Terpenoids in essential oils: Chemistry, classification, and potential impact on human health and industry

Terpenoids, present in essential oils (EOs), have gained significant attention due to their diverse pharmacological properties and their alignment with the growing global interest in natural and sustainable products. EOs, derived from various plants, have shown promise in antimicrobial, anti-inflammatory, antioxidant, and other valuable applications. This comprehensive review aims to elucidate the chemistry and pharmacological roles of terpenoids and EOs, covering their classification, extraction techniques, and potential pharmaceutical applications. We delve into their functions in the human immune system, their impact on health, and their contributions to environmental sustainability. The review synthesizes existing literature, categorizing terpenoids into distinct classes, including monoterpenoids, sesquiterpenoids, diterpenoids, sesterterpenoids, and triterpenoids. We explore various extraction and purification methods, such as steam distillation, solvent extraction, and chromatography. Additionally, we discuss the pharmacological properties of terpenoids, including their antioxidant, antimicrobial, and anticancer activities. Terpenoids and EOs exhibit potent antimicrobial and antioxidant activities, making them pivotal in plant disease resistance. They also offer potential therapeutic applications in phytomedicine, aromatherapy, and beyond, with the capacity to enhance the human immune system and combat viruses, inflammation, and cancer. Terpenoids and EOs have demonstrated multifaceted pharmacological benefits, contributing to human well-being and environmental sustainability. This review highlights their potential in medical treatments and everyday life, emphasizing the need to understand their pharmacokinetics and efficacy for harnessing their full potential in pharmaceutical applications and beyond.