Composition and Acetyl Cholinesterase Inhibitory Properties of the Essential Oil of Xylopia Aethiopica (Dun) A. Rich (Annonaceae) Stem Bark from South East Nigeria

Abstract

The chemical composition of the essential oil of Xylopia aethiopica stem bark from Nigeria was investigated by gas chromatography/mass spectrometry analyses. A total of 57 compounds were identified in the oil, thus representing 94.6% of the total oil and the major constituents include ?-terpineol (4.9%), benzaldehyde (4.9%), cyperene epoxide (5.8%), camphene (6.3%), ?-guaiol (6.6%), ?-thujene (9.5%) and tricyclene (16.5%). The monoterpene hydrocarbons and oxygenated monoterpene formed the main portion in the oil with 42.5% and 28.9% respectively. The acetyl cholinesterase inhibitory property of the essential oil was investigated comparing it with the standard drug Huperzine A. The oil recorded a significant inhibitory concentration against the enzyme acetyl cholinesterase at the minimum concentration of 5 ppm; an indication that the essential oil can be explored in treatment of cases related to memory improvement.