Chemical Composition and Antioxidant Effect of Mentha rotundifolia Extracts

Aim: This report was aimed to investigate both the chemical composition and the antioxidant activity of two extracts from Mentha rotundifolia aerial parts. Methods: Aqueous and acetonic extracts were obtained by decoction and Soxhlet apparatus, respectively. Total polyphenols contents were determined using Folin- Ciocalteu reagent whereas flavonoids were evaluated by AlCl₃ method. LC-MS/MS method was carried out to reveal the phytochemical composition of extracts. Some tests were used to evaluate the in vitro antioxidant activity of extracts such as DPPH free radical scavenging assay, ABTS⁺ radical cation decolorization assay, OH^• radical scavenging assay, ferrous ion chelating, reducing power and β-caroten/linoleic acid bleaching assay. Results: The results showed that the aqueous extract was richer on polyphenols and flavonoids comparing to the acetonic extract. The analysis by LC-MS/MS allowed to identify many phenolic compounds in extracts, predominated by rosmarinic acid. In addition, the extracts were found to possess a significant antioxidant activity. Conclusion: Accordingly, it can be concluded that M. rotundifolia is quite rich in phenolic compounds and has a good antioxidant activity.