Chemical constituent from the twigs of Malaysian Syrygium griffithii

Abstract

Genus Syzygium (Myrtaceae), known as kelat, is the largest genus in Malaysia. Plants of this genus are scattered throughout all parts of Malaysia from high tide level to the summit of Gunung Tahan. Kelat or Kayu kelat is the name for most wild species that have small or inedible fruits and it refers to the peculiarly rigid bark. Some Syzygium species were traditionally used for the treatment of numerous ailments such as fever, diarrhoea, dysentery, catarrh, diabetes, and asthma [1]. Previous study on Syzygium griffithii (Duthie) Merr. & L. M. Perry showed the presence of alkaloids, flavonoids, phenols, steroids, terpenes, and tannins in the leaves, twigs, and heartwood extracts [2]. As part of our continuing search to explore novel natural compounds from S. griffithii, a phytochemical study of the twig extract of S. griffithii was carried out. As a result, one flavonoid and five terpenes were successfully isolated and identified as pinocembrin (1), friedelin (2), lupeol (3), ß-sitosterol (4), ß-amyrin (5), and lupeol-3-acetate (6). Their structures were elucidated by extensive spectroscopic data analysis and comparison with respective literature data. The methanol extracts were also tested for their antioxidant (DPPH, ABTS, and FRAP) and a-glucosidase inhibitory activity. To the best of our knowledge, there are no reports on chemical constituents and bioactivity studies on twigs of S. griffithii.