Isolation of tetramer stilbenoids from Shorea leprosula Miq., acetylcholinesterase inhibitory activity and molecular docking study

Shorea leprosula Miq. or locally known as “meranti tembaga”, belongs to the family of Dipterocarpaceae [1]. The wood of S. leprosula is used for utility furniture and ceilings whilst the resin is beneficial as an adhesive and medicine [2]. Besides being of importance in timber production, the genus of Shorea is also rich in oligostilbenoids which possess various biological activities [3],[4]. Due to that, S. leprosula has been selected to be phytochemically studied. The aim of this study are to isolate the chemical constituents from the stem bark of S. leprosula, to evaluate the acetylcholinesterase (AChE) inhibitory activity and to investigate the molecular docking study of the compounds. The isolation process was done by using several chromatographic methods to afford three pure compounds. Based on the analyses of UV, IR, NMR and comparison with the literature data, the pure compounds were elucidated as hopeaphenol (1), isohopeaphenol (2) and hemsleyanol D (3). The acetylcholinesterase inhibitory assay displayed good activity in compound 1 with the IC₅₀ value of 10.00 M while compound 3 showed moderate activity with the IC₅₀ value of 19.45 M. The capability of compounds 1-3 to form interactions with Tyr 72, Tyr 124 and Trp 286 is highly important due to the location of amino acid at the peripheral anionic site of AChE which suggest these compounds may block the entrance of active site gorge in preventing acetylcholine from binding to AChE [5] [Fig. 1]. Thus, the molecular docking study is in good agreement with the AChE inhibitory assay.

Fig. 1 Binding interactions of compounds 1-3 in acetylcholinesterase enzyme

• References

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