Aromatic Volatile Compounds of Essential Oils: Distribution, Chemical Perspective, Biological Activity, and Clinical Applications

Volatile, or essential, oils are the principal odorous components of certain plant species and constitute aliphatic and aromatic compounds in the oils' natural mix. The aromatic compounds are present in significant proportions in the oils of several plant species, usually referred to as aromatic plants, and hence the aromatic essential oils. These aromatic classes of compounds are abundant in oils of cloves, thyme, wintergreen, etc. The aromatic volatile compounds of essential oils (ACEO) are used in the treatment of several disorders, including infection, inflammation, irritable bowel syndrome (IBS), and as antihelminthics, among others. The ACEO are used in confectionary, beauty products, food, pharmaceuticals, and other medicaments. A plentiful number of over-the-counter (OTC) products are also prepared by ACEO and are abundantly distributed in the market. The present review deliberates on the origins, biogenesis, chemical structures, and bioactivities of the ingrained aromatic constituents of the essential oils sourced from different plant species. The review also highlights the importance of ACEO in modern food, cosmetics, and pharmaceutical industries. An overview of the clinical trials of the aromatic constituents and their applications in aromatherapy domains is also outlined. The review addresses a gap in the current literature concerning the aromatic components of essential oils by utilizing prior reviews and research articles. This review serves as a comprehensive source, detailing the chemistry, bioactivity, and therapeutic applications of the aromatic constituents of essential oils, along with their uses in both traditional and contemporary medicine, as well as the mechanistic aspects of the biological activity of these constituents derived from various plant-sourced essential oils.