Chemical composition and biological properties in Mentha spicata under conventional and organic fertilization

Introduction: Spearmint (Mentha spicata) is widely used in the pharmaceutical and food industries, thanks to chemical properties largely influenced by genetic and environmental factors, especially soil conditions. Objective: To determine the effect of conventional and organic fertilization on the chemical and biological properties of M. spicata. Methods: We conducted field trials in a randomized block experimental design, with four replications, using unfertilized crops and crops fertilized with urea (0,15 t ha-1) or vermicompost (5 and 10 t ha-1). Results: All fertilization treatments increased essential oil yield, carvone content, and total polyphenol concentration with respect to the control. They also increased the antioxidant capacity and the inhibitory activity of the acetylcholinesterase, butyrylcholinesterase, α-amylase, and α-glycosidase enzymes. The effect was more marked in the crop fertilized with 5 t ha-1 vermicompost. Conclusions: Both conventional and organic fertilization increase the yield and quality of M. spicata essential oils. However, organic fertilization with 5 t ha-1 vermicompost yields rich total polyphenols and carvone. This improves antioxidant and medicinal properties, acting on enzymes related to Alzheimer's disease and diabetes.