Characterisation of agarwood type resin of Gyrinops walla Gaertn growing in selected populations in Sri Lanka

•Current authors were the first to report agarwood type resins from Gyrinops walla, this was the follow-up study with a phytochemical and forestry perspective.•This is the first systematic analysis of agarwood type resins from Gyrinops walla in Sri Lanka.•During this study a method for GCMS analysis of agarwood type resins from Gyrinops walla was developed. This method would be validated and used as a standard method for routine analysis of this resinous wood.•Key chemical compounds were identified from the Gyrinops walla resins which were reported for agarwood resins from Aquillaria spp.•Cluster analysis was performed on 18 samples and six clusters were identified which were discussed based on botanical and geographical data.•Gyrinops walla is a highly protected species in Sri Lanka. Differentiation of resins obtained from G. walla from plantation Aquliaria spp. due to the lack of unavailability of systematic study on resin characteristics. Current study information and future studies on this path would help to tackle the ongoing illegal harvesting.•Findings of the current study are the steps toward commercial plantations of Gyrinops walla in Sri Lanka.

Gyrinops walla is the only agarwood producing tree growing in Sri Lanka which is believed to be endemic. Agarwood is valuable resinous heartwood of Thymalaeaceae family. Present study is aimed to identify the characteristics of naturally formed agarwood type resins in G. walla stems. Samples were isolated from trees growing three different location in the wet zone of Sri Lanka. Naturally formed resinous part of wood was solvent extracted and analysed by GCMS. Further, the current study has developed an effective GCMS method to analyse agarwood type resin from G. walla. Tree diameters and the heights varied in the trees samples, which had no effect on resin formation. Resin contents were not significantly different between three populations although the chemical variations were considerably high. Among the 19 constituents identified by GCMS in the agarwood resins, free fatty acids and isopropyl naphthalene, 2-phenylethyl chromone compounds found to be common for most of the G. walla trees tested. Comonly found sesquiterpene compounds from the G. walla resin were Jinkhol, γ-eudesmol, valerenol and valerinal. Similar compounds have been reported in resin from Aquliaria spp. which is the more established source of agarwood. A future study would experiment on artificial resin induction methods and establishing plantations of G. walla to sustain its supply.