Oligostilbenoids from the stem bark of Dryobalanops aromatica
Dryobalanops is one of the Dipterocarpaceae families which contain oligostilbenoid that show various biological activities . The oligostilbenoid in Dryobalanops genera is very unique, as some compounds such as cis- and trans-diptoindonesin B and malaysianol A have difference oxidative pattern compared to other oligostilbenoids in Dipterocarpaceae [2, 3]. The aim of this study is to isolate the oligostilbenoid constituents in Malaysian D. aromatica C.F.Gaertn. and to determine their cytotoxic activity. The dried powder of the stem bark of D. aromatica was macerated with acetone and evaporated under reduced pressure. The crude of acetone extract was subjected to vacuum liquid chromatography (VLC) to give 10 major fractions. Purification of the sixth fraction with radial chromatography gave laevifonol (1) (93mg) and ampelopsin E (2) (397mg) while the fifth fraction afforded α-viniferin (3) (91mg) and ε-viniferin (4) (20mg) and the tenth fraction yielded diptoindonesin A (5) (30mg). The effect of the isolated compounds (1–3) against HL-60, MCF-7, HepG2, A-549 and WRL-68 cell lines were evaluated by using MTT assay . Compound 3 was found to inhibit very strongly the growth of HL-60 cell lines (IC50 2.7µg/ml) and display moderate activity against MCF-7 cell line (15.7µg/ml). Besides that, 2 was found to moderately inhibit MCF-7 cell line (14.3µg/ml).
Acknowledgement: The authors would like to thank The Ministry of Higher Education, Malaysia for the financial support under the Fundamental Research Grant Scheme; 600-RMI/ST/FRGS/5/3/Fst (12/2010).
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