RESUMO
OBJECTIVES: Alzheimer's disease (AD) is a degenerative brain disease characterized by confusion, behavior changes, decline in memory and cognitive skills. One of the strategies in the treatment of AD is to use acetylcholinesterase (AChE) inhibitors. The current study aims to determine the AChE inhibitory activities of the extract and fractions of the root of Rauvolfia serpentina. METHODS: Extraction was carried out by maceration method using ethanol, followed by liquid-liquid partition using n-hexane, ethyl acetate and n-butanol. Further fractionation was conducted by using vacuum liquid chromatography (VLC). The AChE inhibitory assays were performed by using Ellmann's method. Phytochemical screening was carried out by TLC method. RESULTS: The ethanolic extract of R. serpentina showed inhibition against AChE enzyme with an IC50 value of 7.46 µg/mL. The extract and fractions showed higher inhibition against butyrylcholinesterase (BChE) compared to AChE. Amongst three fractions obtained, the n-butanol fraction showed the strongest inhibition with an IC50 value of 5.99 µg/mL against AChE. VLC fractionation of the n-butanol fraction yielded 13 subfractions (VLC 1-VLC 13). Four out of 13 subfractions gave more than 80% inhibition against AChE, namely subfractions 4-7, with IC50 values ranging from 4.87 to 47.22 µg/mL. The phytochemical screening of these subfractions suggested the presence of alkaloids. CONCLUSIONS: The ethanolic extract, as well as fractions of R. serpentina root, are potential for AChE inhibitor. The alkaloid compound may be responsible for this activity.
