Solvent-driven modulation of phenolic composition and biofunctional activities of three Mentha aquatica formulations: integrated in vitro and in silico insights

The goal of this work was to examine the effect of different solvents (Water, EtOH 70%, and acetone) on the phenolic composition, antioxidant, and antibacterial capacity of Moroccan Mentha aquatica L. leaf extract. To this end, HPLC-ESI-FULL-MS was used to characterize the extracts, while the Folin-Ciocalteu and aluminum trichloride techniques were used to evaluate the total phenolic and flavonoid contents. To assess the antibacterial capacity, the microdilution technique was performed to calculate the minimal inhibition concentration (MIC), and minimal bactericidal concentration (MBC). Phytochemical profiling revealed that the extracts were rich in bioactive constituents, particularly ferulic acid derivative, caffeoyl-protocatechuic acid derivative, quercetin, and diosmetin 7-O-beta-D-glucuronide. The hydroethanolic extract contained the highest levels of total phenolic (62.2 ± 1.2 mg GAE/g DW) and flavonoid (29.15 ± 0.09 mg QE/g DW) contents, exceeding those of the acetonic extract (22.2 ± 0.6 and 10.17 ± 0.07 mg GAE/g DW, respectively) and the water extract (22.4 ± 0.6 and 10.9 ± 0.6 mg QE/g DW, respectively). This extract also showed the strongest antioxidant effect, recording an IC₅₀ of 0.060 ± 0.001 mg/mL in the DPPH assay, and an EC₅₀ of 80 µg/mL in the RP test. In addition, it shows a great total antioxidant capacity, reaching 75.1 ± 2.0 mg EAA/g DW when compared to water and acetonic extracts (28.5 ± 1.4 and 21.1 ± 0.1 mg EAA/g DW, respectively). The antibacterial potential ranges from 0.78 ± 0.05 mg/mL to 12.6 mg/mL. In-silico prediction highlighted diosmetin 7-O-beta-D-glucuronide, quercetin, and equisetumpyrone as the key contributors to antioxidant capacity, while quercetin, 2,3,8-Tri-O-methylellagic acid, and diosmetin 7-O-beta-D-glucuronide were involved in antibacterial activity.