Effect of Solvent Types on Gaharu (Aqualaria malaccensis) Extract Quality and its Chemical Compound

Gaharu oleoresin is a mixture of wood resin and essential oil substances that naturally accumulates in the gaharu plants species. The aim of this study was to determine the appropriate solvent types and the contents of oleoresin and oil as well as the chemical compounds present in the gaharu extracts. Gaharu oleoresin can be extracted from gaharu powder using polar solvents and the essential oil can be separated using non-polar solvents. The extraction was done by Soxhlet method using methanol and ethanol for oleoresin extraction, and n-hexane and toluene for oil extraction from which the most appropriate solvents, extraction yields and the extracts quality were determined. The percentage of oleoresin extraction yield was found highest in methanol (6.97 %) followed by ethanol (6.85 % w/w). Meanwhile, the gaharu oil was found higher in toluene extract (1.06 %) compared to n-hexane (0.38 % w/w). The GC-MS results showed the extracts from ethanol and n-hexane solvents are the best quality due to the present of key compounds of 4-phenyl-2-butanone, β-guaiene, agarospirol, α–bisabolene, alloaromadendrene oxide, γ-Gurjunen and aromadenderene oxide. Different chemical component in gaharu oil determines the characteristic or quality of the gaharu. Meanwhile, the sesquiterpene compounds in gaharu produce its specialty aroma characteristics. Therefore, ethanol and n-hexane solvents are suitable to be used for oleoresin and oil extraction beside less expensive and more environmental-friendly.