Oligomer resveratrols from Shorea bracteolate

Shorea bracteolate is a big forest tree and locally known as 'Meranti paang'. These Shorea species are known to contain different natural compounds such as terpenoids, flavonoids, coumarins, and resveratrol oligomers. The existing data showed that the most isolated compounds are resveratrol oligomers. The chemistry of known organic compounds such as terpenoids, coumarin and resveratrol oligomers is interrelated with biological activities. However, the knowledge of the other isolated compounds is very limited. Resveratrol oligomers isolated from the genus Shorea and its extracts show good biological activities including brine shrimps lethality bioassay, anti HIV-activity [1], antibacterial activity, 5α-reductase inhibitor activity [2], antihepatotoxic activity, and cytotoxicity [3]. The air-dried stem bark of S. bracteolate was extracted with 6L of acetone and concentrated at 60^oC with rotary evaporator to afford 47.7 g of free tannin crude extract. The crude extract was fractionated using vacuum liquid chromatography (VLC). Isolation and purification of compounds used several chromatographic methods including radial, column and preparative thin layer chromatografies to obtaine three known resveratrol oligomers namely laevifonol (1), hemsleyanol D (2) and diptoindonesin F (3). The structure of the isolated compound was determined based on analysis of spectroscopic data, including NMR, UV, IR and comparison with previous reported data.

Fig. 1

Universiti Teknologi MARA is acknowledged for financial and technical supports.

[1] Dai, J.R, Hallock, Y.F, Cardellina II, J.H.; Boyd, M.R. J. Nat. Prod, 1998, 61, 351 – 353

[2] Hirano, Y, Kondo, R, and Sakai, K. J. Wood Sci, 2001, 47, 308 – 312.

[3] Patcharamun, W, Sichaem, J, Siripong, P, Khumkratok, S, Jong-aramruang, J, Tip-pynag, S, 2011, 82, 489 – 492