A comparative study of the chemical composition and antioxidant capacity of the essential oils from three species of Mentha cultivated in Morocco

Context: Mentha species are well known for their health benefits. Products extracted from aromatic plants of this genus (Mentha) are increasingly being studied for their active constituents in order to replace synthetic products that are harmful to health. Aims: To determine the chemical composition, physicochemical parameters, and antioxidant properties of essential oils of M. spicata, M. piperita, and M. pulegium. These plants were collected from three different geographical areas in the Rabat-Sale-Kenitra region of Morocco, with an additional focus on analyzing the fluctuation of their chemical composition based on their locations. Methods: Essential oils obtained through hydrodistillation of the fresh aerial parts of the plants were analyzed via gas chromatography and gas chromatography-mass spectrometry. The antioxidant capacity was measured by several chemical tests: DPPH, ABTS, and FRAP. Results: Multiple major components were identified, showcasing variations in composition between species as well as between plants of the same species. M. spicata was characterized by carvone, piperitone, 1,3,8-p-menthatriene; while M. piperita features linalool, D-carvone, 1,3,8-p-menthatriene; and M. pulegium had a single major component which is pulegone. To the best of our knowledge, it is assumed that a new set of chemotypes may be defined based on the geographical regions studied. The examined essential oils demonstrated notable antioxidant efficacy. Conclusions: These findings suggest the potential use of extracts from these plants as an alternative to synthetic chemical products. Therefore, they could find applications in complementary medicine as well as in the pharmaceutical and food industries.