Phytochemistry, antioxidant and antimicrobial activities of the essential oils of Mentha rotundifolia L. in Tunisia

- This is the first phytochemical study of Mentha rotundifolia L. in Tunisia.
- Two chemotypes were defined based on this study.
- The first is a mixture of β-Caryophyllene, Germacrene D and Carveol.
- The second one is a mixture of Pulegone, Piperitenone oxide and 5-Acetyl Thiazole.
- Considerable antioxidant, antibacterial and antifungal activities were observed.

The present study is the first investigation of the chemical composition, antioxidant and antimicrobial activities of Mentha rotundifolia L. essential oils in Tunisia. Results show that essential oils from Beja locality were most complex and present 45 compounds representing 96.83% of the total oil composition. The major components of the studied oils in this site are β-Caryophyllene (26.67%), Germacrene D (12.31%) and Carveol (7.38%). 40 components representing 95.81% of the total oil were identified in Bizerte site. Those essential oils are dominated by Pulegone (32.09%), Piperitenone oxide (17.28%) and 5-Acetyl Thiazole (11.26%). Considerable levels of antioxidant activities of the investigated essential oils were highlighted. Variations in antioxidant activities may be attributed to the concentrations of major components and the presence of some phenolic compounds like Diosphenol and 2-Allyl-4-methylphenol. Our results showed strong activities of the investigated oils against all tested microorganisms. The highest antimicrobial activities were observed against Gram+ bacteria followed by Gram− ones then fungal species.