Botanical Name – Glycyrrhiza glabra Linn.
Family – Leguminosae
English – Indian Liquorice
Hindi – Mulethi
Sanskrit – Yashtimadhu
Parts used – Stems, Roots
The plant thrives in a dry and sunny climate and is cultivated in the subtropical and warm temperate regions, chiefly in the Mediterranean region
It is reported abundant in Western China, parts of Asia Minor, Persia and Afghanistan. It is also cultivated in Punjab & Sub Himalayan tracts in India.
- Roots contain several active compounds including Flavonoids, such as Liquirtin, Rhamnoliquirilin, Liquiritigenin, Prenyllicoflavone A, Glucoliquiritin apioside, 1-metho-xyphaseolin, Shinpterocarpin, Shinflavanone, Licopyranocoumarin, Glisoflavone, Licoarylcoumarin, and Coumarin-GU-12
- Saponins – glycyrrhizin
- Isoprenoid-substituted phenolic constituents (Isoangustone A, Semilicoisoflavone B, Licoriphenone, and 1-methoxyficifolinol), Kanzonol R (prenylated isoflavan derivative) and several volatile components (Pentanol, Tetramethyl pyrazine, Hexanol, Terpinen-4-ol, Linalool oxide A and B, Geraniol, and α-terpineol)
- Glycyrrhizin, a saponin compound, as well as its Aglycone Glycyrrhetinic Acid, are the potent components in glabra. Glycyrrhizin consists of Glycyrrhetic acid and Triterpenoid Aglycone, associated with Glucuronic acid disaccharide, and it can be found naturally as calcium and potassium salts in licorice roots
Uses of Mulethi
Effect on Respiratory System
Licorice powder and it’s extracts act as an antitussive, expectorant, and demulcent. Pharmacologically, it is used to treat bronchial cough, catarrh, and sore throat, these activities is attributed due to the presence of Glycyrrhizin, which helps relieve congestion in the upper respiratory tract by accelerating the secretion of the bronchial mucosa. Liquorice has been shown to work as efficiently as codeine in sore throat. It decreases irritation and produces expectorant effects. Carbenoxolone (a semi synthetic compound derived from Glycyrrhiza) stimulates gastric mucus secretion. Liquorice extract is able to stimulate tracheal mucus secretions producing demulcent and expectorant effects. Glycyrrhizin is responsible for demulcent action of liquorice. Liquiritin apioside, an active compound present in the methanolic extract of liquorice which inhibits capsaicin induced cough.
Decoction of Mulethi (Boiling Mulethi sticks in water) is used to cure cough and cold. It can also be used in powdered form mixed with honey to get relief from cough and sore throat.
The phenolic content of Mulethi is responsible for the powerful antioxidant activity, attributed this activity to flavonoids, mostly Isoflavones, such as Glabridin, Hispaglabridin A, and 30‐hydroxy‐4‐O‐methylglabridin, are the responsible compounds. Also, Licochalcones B and D present in G. glabra, shows a strong scavenging activity on DPPH radical and the ability to inhibit the microsomal lipid peroxidation. The Phenolic compounds are effective in the protection of biological systems against oxidative stress, being able to inhibit the onset of skin damages.
The pharmacological effects showed an increase in the secretion of Serotonin and Prostaglandins in the stomach that led to a decrease of gastric inflammation. The anti‐inflammatory action is primary mediated by Glycyrrhizin, which inhibit factors responsible for inflammation as well as promote the healing of stomach and mouth ulcers. The anti‐inflammatory effects of glycyrrhizin are similar to those of glucocorticoids and mineralocorticoids. It is also used in renal and liver complications on the basis of its strong anti‐inflammatory effects leading to the inhibition of liver granuloma formation and the inflammatory cytokine production by glycyrrhizin.
Glycyrrhiza glabra possess antimicrobial properties particularly on Gram‐positive and Gram‐negative bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Bacillus subtilis. The antibacterial activity observed is due to the presence of secondary metabolites, namely, Saponins, Alkaloids, and Flavonoids. In particular, Glabridin, Glabrol, Glabrene, Hispaglabridin A, Hispaglabridin B, 40‐methylglabridin, and 3‐hydroxyglabrol, isolated from G. glabra, are responsible for this activity. It showed inhibition of bacterial growth, and the reduction of bacterial toxin production.
Liquiritigenin, one of the most active compounds of liquorice, demonstrated the capacity to prevent human lung cells (A549) from α-hemolysin-mediated injuries, by decreasing α‐haemolysin production. Similarly, Glabrin and Glycyrrhetinic acid have shown antibacterial activity against S. aureus.