In this review, we provide an overview of the current understanding of the main mechanisms of pharmacological action of essential oils and their components in various biological systems. A brief introduction on essential oil chemistry is presented to better understand the relationship of chemical aspects with the bioactivity of these products. Next, the antioxidant, anti-inflammatory, antitumor, and antimicrobial activities are discussed. The mechanisms of action against various types of viruses are also addressed. The data show that the multiplicity of pharmacological properties of essential oils occurs due to the chemical diversity in their composition and their ability to interfere with biological processes at cellular and multicellular levels via interaction with various biological targets. Therefore, these natural products can be a promising source for the development of new drugs.

The constituents of essential oils are widely found in foods and aromatic plants giving characteristic odor and flavor. However, pharmacological studies evidence its therapeutic potential for the treatment of several diseases and promising use as compounds with analgesic-like action. Considering that pain affects a significant part of the world population and the need for the development of new analgesics, this review reports on the current studies of essential oils’ chemical constituents with analgesic-like activity, including a description of their mechanisms of action and chemical aspects.

Epilepsy is a most disabling neurological disorder affecting all age groups. Among the various mechanisms that may result in epilepsy, neuronal hyperexcitability and oxidative injury produced by an excessive formation of free radicals may play a role in the development of this pathology. Therefore, new treatment approaches are needed to address resistant conditions that do not respond fully to current antiepileptic drugs. This paper reviews studies on the anticonvulsant activities of essential oils and their chemical constituents. Data from studies published from January 2011 to December 2018 was selected from the PubMed database for examination. The bioactivity of 19 essential oils and 16 constituents is described. Apiaceae and Lamiaceae were the most promising botanical families due to the largest number of reports about plant species from these families that produce anticonvulsant essential oils. Among the evaluated compounds, β-caryophyllene, borneol, eugenol and nerolidol were the constituents that presented antioxidant properties related to anticonvulsant action. These data show the potential of these natural products as health promoting agents and use against various types of seizure disorders. Their properties on oxidative stress may contribute to the control of this neurological condition. However, further studies on the toxicological profile and mechanism of action of essential oils are needed.

Over the last decade, there has been a dramatic increase in the prevalence and gravity of systemic fungal diseases. This study aimed therefore at evaluating the antifungal potential of ester derivatives of benzoic and cinnamic acids from three Candida species. The compounds were prepared via Fischer esterification, and the antifungal assay was performed by the microdilution method in 96‐well microplates for determining the minimal inhibitory concentrations (MICs). The findings of the antifungal tests revealed that the analogue compound methyl ferulate, methyl o‐coumarate, and methyl biphenyl‐3‐carboxylate displayed an interesting antifungal activity against all Candida strains tested, with MIC values of 31.25‐62.5, 62.5‐125, and 62.5 μg/ml, respectively. A preliminary Structure‐Activity Relationship study of benzoic and cinnamic acid derivatives has led to the recognition of some important structural requirements for antifungal activity. The results of molecular docking indicate that the presence of the enoate moiety along with hydroxyl and one methoxy substitution in the phenyl ring has a positive effect on the bioactivity of compound 7 against Candida albicans. These observations further support the hypothesis that the antifungal activity of compound 7 could be due to its binding to multiple targets, specifically to QR, TS, and ST‐PK. Additional experiments are required in the future to test this hypothesis and to propose novel compounds with improved antifungal activity.

Cinnamomum osmophloeum, commonly known as indigenous cinnamon, is a tree species native to Taiwan’s hardwood forests. It has been extensively investigated for its chemical composition and bioactivities. Several reports have shown that C. osmophloeum leaves are rich in aromatic oils, which are grouped into various chemotypes based on their major constituents. Components of the volatile oils included phenylpropanoids, monoterpenoids, sesquiterpenoids, phenols, coumarins, and other miscellaneous compounds. In addition, other secondary metabolites previously identified in this species included flavonol glycosides, phenolic acids, lignans, proanthocyanidins, and cyclopropanoids. C. osmophloeum is widely recognized for its medicinal and industrial applications, particularly its essential oils. In general, essential oils exhibit remarkable anti-inflammatory and antioxidant actions, enabling them to modulate key inflammatory mediators and neutralize free radicals. This review explored the phytochemical composition of the essential oils and extracts from C. osmophloeum as well as therapeutic potential of this species, focusing on the action mechanisms and clinical potential. We hope that this review will contribute to a better understanding of the biological effects of this plant and its potential applications in the management of conditions associated with inflammation and oxidative stress.