Optimization of essential oil extraction from Satureja sahendica Bornm.

The quantity and quality of essential oil extracted from the plant is strongly influenced by the extraction conditions, so optimizing the extraction conditions can help us to achieve the most essential oil content with the best quality. Satureja sahendica Bornm. is an endemic medicinal plant of Iran, which is of great importance due to its high essential oil and thymol content. In this research, the effect of plant particle size (mesh size 12, 18 and 35) and the ratio of plant material to water (1:5, 1:10 and 1:15 w/v) on essential oil content and compositions of this plant were evaluated. The essential oils were extracted based on hydro-distillation method by Clevenger’s apparatus and then analyzed using GC/MS and GC/FID. The results indicated that the extracted essential oil decreased with the decrease in the plant particle size. The optimal ratio of plant material to water in order to obtain more essential oil was different depending on the plant particle size. The highest of essential oil content (2.15% v/w) was obtained from plant material with mesh size 12 in the ratio of 1:15 plant material to water. The number, type and amount of essential oil compounds were strongly affected by different treatments. The highest amount of thymol (81.79%) as the most important component of the Satureja sahendica essential oil was obtained from samples with mesh size 35 and a ratio of 1:10 plant material to water. Determining the most appropriate extraction conditions can be different depending on the purpose and desired chemical composition of the essential oil.