The Ancient Roots of Gan Cao: Traditional Chinese Medicine
In Traditional Chinese Medicine (TCM), Glycyrrhiza uralensis is famously known as Gan Cao, which translates to "sweet herb". Its role is multifaceted and highly valued, frequently appearing in TCM prescriptions to perform several key functions:
- Harmonizing Other Herbs: Gan Cao is considered a "guiding herb" or "wise elder statesman," helping to mitigate the harsh properties of other potent herbs within a formula. It facilitates the assimilation of a remedy by tempering extreme actions and ensuring a more balanced therapeutic effect.
- Tonifying Qi: It is used to bolster the body's energy (qi), particularly supporting the functions of the Spleen and Stomach systems. This helps improve digestion, combat fatigue, and address symptoms like poor appetite and loose stools.
- Detoxifying: Traditionally, it has been used to help clear heat and detoxify the body from various toxic substances, including mitigating the adverse effects of certain other herbs.
- Soothing and Moistening: Its sweet nature is believed to have a moistening effect, making it useful for treating dry conditions, especially in the respiratory tract. It can alleviate both productive and dry coughs.
Modern Pharmacology: Validating Traditional Wisdom
Modern scientific investigations have uncovered the complex chemical profile of G. uralensis, revealing the mechanisms behind its traditional uses. The root and rhizome contain hundreds of active compounds, most notably the triterpene saponin glycyrrhizin and a wide variety of flavonoids.
Anti-inflammatory and Immunomodulatory Effects
Several compounds in G. uralensis, including glycyrrhizin, glycyrrhetinic acid, and specific flavonoids, exhibit potent anti-inflammatory and immunomodulatory activities.
- Inhibiting Inflammation: These compounds work by suppressing key inflammatory pathways, such as the NF-κB signaling pathway, which reduces the production of pro-inflammatory cytokines like TNF-α and IL-1β.
- Treating Inflammatory Conditions: Research supports its use for inflammatory bowel diseases like ulcerative colitis, pulmonary inflammation, and skin conditions such as eczema and dermatitis.
Antiviral and Antimicrobial Actions
G. uralensis has a long history of use for treating infections, a use now validated by numerous studies demonstrating its broad-spectrum antiviral and antimicrobial properties.
- Antiviral Mechanisms: Glycyrrhizin, in particular, has been shown to inhibit the replication and entry of a variety of viruses, including herpes simplex, influenza, and has been explored for its potential against coronaviruses like SARS-CoV and SARS-CoV-2.
- Targeting Bacteria: Flavonoids and other compounds within licorice have shown effectiveness against problematic bacteria such as Helicobacter pylori, the primary cause of peptic ulcers, and methicillin-resistant Staphylococcus aureus (MRSA).
Hepatoprotective and Digestive Benefits
- Liver Protection: The root's compounds have a protective effect on the liver, reducing liver enzyme levels and potentially slowing fibrosis in conditions like chronic hepatitis B and C.
- Healing Ulcers: Its flavonoids and glycyrrhetinic acid help heal and protect the lining of the digestive tract. Deglycyrrhizinated licorice (DGL), with the problematic glycyrrhizin removed, is particularly effective for peptic ulcers, heartburn, and canker sores.
Antioxidant Properties
G. uralensis is a powerful antioxidant due to its rich flavonoid content, which scavenges free radicals and protects cells from oxidative damage. This mechanism contributes to its overall therapeutic effects, including its anti-inflammatory and anti-cancer potential.
Glycyrrhiza Uralensis vs. Glycyrrhiza Glabra: A Comparative Look
While both G. uralensis (Chinese licorice) and G. glabra (European licorice) are valuable medicinal plants, they differ in their phytochemical composition, which can affect their therapeutic properties.
| Feature | Glycyrrhiza uralensis | Glycyrrhiza glabra |
|---|---|---|
| Common Name | Chinese licorice, Gan Cao | European licorice, Spanish licorice |
| Geographical Origin | Central Asia, Mongolia, Northern China | Mediterranean region, Southwestern Asia |
| Distinguishing Marker | Contains quercetin, which is absent in G. glabra | May contain uralsaponin B, unlike some commercial varieties |
| Key Flavonoids | Higher levels of isoliquiritin and liquiritigenin | Distinct flavonoid profile |
| Antioxidant Activity | Slightly higher radical scavenging activity | Strong, but slightly less than G. uralensis |
| Appearance | Pods are often covered with echinate glandular hairs | Pods are typically glabrous (hairless) |
Safety Profile, Precautions, and DGL
While generally safe in food and moderate doses, licorice containing the compound glycyrrhizin carries significant risks with high or prolonged consumption.
Risks Associated with Glycyrrhizin
- Cardiovascular Effects: Glycyrrhizin can cause a condition known as pseudohyperaldosteronism by inhibiting an enzyme that breaks down cortisol. This leads to sodium and water retention and potassium excretion, causing hypertension (high blood pressure) and hypokalemia (low potassium). These effects can trigger arrhythmias and, in severe cases, cardiac arrest.
- Hormonal Disruption: Long-term use can interfere with hormone levels, potentially causing decreased libido and other hormonal imbalances.
- Pregnancy and Other Conditions: Due to the risk of premature delivery and other complications, pregnant women are advised against using licorice. It is also contraindicated for individuals with heart conditions, high blood pressure, and kidney disease.
A Safer Alternative: Deglycyrrhizinated Licorice (DGL)
For therapeutic applications, particularly for digestive issues, Deglycyrrhizinated Licorice (DGL) is widely used. This form of licorice has had the glycyrrhizin removed, eliminating the risk of side effects like hypertension and hypokalemia.
- How to Use DGL: DGL is typically used in chewable tablet or powder form for treating stomach ulcers and acid reflux, as it must mix with saliva to be activated.
Important Contraindications
Do not use licorice containing glycyrrhizin if you have:
- High blood pressure
- Heart conditions or congestive heart failure
- Kidney disease
- Low potassium levels
- Are pregnant
- Are on medications that deplete potassium, like diuretics
Conclusion
Glycyrrhiza uralensis is a powerful medicinal herb with a rich history in TCM, supported by modern pharmacological evidence. Its diverse applications range from harmonizing herbal formulas to offering significant anti-inflammatory, antiviral, and protective benefits for the digestive system and liver. The broad therapeutic potential of its compounds, particularly flavonoids and glycyrrhizin, is well-documented. However, its use requires careful consideration, especially concerning the risks associated with high glycyrrhizin levels. For most applications, and to avoid dangerous side effects, consulting a healthcare provider and opting for safer preparations like Deglycyrrhizinated Licorice (DGL) is recommended. With proper care, this ancient "sweet herb" remains a valuable asset to herbal and modern medicine.
Research on Glycyrrhiza's Mechanism and Potential
One study, published in Traditional Uses, Pharmacological Effects, and Molecular Mechanisms of Licorice against COVID-19 and Related Diseases, explored how glycyrrhizin and licorice extract could combat features of SARS-CoV-2. It highlighted licorice's beneficial activities, such as binding to viral proteins, and its anti-inflammatory and immunomodulatory effects, offering rationale for its use in related treatments.
