Phytochemical investigation of Rhus tripartita and its activity against cyclooxygenases and acetylcholinesterase
Purpose: To investigate the inhibitory activity of crude methanol extract, fractions and two pure compounds from Rhus tripartita stem cyclooxygenases (COX-1 and COX-2) and acetylcholinesterase (AChE); also, to evaluate their antioxidant properties in in-vitro assays.
Methods: R. tripartita extract and fractions were examined as inhibitors of COX-1 and COX-2 and AChE. Their antioxidant properties were also evaluated using various antioxidant tests, including free radical scavenging, nitric oxide, and total antioxidant capacity.
Results: Ethyl acetate fraction (RT2), aqueous fraction (RT4), subfraction RT2-II, and subfraction RT2-III had a potent inhibitory effect on AChE with low IC50 values. At the same time, a subfraction (RT2-III) was an effective COX-2 inhibitor (94.5 % at 10 μg/mL) followed by ethyl acetate fraction (RT2; 79.39 %), aqueous fraction (RT4; 70 %), total extract (RT; 66.18 %), subfraction RT2-III (64.08 %), compound 5 (epicatechin; 61.25 %), compound 2 (taxifolin; 55.63 %), subfraction RT2-II (46.85 %), and butanol fraction (RT3; 40.80%). RT2, RT4, RT2-II, RT2-III, and compound 2 each showed 100 % inhibition at 20 μg/mL.
Conclusion: The ethyl acetate fraction (RT2), aqueous fraction (RT4) and subfractions RT2-II and RT2- III are effective natural inhibitors of AChE. Subfraction RT2-III is the best COX-2 inhibitor, followed by ethyl acetate fraction RT2 and aqueous fraction (RT4). These bioactive materials can be considered natural COX-2 and AChE inhibitors
Keywords: Cyclooxygenase, Anti-nflammatory, Acetylcholinesterase, Anacardiaceous, Taxifolin, Epicatechin