Enzyme inhibition andantioxidant properties of different Melissa officinalis L. extracts: experimental, DFT,...

The present paper focuses on the analyses of enzyme Inhibition and antioxidant properties of acetone, ethanol and water extracts of Melissa officinalis L. The biologically active molecular components of the mentioned extracts of the plant were reported with the help of through validated LC-MS/MS method. Validated LC-ESI-MS/MS analysis identified quinic acid, protocatechuic acid, protocatechuic aldehyde, vanillin, p-coumaric acid, naringenin, luteolin, apigenin, kaempferol, hesperetin, and acacetin as representative phytochemicals exhibiting distinct solvent-dependent distribution patterns. To test the antioxidant capacity of the extracts, several popular antioxidant capacity determination methods were used, including DPPH, ABTS, CUPRAC, and FRAP assays. The acetone extract exhibited the strongest antioxidant activity, showing DPPH, ABTS, CUPRAC, and FRAP values of 195.10, 246.39, 467.09, and 266.96 mg TE/g, respectively. Enzyme inhibition studies demonstrated that the ethanol extract showed the highest inhibitory activity against AChE (2.88 mg GALAE/g), BChE (1.92 mg GALAE/g), tyrosinase (55.90 mg KAE/g), α-amylase (0.18 mmol ACAE/g), and α-glucosidase (3.35 mmol ACAE/g). In the theoretical part of the study, chemical reactivity analyses about the major molecular components in the extracts were done using Density Functional Theory (DFT) based parameters and electronic structure principles. In addition, the strength and mechanisms of interaction of these molecules with the enzymes studied in the experimental part were tested through molecular docking and molecular dynamics simulations. Experimental and computational analyses were supported each other.