Cholinesterase, a-glucosidase, tyrosinase and urease inhibitory activities of compounds from fruits of Rinorea oblongifolia CH Wright (Violaceae)

From Rinorea oblongifolia fruits, 3-Nor-4 beta-friedelan-24-ol (1) and 3-decyl-6,7,8-trimethoxy-2H,5H-furo[4,3,2-de]isochromene-2,5-dione (4), new derivatives alongside, 28-hydroxyfriedelan-3-one (2), friedelin (3), 3,3',4,4',5'-pentamethylcoruleoellagic acid (5), hexamethylcoruleoellagic acid (6), 3',4,4',5,5'-pentamethylcoruleoellagic acid (7), and fatty compounds 8-11 were isolated and characterized using HRESIMS, EIMS, 1D and 2D NMR. In vitro enzyme inhibition of compounds 1, 2, 4, 5, 6 and 7 were evaluated on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), alpha-glucosidase, urease and tyrosinase. Against AChE and BChE, the phenolic compounds 4, 5, 6, and 7 had good activity probably due to the phenolic nature and methoxy substituents. Compounds 4, 5, 6 and 7 exhibited good alpha-glucosidase inhibition especially compound 4 whose IC50 = 42.45 & PLUSMN; 0.46 mu g/mL was close that of acarbose (IC50 = 20.52 & PLUSMN; 0.84 mu g/mL) standard drug. Urease and tyrosinase were appreciably inhibited by the compounds. Overall results of enzyme inhibitory assays indicate Rinorea oblongifolia, fruits and its constituents as potential remedy for enzymatic disorders.

Automated summary

New derivatives, 3-Nor-4 beta-friedelan-24-ol (1) and 3-decyl-6,7,8-trimethoxy-2H,5H-furo[4,3,2-de]isochromene-2,5-dione (4), were isolated and characterized from Rinorea oblongifolia fruits, along with other known compounds. The enzyme inhibitory activities of these compounds were evaluated, showing good activity against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), alpha-glucosidase, urease and tyrosinase. The results suggest that Rinorea oblongifolia and its constituents have potential therapeutic applications for enzymatic disorders.