Biological activities of Centaurium erythraea and its main chemotypes: menthol, carvacrol, and tricosane

Here, we investigated the antioxidant, antidiabetic, dermatoprotective, and antibacterial capacities of Centaurium erythraea essential oil (CEEO) and its major compounds namely menthol, carvacrol, and tricosane. The main findings revealed that CEEO, menthol, and tricosane impeded the proliferation of Gram-positive bacteria more efficiently than that of Gram-negative bacteria. The most active molecules in the FRAP assay were carvacrol (59.96 ± 2.60 µg/mL) and menthol (57.93 ± 15.63 µg/mL), while the DPPH and ABTS tests demonstrated a potent activity of CEEO. For the antidiabetic tests, CEEO displayed significantly lower IC50 values, 168.62 μg/mL for α-amylase and 87.18 μg/mL for α-glucosidase. These values indicated a marked inhibition compared to menthol, carvacrol, and tricosane as they exhibited a moderate inhibition of α-amylase (IC50 = 471.50 μg/mL, IC50 = 566.20 μg/mL, and IC50 = 385.26 μg/mL, respectively) and α-glucosidase (183.25 μg/mL, 201.18 μg/mL, 192.30 μg/mL, respectively). With an IC50 of 41.863 ± 0.031 μg/mL, CEEO also showed excellent efficacy against tyrosinase. For the inhibition of elastase, similar IC50 values for CEEO (113.02 ± 3.37 μg/mL) and menthol (112.06 ± 3.70 μg/mL) were reported while those of carvacrol and tricosane were 124.68 ± 4.31 and 145.26 ± 4.62 μg/mL, respectively. To sum up, CEEO, carvacrol, menthol, and tricosane exert various biological activities that need to be deeply investigated and optimized to select the best compound and/or combination. Main compounds of Centaurium erythraea L., essential oils, menthol, carvacrol, and tricosane, showed important antimicrobial and anti-enzymatic effects. Menthol is responsible for the dermatoprotective activity of CEEO. Tricosane and carvacrol revealed the most prominent antibacterial and antidiabetic effects.