Introduction
Glycyrrhiza glabra (licorice) is a well-documented medicinal plant widely used in traditional and modern dermatological formulations due to its rich profile of bioactive compounds, including glycyrrhizin, liquiritin, glabridin, flavonoids, and phenolic acids. Recent advances in cosmeceutical science have highlighted glycerolic extracts of licorice as effective delivery systems that enhance solubility, skin penetration, and stability of phytoconstituents.
Cosmeceuticals derived from licorice are increasingly recognized for their multifunctional skin benefits, particularly in hyperpigmentation disorders, inflammatory dermatoses, photoaging, and barrier dysfunction.
Phytochemical composition of glycerolic Glycyrrhiza glabra extracts
Glycerolic extraction preserves both hydrophilic and moderately lipophilic constituents, making it suitable for topical dermatological applications. Key bioactive compounds include:
- Glycyrrhizin (triterpenoid saponin)
- Glabridin (isoflavan)
- Liquiritin and liquiritigenin (flavonoids)
- Chalcones and phenolic acids
- Antioxidant polysaccharides
These compounds collectively contribute to antioxidant, anti-inflammatory, depigmenting, and skin-repair activities.
Mechanisms of action in skin biology
Antioxidant and photoprotective effects:
Licorice-derived flavonoids neutralize reactive oxygen species (ROS) generated by ultraviolet radiation, thereby reducing oxidative stress–induced cellular damage and preventing premature skin aging.
Anti-inflammatory modulation:
Glycyrrhizin and glabridin inhibit pro-inflammatory mediators such as TNF-α, IL-1β, and COX-2, thereby reducing cutaneous inflammation in acne, dermatitis, and rosacea-like conditions.
Melanogenesis inhibition:
Glabridin and liquiritin regulate melanogenesis by:
- Inhibiting tyrosinase activity
- Modulating MITF signaling pathways
- Dispersing existing melanin in epidermal layers
This supports its clinical use in hyperpigmentation, melasma, and post-inflammatory pigmentation.
Skin barrier restoration:
Licorice extracts enhance epidermal lipid balance and improve stratum corneum integrity, reducing transepidermal water loss (TEWL) and improving hydration.
Role of glycerolic extracts as a delivery system:
Glycerol acts as a biocompatible solvent and humectant that improves:
- Solubility of polar phytoconstituents
- Dermal absorption and penetration
- Stability of flavonoids and saponins
- Moisturizing effect on the stratum corneum
This makes glycerolic extracts particularly suitable for sensitive and dry skin formulations.
Cosmeceutical applications in dermatology
Hyperpigmentation disorders:
Glycerolic licorice extracts are widely used in formulations targeting:
- Melasma
- Post-inflammatory hyperpigmentation
- Solar lentigines
Anti-aging and photoaging:
Due to antioxidant and collagen-protective effects, these extracts reduce:
- Wrinkle formation
- Elastin degradation
- UV-induced dermal damage
Acne and inflammatory skin conditions:
Anti-inflammatory and antimicrobial properties contribute to:
- Reduction in erythema and swelling
- Regulation of sebum-associated inflammation
- Supportive care in acne-prone skin
Sensitive and dry skin care:
Humectant and barrier-repair actions make glycerolic extracts suitable for:
- Atopic-prone skin
- Irritated or compromised skin barriers
- Post-procedural dermatological care
Evidence from research and review studies
Multiple experimental and clinical studies have demonstrated that licorice extracts exhibit:
- Significant tyrosinase inhibition comparable to synthetic depigmenting agents
- Reduction in UV-induced erythema and oxidative stress markers
- Improvement in melanin distribution in epidermal models
- Anti-inflammatory effects comparable to mild corticosteroid alternatives in topical applications
Review literature further supports its role as a multifunctional botanical cosmeceutical with a favorable safety profile and low irritancy potential.
Advantages of glycerolic Glycyrrhiza glabra extracts
- Multitarget activity (antioxidant, anti-inflammatory, depigmenting)
- High skin compatibility and low irritation risk
- Enhanced phytochemical stability in glycerol base
- Suitable for long-term dermatological use
- Natural alternative to synthetic skin-lightening agents
- Supports barrier repair and hydration simultaneously
Therapeutic role in skin health management
Glycerolic licorice extracts act as comprehensive skin modulators by:
- Reducing oxidative stress and inflammation
- Regulating melanogenesis and pigmentation disorders
- Enhancing epidermal hydration and barrier function
- Supporting skin rejuvenation and repair processes
- Providing adjunctive benefits in acne and photoaging management
Conclusion
Glycerolic extracts of Glycyrrhiza glabra represent a promising class of bioactive cosmeceutical agents with multifunctional dermatological benefits. Their combined antioxidant, anti-inflammatory, and depigmenting actions,1 along with improved dermal delivery through glycerol-based extraction, make them highly relevant for modern skin care formulations. However, further standardized clinical investigations are required to fully establish their therapeutic potential and optimize their application in evidence-based dermatology and cosmeceutical science.
References:
- Ciganović P, Jakimiuk K, Tomczyk M, Zovko Končić M. Glycerolic Licorice Extracts as Active Cosmeceutical Ingredients: Extraction Optimization, Chemical Characterization, and Biological Activity. Antioxidants (Basel). 2019;8(10):445. Published 2019 Oct 1. doi:10.3390/antiox8100445. https://pmc.ncbi.nlm.nih.gov/articles/PMC6826613/