Chemical Constituents of Shorea macroptera Dyer.

Shorea is the largest and economically most important genus in Dipterocarpaceae family which consists of 150 species [1]. This genus is known to contain abundant sources of oligostilbenoids which possesses broad spectrum of biological activities [2]. Shorea macroptera which is known by the locals as 'melantai' was selected to examine the phytochemical study. The dried powdered (6 kg) stem bark of was macerated in acetone at room temperature and repeated for 72 hours. The extract was filtered and dried by using rotary evaporator to yield acetone crude extract. The acetone crude extract (300 g) was subjected to vacuum liquid chromatography (VLC) with the eluent hexane:ethyl acetate:methanol to give six combined fractions. Fraction 1 (6.2 g) was fractionated by VLC with the same eluent to afford ten subfractions. Subfraction 1 – 3 was combined and washed with hexane to obtain a pure compound (1) (50 mg). Fraction 5 (33.9 g) was isolated by the same chromatographic technique with chloroform:methanol to give five subfractions. Subfraction 4 (27.41 g) was subjected to VLC again with the gradient eluent hexane:ethyl acetate:acetone to obtain six subfractions. Subfraction 5 (394.7 mg) was further purified by radial chromatography with the solvent system chloroform:acetone:methanol in increasing polarity to afford a pure compound (2) (7 mg). Based on the spectroscopic analyses, the compounds were characterised as (E)-pentacosyl 3-(3-hydroxy-4-methoxyphenyl) acrylate (1) and gnetol (2).

Greatest appreciation to Society for Medicinal Plant and Natural Product Research for the GA travel grant, MOHE (RAGS/1/2014/SG01/UITM/4) and Faculty of Applied Sciences for the financial support.

[1] Cronquist A. An Integrated System of Classification of Flowering Plants. New York: Columbia University Press, 1981

[2] Seo EK, Douglas KA. Studies in Natural Products Chemistry 2000; 23: 531 – 561

[3] Symington CF. Foresters' Manual of Dipterocarps. Kuala Lumpur: Universiti Malaya;1974