Comparison of oil recovered from tea tree leaf by ethanol extraction and steam distillation

Two methods for the determination of oil and oil major components from tea tree (Melaleuca alternifolia) leaf are quantitatively compared. A microwave assisted ethanol extraction and a 2-h hydrodistillation technique were use d on both dry and fresh leaf from a low and a high oil concentration tree. There was no significant difference between dry and fresh leaf. The distill ation technique recovered 88% and 82% of the extractable oil for the low an d high concentration material, respectively. For both samples this distille d oil was composed of lower absolute amounts of sesquiterpenoids and margin ally lower amounts of monoterpenoids. Extending the distillation to 6 h inc reased the sesquiterpenoid recovery but this resulted in a reduction in bot h the absolute and relative amounts of the oxygenated monoterpenoids, terpi nen-4-ol and 1,8-cineole.