent (GAE)/g dry weight (DW)] and FRAP activity 577.09 +/- 46.02 mu mol Trolox equiv/g DW were obtained from Clone 13 (M. spicata), while M. piperita clones were higher for TEAC activity (800.02 +/- 1.10 mu mol Trolox equiv/g DW). The results were first records for M. villoso nervata. FRAP and TEAC activities selected clones were correlated with total phenolic content (r=0.77; 0.73 respectively). Conclusion: According to the results, it can be suggested that Clone 13, Clone 5, (M. spicata) Clone 3 and Clone 8 (M. piperita) are more suitable for use as spice, herbal tea, and antioxidant agents. The clones must be selected for commercial cultivation by the grower and they can be used as spices and herbal teas.