Essential oils of Mentha viridis rich phenolic compounds show important antioxidant, antidiabetic, dermatoprotective, antidermatophyte and antibacterial properties

The aim of this study was the investigation of the in vitro antioxidant, antidiabetic, dermatoprotective, antidermatophyte, and antibacterial properties of Mentha viridis essential oil (MVEO). Chemical composition of MVEO was determined using GC-MS analysis. Antioxidant activity was estimated by three complementary methods: DPPH, FRAP and ABTS. The in vitro antidiabetic effect was evaluated by the inhibition of α-Amylase and α-Glucosidase. Inhibitory effects of tyrosinase and elastase were used to reveal the dermatoprotective property of MVEO. Antibacterial activity was tested against five strains using agar well diffusion assay and microtitration method. The chemical composition determination of MVEO revealed the presence of carvone (37.26), 1.8-Cineole (11.82), and Terpinen-4-ol (08.72%) as the main compounds. MVEO presented remarkable antioxidant effects by IC50 values of 80.45 ± 1.86 μg/mL, 101.78 ± 3.14 μg/mL, and 139.59 ± 3.12 μg/mL obtained by DPPH, FRAP and ABTS tests respectively. In vitro inhibition of enzymes implicated in hydrocarbures degradation showed that MVEO exhibited important inhibitory effects against α-Amylase (IC50 = 101.72 ± 1.86 μg/mL) and α-Glucosidase (IC50 = 86.93 ± 2.43 μg/mL). Moreover, MVEO demonstrated remarkable inhibition of tyrosinase (IC50 = 55.13 ± 1.01 μg/mL) and elastase (IC50 = 114.24 ± 1.22 μg/mL). The antifungal activity showed important inhibitions of three dermatophyte species (T. mentagrophytes, T. tonsurans and T. violaceum). The antibacterial activity showed an important bactericidal action against tested strains, especially, Staphylococcus aureus and Listeria monocytogenes (MIC = MBC = 0.25%). The findings of this work showed that volatile components of MVEO could constitute a new source for antioxidant, antidiabetic, dermatoprotective, antidermatophyte and antibacterial properties. However, further investigations regarding the isolation of MVEO main compounds and investigations of their biological properties are required.