Licorice - Glycyrrhiza glabra (in the Fabaceae or Legume family)
Part used: Root.
Taste/smell: Sweet, nutritious.
Dosage: Decoction: 1 teaspoon per cup of water; or 1:3 dry strength liquid extract: 20-60 drops 1-4 times per day.
Use: (a) Demulcent, (b) Adrenalmodulator, (c) Antibacterial, (d) Antiviral, (e) Antimutagen, (f) Anti-allergenic, (g) Expectorant with secretolytic and secretomotor activity, (h) Anti-inflammatory, (i) Nutritive, (j) Spasmolytic, (k) Antioxidant, (l) Estrogenic, (m) Immunomodulator, (n) Mild laxative, (o) Hepatoprotective.
Licorice is most known for its soothing effect on inflamed mucous membranes of the throat, lungs, stomach and intestines. The root is used for coughs, all throat and bronchial irritations, urinary tract irritation, adrenal fatigue, immune deficient states, allergies, gastric and duodenal ulcers, liver disorders, exhaustion due to adrenal stress, and dermatological detoxification. It is effective for chronic hepatitis, useful in HIV and is specific for conditions like mononucleosis, where the patient has abnormally high liver enzymes, a sore throat and needs immune system support. It is also a wonderful herb for Chronic Fatigue Syndrome. Due to its sweet taste, licorice makes a nice addition to formulas that are unpalatable.
Experiments with both methanol extract of licorice and the constituent glycyrrhizin appear to activate glucuronidation and suggest the possibility that it may influence detoxification of xenobiotics in the liver. Subdural injection of licorice root has inhibited RC mammary carcinoma and lymphosarcoma 150 in mice. A number of constituents in licorice have shown anti-tumor activity in animal research.
The saponin known as glycyrrhizin, also known as glycyrrhizic acid or glycyrrhizinic acid, is the main ingredient in licorice root. It and its aglycone, glycyrrhetinic acid, exert most of the medicinal effects and are essential active components. Glycyrrhetinic acid is formed from glycyrrhizin via hydrolysis that is assisted by intestinal flora enzymes. It decreases inflammation by enhancing movement of leucocytes towards inflamed areas. Glycyrrhizin also increases interferon production and inhibits the activity of phospholipase A and the formation of prostaglandin E2 in activated peritoneal macrophages. Additionally it inhibits the effect of several tumor promoters. It contains 3-dehydro-18 beta-glycyrrhetinic acid, 2-15% triterpenoid saponins, largely glycyrrhizin that is ammonium and calcium salts of glycyrrhizinic acid and 24-hydroxyglycyrrhizin. Glycyrrhizinic acid hydrolyzes to diglucuronic acid and the aglycone glycyrrhetinic acid. There are other triterpenoid saponins, including sitosterol and stigmasterol, flavonoids and isoflavonoids, coumestans, coumarins, resins, gums, tannin, starch and a bitter principle. The isoflavone in licorice called formononetin, has very weak estrogenic activity compared with natural estrone or synthetic DES. Phytoestrogens can behave like anti-estrogens by competing with estradiol for cytoplasmic receptors in estrogen-sensitive tissues, possibly acting as protection against stronger estrogenic action from estradiol and protecting against cancers that are estrogen receptor positive.
Since licorice inhibits 5-beta-reductase that regulates cortisol and aldosterone metabolism, it may retard the metabolic excretion of corticosteroids and extend the biological half-life of cortisol and aldosterone.
Contraindications: Licorice is contraindicated in high blood pressure, heart failure, kidney disease, liver cirrhosis and cholestatic liver disorders. Chronic licorice use mimics aldosteronism by increasing sodium resorption and potassium excretion by the kidneys. This action is due to glycyrrhizin content. De-glycyrrhinized licorice has been investigated for its clinical use and saftey. Its use has been controversial. There is 2-9% glycyrrhizin in licorice root. The de-glycyrrhinized root extract has a maximum of 3% glycyrrhizin in it.
The toxic symptoms are hypertension, edema, hypokalemia, vertigo and headache. This ceases when it is withdrawn or by concurrent use of antialdosterone agents. Doses of 3 or more grams a day should not be taken for more than 6 weeks unless monitored under the guidance of a qualified health care practitioner. Elderly people are more prone to pseudoaldosteronism due to a greater increase of glycyrrhetinic acid levels from increased production by their gut bacterial flora enzymes on glycyrrhizin. Licorice potentiates the activity of anthraquinone drugs or herbs containing anthraquinones, like cascara and buckthorn, by increasing the wettability of the bowel contents because of the high surfactant activity of glycyrrhizin. It also potentiates the toxicity of cardiac glycosides like digitalis due to potassium loss in the urine. There may also be an additive effect with thiazide diuretics. When used with corticoid treatment, glycyrrhizin interferes with 5 beta-reductase breakdown of corticosteroids, thus prolonging its biological half-life. When someone discontinues the use of licorice after consuming it over a long period of time, they should withdraw from it slowly, unless they are discontinuing it due to side effects. In the case of dangerous side effects, they should immediately withdraw from its use.