Aquilaria subintegra, locally known as “Gaharu”, belongs to the Thymelaeceae family. This plant’s leaves
have been claimed to be effective for the treatment of Alzheimer's disease (AD) by Malay traditional practitioner in Malaysia.
In this research, the chloroform extracts of the leaves and stem of A. subintegra were tested for acetylcholinesterase
(AChE) inhibitory activity. The Thin Layer Chromatography (TLC) results indicated the presence of phenols,
flavonoids, terpenoids, and alkaloids compounds in the extracts. Analysis of the stem chloroform extracts with LCMS/MS
displayed that it contains kaempferol 3,4,7-trimethyl ether. The AChE inhibitory activity of leaves and stem chloroform
extracts and kaempferol were 80%, 93% and 85.8%, respectively. The Brine Shrimp Lethality Assay (BSLA) exhibited
low to moderate toxicity of the chloroform extract from leaves (LC50=531.18 ± 49.53 μg/ml), the stem chloroform extract
(LC50=407.34 ± 68.05 μg/ml) and kaempferol (LC50=762.41 ± 45.09 μg/ml). The extracts and kaempferol were not cytotoxic
to human umbilical vein endothelial cells (HUVEC), human normal gastric epithelial cell line (GES-1) and human
normal hepatic cell line (WRL-68). The effect of leaf and stem chloroform extracts and kaempferol were determined in
the Radial Arm Maze (RAM) after administration by oral gavage to ICR male and female mice with valium-impaired
memory. Administration of kaempferol to the mice significantly reduced the number of repeated entries into the arms of
maze in males and females. In conclusion, the inhibition of AChE by leaf and stem chloroform extracts of A. subintegra
could be due to the presence of kaempferol. This extract is safe for use as a natural AChE inhibitor as an alternative to
berberine for the treatment of AD.