**2. Location and yield of essential oil**

Plants have the natural ability to produce volatile compounds in trace amounts. However, only a small percentage of plant species, around 10%, are considered "aromatic". This property of accumulating essential oils is found in specific plant families distributed throughout the plant kingdom, including Pinacea (pine and fir), Cupressaceae (cedarwood), and angiosperms. The most significant families are dicotyledons such as Asteracea (chamomile), Apiaceae (coriander), Geraniaceae (geranium), Lamiaceae (mint), Illiciaceae (anise), Lauraceae (cinnamon), Rosacea (rose), Sandatalacea (sandalwood), Myrtaceae (eucalyptus), Myristicaceae (walnut), Oleacea (jasmine), and Rutacea (lemon). Monocotyledons are mainly represented by the families Zingiberaceae (ginger), and Poacea (vetiver) [9, 10].

EOs are natural secretions produced by cells and found in plant parts such as flowers (rose), leaves (lemongrass), flowering tops (lavender), bark (cinnamon), roots (iris), bulbs (garlic), fruits (vanilla), seeds (nutmeg), or rhizomes (ginger). Essential oils are extracted from specific parts of plants, such as sage or lavender. The most concentrated or secretory parts of the plant are harvested at the optimum yield period, which varies depending on the plant. For example, mints are harvested before flowering, lavenders during flowering, and seed plants after flowering or after morning dew for fragile flowers. It is important to note that plant growth conditions can also affect yield and essential oil content. The collection period and drying methods can also impact the yield. Therefore, it is crucial to choose the right harvesting time and drying and extraction methods to obtain the maximum yield and quality of essential oils [8].

This text reviews both traditional and "green" extraction techniques, comparing their performance with conventional methods and emphasizing the benefits of "green" technology in plant extraction research.
