Licorice and respiratory health
Many of you who have consulted me when suffering from a sore throat or cough may have not escaped my clinic without clutching a small brown bottle of a delicious herbal mix. I’m sure you have not forgotten!
Often a herbal mix for such conditions will include licorice root. Other herbs may include marshmallow root, elder flower, wild cherry bark, echinacea and white horehound. But let’s just focus on the lovely licorice root for the time being.
Licorice (Glycyrrhiza glabra) is one of the world’s most ancient herbal remedies. The medicinal use of licorice predates the Greek and Roman empires. The genus Glycyrrhiza is derived from the Greek words glykos (sweet) and rhiza (root). It is a valuable medicinal herb in Western herbalism as well as Ayurvedic and Traditional Chinese Medicine (TCM).
It is mainly used to treat lower respiratory viral and bacterial disorders. These conditions include cough, asthma, catarrh, lung fibrosis, bronchiectasis and most resistant infections.
Lower respiratory viral and bacterial infections
Licorice has been found to be active against many viral and bacterial pathogens that can cause acute and chronic infections. These viruses include avian infections, bronchitis virus, cytomegalovirus (CMV), dengue, Epstein-Barr virus, HIV, influenza A, rotavirus, SARS-related coronavirus, viral bronchitis and viral pneumonia. A tough little herb is this one!
Licorice has many modes of action against viral infections including inhibition of viral replication, growth and uptake into host cells.
Resistant infections
Licorice has proven activity as a “resistance inhibitor” by either reducing resistance to several drug-resistant bacteria and viruses, or by improving the activity of pharmaceutical antibiotics and antivirals via the inhibition of several pathogen-resistant mechanisms (e.g. efflux pumps).
Cough
Licorice has anti-tussive properties (cough stopping), in vivo studies have found the arabinogalactans (active component of the plant) extracted from licorice to have strong cough-suppressive activity, and over certain time
intervals (that is, one, two and five hours) had a stronger effect than codeine. Licorice is also a soothing demulcent and is highly indicated for use in patients with an irritated cough.
Asthma
Several preclinical trials have found licorice to have anti-asthmatic and antiallergic activities. It has demonstrated an ability to inhibit airway constriction and hyper-reactivity, lung inflammation, infiltration of eosinophils (white blood
cells that can increase inflammation) into the bronchial area, as well as preventing chronic cell and tissue changes within the lung.
So, quite a hard-working plant with multiple applications for respiratory health, and it is actually pleasant tasting. It’s true!
However, don’t go rushing out for some Darrell Lea licorice to soothe a sore throat or cough… not much licorice root in that bag of sweeties, and you’ll end up with a stomach ache!