Phytochemical Analysis and Screening of Acetylcholinesterase and Carbonic Anhydrase I and II Isoenzymes Inhibitory Effect of Heptaptera triquetra (Vent.) Tutin Root

Alzheimer's disease (AD) is characterized by progressive memory loss, deterioration of other cognitive functions, and inability to perform activities of daily living. Inhibiting the AChE enzyme causes Ach accumulation in cholinergic synapses and is expected to increase cognitive functions. Carbonic anhydrase enzymes (CAs) are ubiquitous in all living organisms. They have crucial physiological and pathological roles. CA inhibitors bind to catalytic zinc ion in the active site of CA isoenzymes and block their activity. The clinical use of CAIs had been established as antiglaucoma, anticonvulsant agents, diuretics, and anti-obesity drugs, in the management of mountain sickness, gastric and duodenal ulcers, neurological disorders, osteoporosis, and tumors. To evaluate the bioactive profile of dichloromethane extract prepared from Heptaptera triquetra root, isolation studies, AChE, and hCA I and II inhibitory activities were performed. According to isolation studies, one fatty acid, coniferyl palmitate (1); four sesquiterpene coumarins, umbelliprenin (2), badrakemin acetate (4), colladonin (5), karatavicinol (6); and two sterols, stigmasterol (3a), β-sitosterol (3b) were isolated. The dichloromethane extract and all isolated compounds showed high potency against all enzymes (except badrakemin acetate for AChE) when compared to standards. Umbelliprenin (2) with IC50 value of 31.500 nM against hCA I, colladonin (5) with IC50 value of 36.473 nM against hCA II and stigmasterol (3a), and β-sitosterol (3b) mixture with IC50 value 9.000 nM against AChE demonstrated the best activity.