1,5,9-epideoxyloganic acid (ELA) was isolated from the aerial parts of endemic Nepeta aristata Boiss Et Kotschy Ex Boiss crude extract (methanol:chloroform) using silica gel (hexane, chloroform, ethyl acetate, and methanol) and sephadex LH-20 (65% methanol-35% chloroform) columns. Activity-guided isolation was performed on methanol sub-fractions with DNA protection and enzyme inhibitory activities, and then the ELA was purified by prep-HPLC. The ELA structure, bio-guided isolate, was determined via 1H NMR, 13C NMR, and MS spectrometry. ELA's enzyme inhibition and DNA protection activities were investigated and compared with standard drugs. The inhibition capacity of ELA against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), urease, carbonic anhydrase (CA), α-glucosidase, α-amylase, lipase, and tyrosinase enzymes was evaluated by kinetic and molecular docking results. The ELA displayed the best inhibitory activity on AChE, BChE, α-glucosidase, urease, α-amylase, and tyrosinase with IC50 values of 2.53 ± 0.27, 3.75 ± 0.11, 3.98 ± 0.07, 4.40 ± 0.01, 6.43 ± 0.54 and 7.39 ± 0.00 µg/mL, respectively. ELA acted as a competitive inhibitor against BChE and α-glucosidase and a non-competitive inhibitor against AChE. The ELA's binding affinity values on AChE, BChE, and α-glucosidase were -7.70, -8.50, and -8.30 kcal/mol, respectively. DNA protection activity of the ELA molecule was determined as 57.53% for form I and 53.57% for form II. In conclusion, the inhibitory activity of ELA demonstrated its effectiveness in terms of its suitability in the pharmaceutical industry.Communicated by Ramaswamy H. Sarma.
Keywords: 1,5,9-epideoxyloganic acid; DNA protection activity; activity-guided isolation; enzyme inhibition; molecular docking.