**3. Extraction of volatile oils**

The oils contained within the plant cells are liberated through heat and compression from different organs of the plant, for example, the leaves, flowers, fruit, bark, and gums. The extraction of the oils from different plant organs is achieved by different methods, such as hydro-distillation, which is the most common method of extraction [18, 19]. Essential oils are composed of a mixture of volatile components and consist of about 20–60 individual compounds, and some may contain more than 100 components as jasmine, lemon, and cinnamon volatile oils [20–23].
