Abstract
Essential oils which are complex blends of volatile compounds particularly
present in a copious amount in aromatic plants, and are mainly composed of terpenes
biochemically generated through the mevalonate pathway. In natural conditions,
essential oils play a significant role in the defense mechanism of plants as antibacterial,
antiviral, antifungal, insecticides and protect from herbivores by reducing their taste for
such plants. Because of their chemical constituents, essential oil holds various
biological activities such as antioxidants, antimicrobial, anti-inflammatory, etc. which
finds important applications in food, cosmetic, agriculture, industrial, and medical
fields. This chapter covers the chemical constituents and chemistry of essential oils on
the one hand and their biological activities on the other hand.