Bioactivity, medicinal applications, and chemical compositions of essential oils: detailed perspectives

Essential oils are a complex composition of various polar and nonpolar compounds which are characterized by aromatic plants. These are also known as volatile oils and applied in cuisines, aromatherapy, perfumes, cosmetics, spices, and nutrition all around the world. They have been utilized for phytotherapy and other therapeutic purposes. Essential oils have a wide variety of bioactivities and synergistic effects of the essential oil constituents as antioxidant, antibacterial, antifungal, and chemopreventive agents. Essential oils are concentrated in certain cells and can be found in various sections of the plant such as seeds, flowers, leaves, roots, bark, and gland. Volatile oils give plants their particular aromas, flavors, and other properties. Hydrocarbons like monoterpenes and sesquiterpenes produce various oxygenated complex forms of alcohols, aldehydes, esters, ethers, ketones, phenols, and oxides. Phenylpropenes and sulfur- or nitrogen-containing molecules are found in other substances. As a consequence, study of the biological activities of essential oils becomes increasingly relevant in the search for natural and safe alternative treatments. This chapter focuses on bioactivity and potential medicinal applications of various essential oils.