Chemistry, bioactivities, mode of action and industrial applications of essential oils

Background: Essential oils (EOs) have remained in the limelight of the scientific community due their versatility coupled with consumers increasing demand for natural, safe and effective health products. Besides, their applications in the food, pharmaceutical, agricultural and textile industries amongst others have consolidated their popularity. Scope and approach: EOs are rich sources of pharmacologically active phytoconstituents which justifies their health and industrial applications. Despite their wide applications, their low aqueous solubility, high volatility and sensitivity to light, temperature and oxygen compromise the exploration of their abounding benefits. Hence, this paper focuses on disseminating the chemistry, pharmacology, modes of action as well as the applications of EOs in various industries. Additionally, it focuses on the factors affecting their yield and composition as well as novel methods (micro-/nano-technology) that can be employed to optimize or potentiate their effects. Key findings and conclusions: The pharmacological properties (anti: microbial; oxidant; hyperpigmentation; diabetic; viral; and cancer properties as well as the cardio-, hepato- and neuro-protective effects) of EOs have been validated through various studies and their corresponding mechanisms of action have been reported in this paper. Notably, their antimicrobial and antioxidant attributes have enabled their exploration in active packagings whereby they extend the shelf-life alongside maintaining food quality. On the other hand, their encapsulation in nanodelivery sytems allows to target and modulate their release, thereby enhancing their pharmacological potentials for biomedical applications. In addition to imparting fragrance, they serve as antimicrobials in fabrics in textile industry, while their biocidal effects makes them effective eco-friendly pesticides for agricultural uses.