Effect of chemical elicitors on peppermint (Mentha piperita) plants and their impact on the metabolite profile and antioxidant capacity of resulting infusions

Infusions are widely consumed all over the world and are a source of dietary antioxidants, which can be improved in plants using elicitors. The aim of this study was to evaluate the foliar application of salicylic acid (SA) (0.5, 1 and 2 mM) or hydrogen peroxide (H2O2) (0.05, 0.1 and 0.5 mM) on peppermint (Mentha piperita) plants and its effect on the metabolite profile and antioxidant capacity of resulting infusions. Whereas 2 mM SA treatment improved plant growth parameters and metabolite profile (carbohydrates and amino acids), 0.5 and 1 mM SA treatments increased phenolic compound concentration. Sinapic acid, rutin and naringin were detected only in SA treatments; antioxidant capacity was also improved. Regarding H2O2 treatments, no differences in plant growth parameters, metabolite profile or antioxidant capacity were found. Therefore, the application of SA to peppermint is recommended in order to improve bioactive compounds and the antioxidant capacity of infusions.