Salicylic acid is a phenolic plant growth regulator that affects the secondary metabolite production of medicinal plants. Moreover, Zinc is one of the necessary micronutrients that has a positive effect on the growth parameters and physiological characteristics of the plants. This study aimed to evaluate the interaction effects of foliar application (distilled water (as control), ethanol 1% (as solvent), 1 and 2 mM salicylic acid and zinc application containing (0 (Zn omission), 0.025, 0.05, and 0.1 mgL-1) on the growth, phenolic compounds profile and antioxidant capacity of the peppermint. Results showed that response of most investigated traits to the application of zinc was differing with the levels of salicylic acid applications. In this experiment, variation among methods of antioxidant activity assay was observed. The highest antioxidant activity based on IC50 (0.16 mg mL-1) was observed in Zn omission and 1 mM SA application. In contrast, the highest rosmarinic acid (34.23 ± 0.04 mg g DW-1) and gallic acid (14.99 ± 0.06mg g DW-1), as the major PCs, were observed in 0.1 mgL-1 Zn and 1 mM SA application. SA application, as an elicitor, can enhance PCs and antioxidant activity of peppermint at the highest Zn level (0.1mgL-1) and Zn omission due to the stress condition of these Zn levels. Overall, these findings indicated that by increasing appropriate Zn levels and salicylic acid application, the accumulation of PCs and antioxidant activity of peppermint enhanced.

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