Chemical Profile and Bioactivities of Three Species of Mentha Growing in the Campania Region, Southern Italy

The genus Mentha (Lamiaceae), comprising aromatic perennial plants widely distributed in temperate regions, holds significant medicinal and commercial value. This study aimed to investigate the chemical profile and bioactivities of hydroalcoholic extracts from Mentha longifolia (L.) L., Mentha pulegium L., and Mentha spicata L. harvested from the Campania region, Southern Italy. Chemical analysis using LC-HRESIMS/MS identified a total of 21 compounds. The extracts, particularly M. pulegium, exhibited notable antioxidant activity, evaluated through DPPH and FRAP assays, probably related to their chemical composition. Both M. pulegium and M. longifolia demonstrated a higher phenolic content, with M. pulegium also containing the highest levels of flavonoids. In addition, the extract’s ability to inhibit biofilm formation was evaluated against several pathogenic strains, including Gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus) and Gram-negative bacteria (Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli) using crystal violet and MTT assays. All extracts effectively inhibited biofilm formation in A. baumannii and P. aeruginosa, with M. pulegium also showing moderate activity against the metabolism of L. monocytogenes. The pronounced antibacterial and biofilm-inhibitory properties of M. pulegium highlight its potential for pharmaceutical applications.