Chemistry of Essential Oils

Abstract

Essential oils contribute significantly to the world economy in various industries. They have received continuous attention from the scientific community and acquired popularity due to their pluripotent bioactivity and increasing consumer demands for natural, safe, and effective health products, as proven by several areas of research. Chemically, essential oils are composed of various hydrocarbons and oxygenated terpenoids and nonterpenoid derivatives that contain functional groups such as alcohols, aldehydes, and ketones. Essential oils typically contain between 20 and 60 compounds, with approximately 85–99% being volatile compounds and the remainder (approximately 1–15%) being nonvolatile compounds. The chemical ingredients in essential oils vary significantly by species, season, geographic location, and plant growth stage. While essential oils provide a variety of health benefits and are economically significant on a global scale, their applications are typically restricted due to their high volatility, hydrophobicity, and susceptibility to oxidation. Understanding the chemistry of essential oil constituents can provide a solid foundation for advancing their use. This chapter intends to foster an interdisciplinary discussion of recent advances in the chemistry of essential oils, with a focus on their chemical compositions, biosynthetic pathways, factors affecting their chemical compositions, modern extraction technologies aimed at minimizing global adverse effects and promoting sustainable development, and modern analytical methods. Bibliometric analysis is also used to discuss the current situation and advancements in essential oil research. The final section of this chapter will outline the opportunities, challenges, and future research directions that should be pursued to fill scientific knowledge gaps. The value derived from the content of this chapter will be of great interest to essential oil researchers in both academia and industry.