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Review
. 2025 Jun 3;30(11):2450.
doi: 10.3390/molecules30112450.

Anti-Inflammatory Activity of Thymol and Thymol-Rich Essential Oils: Mechanisms, Applications, and Recent Findings

Custódia Gago  1 , Ana Serralheiro  2 , Maria da Graça Miguel  1
Affiliations
Review

Anti-Inflammatory Activity of Thymol and Thymol-Rich Essential Oils: Mechanisms, Applications, and Recent Findings

Custódia Gago et al. Molecules. .

Abstract

Thymol, a monoterpenoid phenol present in the essential oils of several aromatic plants, has attracted considerable attention for its anti-inflammatory effects, often in combination with other bioactive compounds. This work explores the mechanisms behind the anti-inflammatory activity of thymol and thymol-rich essential oils, summarizing recent experimental findings. Inflammation, a key factor in numerous chronic diseases, can be modulated by targeting essential molecular pathways, such as MAPK, NF-κB, JAK/STAT, and arachidonic acid signaling. Thymol has been shown to influence these pathways, reducing the production of pro-inflammatory cytokines and mediators. Beyond its anti-inflammatory effects, thymol also exhibits a broad range of biological activities, including antimicrobial, antioxidant, and anticancer properties. The applications of thymol and thymol-containing essential oils in therapeutic formulations, food additives, and veterinary medicine are also reviewed. Despite promising preclinical results, challenges such as low bioavailability and toxicity at high doses limit their clinical use. Recent developments in drug delivery systems, such as encapsulation in micro- and nanoparticles, are suggested as strategies to enhance efficacy. Additionally, the synergistic effects of thymol with other natural products are examined, offering the potential for improved therapeutic outcomes.

Keywords: chemotherapy; encapsulation; in vitro; in vivo; livestock; mechanism; synergism.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Chemical structures of carvacrol and thymol.
Figure 2
Figure 2
Main intracellular signaling pathways involved in the inflammatory response.
Figure 3
Figure 3
Canonical and non-canonical nuclear factor-kappa-B (NF-κB) signaling pathway.
Figure 4
Figure 4
Schematic biosynthesis of γ-terpinene, thymol, and carvacrol (adapted from [66]).
Figure 5
Figure 5
Schematic diagram illustrating the protective effects of thymol in a mouse model of acute lung injury caused by lipopolysaccharides (LPS) exposure. formula image inhibition; formula image stimulation.
Figure 6
Figure 6
Schematic diagram illustrating the suppressive effects of thymol on lipopolysaccharides (LPS)-induced inflammation and its possible interplay with Ras homolog family member A/Rho-associated coiled-coil containing protein kinase (RhoA/ROCK) signaling pathway. formula image inhibition; formula image potential stimulation.
Figure 7
Figure 7
Schematic diagram illustrating the inhibitory effects of thymol in microglia-mediated neuroinflammation subsequent to ischemic stroke, as well as microglial autophagy promotion. formula image inhibition.
Figure 8
Figure 8
Anti-inflammatory activity of thymol in livestock (created in BioRender (https://www.biorender.com/, accesed on 2 May 2025). IL-1β, interleukin-1β; IL-6, interleukin-6; SOD, superoxide dismutase; TLR4, toll-like receptor-4; TNF-α, tumor necrosis factor-alpha; ↓, decrease; ↑, increase.
Figure 9
Figure 9
Number of publications per year since 1986.
See this image and copyright information in PMC

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