Shorea species is the largest subfamily of Dipterocarpaceae and are the source of resveratrol oligomers (oligostilbene),
sesquiterpenes and triterpenes. Shorea bracteolate also called white meranti is locally known as “Meranti Pa’ang” and is widely
distributed in Sumatera, Peninsular Malaysia, Indonesia and Singapura. The tree is up to 50m in height and the timber is light
hardwood. The study was undertaken to extract and isolate the chemical constituents from the stembark of Shorea species
namely Shorea bracteolate and to elucidate the structures of the chemical constituents isolated by using modern spectroscopic
methods and evaluated their antioxidant chemiluminescence. The structure of the isolated compounds was determined based on
analysis of spectroscopic data, including NMR, UV, IR and comparison with previous reported studies. Five oligomers
resveratrol were isolated from the acetone extract of stem bark Shorea bracteolate namely hemsleyanol E (1), vaticanol A (2),
ampelopsin H (3), hopephenol (4) and hopeaphenol A (5). The result showed that in antioxidant chemiluminescence, compound
(3) and (2) showed moderate activity ( IC50:6.7µmol/ml and 10.7µmol/ml) as compared to ascorbic acid (IC50:1.71 µmol/ml).
However, compound (1), (2) and (3) displayed low activity IC50: 17.1 µmol/ml, 15.8 µmol/ml and 14.3 µmol/ml.