Efficiency of Palaquium gutta and Pometia pinnata heartwood extracts on the protection of Hevea brasiliensis against Asian subterranean termites, Coptotermes gestroi (Wasmann)

Abstract

The aim of this study focussed on identifying chemical compounds (wood extractives) using different solvents, as well as their performance as a wood preservative against subterranean termites, Coptotermes gestroi (Wasmann) attack. The source of wood extractives was from Palaquium gutta (Hook.f.) Baillon and Pometia pinnata J.R. Forster & J.G. Forster, heartwood extracted with different solvents; absolute ethanol (EtOH), absolute methanol (MeOH) and petroleum ether (PETETHR). Compound identification was performed under Gas Chromatography and Mass Spectrometry (GC–MS). Besides that, the efficacy of extracts from both timber species was also assessed in various bioassays (antitermitic, repellent, antifeedant & test of wood extractives applied to Hevea brasiliensis). A total of 20 and 22 compounds were identified from P. gutta and P. pinnata heartwood extracts, respectively. Decalactone, isobornyl isobutanoate, carvacrol, rosifoliol, incensole acetate, citronellyl pentanoate, allyl cinnamate, thujic acid, cubebolo, citronellol, manool, neoisopulegol, widdrol and methyl decyl ketone were among the bioactive compounds of varying proportions among the studied timbers. The heartwood extracts from both timber species with MeOH solvent had a significantly lower percentage of paper consumption and higher percentage of feeding inhibition and repellent activity, followed by EtOH and PETETHR. Both timber species extracts had the potential to be developed as a new natural bio preservative in wood industries.