Glycyrrhizin

Glycyrrhizin, glycyrrhizinic acid or glycyrrhizic acid, is the active principle of liquorice root. It is a powerful sweetener, 30–50 times as potent as sucrose (table sugar).

Chemically, glycyrrhizin is a triterpenoid glycosidic saponin. The acid form is not particularly water-soluble, but its ammonium salt is soluble in water at pH greater than 4.5.

Although sweet, the taste of glycyrrhizin is different from that of sugar. The sweetness of glycyrrhizin has a slower onset than sugar, and lingers in the mouth for some time. Additionally, its characteristic licorice flavor makes it unsuitable as a direct flavor substitute for sugar. Unlike the artificial sweetener aspartame, glycyrrhizin maintains its sweetness under heating.

In the United States, glycyrrhizin is classified as "generally recognized as safe" as a flavoring agent, although not as a sweetener. Glycyrrhizin is used as a flavoring in some candies, pharmaceuticals, and tobacco products.

In Japan, where concern over the safety of artificial sweeteners during the 1970s led to a shift towards plant-derived sugar substitutes, glycyrrhizin is a commonly used sweetener, often used in combination with another plant-based sweetener, stevia. However, glycyrrhizin appears to have some pharmacological side effects, and the Japanese government has asked its citizens to limit their consumption to 200 milligrams per day.

Health effects
Glycyrrhizin and other licorice root products have been used for numerous medical purposes, particularly treatment of peptic ulcers and as an expectorant. The triterpene derivative of glycyrrhizin, glycyrrhetinic acid, is itself effective in treatment of peptic ulcer. A synthetic analog, carbenoxolone, was developed in Britain. Both glycyrrhetinic acid and carbenoxolone have a modulatory effect on neural signaling through gap junction channels.

The most widely reported side effects of glycyrrhizin use are hypertension and edema (water retention). Deglycyrrhizinated licorice is a preparation used for treating ulcers which has had the glycyrrhizin removed in order to avoid the side effects.

Recently researchers have demonstrated that doses of licorice root extract, delivering the constituent glycyrrhizin in amounts similar to that contained in standard medical doses of the root, rapidly and significantly lowered levels of circulating testosterone in males.

Liquorice consists of dried, peeled or unpeeled, root and stolons of Glycyrrhiza glabra, which belongs to the family leguminosae.

Why hypertension?
Glycyrrhizin inhibits the conversion of cortisol to cortisone by inhibiting the enzyme 11Beta Hydroxysteroid dehydrogenase. As a result, cortisol levels are high within the collecting duct of the kidney. Cortisol has intrinsic mineralocorticoid properties (that is, it acts like aldosterone and increases sodium reabsorption) that work on ENaC channels in the collecting duct. Hypertension develops due to this mechanism of sodium retention. People often have high blood pressure with a low renin and low aldosterone blood level.