Blooming stages of Turkish hyssop (Hyssopus officinalis L.) affect essential oil composition

Hyssop (Hyssopus officinalis L.), native to the Caucasus, North Western Iran, Turkish North Eastern Black Sea region, and Southern Anatolia, is a highly valued medicinal plant. The experiment was conducted to find the effect of harvesting at different blooming stages of the plant on fresh and dry herbage yield, dry leaf yield, essential oil content, and essential oil components. In total, twenty-nine components were identified in hyssop essential oil by GC/MS. Isopinocamphone was the dominating component (47.9-51.4%) in the all analysed oil samples. The results clearly demonstrated that oil contents are seriously affected by the environmental conditions and stage of blooming, with the highest oil yield and oil contents at the post-blooming stage.