Licorice

Glycyrrhiza glabra L.  Fabaceae.  The common name is licorice or liquorice.  Kan-Tsao. Glycyrrhiza uralensis is the plant generally used in Chinese medicines, it is chemically very similar to G. glabra.

The history of Glycyrrhiza in the Western world as medicine and food flavoring can be traced back 3000 years to the Egyptians and Assyrians.  The Greeks were introduced to it by the Scythians.  The Greeks and Romans both extolled its uses.  It is mentioned by Theophrastus, Pliny the Elder, Hippocrates, Culpepper and numerous other herbalists over the centuries.  The Chinese and India’s Ayurvedic tradition also report ancient usage.

The majority of Glycyrrhiza imported into the United States is used by the tobacco and confectionery industries.  Licorice candy in the U.S. is actually usually flavored with anise.  European licorice candy is more often made of the real thing.  The tobacco industry uses it for flavoring and conditioning and it is in pipe tobacco, cigarettes, cigars and chewing tobacco.  The powder is used by the pharmaceutical industry to enhance the consistency and to coat the surface of pills.

Glycyrrhiza has always been considered a safe herb, and is on the U.S. GRAS list.  It has traditionally been used in small amounts mixed with other herbs.  It is 50 time sweeter than sugar and is unpleasant in strong dosages.  The toxicity levels, as a problem, are relatively new phenomena due primarily to the much larger doses being taken, and being taken as a single herb instead of in a formula of mixed herbs.

Most of the recorded cases of serious side effects are traced back to over-consumption of licorice candy, and occasionally to over-consumption of chewing tobacco or Lydia Pinkham’s Vegetable Compound.

Glycyrrhiza is a 4 to 5 foot shrub that grows in temperate climates.  It is a member of the Fabaceae or pea family and looks similar to a large sweet pea plant.  The mature plants have a long taproot that sends out creeping horizontal rhizomes, creating a tangled mass of underground growth.  The rhizomes are harvest during fall of the third or fourth year and are shade dried for six months.

The rhizome and roots are the parts used.  Glycyrrhiza is available in bulk herb form, tea, hydroalcoholic extracts, glycerites and capsules.  Deglycyrrhizinated (DGL) products are also available. Glycyrrhiza is commonly found in teas as a sweetener and flavoring agent, or to harmonize the blend.  It is also frequently used in herbal preparation compounds, particularly Chinese blends.  It is used in cough drops, candy and tobacco.

The use of Glycyrrhiza for ulcer patients is well documented.  It is anti-inflammatory and is effective at healing gastric ulcers, but with lesser effect on duodenal ulcers.   Another of the antiulcer effects of Glycyrrhiza is the ability of the terpinoid glycoside glycyrrhizin (GL) and aglycone glycyrrhetinic acid (GA) to inhibit the enzymes 15-hydroxyprostagandin dehydrogenase and D-13-prostaglandin reductase, which inactivates the protective prostaglandins (PG) in the gastric mucosa.  This elevates the concentration of PGs and provides a protective effect against mucosal damage.¹

Due to the fairly high incidence of side effects of Glycyrrhiza at dosages high enough to be effective at healing ulcers, deglycyrrhizinated (DGL) licorice was developed in the 1970s.  This process removes most of the GL from the product (GL is content is not to exceed 3%).  The trials have been controversial, some with negative results and some with positive results.  The most recent studies have shown DGL to be as effective at healing ulcers as CB, cimetidine and ranitidine.  DGL is widely used in Europe and Australia, but has not been particularly favored in the United States.²

Glycyrrhiza has been shown in vitro and in vivo to be effective against viruses.   Further studies are being done with HIV, hepatitis A, B, C and herpes viruses.  The mechanism for this effect is both a direct inhibitory action on viral replication and stimulation of interferon production by T-cells.³   It has also been shown effective against Candida albicans, Staphylococcus aureus and Mycobacterium smegmatis.

Glycyrrhiza has a history of treating inflammatory conditions such as asthma, skin diseases like psoriasis or eczema, ulcers and even rheumatoid arthritis.  The anti-inflammatory effects of GA and GL are very similar to cortisol’s effect on the inflammation process.⁴  GL is chemically similar to the hormones produced by the adrenal cortex, particularly desoxycorticosterone (DOCA) and cortisone.  This is also what causes many of Glycyrrhiza’s side effects.⁵

Glycyrrhiza has shown anti-tumor effects in animal studies.  Several compounds  (glabridin, the most active) has been shown to be effective against LDL oxidation.  Japan has been using it by injection to treat acute and chronic hepatitis.   It also has a long history, but little research, as an expectorant and cough suppressant.  Glycyrrhiza is used in the treatment of Addison’s disease.

Glycyrrhiza has a long folk tradition as a cough remedy, and is used as a tea, hydroalcoholic extract, cough syrup or lozenge.  It is usually mixed with other herbs that are also used for pulmonary complaints.  It is chewed by singers and speakers to moisten their throat, as it stimulates saliva and mucous.  The whole root is also chewed by smokers as an aid to breaking their habituation to tobacco.

It has traditionally been used in formulas for women to regulate hormone production.  It is  considered estrogenic, although research has not proven this.  Glycyrrhiza is a traditional ingredient of the famous Lydia E. Pinkham’s Vegetable Compound, used for menstrual difficulties.  Glycyrrhiza is being used for chronic fatigue syndrome (CFS) with some success.⁶  It is also applied topically to herpes lesions, eczema, psoriasis and hives.

Glycyrrhiza is highly valued and extensively used in China, they classify it as a superior herb.  It is used in small amounts in many formulas to harmonize the action of the other herbs.  It is called the “peacemaker.”

Glycyrrhiza’s main active ingredient is the triterpenoid glycoside, glycyrrhizin, varying from 2% to 14% and is 50 times sweeter than sugar.  Glycyrrhizin is partially hydrolyzed by a glucuronidase to its aglycone glycyrrhenetinic acid, which is considered an important active ingredient.  It also contains antioxidant, antiviral and antimicrobal substances.⁷

It is recommended that small doses be used, below 10 grams a day, and for a period of no more that six weeks.  Blood potassium levels and blood pressure should be monitered. It is recommended that persons taking Glycyrrhiza eat a low sodium-high potassium diet.  Particular caution should be taken with the elderly and patients with hypertension or cardiac, renal or heart disease.

It is contraindicated in pregnancy, severe kidney or urinary tract inflammation, low blood potassium, cardiac disease, liver cirrhosis, bile stasis disorders or chronic hepatitis.

Excess Glycyrrhiza can cause hyperaldosteronism, with symptoms of hypertension; sodium, chloride and water retention with edema.  It can also cause hypokalemia with symptoms of arrhythmia, ECG abnormalities and death.  Excess licorice ingestion may cause lethargy, muscle pain, muscle weakness, numbness of the extremities, mental slowness and weight loss.  The person may experience rhabdomyolosis, a disintegration of the striated muscle fibers, which can result in acute renal failure.

Glycyrrhiza potentates the toxicity of cardiac glycosides, such as digitalis because of potassium loss in the urine.  It also increases the potassium loss of thiazide diuretics, and should not be used while taking spironolactone or amiloride.  It should also not be taken along with corticoid medications as it interferes with 5b-reductase breakdown of corticosteroids, thus prolonging their half-life.⁸  It may interfere with contraceptive pills.⁹

⁹ “Licorice-The Universal Herb”. MediHerb Newsletter: (June, 1989):  Australia.