Phytochemical screening and in vitro antioxidant activities of Mentha suaveolens Ehrh. extract

Within the framework of the valorization of the medicinal and aromatic plants of Morocco, we were interested during this study in the characterization and the phytochemical identification of some secondary metabolites present in Mentha suaveolens Ehrh. and the evaluation of the antioxidant activity of this species using four methods: DPPH free radical scavenging test, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid, (ABTS) radical cation scavenging test, FRAP test measuring antioxidant power, and β bleaching-carotene. Mentha suaveolens is a species belonging to the Lamiaceae family, harvested in southern Morocco, and widely used in traditional medicine for its biological properties attributed mainly to phenolic compounds. Just as they protect plants, secondary metabolites also have a protective role in the human body and are therefore beneficial to our health. They are attributed, in particular, with antioxidant, anti-inflammatory, and antibacterial properties. In this regard, characterization and identification tests of secondary metabolites revealed the presence of alkaloids, flavonoids, catechic tannins, and terpenes in this plant, whereas, the aerial parts of this species are devoid of coumarins, cyanogenic compounds, saponins and free quinones. The quantification of the phenolic compounds gave high contents, with contents of total phenols (54.75 ± 5.62) μg GAE/mg, total flavonoids (32.41 ± 0.41) μg QE/mg, and total condensed tannins (27 ± 1) μg CE/mg. In addition, the results obtained show that Mentha suaveolens extract has stronger antioxidant activity using the β-Carotene method with IC50 (0.24 ± 0.06) mg/mL against IC50 (0.021 ± 0.001) mg/mL for the standard antioxidant by the DPPH free radical scavenging test.