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Modulation of transient receptor potential (TRP) channels by plant derived substances used in over-the-counter cough and cold remedies

Stinson, Rebecca J.; Morice, Alyn H.; Sadofsky, Laura R.


Rebecca J. Stinson


Background: Upper respiratory tract infections (URTIs) impact all age groups and have a significant economic and social burden on society, worldwide. Most URTIs are mild and self-limiting, but due to the wide range of possible causative agents, including Rhinovirus (hRV), Adenovirus, Respiratory Syncytial Virus (RSV), Coronavirus and Influenza, there is no single and effective treatment. Over-the-counter (OTC) remedies, including traditional medicines and those containing plant derived substances, help to alleviate symptoms including inflammation, pain, fever and cough. Purpose: This systematic review focuses on the role of the major plant derived substances in several OTC remedies used to treat cold symptoms, with a particular focus on the transient receptor potential (TRP) channels involved in pain and cough. Methods: Literature searches were done using Pubmed and Web of Science, with no date limitations, using the principles of the PRISMA statement. The search terms used were ‘TRP channel AND plant compound’, ‘cough AND plant compound’, ‘cough AND TRP channels AND plant compound’, ‘cough AND P2X3 AND plant compound’ and ‘P2X3 AND plant compound’ where plant compound represents menthol or camphor or eucalyptus or turpentine or thymol. Results: The literature reviewed showed that menthol activates TRPM8 and may inhibit respiratory reflexes reducing irritation and cough. Menthol has a bimodal action on TRPA1, but inhibition may have an analgesic effect. Eucalyptus also activates TRPM8 and inhibits TRPA1 whilst down regulating P2X3, aiding in the reduction of cough, pain and airway irritation. Camphor inhibits TRPA1 and the activation of TRPM8 may add to the effects of menthol. Activation of TRPV1 by camphor, may also have an analgesic effect. Conclusions: The literature suggests that these plant derived substances have multifaceted actions and can interact with the TRP ‘cough’ receptors. The plant derived substances used in cough and cold medicines have the potential to target multiple symptoms experienced during a cold.


Stinson, R. J., Morice, A. H., & Sadofsky, L. R. (2023). Modulation of transient receptor potential (TRP) channels by plant derived substances used in over-the-counter cough and cold remedies. Respiratory Research, 24(1), Article 45.

Journal Article Type Review
Acceptance Date Jan 27, 2023
Online Publication Date Feb 8, 2023
Publication Date Dec 1, 2023
Deposit Date Feb 9, 2023
Publicly Available Date Feb 9, 2023
Journal Respiratory Research
Print ISSN 1465-9921
Electronic ISSN 1465-993X
Publisher BioMed Central
Peer Reviewed Peer Reviewed
Volume 24
Issue 1
Article Number 45
Keywords Menthol; Camphor; Eucalyptus; Thymol; TRP channels; Cough; Cold; Over-the-counter therapies
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Additional Information Received: 6 October 2022; Accepted: 27 January 2023; First Online: 8 February 2023; : ; : Not applicable.; : Not applicable.; : LS received funding from Procter & Gamble to support this work.


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© The Author(s) 2023.
Open Access .This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

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