Licorice Root And Stolon Extract
Also known as: Licorice root, liquorice, Glycyrrhiza, Licorice root and stolon extract, Glycyrrhiza glabra
Overview
Licorice root and stolon extract is derived from the roots and horizontal stems (stolons) of Glycyrrhiza glabra and related species. It contains bioactive compounds such as glycyrrhizin, flavonoids (isoliquiritigenin, liquiritigenin, glabridin), and saponins. Traditionally, it has been used for respiratory infections, liver diseases, throat infections, and as an anti-inflammatory agent. Modern applications include hepatoprotection, anti-inflammatory, antioxidant, and metabolic regulation. The research maturity is moderate to high, with numerous in vitro, animal, and human clinical studies, including systematic reviews and meta-analyses. However, clinical evidence varies by indication, with quality ranging from well-conducted RCTs (especially in liver disease and sore throat prevention) to preliminary or observational data in other areas.
Benefits
Licorice root and stolon extract offers several evidence-based benefits. It demonstrates significant hepatoprotective effects, particularly in chronic liver disease. For instance, Stronger Neo-Minophagen® C (SNMC), a licorice preparation, has shown efficacy in improving liver function and reducing ALT levels in patients with viral hepatitis, as evidenced by RCTs involving over 200 individuals. It also possesses anti-inflammatory and analgesic properties; a randomized, double-blind, placebo-controlled trial with 236 participants found that gargling with licorice extract significantly reduced postoperative sore throat incidence by approximately 50%. Furthermore, a systematic review and meta-analysis indicated that licorice consumption leads to statistically significant reductions in body weight and BMI in overweight patients, suggesting potential metabolic benefits. Preclinical studies also support its antioxidant and immunomodulatory properties, with licorice flavonoids exhibiting antioxidant activity and potential neuroprotective and anticancer effects.
How it works
Licorice's bioactive compounds exert their effects through various mechanisms. Glycyrrhizin, a key component, inhibits enzymes that degrade endogenous corticosteroids, thereby enhancing their anti-inflammatory activity. Other compounds, such as flavonoids, modulate inflammatory pathways by inhibiting NF-κB and cytokine production. Flavonoids like isoliquiritigenin also exhibit antioxidant effects by activating the SKN-1 pathway and insulin-like signaling, which helps reduce oxidative stress. The hepatoprotective effects may involve modulating liver enzymes and reducing viral replication or liver inflammation. Glycyrrhizin is metabolized by intestinal bacteria into glycyrrhetinic acid, its active form. Absorption and bioavailability can vary, with complexation methods like cyclodextrins improving the solubility and stability of its flavonoid components.
Side effects
Licorice root extract is generally considered safe at recommended doses, with most side effects being mild. Common side effects, affecting more than 5% of users, include mild gastrointestinal discomfort and headache. Uncommon side effects (1-5%) involve electrolyte imbalances, specifically hypokalemia, and hypertension, which are attributed to the mineralocorticoid-like effects of glycyrrhizin. Rare but more severe side effects, occurring in less than 1% of users, can include severe hypertension, edema, and hypokalemia potentially leading to cardiac arrhythmias, especially with high doses or prolonged use. Licorice can interact with other medications, potentiating the effects of corticosteroids and antihypertensive drugs. It is contraindicated in individuals with pre-existing hypertension, heart failure, or those at risk of hypokalemia. Pregnant women and children should avoid high doses due to potential adverse effects and increased sensitivity.
Dosage
The minimum effective dose of licorice root extract varies depending on the specific indication. For instance, a single gargle with 0.5 g of licorice extract has been shown to be effective in preventing postoperative sore throat. In the context of chronic liver disease, preparations like Stronger Neo-Minophagen® C (SNMC) are typically administered in Japan at doses ranging from 40 to 80 mL per week (equivalent to 40-80 mg/day of glycyrrhizin), often intermittently. While a firm maximum safe dose is not established, prolonged intake of glycyrrhizin exceeding 100 mg/day is generally associated with an increased risk of adverse effects, necessitating careful monitoring. Timing of administration depends on the formulation and desired effect; topical applications for sore throat are typically immediate preoperative, while oral dosing for metabolic or liver benefits usually involves chronic intake. Absorption can be enhanced by certain formulations, such as complexation or co-administration with compounds like glycine and L-cysteine.
FAQs
Is licorice root extract safe for long-term use?
It is generally safe if glycyrrhizin intake is controlled. However, long-term high doses can lead to adverse effects such as hypertension and hypokalemia, so monitoring is crucial.
Can licorice root extract be used for weight loss?
Evidence suggests modest reductions in body weight and BMI with licorice consumption. However, it should be considered as a supportive measure and not a replacement for standard weight management strategies.
Does licorice extract help with liver diseases?
Yes, particularly in chronic viral hepatitis, licorice preparations like SNMC have been shown to improve liver enzyme profiles and overall liver function.
Is licorice effective for sore throat?
Yes, topical gargling with licorice extract has been demonstrated to significantly reduce the incidence of postoperative sore throat.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8703329/ – This comprehensive review synthesizes various clinical and preclinical studies on licorice, highlighting its hepatoprotective, anti-inflammatory, and antioxidant effects. It elucidates the molecular mechanisms behind these actions, providing a broad overview of licorice's therapeutic potential. The review's quality is moderate to high, integrating both in vitro and in vivo data, though it acknowledges the variable quality of some included clinical trials.
- https://journals.sagepub.com/doi/10.1177/20451253211024873 – This randomized, double-blind, placebo-controlled trial involving 236 adults undergoing thoracic surgery investigated the effect of licorice gargle on postoperative sore throat. The study found that a single intervention with licorice gargle effectively halved the incidence of postoperative sore throat. This high-quality, well-designed RCT provides strong evidence for licorice's efficacy in this specific application, despite being a single-center study with a short-term outcome.
- https://pubmed.ncbi.nlm.nih.gov/29433679/ – This systematic review and meta-analysis evaluated the effects of licorice consumption on body weight and BMI across multiple randomized controlled trials, each with at least 30 participants per group, focusing on overweight/obese adults. The analysis concluded that licorice consumption leads to statistically significant reductions in both body weight and BMI. The study is of high quality, employing meta-analysis with trial sequential analysis to provide robust evidence, despite potential heterogeneity in doses and formulations across the included studies.
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