It grows in the sub- tropical and warm temperate regions of the world, chiefly in Mediterranean countries and China.
Morphology Description (Habit)
It is a hardy herb or undershrub; the leaves are multifoliolate, imparipinnate; the flowers are in axillary spikes, papilionaceous, lavender to violet in colour; the pods are compressed and contain reniform seeds. The rootstock, which is stout, throws off a large number of perennial roots. The dried, peeled or unpeeled underground stems and roots constitute the drug known in the trade as Licorice.
The principal constituent of liquorice to which it owes its characteristic sweet taste is glycyrrhizin, which is present in different varieties in a concentration of 2-14%. This principle is not found in the aerial parts of the plant. Other constituents present in liquorice are: glucose (up to 3.8%), sucrose (2.4-6.5%), mannite, starch ( 30% ), asparagine, bitter principles, resins (2-4%), a volatile oil (0.03-0.035%) and coloring matter. The yellow color is due to the anthoxanthin glycoside, iso liquiritin which, undergoes partial conversion to liquiritin during drying and storage of roots. Iso liquiritin gives on hydrolysis iso liquiritigenin, while liquiritin gives liquiritigenin as a glucone. Both iso liquiritin and liquiritin are bitter with a sweet after-taste and stimulate the salivary glands. Commercial samples contain c. 2.2% of iso liquiritin. A steroid estrogen, possibly estriol, is also reported to be present in liquorice. The presence in the inner bark of a hemolytically active saponin has been reported1. The plant contains phytoestrogens in the form of isoflavones such as formononetin; glabrone, neoliquiritin and hispaglabridin A & B.
Glycyrrhizin, a glycoside obtained from G. glabra was studied for its anti-arthritic and anti-inflammatory effect on formaldehyde induced rat-paw edema in adrenalectomised rats. It was found to potentiate the anti-arthritic action of hydrocortisone in rats2.
The oral administration of the powdered root of G.glabra in 5 cases of pemphigus, who had been kept free from the bullae with prednisolone, could considerably reduce the dose of prednisolone without the reappearance of the lesions. The potentiating effect of G.glabra appeared to be due to its inhibitory effect on the metabolic degradation of prednisolone3. A controlled clinical trial on 92 randomly selected cases of post operative traumatic inflammation following tonsillectomy with powdered G.glabra given in a dose of 3g t.d.s in 28 cases. In another series of 24 cases, oxyphenbutazone 2 tabs t.d.s were given. On sequential analysis, the anti-inflammatory response of G.glabra was found to be equivalent to that of oxyphenbutazone. G.glabra appeared to possess a more potent antipyretic and anti-exudative activity in comparison to oxyphenbutazone4.
Excessive amounts of the root, herbal teas or candy derived from G. glabra may be harmful. Licorice increases salt retention and depletes the potassium in the body, causing lack of energy, weakness and even death. People with hypertension or heart problems should avoid licorice5.
Licorice is used for the treatment of asthma, acute and chronic bronchitis and chronic cough. It is a mild anti-inflammatory for arthritis and rheumatism and is used to treat gastric, duodenal and oesophageal ulceration or inflammation, heartburn and mouth ulcers.
- Houseman, loc. cit.; Thorpe, VII, 362; Kapur et. al., loc. cit.; Trease, 393; McIlroy, 40; Puri & Seshadri, J. sci. industr. Res., 1954, 13B, 475; Chem. Abstr., 1950, 44, 4635.
- Gujral, M.L., Sareen, K., Phukan, D.P. and Amma, M.K.P. 1961a. Anti-arthritic activity of glycyrrhizin in adrenalectomised rats. Indian J. Med. Sci. 15, 625.
- Saxena, et. al., J. Ind. Med. Profes., 1970, 12, 5575.
- Saxena, et. al., J. Ind. Med. Profes., 1970, 17, 7532.
- Anonymous, 1986. Magic Medicine of plants, Readers Digest Assn. Inc., New York, 337.