Licorice root (herb - Glycyrrhiza glabra)

Licorice root (herb - Glycyrrhiza glabra)

Licorice root contains both the isoflavone Licochalcone-A and triterpenoid saponin. Regarding Licochalcone-A, in a scientific study: "Cells from patients with leukemia, breast and prostate cancer that were grown in cultures in the lab, he says, were killed when he added enough of the extract." Regarding triterpenoids, in a study: "They may block the production of prostaglandin - a hormone-like fatty acid that may be responsible for stimulating the growth of cancer cells - and help get rid of cancer-causing invaders. Triterpenoids have been shown in test tubes to stunt the growth of rapidly multiplying cells, like cancer cells, and they may even help precancerous cells return to normal." As if that weren't enough: "Medical researchers have isolated several active substances in licorice root including glycosides, flavonoids, asparagine, isoflavonoids, chalcones and coumarins. Primary of these is Glycyrrhetinic acid." Licorice root is toxic, so much work need to be done on this herb.

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About 35% of all cancer deaths in the United States are diet-associated, according to the National Research Council. As a result, the National Cancer Institute (NCI) has launched an Experimental Food Program to examine possible links. Some naturally occurring substances in plants, known as phytochemicals, are being examined as possible cancer preventives. Among the first six foods and food components being examined is licorice.

To date, more than 200 phytochemicals have been identified in licorice. Twenty-nine of them appear to have biological activity as possible cancer preventives. Of these, flavonoids, coumarins, tri-terpenes, and phenolic acid appear to be the most promising for investigation.

Research is daunting, for phytochemical compositions of substances such as licorice are highly complex. For example, different varietal species of licorice root from China show widely different phytochemical compositions. Even licorice root from the same variety, but grown in different regions, has vastly different amounts and combinations of phytochemicals. Recovery of important phytochemicals such as coumarins and flavonoids may depend on extraction techniques. Biologically active phytochemicals, potentially beneficial at one level, may become toxic consumed at another level. This characteristic is true with licorice.

Although the research on licorice root focuses on one component, glycyrrhizin, which comprises up to 14% of the plant, the licorice root also contains amino acids, amines, lignin, gums, wax, volatile oil, coumarin, flavonoids, steroids, tri-terpenes, saponins, glucose, mannose, sucrose, mannitol, starch, tannins, stilbenes, and salicylic acid. Some of the substances, in addition to glycyrrhizin, are biologically active and, used at high levels or repeatedly, can affect the body.

In addition to licorice's potential as a cancer preventive, NCI is investigating its possible roles in protecting the liver and slowing cell mutations. Recent experiments showed that licorice contains a substance that helps inhibit tumors that commonly are promoted by other substances. Other investigators are exploring its uses to prevent the complications of diabetes, to manage allergies, and to help burn patients avoid infections.

Licorice root has a long history of medical use. Various components have been used to speed the healing of gastric and intestinal ulcers, as well as mouth ulcers and other oral and pharyngeal conditions. A solution of a licorice component, applied to the skin, has been used for skin diseases such as atopic dermatitis. A licorice component has been used with Addison's disease, a debilitating ailment marked by a deficient secretion of adrenal corticoid hormone.

Licorice has a chemical structure similar to corticosteroids (adrenal gland hormones) and has similar steroidal activity and other biological effects. Glycyrrhizin can alter the body's electrolyte system, cause the body to retain sodium, lose potassium, elevate blood pressure, and lead to fluid retention. At high doses, glycyrrhizin can precipitate heart failure. Also, the chemical composition of glycyrrhetinic acid (prepared from glycyrrhizic acid) is closely related to cancer-causing hydrocarbons.

The public is familiar with licorice as a flavoring agent but has little knowledge about its potent biological activity.

For many years, food processors used licorice root as a flavoring agent. Such use made it self-limiting. Due to the intense sweetness of licorice, it has been used as a sweetness potentiator in recent years. For example, licorice intensifies chocolate flavor, which permits food processors to reduce the amount of chocolate in a product up to 10% by adding licorice.

Among its many food applications, licorice is used to add sweetness to flavorings in many non-traditional applications, as with meats (especially bacon), dehydrated and canned soups, dairy products, cheese spreads, mushrooms, pickles, barbecue sauces, and gravy mixes. Licorice is used to flavor and add body to low-calorie, low-sodium, and low-sugar food products. Also, it is used to improve the after-taste of artificial sweeteners, such as saccharin; to mask the bitterness of some nutritional supplements, such as iron; and to lessen the unpleasant taste of some medications. Licorice is used to flavor cough drops and syrups, laxatives, throat lozenges, medicated candy, mouth washes, dentifrices, and oral antiseptics. Licorice extracts have been used universally to flavor and sweeten pipe tobacco, cigarettes, chewing tobacco, and snuff.

With this greatly expanded use of licorice as a sweetness potentiator, rather than merely a flavoring agent, amounts are no longer self-limiting. High levels of consumption can result in total intake never anticipated originally when licorice was granted GRAS status (Generally Recognized as Safe). This feature needs to be considered by the NCI's Experimental Food Program before making any final judgment about licorice's potential benefits.

Individuals who have over-indulged in licorice candy or licorice-containing chewing tobacco (swallowed in saliva) frequently have required hospitalization. Chronic licorice abusers may suffer from a range of symptoms, including muscle weakness, heart palpitations, irregular heartbeat, difficult breathing, and weight change. For individuals who need to avoid licorice-containing products, label reading is not helpful. The word "licorice" may not appear on a food label but be hidden in a vague phrase "natural flavoring(s)."

PHOTO: Beatrice Trum Hunter



By Beatrice Trum Hunter

Beatrice Trum Hunter is the author of a number of books concerning food topics of importance to consumers. The most recent ones include The Great Nutrition Robbery, The Mirage of Safety, and The Sugar Trap and How to Avoid It. Mrs. Hunter is a frequent guest lecturer at universities and at meetings of health professionals and from time to time she appears on national commercial and public television programs.