Introduction
Coughing is an essential protective mechanism of the respiratory system that helps remove mucus, harmful substances, and infectious agents from the airways. It is a complex physiological response triggered by various irritants and may present as dry, productive, hacking, or persistent cough depending on the underlying condition. Nearly all respiratory pathologies can produce cough, highlighting its importance as both a symptom and a defense mechanism.1
Physiology of the cough reflex
The cough reflex is regulated through a coordinated interaction between peripheral receptors, neural pathways, and central nervous system structures.
Key components include:
- Cough receptors located in the airway mucosa
- Sensitivity to irritants such as dust, smoke, chemicals, and accumulated secretions
- Transmission of signals to the cough center in the brainstem
- Activation of respiratory muscles involved in coughing
The cough center, located in the medulla oblongata and the nucleus of the solitary tract, integrates incoming signals and coordinates the sequence of events necessary for cough generation. This process involves the diaphragm, intercostal muscles, abdominal muscles, and laryngeal muscles working together to expel irritants from the respiratory tract.2,3
Natural ingredients used in cough management
A variety of natural products and herbal ingredients have traditionally been used to support respiratory health and cough management.
- Carob syrup (Ceratonia siliqua):
- Carob syrup is derived from carob fruits whose pods contain carbohydrates, proteins, minerals such as potassium, phosphorus, and calcium, as well as polyphenols.
- Honey:
- Honey has long been used as a sweetening agent in cough preparations and represents one of the earliest ingredients incorporated into remedies intended for respiratory symptoms.
- Black currant dry extract (Ribes nigrum folium):
- Black currant extract is rich in anthocyanins and proanthocyanidins. It has demonstrated antiviral activity against influenza A viruses by interfering with viral internalization.
- Caraway fruit dry extract (Carum carvi):
- Traditionally, caraway has been used for digestive complaints, relief of abdominal discomfort, and respiratory conditions including pneumonia because of its antimicrobial properties.
Herbal medicines with respiratory benefits
Several herbal ingredients are recognized for their relevance in respiratory disorders and cough management.
- Ginger rhizome dry extract (Zingiber officinale) has been used in Ayurveda for fever, cough, and respiratory difficulty and is described as possessing significant antitussive activity.
- Althaea officinalis root extract has traditionally been used in children and infants and is considered safe during pregnancy and breastfeeding.
- Ivy leaf dry extract (Hedera helix) has been widely utilized in productive cough, where facilitation of mucus clearance is desirable rather than suppression of cough.
- Thyme (Thymus vulgaris) has been traditionally used for cough, fever, influenza, respiratory disorders, and digestive complaints. Its constituents possess antibacterial, antifungal, antioxidant, anti-inflammatory, antipyretic, and antinociceptive properties.4
Conclusion
Cough serves as an important physiological defense mechanism that protects the respiratory tract from harmful substances and infectious agents. A range of natural ingredients, including honey, carob, black currant, caraway, ginger, ivy leaf, Althaea officinalis, and thyme, have been traditionally used to support respiratory health. Their diverse biological properties highlight the growing interest in natural and herbal approaches for cough management and respiratory care.5
References:
1. Lovie-Toon YG, Chang AB, Newcombe PA, et al. Longitudinal study of quality of life among children with acute respiratory infection and cough. Qual Life Res. 2018;27(4):891-903. doi:10.1007/s11136-017-1779-y. https://link.springer.com/article/10.1007/s11136-017-1779-y
2. Davenport PW, Vovk A. Cortical and subcortical central neural pathways in respiratory sensations. Respir Physiol Neurobiol. 2009;167(1):72-86. doi:10.1016/j.resp.2008.10.001. https://www.sciencedirect.com/science/article/pii/S1569904808002784?via%3Dihub
3. Mazzone SB, McGovern AE, Yang SK, et al. Sensorimotor circuitry involved in the higher brain control of coughing. Cough. 2013;9(1):7. Published 2013 Mar 6. doi:10.1186/1745-9974-9-7. https://pmc.ncbi.nlm.nih.gov/articles/PMC3602068/
4. Naceiri Mrabti H, Doudach L, El Menyiy N, et al. Phytochemistry and Pharmacology of Thymus broussonetii Boiss. Evid Based Complement Alternat Med. 2021;2021:6350035. Published 2021 Sep 4. doi:10.1155/2021/6350035. https://pmc.ncbi.nlm.nih.gov/articles/PMC8437615/
5. Pecoraro L, Peterle E, Dalla Benetta E, Piazza M, Chatziparasidis G, Kantar A. Well-Established and Traditional Use of Vegetal Extracts as an Approach to the "Deep Roots" of Cough. Children (Basel). 2024;11(5):584. Published 2024 May 11. doi:10.3390/children11050584. https://pmc.ncbi.nlm.nih.gov/articles/PMC11120585/#ack1