Liquorice Root Extract

Liquorice root extract is obtained from the Glycyrrhiza glabra plant and is characterised by its many positive properties. The use of liquorice root extract in cosmetics has gained popularity in recent years due to its many benefits for the skin. The anti-inflammatory and antioxidant components help to soothe the skin, while the skin-brightening properties can help to reduce hyperpigmentation. The extract is known for its ability to improve skin elasticity and protect it from external influences. This makes liquorice root extract a valuable ingredient in cosmetic products aimed at promoting skin health.

Botany

The genus Glycyrrhiza LINNÉ belongs to the legume family (= Leguminosae) and consists of 20 to 30 species. The drug-producing species include liquorice root, G. inflata and G. uralensis. The liquorice root, also known as liquorice, is grown in the temperate to subtropical countries of the Mediterranean region, Russia, West and Central Asia, Australia and America.

The liquorice root is a perennial, up to 1.5 m high perennial with a lifespan of approx. 15 years, which initially develops a long, strong taproot and later secondary roots and a strongly woody rootstock. The underground parts of the plant are up to 2 cm thick and are surrounded by cork in older plants. Stems and leaves sprout annually. The flowers are 1 to 1.5 cm long, bluish to light purple and short-stalked.

The roots and root runners as well as the rhizomes are used to obtain the extract, whereby the main root is usually left standing. Harvesting takes place from late autumn to spring, before the new shoots appear. Harvesting takes place regularly every three years. The whole drug is traded as peeled or unpeeled root pieces and root runners, which are usually 1 to 2 cm thick and up to 30 cm long. Other commercial forms are the cut and powdered drug.

Active ingredients of liquorice root

In addition to terpene compounds, the main ingredients of liquorice root are approx. 5 % sucrose, approx. 2.5 % glucose and 20-30 % starch. It also contains small amounts of flavonoids and coumarins as well as essential oils. The terpenes isolated from liquorice root to date belong predominantly to the group of pentacyclic triterpenes with an olean framework. One of the main representatives of this group of substances in liquorice root is saponin.

One of the main active ingredients is glycyrrhizic acid (glycyrrhetinic acid 3-O-diglucuronide), which occurs in the drug as potassium, ammonium and calcium salts. The mixture of these salts of glycyrrhizic acid is also known as glycyrrhizin. Depending on its origin and the part of the plant used, the drug contains 2 to 15 % glycyrrhizic acid. Acidic or enzymatic hydrolysis of glycyrrhizic acid produces its aglycone, 18b-glycyrrhetinic acid, traces of which are also contained in the extract. In addition to glycyrrhizic acid and 18b-glycyrrhetinic acid, other triterpene compounds have been detected in root extracts, including deoxyglabrolide, glabrolide, 18a-glycyrrhetinic acid, glycyrrhetinic acid methyl ester and glycyrrhetol.

The coumarin derivatives isolated to date include herniarin and umbelliferone. Reiners’ research group isolated a fraction from liquorice roots that also contained coumarin derivatives. In addition to the coumarins mentioned above, two phenolic acids, ferulic acid and synapinic acid, were detected in this fraction.

Effects and applications of liquorice root

Numerous effects are attributed to the ingredients of liquorice root, especially the triterpene compounds. Liquorice root is used both therapeutically and cosmetically, primarily because of its anti-inflammatory effect. Glycyrrhizic acid and its aglycone, 18b-glycyrrhetinic acid, play a decisive role in the topical application of liquorice root extracts and their preparations.

The anti-inflammatory effects of glycyrrhizic acid and 18b-glycyrrhetinic acid are based on the inhibition of various mediator systems of inflammatory reactions. Influencing steroid metabolism plays a key role in the anti-inflammatory effect of glycyrrhizic acid and 18b-glycyrrhetinic acid. Both compounds, but especially 18b-glycyrrhetinic acid, inhibit D-5b-steroid reductase even in relatively low concentrations. Inhibiting this enzyme delays the metabolic elimination of corticosteroids and prolongs the biological half-life of cortisone and aldosterone. It is known that preparations from liquorice root are used to support long-term treatment with cortisone in order to reduce the side effects of cortisone.

Other dermatological benefits of liquorice root are its antioxidant and antimicrobial properties. The antioxidant properties of liquorice root are due to the active ingredients glabrene, licochalcone A and licochalcone B, among others. Glabrene from Russian liquorice, for example, has an antioxidant effect three times greater than vitamin E.

The phenolic compounds of liquorice root in particular show a weak antimicrobial effect. The active ingredients identified include glabrene and glabridin.

The main therapeutic use of liquorice root is topical application for allergic skin reactions, skin inflammation and skin rashes. Liquorice root has an anti-inflammatory effect, promotes wound healing and is effective against skin itching (puritis). When taken orally in the form of tea or liquorice in higher doses, liquorice root extracts can influence the metabolism of the adrenal cortex hormones aldosterone and cortisol. This results in increased sodium and decreased potassium levels in the blood. In order not to increase this effect, we use potassium salts instead of sodium salts in our cosmetic products.

Skin compatibility of liquorice root

The skin tolerance of glycyrrhizic acid was investigated in a study using a plaster test. A 5% aqueous solution of glycyrrhizic acid was applied to the inside of the elbow of 21 female volunteers and covered occlusively with a plaster. No inflammatory reaction was visible on the skin after 48 hours. Even after irradiation of the test areas, no inflammatory changes in the skin areas were observed in any of the test subjects.

The tolerance is excellent, so that the use of liquorice root in after-sun products and medical dermatological preparations is obvious.

Clinical studies show that formulations with 18b-glycyrrhetinic acid as an active ingredient do not cause any negative skin changes. No side effects and no sensitisation of the skin were observed in the long-term treatment of dermatoses with a 2% ointment containing 18b-glycyrrhetinic acid.

Leading substances of Glycyrrhiza Glabra

Glycyrrhizic acid is a main ingredient of liquorice root with contents of 2 to 15 %. Hydrolysis of glycyrrhizic acid produces 18b-glycyrrhetinic acid, which is also detectable in traces in the plant extract. As these triterpene compounds are responsible for the positive effects of liquorice root, a high-quality liquorice root extract should be characterised on the basis of these compounds.

Characteristics

INCI: Glycyrrhiza Glabra (Licorice) Root Extract

CAS number: 68916-91-6

Origin: liquorice root (botanical name: Glycyrrhiza glabra)

Properties: anti-inflammatory, antioxidant, skin lightening, soothing

We work with these liquorice root extracts and active ingredients:

Cosmetic innovation: Effective skin care with liquorice root extract from Cosmacon

To summarise, liquorice root extract represents a remarkable enrichment for the cosmetics industry. With its anti-inflammatory, antioxidant and skin-lightening properties, this extract offers a versatile range of benefits for skincare. The ability to soothe the skin, reduce inflammation and improve skin elasticity makes liquorice root a popular ingredient in a variety of skincare products. From traditional applications to modern formulations, liquorice root gives cosmetics a natural boost that is valued in both traditional and contemporary skincare. Rely on Cosmacon’s expertise to reap the benefits of liquorice root in your customised cosmetic products.

Sources:

Anti-Inflammatory Effect of a Novel Topical Herbal Composition (VEL-091604) Consisting of Gentian Root, Licorice Root and Willow Bark Extract.; Seiwerth J, Tasiopoulou G, Hoffmann J, Wölfle U, Schwabe K, Quirin KW, Schempp CM.Planta Med. 2019 May;85(7):608-614. 

Allergic contact dermatitis to Glycyrrhiza inflata root extract in an anti-acne cosmetic product.; Gatica-Ortega ME, Pastor-Nieto MA.Contact Dermatitis. 2021 Oct;85(4):454-455. 

n Vitro Analysis of Licorice (Glycyrrhiza glabra) Root Extract Activity on Streptococcus mutans in Comparison to Chlorhexidine and Fluoride Mouthwash.; Malvania EA, Sharma AS, Sheth SA, Rathod S, Chovatia NR, Kachwala MS.J Contemp Dent Pract. 2019 Dec 1;20(12):1389-1394.