Licorice

• Properties and Uses
• Toxicity Levels

DESCRIPTION

Licorice is a perennial plant indigenous to southern Europe, the Middle East and northern China; it is cultivated in many parts of the world. The rootstock is brown, wrinkled, and woody, producing an erect striated stem two to five feet in height. The leaves are alternate, odd-pinnate, and have four to seven pairs of ovate, smooth, dark green leaflets. Purplish or yellowish white flowers grow in axillary racemes and bloom from June to August. The medicinal part is the rootstock.

Other common names for this plant are:

CHEMICAL COMPOSITION

* For definition of some of the above terms see the dictionary section of this book.

NUTRIENT COMPOSITION

Properties and Uses

Aperient - a mild laxative used to stimulate the bowels.

Demulcent - an agent which smooths the mucous membranes on contact.

Diuretic - Diuretics form a class of drugs which increase the volume of urine produced by the kidneys. It can be used effectively to treat mild cases of edema when kidney function is good and when the underlying abnormality of cardiac function, capillary pressure, or salt retention is being corrected simultaneously. Diuretics are not an appropriate treatment for edema caused by inflammation of the kidneys, and are useless in cardiac edema associated with advanced kidney insufficiency.

Emollient - a skin dressing or soothing ointment.

Expectorant - an agent which stimulates the outflow of mucus from the lungs and bronchials.

Laxative - an agent which acts to loosen the bowels; it is therefore used to treat constipation. Laxatives may act by increasing peristalsis by irritating the intestinal mucosa, lubricating the intestinal walls, softening the bowel contents by increasing the amount of water in the intestines, and increasing the bulk of the bowel content.

Pectoral - an agent which relieves chest conditions such as a cough.

Sialogogue - an agent which stimulates the secretion of saliva.

Stimulant - an agent that temporarily increases activity or physiological processes. Stimulants may be classified according to the organ upon which they act; for example, an intestinal stimulant is that which stimulates the intestines.

Licorice works as a stimulant on the adrenal glands, and contains glycosides which can chemically purge excess fluid from the lungs, throat, and body, which makes it very useful for coughs and chest complaints. It works as a laxative, helps in inflammation of the intestinal tract, relieves ulcer conditions, and has stimulating action to counteract stress. Licorice root is a source of estrogen, and therefore useful for the female system.

It exhibits many pharmacological activities, including estrogenic activities in laboratory animals; it is anti-tumoral, anti-trichomonas, anti-inflammatory, anti-allergenic, anti-toxic, anti-tussive (comparable to codeine for severe coughing), anti-convulsive, and anti-bacterial.

It will relieve bronchitis, sore throat, and coughing. Its unique glycosides chemically purge excess fluid from the lungs and throat and eliminate them from the body through the urinary tract. It is a remarkable herb for endurance; since viral illnesses often weaken the patient, licorice can be used to supply the energy necessary to allow more activity during recovery.

It has been used clinically in the People's Republic of China in treating gastric and duodenal ulcers, bronchial asthma, infectious hepatitis, malaria, diabetes, contact dermatitis, and hypoglycemia. This herb owes most of its sweet taste to glycyrrhizin, which is the potassium and calcium salts of glycyrrhizinic acid. The yellow of the root is due to flavonoids.

There are several varieties of licorice on the world market, including Italian, Russian, Syrian, Anatolian, Turkish, Arabian and three kinds of Spanish. The average glycyrrhizin content of licorice is about 7%, with the general range between 6 - 13%.

Recent clinical investigation has shown various uses for glycyrrhizin in the treatment of rheumatoid arthritis, Addison's disease and various types of inflammation. Glycyrrhizin is very soluble in hot water and alcohol, but extremely incompatible with acids (this is somewhat modified when combined with other herbs). The glucosides which make up glycyrrhizin act as a form of natural glucose which, when combined with goldenseal, work on the pancreas to produce insulin. When combine with other herbs, glycyrrhizin serves as a vehicle for those herbs.

Toxicity Levels

Licorice root contains glycyrrhizin, the source of most of the pharmacological effects of licorice root and rizome. Glycyrrhizin is about 50 times sweeter than sugar; it has a powerful cortisone-like effect which may result in minor "poisoning" if overconsumed. Glycyrrhizin increases extracellular fluid and plasma volume and induces sodium retention and loss of potassium, often leading to edema or water retention. Licorice extracts produce estrogenic activity due to the phenolic compound clycestrone which is 1/533 of the potency of estrone. Too much licorice can cause cardiac depression and edema.

DRUG PRECAUTIONS AND INTERACTIONS

Known Interactions

A mixture containing astragalia radix, cinnamon, peony cnidii rhioma, angelica root, ginseng root, and licorice root has been shown to enhance antitumor activity and to decrease toxicity of mitomycin C.

This herb reduces aspirin absorption and protects gastric mucosa against aspirin toxicity. Possible Interactions

It may induce interferon production, which in turn, may inhibit the antiviral activity of puromycin.

Conversely, the adrenocortical or corticosteroidal action of licorice may be antagonized by the use of heparin.

The presence of corticosteroids in licorice may interact with uterine relaxants, such as ritodrine HCL, to produce pulmonary edema. Furthermore, because this herb can affect blood serum potassium levels, it may potentiate the hypokalemic property of sodium polystyrene sulfonate.

Adrenocortical responsiveness to licorice may be impaired by the use of aphotericin B. The anti-inflammatory activity of the herb can be seriously inhibited by phenobarbital and certain other sedatives and hypnotics, such as chloral hydrate and meprobamate. This is also true of beta-adrenergic blocking agents such as propranolol.

The presence of estrogen-like substances in licorice may increase the production of procoagulant factors which, in turn, may inhibit the anticoagulant action of heparin or coumarin. These estrogenic constituents may also potentiate oral anti-diabetics, folic acid antagonists, and some corticosteroids.

The presence of estrogen in licorice can inhibit anti-hypercholesterolemics by inducing hyperlipemia, and can inhibit the activity of most parenteral medications by reducing the rate of spreading.

The estrogenic activity of licorice may be inhibited by meprobamate and phenobarbital. Due to the presence of estrogenic substance in this herb, oxytocin may augment the electrical and contractile activity of uterine smooth muscle. Furthermore, the estrogen in this herb may raise blood glucose levels enough to alter insulin requirements in diabetics.

Comments

To the extent that licorice's action depends on the presence of cholinergic substances, it will be affected by the decrease in cholinergic-receptor stimulation produced by anticholinergics.

The fact the rifampin stimulates the metabolism of corticosteroids indicates that the drug may lower the mineral and glucocorticoid action of licorice. Furthermore, oral estrogen supplementation may retard the metabolism of licorice's steroidal hormones.

It should be noted that in hypertensive persons, regular consumption of licorice candy or carbenoxolone sodium may induce hypokalemia, subsequently potentiating the toxic effect of cardiac drugs and counteracting hypertensive medication.

Although the coumarin content of this herb is not high at normal usage levels, it is important to note that coumarins can affect the action of almost any drug.

There is evidence to show that combining bactericidal and bacteriostatic agents will lower the effectiveness of the bacteriostatic agent. How this finding applies to herbal anti-infectives is still unknown.