Abstract

Peltophorum pterocarpum, family Leguminosae is a tree natural to tropical South-Eastern Asia and was brought to Nigeria by immigrants. It has been used traditionally by the South Western people of the country as memory enhancer and anti-ageing. The present study was done to assess the cholinesterase inhibitory activity of the extracts and fractions of P. pterocarpum using spectrophotometric and thin layer chromatography (TLC) bioautographic assay methods. Eserin was used as reference cholinesterase inhibitors. The methanolic extract of the leaves, root bark and stem bark were found to be active. The stem-bark gave the highest activity (68.85±3.53%) and better selectivity towards acetylcholinesterase (AChE) at a dose of 42.5 µg/ml followed by the root bark which inhibited both AChE and butyrylcholinesterase (BuChE) at 48.46±4.47 and 51.77±2.20, respectively and then the leaves with values of 47.50+2.41 and 48.91+0.71 against AChE and BuChE, respectively. Fractionation of the various plant parts showed that the active constituent many be moderately polar being mostly extractable in ethyl acetate and that purification leads to improved activity. These results demonstrate that P. pterocarpum inhibits cholinesterase and thus may be relevant in the treatment of memory dysfunctions and neurodegenerative disorders such as Alzheimer’s disease.

Key words: Peltophorum pterocarpum, acetylcholinesterase, butyrylcholinesterase, memory dysfunctions.