Extraction of Essential Oils from Melaleuca alternifolia sp. (Australian Tea Tree Plant) using Solvent Extraction Method

In this report, the Melaleuca alternifolia genus, commonly known as the Australian tea tree plant were chosen for essential oil extraction study, as the oil being extracted from this plant possess natural therapeutic medicinal values which serves as an anti-fungal, anti-microbial and anti-inflammatory agent to fight against various infections and illnesses. The major component in the tea tree oil (TTO) that largely contributes to its medicinal function is based on terpinen-4-ol components, which constitutes about 40.02% from the overall composition of the TTO. Other components, such as 1,8-cineole, also reveals antimicrobial properties, similar to those of the terpinen-4-ol components. In this research, the extraction of the tea tree oil, via solvent extraction method, is studied and the percentage yield of tea tree oil extracted is determined and the composition of tea tree absolutes (terpinen-4-ol, 1,8-cineole, γ-terpinene and α-terpineol) extracted was compared with standard tea tree oil as well as with ISO 4730 Melaleuca oil standard via GC-MS technique. A feasibility study was also conducted to compare the choices and favourability of different types of solvents (n-hexane, petroleum ether, ethanol and methanol) being studied in the solvent extraction method to identify the desired selectivity of solvents resulting in higher percentage yield of the tea tree oil, without any deterioration in the extracted oil quality. The selectivity of petroleum ether as compared to n-hexane, ethanol and methanol, was much higher, as the yield of tea tree absolute was profoundly higher (1.06 % on a wet basis) as compared to the rest of the solvents. The composition of terpinen-4-ol, 1,8-cineole and α-terpineol found in the tea tree extract based from the studied solvents were in the range of 17.22-39.34%, 0.83-1.46% and 2.17-3.70%, however the γ-terpinene compound were significantly low (1.07-3.28%) as compared to its composition in the standard tea tree oil (20.47%).