Glycyrrhiza glabra, commonly known as licorice, is a perennial herb native to Europe and Asia. It is widely recognized for its sweet-tasting root, which has been used for centuries in traditional medicine for its anti-inflammatory, expectorant, and soothing properties. The plant’s root extract is a key ingredient in both medicinal and confectionery applications, often employed to treat respiratory and digestive issues and enhance skin health.
Botanical Classification
- Kingdom: Plantae
- Clade: Tracheophytes
- Class: Magnoliopsida
- Order: Fabales
- Family: Fabaceae
- Genus: Glycyrrhiza
- Species: Glycyrrhiza glabra
Plant Characteristics
Glycyrrhiza glabra is a hardy herbaceous plant that can grow up to 1–1.5 meters in height. It has pinnate leaves with multiple pairs of leaflets, and its purple to pale blue flowers bloom in summer, forming clusters along the stems. The plant’s taproot is thick and fibrous, with a sweet, distinctive flavor due to its high glycyrrhizin content. This root is the part used in medicinal and culinary applications.
Chemical Composition and Structure
The medicinal properties of Glycyrrhiza glabra root are attributed to its complex chemical composition, including:
Glycyrrhizin: A triterpenoid saponin that is largely responsible for the sweet flavor of licorice root and its anti-inflammatory, antiviral, and hepatoprotective properties.
Flavonoids: Including liquiritin and isoliquiritigenin, which contribute to its antioxidant and anti-inflammatory effects.
Polysaccharides: Complex carbohydrates that may have immune-boosting effects and help soothe irritated mucous membranes.
Phenolic Compounds: Known for their antioxidant activities, helping to reduce oxidative stress in cells.
Phytoestrogens: Plant-derived compounds that can mimic estrogen in the body, which may benefit hormonal balance in certain populations.
How to Cultivate Glycyrrhiza glabra
Cultivating Glycyrrhiza glabra requires well-prepared soil and an adequate climate:
Climate: Thrives in warm, temperate regions with plenty of sunlight. It is drought-resistant once established but sensitive to frost.
Soil Requirements: Prefers deep, well-drained sandy or loamy soils with a neutral to slightly alkaline pH. Soil preparation with organic matter enhances root development.
Propagation: Propagated by seeds or root cuttings. Seeds should be soaked before planting to improve germination, while root cuttings are placed directly in prepared soil in spring.
Watering and Maintenance: Requires moderate watering, especially during the first growing season. Mulching around the base can help retain moisture and regulate soil temperature.
Harvesting: Roots are typically harvested after 3–5 years when they have developed fully, ensuring maximum glycyrrhizin content. The roots are then cleaned and dried for use in various applications.
Uses and Benefits
In traditional and modern medicine, Glycyrrhiza glabra is highly valued for its therapeutic properties:
Respiratory Health: Commonly used as an expectorant to help relieve coughs, soothe sore throats, and clear mucus from the respiratory tract.
Digestive Health: Known for its soothing effects on the gastrointestinal tract, it is used to relieve symptoms of indigestion, gastritis, and ulcers.
Anti-inflammatory and Antiviral Properties: Glycyrrhizin and flavonoids in licorice root have anti-inflammatory and antiviral effects, making it useful for conditions like skin inflammation and certain viral infections.
Hormonal Support: Due to its phytoestrogen content, Glycyrrhiza glabra may assist in managing symptoms related to menopause and hormonal imbalances.
Skin Health: Licorice extract is often used in skin care for its potential to lighten pigmentation, reduce redness, and promote skin clarity.
Applications
Medical: Widely used in traditional and modern formulations for respiratory and digestive issues. Licorice root is included in teas, syrups, and lozenges for cough and sore throat relief. It is also an ingredient in some supplements aimed at reducing inflammation and supporting liver health.
Cosmetic: Popular in skincare for its anti-inflammatory and brightening properties, often used in creams and serums targeting hyperpigmentation, irritation, and acne-prone skin.
Culinary: Licorice root is used in the production of sweets and flavorings. Its natural sweetness is used to enhance candies, teas, and beverages.
Environmental and Safety Considerations
Glycyrrhiza glabra is generally safe when used in moderation, but excessive consumption of glycyrrhizin can lead to side effects, including high blood pressure and reduced potassium levels. Licorice products containing glycyrrhizin should be used cautiously by individuals with hypertension or heart conditions. Sustainable harvesting practices and careful cultivation help protect natural populations and maintain a high-quality supply of licorice root. As with all botanicals, individuals with allergies or sensitive skin should test products containing Glycyrrhiza glabra before extensive use.
Studies
It has been a flavour and medicine in traditional medical science for centuries and contains around 70 flavonoids and triterpenoid glycosides that exert antioxidant and hepatoprotective activity (1).
Glycyrrhiza glabra extract has demonstrated both alone and together with Adriamycin (an antibiotic and antitumour agent), antiproliferative properties against PC-3 prostate cancer cells, which are mediated by both apoptosis and autophagy mechanisms (2).
This study considers Glycyrrhiza glabra to have antihyperglycaemic activity due to the presence of bioactive phytoconstituents, although further studies would be required to identify, isolate and characterise the specific bioactive phytoconstituents responsible for the plant's antihyperglycaemic activity (3).
Glycyrrhiza glabra root contains Glabridin, a bioactive component, a phytoestrogenic isoflavonoid, with biological antioxidant, anti-inflammatory, neuroprotective, anti-atherogenic, antitumour, anti-nephritic, antibacterial and skin whitening properties (4). Glabridin appears industrially in the form of a white powder.
Safety
Excessive intake of liquorice can cause a possible rise in blood pressure.
For more information:
Typical commercial product characteristics Glycyrrhiza glabra root extract
| Appearance | Yellow brown Powder |
| Loss on Drying | ≤5% |
| Ash | ≤5% |
| Mesh Size | 100 % pass 80 mesh |
| Heavy Metal | ≤10ppm |
| Pb | ≤ 2.0 mg/kg |
| As | ≤ 1.0 mg/kg |
| Hg | ≤ 0.1mg/kg |
| Total Plate Count | ≤10000cfu/g |
| Yeast & Mold | ≤1000cfu/g |
| Shelf life | 2 years |
