Drying effect on yield and antimicrobial activity of essential oils

The present paper highlights the drying effect on yield and activity of some medicinal and aromatic plants. For this purpose we have chosen nine plants, four trees and five herbs. Each plant species represents one of the great aromatic families in Mediterranean. Drying was carried out at the dark at room temperature. Essential oils were obtained by hydrodistillation, where, we have noticed a significant decrease in yield of essential oil after drying in all plants. This loss was in strong relation with moisture decrease by drying. Drying effect on antimicrobial activity of essential oils has been evaluated by agar disk diffusion method. We have found a significant decrease in antimicrobial activity among all active essential oils after drying. Finally, we have concluded that drying significantly affects the essential oil quantity and quality.