Cough plays a vital role in clearing irritants and infections from the respiratory tract, but persistent coughing can be annoying. The best treatment for a cough will depend on its underlying cause. There are many possible causes of coughs, including allergies, infections, and acid reflux.
Some natural remedies may help to relieve cough. Prominent amongst them is ginger. Although the beneficial effect of ginger on cough has been known for a long time, a scientific, biochemical explanation of its mechanism of action is now forthcoming. The anti-inflammatory compounds in ginger relax membranes in the airways, which could reduce coughing.
As many as 40% of patients with asthma use herbal therapies to manage asthma symptoms, often without proven efficacy or known mechanisms of action. Therefore, investigations of both the therapeutic and possible detrimental effects of isolated components of herbal treatments on the airway are important. Scientists have shown that ginger and its active components induce bronchodilatation by modulating intracellular calcium ([Ca2+]i) in airway smooth muscle (ASM). In isolated human ASM, ginger caused significant and rapid relaxation.
Purified constituents of ginger were subsequently tested for ASM relaxant properties in both guinea pig and human tracheas: -gingerol, -gingerol, and -shogaol induced rapid relaxation of precontracted ASM, whereas -gingerol failed to induce relaxation. In human ASM cells, exposure to -gingerol, -gingerol, and -shogaol, but not -gingerol (100 μM), blunted subsequent Ca2+ responses to bradykinin In mice, the nebulization of -gingerol (100 μM), 15 minutes before methacholine challenge, significantly reduced airway resistance.
Taken together, these novel data show that ginger and its isolated active components, -gingerol, -gingerol, and -shogaol, relax ASM, and -gingerol quietens airwayhyper-excitability, in part by altering [Ca2+]i regulation. These purified compounds may provide a therapeutic option alone or in combination with accepted therapeutics, including β2-agonists, in airway diseases such as asthma (Am J Respir Cell Mol Biology 2013, February Vol 42, pp 157-163).
Revalidation of traditional herbal medicine with the use of modern research methods is a laudable attempt and this particular case illustrates how convincingly it can be carried out with appropriate measures.