Prolonged Water Deficit Stress and Methyl Jasmonate-Mediated Changes in Metabolite Profile, Flavonoid Concentrations and Antioxidant Activity in Peppermint (Mentha x piperita L.)

Peppermint (Mentha x piperita L.) infusion is one of the main important sources of antioxidants. This antioxidant property can be enhanced by using elicitors and inducing abiotic stress. This study was conducted to evaluate the foliar application of Methyl Jasmonate (50 mu M) and water deficit stress (no stress, mild stress and moderate stress as 100, 75 and 50% of field capacity, respectively) and their interactions on cultivated peppermint on plant growth, secondary metabolite and antioxidant capacity of infusions made under different treatment. Water deficit stress treatments increased flavonoid contents and total phenolic as well as antioxidant capacity significantly. Some phenolic compound such as luteolin, naringenin, coumaric acid, and quercetin were detected only in some drought and Methyl Jasmonate treatments. Also, fewer amino acids such as L-serine, Threonine, 4-aminobutiric acid, 5-oxo-L-proline and unsaturated fatty acids were identified. Also, foliar application of 50 mu M Methyl Jasmonate treatment improved plant growth parameters and metabolite profile such as carbohydrates and amino acids in non-stress and stress conditions. Therefore, inducing water stress and applying MeJA is recommended to enhance the biologic properties of peppermint and improve bioactive compounds and the antioxidant capacity of peppermint infusions.