Glycyrrhizic acid is the primary sweet-tasting compound derived from the root of the licorice plant, scientifically known as Glycyrrhiza glabra. This natural substance, also referred to as glycyrrhizin, has been recognized for its distinct flavor and properties for centuries. Today, it continues to be a component found in a range of consumer products globally.
Natural Sources and Commercial Uses
Glycyrrhizic acid is extracted from the dried roots of the licorice plant, Glycyrrhiza glabra, which is native to central and south-western Asia and the Mediterranean region. The compound is notably sweet, reported to be 30 to 50 times sweeter than sucrose, making it a desirable natural sweetener and flavoring agent.
It is widely incorporated into food products such as confectionery, chewing gum, and beverages. Beyond flavor, glycyrrhizic acid also functions as an emulsifier and a gel-forming agent in foodstuffs. The cosmetic industry uses it as a skin conditioning agent due to its skin-soothing properties, appearing in formulations for makeup, fragrances, hair care, skin care, shaving products, and suntan lotions.
Biological and Pharmacological Effects
Glycyrrhizic acid and its active metabolite, glycyrrhetinic acid, exhibit various biological activities within the body. It possesses anti-inflammatory properties, partly by increasing active cortisol levels.
Other anti-inflammatory mechanisms include the suppression of pro-inflammatory cytokines such as Tumor Necrosis Factor alpha (TNF-α) and interleukins like IL-1β and IL-6. Glycyrrhizic acid also interferes with the translocation of nuclear factor-κB (NF-κB), a protein complex involved in inflammatory responses. Beyond inflammation, glycyrrhizic acid demonstrates broad-spectrum antiviral activity, inhibiting the replication of various viruses, including SARS, herpes simplex virus, and vaccinia virus. It can interfere with early stages of viral replication, such as adsorption and penetration into cells. Furthermore, it possesses antioxidant capabilities by scavenging reactive oxygen species and enhancing the activity of natural antioxidant enzymes like superoxide dismutase and catalase, thereby protecting cells from oxidative damage.
Health Risks and Side Effects
Despite its diverse applications and potential benefits, consuming glycyrrhizic acid, particularly in large or prolonged doses, carries specific health risks. The most recognized adverse effect is a condition known as pseudoaldosteronism. This syndrome mimics primary aldosteronism, but it is caused by the actions of glycyrrhetinic acid, the metabolite of glycyrrhizic acid.
The core mechanism involves glycyrrhetinic acid’s inhibition of the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). This enzyme is responsible for converting active cortisol into its inactive form, cortisone. When 11β-HSD2 is inhibited, active cortisol levels increase in the body, leading to an exaggerated binding to mineralocorticoid receptors in the kidneys.
This overstimulation results in increased sodium retention, excessive potassium excretion (hypokalemia), and fluid retention (edema). The accumulation of sodium and fluid contributes directly to elevated blood pressure, or hypertension.
In severe instances, these electrolyte imbalances can lead to muscle weakness, rhabdomyolysis, irregular heart rhythms, and potentially life-threatening complications such as cardiac arrest.
Safe Consumption and Alternatives
Regulatory bodies offer guidelines for the consumption of glycyrrhizic acid to minimize health risks. The World Health Organization (WHO) suggests that an intake of up to 100 mg per day of glycyrrhizic acid is generally safe for most healthy adults. This amount corresponds to approximately 60 to 70 grams of licorice. The U.S. Food and Drug Administration (FDA) advises individuals aged 40 or older that consuming 57 grams (2 ounces) of black licorice daily for at least two weeks could potentially lead to an irregular heart rhythm.
Certain populations should exercise particular caution with glycyrrhizic acid intake. Individuals with pre-existing conditions such as hypertension or kidney disease, and those who are pregnant, face a higher risk of adverse effects. Elderly individuals are also considered more susceptible. For those seeking the flavor or some traditional benefits of licorice without the associated risks of glycyrrhizic acid, deglycyrrhizinated licorice (DGL) is available. This form of licorice has had the glycyrrhizic acid removed, allowing it to retain certain anti-inflammatory and antioxidant properties without causing the mineralocorticoid side effects like pseudoaldosteronism.