SKIN CARE


Scientific foundations of liquorice in skin care


Diego Lopez – BGG


With sustainability, eco-awareness and naturality now cemented as mainstream consumer concerns worldwide, demand for plant-based ingredients is rising. The global beauty and personal care (BPC) market is no exception, with consumers demonstrating a growing preference for natural solutions. NielsenIQ market research, for example, shows that 18% of all BPC sales feature products incorporating botanic extracts.1 Liquorice fits this trend as a clinically


supported botanical ingredient. The herbaceous perennial has been a mainstay of traditional medicine systems for thousands of years for its antioxidant, anti-inflammatory and antibacterial properties.2


Today, these


attributes and its positioning as a natural, sustainable ingredient are leading to liquorice’s increasing incorporation in modern skin care products. This article reviews the scientific evidence


for the benefits of liquorice extracts from a skin care perspective, with a focus on the bioactive compounds glycyrrhizin, glabridin and licochalcone A and their use for specific skin conditions. These include hyperpigmentation, sun-ageing, eczema, rosacea, skin sensitivity, acne and subcutaneous fat reduction.


Liquorice active constituents and properties Classed as an essential herbal medication and the most frequently prescribed ingredient in traditional Chinese medicine, liquorice (genus Glycyrrhiza) is native to western Asia, southern Europe and north Africa. The three most commonly used species are G. glabra L., G. inflata Batalin and G. uralensis Fisch. Their thick roots and rhizomes are rich in bioactive natural compounds, many of which


18-b GLYCYRRHETINIC ACID O H O + H HO + H Figure 1: Key liquorice saponins and flavonoids www.personalcaremagazine.com January 2025 PERSONAL CARE HO R1 O R2 OCH3 O O CH3 O O H2 C HO CH3 OH


have demonstrated efficacy as cosmeceutical ingredients.3 Over 400 phytochemicals have been


identified in liquorice, including saponins, flavonoids, volatile compounds, phenolic compounds and essential oils.4


The primary


active in the root is the triterpenoid saponin glycyrrhizin (also known as glycyrrhizic acid), a mixture of potassium, calcium and magnesium salts of glycyrrhizic acid.2 It accounts for around 10% of the root’s


dry weight and is responsible for liquorice’s characteristic sweet flavour.2


associated with strong anti-inflammatory and skin-soothing properties.5


Glycyrrhizin is Its primary


metabolite is 18ß-glycyrrhetinic acid (also known as enoxolone), which has been extensively studied for its anti-inflammatory properties.6 Glabridin is the primary isoflavone in liquorice and has been shown to inhibit


GLABRIDIN


melanin production and pigmentation and brighten skin tone.7,8


59


Licochalcone A


is a liquorice flavonoid found primarily in G. inflata.9


inflammatory properties, with demonstrated efficacy for acne and dermatitis.9,10


It has antibacterial and anti- The


structures of these selected compounds are shown in Figure 1.


Overview of mechanisms of action Glycyrrhizin and 18ß-glycyrrhetinic acid have been shown to reduce inflammation by acting on a number of immune-signalling pathways, including three pro-inflammatory pathways – NFx-χb, TLR4/MYD88 and MAPK – and the anti-inflammatory Keap1-Nrf2 pathway.4 Their anti-inflammatory activities include inhibition of pro-inflammatory compounds such as cytokine COX-2, inducible nitric oxide synthase (iNOS), tumour necrosis factor and interleukin 6 (IL-6).11


LICOCHALCONE A


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