Dudai, N., Aromatic, Medicinal and Spice Crops Unit, ARO - Newe Ya'ar Research Center, Ramat ishay 30095, Ireland

Due to its high content of the compounds carvacrol and thymol, oregano essential oil has a number of known potent biological activities, such as antioxidant, antibacterial, fungicide, insecticide, herbicide and nematicide capabilities. The recent trend in using natural preservatives and functional foods increases the demand for oregano essential oils. This has resulted in a growing need for production of essential oils high in carvacrol and thymol. Understanding the way plants respond to the various physiological and environmental factors is a prerequisite for predicting and controlling the quality and quantity of the essential oils produced by a plant. The most important of these factors are genetic, but seasonal variation and the developmental stage of the individual plant also have great impact. This work reviews the genetic, environmental and developmental factors involved in the production of carvacrol and thymol enriched with essential oil of oregano and other related aromatic plants.