Licorice root is one of the most popular herbal medicines around the globe. The major active component of licorice root is a compound known as glycyrrhizin, usually found in concentrations ranging from 6 to 10%. Once ingested, glycyrrhizin is broken down into glycyrrhetinic acid before it is absorbed. These compounds have shown a multitude of pharmacological effects, inclding estrogenic, anti-inflammatory (cortisone-like action), and antiviral actions. Many of the licorice components, such as flavonoids, also have shown significant effects.
Licorice has long been used in treating the symptoms of the common cold. This historical use is justified by its immune-enhancing and antiviral effects, but there are no clinical trials to justify this use.
Licorice components have demonstrated significant anti-inflammatory, antifungal and antiallergy actions in animal studies. Licorice has a long history of use for gastric ulcers that continues into present day. Modern use also focuses on the use of licorice for hormonal issues, such as menopause and PMS, as well as stimulating production of and prolongation of cortical hormones.
Leaves of the licorice plant contain several antifungal and antibacterial compounds. Intavenous treatment with glycyrrhizin solution prevented development of liver carcinoma in patients with chronic hepatitis C. Licochalcone-A, a flavonoid component of licorice, demonstrated cancer-inhibiting activity against acute leukemia, breast and prostate cancer cells. These effects are due to the action of licochalcone's ability to lower the levels of bel-2, the protein that causes resistance to anticancer drugs. This may increase tumor sensitivity to such anticancer drugs.
CONTRAINDICATIONS
Do not use licorice preparations if you have: chronic hepatitis; cholestatic disease of the liver; cirrhosis of the liver; severe renal insufficiency; diabetes mellitus; hypertonic neuromuscular disorders; arrhythmias; hypertension; hypertonia and hypokalemia. Tobacco use has been associated with licorice toxicity.
PRECAUTIONS AND ADVERSE REACTIONS
Licorice should not be used for a prolonged period of time except under the supervision of a qualified health professional. Chronic ingestion of the herb may result in hypertension, edema, cardiac complaints, sodium retention and severe electrolyte imbalances, such as hypernatremia and hypokalemia, resulting in hypotonia, muscular weakness, flaccid paralysis, and in rare cases, myoglobinuria. High consumption of licorice may cause visual disturbances.
DRUG INTERACTIONS
Licorice may reduce the effectiveness or increase the risk of adverse side effects of many drugs including antihypertensive drugs; antiarrhythmics; laxatives; anticoagulants; antidiabetics; combination contraceptives; corticosteroids; diuretics; estrogens; MOIs and insulin production and metabolism.
Licorice should not be administered for more than 4 to 6 weeks without medical advice.