Anticholinesterase and antioxidant constituents from Gloiopeltis furcata

Activity-directed isolation of the ethyl acetate, methylene chloride and n-hexane fractions of Gloiopeltis furcata resulted in the isolation of 18 compounds. Their structures were elucidated as 2-(3-hydroxy-5- oxotetrahydrofuran-3-yl)acetic acid (1), glutaric acid (2), succinic acid (3), nicotinic acid (4), (E)-4-hydroxyhex-2-enoic acid (5), cholesterol (6), 7-hydroxycholesterol (7), uridine (8), glycerol (9), 5-(hydroxymethyl)-2- methoxybenzene-1,3-diol (10), (5E,7E)-9-oxodeca-5,7-dienoic acid (11), (Z)-3-ethylidene-4-methylpyrrolidine-2,5-dione (12), dehydrovomifoliol (13), loliolide (14), cholesteryl stearate (15), palmitic acid (16), cis-5,8,11,14,17-eicosapentaenoic acid (17) and α-linolenic acid (18) on the basis of spectroscopic and chemical evidences. Their anticholinesterase and antioxidant activities were evaluated via inhibitory activities on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) as well as scavenging activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and peroxynitrite (ONOO^-). All isolated compounds (1-18) exhibited moderate AChE inhibitory activities with IC₅₀ values ranging from 1.14-12.50 μg/ml, whereas 1, 7, 9, 17, and 18 showed mild BChE inhibitory activities with IC₅₀ values ranging from 5.57-15.89 μg/ml. Although most of the compounds isolated were lacking the scavenging activity on DPPH radical and ONOO^-, 5 and 10 showed good DPPH radical scavenging activity, and 5, 10, and 16 showed potent ONOO^- scavenging activity.