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|Molar mass||822.93 g mol−1|
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
It is 30–50 times as sweet as sucrose (table sugar). Pure glycyrrhizin is odorless. Although sweet, the taste sensation of glycyrrhizin is different from that of sugar. The sweetness of glycyrrhizin has a slower onset than sugar has, and lingers in the mouth for some time. Unlike the artificial sweetener aspartame, glycyrrhizin maintains its sweetness under heating.
In chemical terms, glycyrrhizin is a triterpenoid saponin glycoside. Upon hydrolysis, the glycoside loses its sweet taste and is converted to the aglycone glycyrrhetinic acid plus two molecules of glucuronic acid. The acid form is not particularly water-soluble, but its ammonium salt is soluble in water at pH greater than 4.5.
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, the Japanese government has asked its citizens to limit their consumption to 200 milligrams per day.
The most widely reported side-effects of glycyrrhizin use are hypertension and edema (water retention). These effects are related to the inhibition of cortisol metabolism within the kidney, and the subsequent stimulation of the mineralocorticoid receptors. Thus, consumption of black licorice can mimic disorders of excess aldosterone.
Glycyrrhizin and other licorice root products have been used for numerous medical purposes, in particular, treatment of peptic ulcers and as an expectorant. The triterpene derivative of hydrolyzed glycyrrhizin glycyrrhetinic acid is itself effective in treatment of peptic ulcer. According to MedlinePlus and the Natural Medicines Comprehensive Database, licorice is "possibly effective" for dyspepsia in combination with other herbs, but there is "insufficient evidence" to rate its effectiveness for other conditions. Regarding stomach ulcers, specifically, there is "some evidence… that specially prepared licorice will speed the healing of stomach ulcers".
An un-blinded study of 82 patients from the early 1980s, published in the British Medical Journal, reported that Caved-S had a therapeutic effect is similar to that of cimetidine in the treatment of gastric ulcers.
Although licorice may produce anti-inflammatory effects, it is uncertain as to whether that is due to glycyrrhizin, glycyrrhetinic acid, or some other licorice derivative.
Glycyrrhizin inhibits liver cell injury caused by many chemicals and is used in the treatment of chronic hepatitis and cirrhosis in Japan. It also inhibits the growth of several DNA and RNA viruses, inactivating herpes simplex virus particles irreversibly, and disrupting H5N1 influenza and H5N1-induced pro-inflammatory gene expression.
Distribution in the body
After oral ingestion, glycyrrhizin is first hydrolyzed to 18β-glycyrrhetinic acid by intestinal bacteria. After complete absorption from the gut, β-glycyrrhetinic acid is metabolized to 3β-monoglucuronyl-18β-glycyrrhetinic acid in the liver. This metabolite then circulates in the bloodstream. The main part is eliminated by bile and only a minor part (0.31–0.67%) by urine. After oral ingestion of 600 mg of glycyrrhizin the metabolite appeared in urine after 1.5 to 14 hours. Maximal concentrations (0.49 to 2.69 mg/l) were achieved after 1.5 to 39 hours and metabolite can be detected in the urine after 2 to 4 days.
- Saponin Glycosides, by Georges-Louis Friedli, URL accessed Dec 2007.
- Opinion of the Scientific Committee on Food on Glycyrrhizinci Acid and its Ammonium Salt (opinion expressed on 4 April 2003), European Commission, 4 April 2003, accessed online 7 June 2008
- Størmer, F.C.; Reistad, R.; Alexander, J. (1993). "Glycyrrhizic acid in liquorice—Evaluation of health hazard". Food and Chemical Toxicology 31 (4): 303–12. doi:10.1016/0278-6915(93)90080-I. PMID 8386690.
- Ferrari, P.; Sansonnens, A.; Dick, B.; Frey, F. J. (2001). "In Vivo 11 -HSD-2 Activity: Variability, Salt-Sensitivity, and Effect of Licorice". Hypertension 38 (6): 1330–6. doi:10.1161/hy1101.096112. PMID 11751713.
- Licorice: MedlinePlus Supplements, United States National Library of Medicine, National Institutes of Health
- Morgan, A G; Pacsoo, C; McAdam, W A (1985). "Maintenance therapy: A two year comparison between Caved-S and cimetidine treatment in the prevention of symptomatic gastric ulcer recurrence". Gut 26 (6): 599–602. doi:10.1136/gut.26.6.599. PMC 1432764. PMID 4007604.
- Morgan, A G; McAdam, W A; Pacsoo, C; Darnborough, A (1982). "Comparison between cimetidine and Caved-S in the treatment of gastric ulceration, and subsequent maintenance therapy". Gut 23 (6): 545–51. doi:10.1136/gut.23.6.545. PMC 1419696. PMID 7042486.
- Pompei, Raffaello; Flore, Ornella; Marccialis, Maria Antonietta; Pani, Alessandra; Loddo, Bernardo (1979). "Glycyrrhizic acid inhibits virus growth and inactivates virus particles". Nature 281 (5733): 689–90. doi:10.1038/281689a0. PMID 233133.
- Michaelis, Martin; Geiler, Janina; Naczk, Patrizia; Sithisarn, Patchima; Leutz, Anke; Doerr, Hans Wilhelm; Cinatl, Jindrich (2011). "Glycyrrhizin Exerts Antioxidative Effects in H5N1 Influenza a Virus-Infected Cells and Inhibits Virus Replication and Pro-Inflammatory Gene Expression". In Pekosz, Andrew. PLoS ONE 6 (5): e19705. doi:10.1371/journal.pone.0019705. PMC 3096629. PMID 21611183.
- Kočevar Glavač, Nina; Kreft, Samo (2012). "Excretion profile of glycyrrhizin metabolite in human urine". Food Chemistry 131: 305. doi:10.1016/j.foodchem.2011.08.081.