The full Regimen Lab Skincare Encyclopedia Entry for Glycyrrhiza Glabra (Licorice) Root Extract is in development. Check back in a few weeks for an update!
Glycyrrhiza glabra (family Fabaceae), commonly known as licorice, is an herbaceous perennial and has been used as a flavoring agent in food and medicinal remedies for thousands of years. Licorice extracts are widely used in traditional medicine and cosmeceuticals. The roots and rhizomes are the main medicinal parts of licorice.
What are its valuable components and benefits?
Licorice contains more than 20 triterpenoids and nearly 300 flavonoids. Among them, glycyrrhizin, 18β-glycyrrhetinic acid, liquiritigenin, licochalcone A, licochalcone E and glabridin are the main active components which possess antiviral and antimicrobial activities.
The active components consist of triterpene saponins such as glycyrrhizin (3-15%), flavonoids including licoricidin, isoflavones such as glabridin, hydroxycoumarins including glycycoumarin, cumestans such as glycynol, sterols, such as beta-sitosterol, and volatile including eugenol.
Licorice and its Cosmeceutical Benefits
(Glycyrrhiza Glabra and Glycyrrhiza Uralensis), marketed as liquiritin, contains flavanoids and a glycoside called glycyrrhizin, and have shown utility in treating melasma. Liquiritin causes depigmentation by two mechanisms: via melanin dispersibility by means of the pyran ring of the color dispersing flavonoidal nucleus of liquiritin, and via amelanodermic and epidermal stain removing property. Acute and chronic toxicity studies have been carried out with no adverse effects. Glabrene and isoliquiritigenin (2,4, 4-trihydroxychalcone) in the licorice extract can inhibit both mono- and diphenolase tyrosinase activities. The effects of glabrene and isoliquiritigenin on tyrosinase activity were dose-dependent and correlated to their ability to inhibit melanin formation in melanocytes. Mechanisms of action in addition to tyrosinase inhibition include melanin dispersion, epidermal melanin removal, and cyclo-oxygenase inhibition (anti-inflammatory activity).
One of the active components, glabidrin, is anti-inflammatory, antioxidant, and inhibits tyrosinase therefore reducing erythema and pigmentation induced by UVB. Other skin lightening constituents of licorice are glaberdines of which are in higher concentration in the roots of the plant. Evidence presented at the 63rd Annual Meeting of the American Academy of Dermatology suggested that licochalcone A is an anti-inflammatory that reduces pro- inflammatory cytokines and prostaglandins following UV irradiation. On another clinical eight-week study of 62 adults, licorice extract has also been used, a topical licochalcone A formulation significantly improved subjects’ rosacea and quality of life ratings.
In addition, G. glabra and glycyrrhizin are found out to inhibited skin tumors when administered orally or topically in murine models.
What are other medicinal benefits of licorice?
Licorice is also a valuable ingredient for wounds and carbuncle therapy, used in Asian medicine. Glycyrrhizin also inhibits the replication of varicella zoster, hepatitis B, cytomegalovirus, and HIV and stimulates IFN production (interferon production). Among its many properties: anti-estrogenic, antistaphylococcal, antiprotozoal, anti-fungal, anti-yeast, antioxidant, anti-inflammatory, antiplatelet, anti-thrombin, anti-cancer and sebostatic effects. In traditional Chinese medicine, licorice has been presented in most prescriptions and was believed to alleviate pain, tone the spleen and stomach, eliminate phlegm and relieve coughing.
The effect of licorice extract as topical preparation was evaluated on atopic dermatitis. After standardizing of topical preparations, the best formulations (1% and 2%) were studied in a double–blind clinical trial in comparison with base gel on atopic dermatitis over two weeks (30 patients in each group). The quantity of glycyrrhizinic acid was determined 20.3% in the extract and 19.6% in the topical preparation. Two percent licorice topical gel was more effective than 1% in reducing the scores for erythema, oedema and itching over two weeks (p<0.05). The results showed that licorice extract could be considered as an effective agent for the treatment of atopic dermatitis.
Dieck K, Ceilley RI, Immeyer J, et al. Anti-inflammatory properties of licochalcone A from Glycyrrhiza inflata on various human skin cells. In: Poster presented at the 63rd Annual Meeting of the American Academy of Dermatology, February 18–22, 2005, New Orleans, LA.
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Weber TM, Scholermann A, Burger A, et al. Tolerance and efficacy of a skin care regimen containing licochalcone A for adults with erythematic rosacea and facial redness. In: Poster presented at the American Academy of Dermatology, February 18–22, 2005, New Orleans, LA.
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Wang, L., Yang, R., Yuan, B., Liu, Y., & Liu, C. (2015). The antiviral and antimicrobial activities of licorice, a widely-used Chinese herb. Acta pharmaceutica Sinica. B, 5(4), 310–315.
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Nerya O, Vaya J, Musa R, et al. Glabrene and isoliquiritigenin as tyrosinase inhibitors from licorice roots. J Agric Food Chem 2003; 51:1201–1207.