Comparative study of chemical composition Antioxidant and Antimicrobial activity of Methanolic Extracts of Mentha rotundifolia

Mentha rotundifolia is a member of the Lamiaceae family and is distributed mainly in traditional medicine in Algeria and the Mediterranean locality. This study aimed to demonstrate how the extraction technique can determine the type of active ingredients obtained, as well as their potential pharmacological and therapeutic effects. The methanolic extracts were obtained by maceration and Soxhlet apparatus. The study of the chemical composition was determined by colourimetric methods and liquid chromatography–mass spectrometry (LC–MS/MS); the antioxidant activity was evaluated in vitro by three tests: DPPH test, ferrous ion chelating test and reducing power test. The antimicrobial effect of extracts was evaluated by agar diffusion assay against six microbial strains. The results demonstrate that the best yield of extraction, Total phenolic and flavonoid contents, and antioxidant activity were found to be higher in the extract obtained by Soxhlet than those obtained by maceration. The phytochemical screening tests identified polyphenols, flavonoids, tannins, terpenoids, and quinones, and anthraquinones and saponins were absent in both extracts. The LC–MS/MS revealed the presence of several phenolic compounds, the predominant in both extracts was rosmarinic acid. The antimicrobial activity shows that both extracts have no effect. In conclusion, this study reveals that extraction by Soxhlet is more suitable than extraction by maceration for this plant.