Oligostilbenoid compounds from the lianas of Gnetum microcarpum

The family Gnetaceae with a sole genus, Gnetum is well known as a rich source of plant-derived stilbenoids which possess unique structures and multi-faceted biological activities[1]. One of the species, Gnetum microcarpum Blume is a large-fruited species of climber which is reported from western Indochina (Thailand, Myanmar) and Malaya Peninsula to Sumatra[2] and has been found in open margins and canopy of secondary forest, on hill slopes and in heath forest. Gnetum microcarpum Blume is not recorded in folk medicines and previously a new stilbenoid compound has been reported from the lianas of the plant [3]. The isolation and purification was carried out on the lianas of this plant by a combination of repetitive radial and preparative thin layer (pTLC) chromatographic techniques to afford a new oligostilbenoid trimer, compound A (1) which consist of two unit of resveratrol and one unit of oxyresveratrol together with ten known stilbenoids (2 – 11). Malaysianol D (3) [4], a trimer resveratrol which was previously reported as a new compound from Dryobalanops beccarii by our group was also isolated from Gnetum Microcarpum for the first time in Gnetum plants. The structures of compounds were determined on the basis analysis of spectral evidence and comparison with the published data. The plausible biopathway of the new compound was also proposed. Some of the isolated compounds were tested for DPPH radical scavenging and PGE2 inhibitory activities and their structure-activity relationship study was discussed.

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UniversitiTeknologi MARA is acknowledged for financial and technical support.

[1] Sotheeswaran S, Pasupathy, V. Phytochemistry1993, 32:1083 – 1092.

[2] Azmin NFN, Ahmat N, Syah YM, Zawawi NKNA, Yusof MIM. Natural Product Communications: 2014, 9:1743 – 1744.

[3] Wibowo A, Ahmat N, Hamzah AS, Latif FA, Norrizah JS, Khong HY, Takayama H. Phytochemistry Letters: 2014,9:117 – 122.