Glycyrrhiza glabra - Licorice

Description

This perennial herb has a stem .6 -1.5 m tall rising from a thick rhizome. The leaves are pinnate with 4 -7 pairs leaflets, ovate, entire, smooth, glutinous beneath dark green. The flower is yellowish-white or purplish born in pulse-shaped racemes. The fruit is a legume, 2.5 cm long, brown, ovate, and flat. The root (rhizome) is basically cylindrical, usually prepared in pieces 14 - 20 cm long and 5 - 20 mm thick. The pieces are yellowish-brown to dark brown, longitudinally wrinkled; yellow inner, radiate; fracture coarsely fibrous.

Part Used

Root (rhizome).

Constituents

The major constituent is 1 - 24% of a triterpene known as glycyrrhizin (also known as glycyrrhizic or glycyrrhizin acid). The variation of this constituent is due to different varieties and growing conditions, but might vary up to 10 fold due solely to analytical techniques. Glycyrrhizin, on hydrolysis, yields glycyrrhentinic (or glycyrrhetic) acid and two glucuronic acid molecules. Other significant triterpenes include glabrolide acetate, 11-deoxoglabrolide acetate, soyasaponin, liquiritic acid, glabrolide, isoglabrolide, deoxoglabrolide and deoxoglycyrrhetic acid. Other constituents are; flavonoids, isoflavonoids (licoflavonol, kumatakenin, licoricone, glabrol, glabrone and others); coumarins (glycycoumarin, liqcoumarin, umbelliferon and others); starch (2 - 20%), 3 - 14% sugar (glucose and sucrose), lignin, 2-4% asparagine, a complex volatile oil, and a trace of tannin. (1-11)

Mode of Action

Many preparations of Licorice to reduce relief in ulcer patients are well documented. Traditionally, the best one is a methanol extract. A modern preparation with glycyrrhizin removed (DGL) is now preferred, as it avoids possible problems with high blood pressure (a recorded effect). The anti-inflammatory properties have been attributed to glycyrrhizin, but most studies and clinical experience shows DGL is quite effective on ulcers, even though there have been conflicting reports. Other constituents also inhibit gastric secretions. It appears that the methanol extract inhibits the liberation of gastrin from pyloric mucosa. Because research has proven that licorice preparation does not inhibit actetylcoline action and does not inhibit spontaneous motility of the stomach, licorice is more useful than chemicals such as atropine.

Licorice is often used for upper respiratory catarrhal conditions, traditionally used for the treatment of sore throats, coughs and ``dry lung`` condition.(12) Glycyrrhizin is 50 times sweeter than sugar and can be used as a sweetener substitute.(13)

Licorice has been shown to be estrogenic in laboratory animals (with possible other steroidal activities), to have mineralocorticoid properties (causing sodium retention and potassium loss), and to inhibit tumors (due to glycyrrhizinic acid salts). It is anti-inflammatory, antitrichomonas, antitussive (comparable to codeine, due to 18-beta-glycyrhinic acid), anticonvulsive and antibacterial. It is useful in Addison`s disease because licorice contributes to mineral balancing of the mineralocorticoids.

Glycyrrhizin is responsible for the anti-inflammatory effect, and it has some impact on the corticoid mechanism. It is presumed not to produce direct hormonal activity. However, it may enhance the activity of both mineral and glucocorticoids indirectly by inhibiting the metabolic activity in the liver. Licorice enhances pharmacological effect of corticosteroids and anti-inflammatory drugs such as prednisolone. Glycyrrhetrinic acid has been shown to suppress dexamethasone stimulated histamine synthesis and arachidonic acid release in rat mast cells. Other hormones are known to interact with this mechanism, such as deoxycorticosterone, progesterone and aldersterone. In China, it is often used as a first aid remedy for cuts, burns, as an antidote to many types of poisoning and to build muscle and bones.(14-25)

Licorice`s pseudoalderosterone activity is due to the glycerrhizin and glycyrrhetinic acid content. This can produce hypertension, hypokalemia, sodium and water retention, low plasma renin activity, and suppressed urine and serum aldosterone levels.(26,27) A person would have to consume over 12 gms of raw herb to induce these effects. As a detoxifier (used for thousands of years by the Chinese), it has been shown to counteract toxins related to diphtheria, tetanus and tetrodotoxin.(28)

Glycyrrhizin and its derivatives have been shown to successfully inhibit several viruses including; Herpes simplex 1, Newcastle disease and vesicular stomatitis. For Herpes, it both reduces pain and revents reoccurrence.(29,30) In clinical practice the glycyrrhetinic acid has been found fairly effective in treating these viruses, but extremely effective in treating hives, both internally and externally. Glycyrrhizin demonstrated an interferon induction ability. This ability has been directly associated with Licorice`s capacity to treat hepatitis B. It has also had success in inhibiting HIV.(31)

Licorice has been successful in preventing cytotoxicity from E. coli. Both tumor promotion and initiation has been inhibited by glycyrrhetic acid. Several of the constituents have demonstrated antihepatotoxic activity, giving more fuel to the Chinese concept that Licorice is the great detoxifier and balancer.(32)

Externally, glycyrrhizin suppresses scalp sebum secretion by a rate of 1 day per week.(33) It has been an effect ointment or Herpes Zoster.

Liquiritigenin and isoliquiritigenin have MOA-inhibitory activity, thus effecting mood.(34)

Therapeutic Action

Demulcent, expectorant, emollient, stomachic, anti-inflammatory, mildly laxative and flavouring.

Energetics

Traditional Chinese

(Raw) sweet and neutral. (Toasted) sweet and warm. Licorice enters all twelve primary meridians, especially the Spleen and Lung. It tonifies the Spleen, replenishes Qi, clears heat, removes toxins, moistens lungs, controls coughs, harmonizes the stomach and spleen, harmonizes all drugs, soothes spasms and acts as the great antidote.(35-37)

Ayurvedic

Rasa - mahura; Guna - guru (heavy), snigdha (pacifies vata); Veerya - sheeta; Vipak - madur. Action: Vat pitta samak, daha, samak, shura bardhak, kapha nisarak, vatanuloman, kantaya, raket sthambk, jawar nasak, jiviniya, sandhaniya, rasayan, balya.(38)

Other

Holmes describes licorice as very sweet, slightly bitter, cool and moist; with secondary qualities of restoring, calming, relaxing with a stabilizing movement. Licorices enters all twelve meridians; influencing the lungs, stomach, intestines, bladder, adrenal cortex, and pituitary. Its organism is warmth and air.(39)

Folklore

This herb is one of the most popular in China. One might claim it is the number one ``drug`` in the world because of the scale of its use. For centuries Licorice has been used as medicine in both Western and Eastern cultures. Traditionally, we find it used for almost everything. Some of the most common uses were: for ulcers, sore throats, insomnia, abdominal pain, bronchitis, blood cleanser, in cough medicines, sores, herpes, abscesses, food poisoning, for treatment of cancer in many cultures and to support the adrenal glands when under stress.(40,41)
There is plenty of documentary evidence for Licorice usage throughout the last 2,000 years in Europe. Examples include German herbals (1264), Gerard (1597), Hill (1751) and throughout the Eclectic era.(42) It is found in Chinese literature in the Divine Husbandman`s Class of the Materia Medica (220 BC).(43) Licorice is also extensively used in Ayurvedic medicine.

Roughly half a dozen Western Aboriginal cultures are known to have made use of Glycyrrhiza lepidota for earaches, toothaches and as a pediatric febrifuge.(44)

Dosage

Powdered root - 1 - 5 g(45)
Fluid extract - 2 - 5 ml(46)
Solid extract - ½ -1 dram(47)

Toxicity and Contraindications

Licorice is a very safe herb in moderate doses. In large doses it can cause sodium retention and potassium depletion and as a result lead to hypertension and edema. It is not recommended for patients with heart or blood pressure problems.(48)

Official Recognition and Medical References

UK - in BHP and General Sale list
Belgium - Accepted for specific indication
France - In Ph. Fr. X accepted for specific indications
Germany - In Commission E., p.161
PDR for Herbal Medicine, p. 875

References

1. Leung, A.Y. and S. Foster, Encyclopedia of Common Natural Ingredients: Used in Food, Drugs, and Cosmetics, John Wiley & Sons, Inc., New York, 1996, p. 347
2. Morton, J.F., Major Medicinal Plants: Botany, Culture and Uses, Charles C. Thomas Inc, Springfield IL, 1977, p. 156.
3. Spoerke, D.G., Herbal Medications, Woodbridge Press Publ. Co., Santa Barbara CA, 1980, p. 107.
4. Snow J.M.; Glycyrrhiza L (monograph); The Protocol J. of Botanical Med.; Winter 1996; pp 9-14%
5. Textbook of Pharmacognosy, J. & A. Churchill Ltd., Rahway, N.J., 1976. (citation not confirmed) p. 386.
6. Wood, H.C. and Osol, A., Dispensatory of the United States of America 23rd Ed., J.B. Lippincott, Montreal, PQ., 1943. p. 500.
7. Gathercoal, E.N. and Wirth, E.H., Pharmacognosy, Lea & Febiger, Phila. PA, 1936. p. 354.
8. Herbal Pharmacology in the People`s Republic of China, Trip Report of the American Herbal Pharmacology Delegation, National Academy of Sciences, Washington DC, 1975. p. 156.
9. Wallis, T.E., Textbook of Pharmacognosy, J & H Churchill, London, 1967. p. 385.
10. Remington`s Pharmaceutical Sciences (16th ed.), Mack Publ. Co., Easton PA, 1980, p. 1233.
11. Osol, A. and Pratt, R. (eds.), The United States Dispensory (27th Ed.), J.B. Lippincott, Phila. PA, 1983, p. 563.
12. Blumenthal et al, Licorice Root monograph; American Botanical Council; 1997 p. 51
13. Cantelli-Forti, G.F., et al Interaction of Licorice on Glycyrrhizin Pharmacokinetics; Enviromental Health Perspectives; Vol. 102; Nov. 1994, p. 65-68.
14. The British Pharmaceutical Codex 1934. Ibid.
15. Leung, A.Y., Encyclopedia of common natural ingredients used in food, drugs, and cosmetics, Ibid.
16. Spoerke, D.G., Herbal Medications, Ibid.
17. Textbook of Pharmacognosy, Ibid.
18. The Merck Index 5th ed., Merck & Co. Inc., Rahway NJ, 1940. p.257.
19. Trease, G.E. and Evans, W.C., Pharmacognosy 11 ed. Ibid.
20. Chen, K.K. and Mukerji, B., Pharmacology of Oriental Plants, McMillan Co., New York, 1965. p. 1.
21. Squire, P.W., Squire`s Companion to the Latest Edition of the British Pharmacopeia, J & A Churchill, London, 1908, p. 570.
22. Thompson, W.A.R., Herbs that Heal, J. of Royal College of General Practitioners, Vol. 26, p. 365 - 370, 1976, p. 369.
23. Larkworthy, W. et al., Deglycyrrihizinised Licorice in Duodenal Ulcer, B.M.J. 2 (6095), Oct 1977. p. 1123.
24. Grieve, M., A Modern Herbal, Jonathan Cape, London, 1931, p. 487.
25. Deglycerrhized Licorice in Gastric Ulcers - A Double Blind Controlled Study, Gut, Vol. 17, No. 5, 1976, p. 397.
26. Takeda, R., et al., Prolonged pseudoaldosterones induce glycyrrhizin, Endoc. Japan 26:, 1979, p. 541-547.
27. Eptien, M., Espiner, E., et al., Effect of eating licorice on renin-angiotensin aldosterone receptors, Br. Med. J. 1: 1977, p. 488-490.
28. Suzuki, H., et al., Effect of glycyrrhizin on biochemical tests in patients with chronic hepatitis - Double blind trial, Asian Med. J. 26:423-38, 1984.
29. Partridge, M., et al., Topical carbonoxolone sodium in management of herpes simplex infection, Br. J. Oral. Max. Surg. 22:138-45, 1984.
30. Csonka, G., et al., Treatment of herpes genitalis with carbonoxolone and cicolone creams: A double blind placebo controlled study, Br. J. Ven. Dis. 60:178-81, 1984.
31. Leung, Ibid.
32. Snow, Ibid.
33. The Review of Natural Products; Licorice; Feb 1998.
34. Leung, Foster; Ibid
35. Hsu, H.Y., Chen, Y.P., et al., Oriental Materia Medica: a concise guide, Oriental Healing Arts Institute, Long Beach, CA, 1986, p. 532-534.
36. Bensky, D. and Gamble, A., Chinese Herbal Medicine: Materia Medica, Eastland Press, Seattle, WA, 1986, p. 463-466.
37. Tierra, M., Planetary Herbology, Lotus Press, Santa Fe, NM, 1988, p. 295-296.
38. Kapoor, L.D., CRC Handbook of Ayurvedic Medicinal Plants, CRC Press, Boca Raton, FL, 1990, p. 194-195.
39. Holmes, P., The Energetics of Western Herbs (2 vols.), Artemis Press, Boulder, CO, 1989, p. 238-241.
40. Leung, A.Y., Ibid.
41. Grieve, M., Ibid.
42. Crellin, J.K. and Philpott, J., Herbal Medicine: Past and Present (Vol. II), Duke University Press, London, 1990, p. 288-290.
43. Bensky, D., and Gamble, A., Ibid.
44. Moerman, D.E., Medicinal Plants of Native America, University of Michigan Museum of Anthropology, Technical Reports, Number 19, Ann Arbor, Michigan, 1986, Vol.1, p.204.
45. Bradley, P.R. (Ed.), British Herbal Compendium, Vol. 1, British Herbal Medicine Association, Bournemouth, UK, 1992, p. 146
46. Bradley Ibid
47. Grieve, M., Ibid
48. Spoerke, D.G., Herbal Medications, Ibid.