LAUSR

Abstract The hexane, chloroform, ethyl acetate, water, and n-butanol extracts of Arcethobium oxycedri (DC.) M.Bieb. (Santalaceae) were evaluated for their inhibitory effects against acetyl- (AChE) and butyrylcholinesterase (BChE), related to Alzheimer's disease at 200 μg/mL using microplate assays. Since oxidative stress contributes much to neurodegeneration, antioxidative effect of the extracts was determined in metal-chelating and ferric-reducing antioxidant power (FRAP) test systems as well as antiradical effect against 2,2-diphenyl-1-picrylhydrazyl (DPPH). Total phenol and flavonoid contents of the extracts were calculated spectrophotometrically. Our findings indicated that the EtOAc extract, the richest one in total phenol and flavonoid amount (455.22 ± 4.35 and 194.45 mg/g extract, respectively) displayed the highest cholinesterase inhibition (45.37 ± 1.23% for AChE and 94.74 ± 2.43% for BChE at 200 μg/mL). Fractionation of the EtOAc led to isolation of (+)-catechin as the major compound. Catechin exerted remarkable antioxidant effect, whereas it did not cause cholinesterase inhibition. Therefore, the EtOAc extract deserves further investigation for its high BChE inhibition.