Glycyrrhiza glabra (Licorice)

Topical Licorice for Aphthous: A Systematic Review of Clinical Trials

Background

Recurrent aphthous stomatitis (RAS) is the most common ulcerative disease that affects oral mucosa. The coating agents, topical analgesics, and topical steroids are usually used as treatment methods. Glycyrrhiza glabra has been used for RAS treatment based on its anti-inflammatory, antioxidant, and immunomodulatory properties. In this study, a systemic review on the therapeutic effect of topical licorice on RAS management was performed.

Methods

Science Direct, Scopus, Cochrane databases, PubMed Google Scholar, and ResearchGate were searched up to September 2021 to find all English randomized clinical trials studying the effect of G. glabra, or its compositions on RAS. Meta-analysis was not conducted because of data heterogeneity. Articles were reviewed qualitatively, and only those with a Jadad score ≥3 were included. Animal studies, in vitro, review papers, non-English papers, and case reports were excluded.

Results

Six studies with 314 subjects were included after screening. The result showed licorice has significant effects on RAS pain reduction, ulcer size, and healing time. Its effectiveness is related to its dose-dependent anti-inflammatory and antioxidant effects through several mechanisms. It also has antibacterial effects against Streptococci mutans and Porphyromonas gingivalis as another mechanism of action in RAS treatment. In addition, licorice can elevate the epidermal growth factor (EGF) level compared to the control group, which has an essential role in oral mucosal tissue integrity.

Conclusion

Licorice extract has been used in different dosage forms, including paste, patch, and mouthwash with concentrations of 1% or 5%. The healing time after licorice therapy is expected to be within 4-8 days. Licorice did not show any adverse effect in the intervention groups, indicating its effectiveness and safety in RAS treatment.

Pharmacokinetic Interactions of a Licorice Dietary Supplement with Cytochrome P450 Enzymes in Female Participants

Licorice, the roots and rhizomes of Glycyrrhiza glabra L., has been used as a medicinal herb, herbal adjuvant, and flavoring agent since ancient times. Recently, licorice extracts have become popular as dietary supplements used by females to alleviate menopausal symptoms. Exposure to licorice products containing high levels of glycyrrhizic acid can cause hypokalemia, but independent from this effect, preclinical data indicate that licorice can inhibit certain cytochrome P450 (P450) enzymes. To evaluate whether clinically relevant pharmacokinetic interactions of licorice with P450 enzymes exist, a phase 1 clinical investigation was carried out using a licorice extract depleted in glycyrrhizic acid (content <1%) and a cocktail containing caffeine, tolbutamide, alprazolam, and dextromethorphan, which are probe substrates for the enzymes CYP1A2, CYP2C9, CYP3A4/5, and CYP2D6, respectively. The botanically authenticated and chemically standardized extract of roots from G. glabra was consumed by 14 healthy menopausal and postmenopausal female participants twice daily for 2 weeks. The pharmacokinetics of each probe drug were evaluated immediately before and after supplementation with the licorice extract. Comparison of the average areas under the time-concentration curves (AUCs) for each probe substrate in serum showed no significant changes from licorice consumption, whereas time to reach peak concentration for caffeine and elimination half-life for tolbutamide showed small changes. According to the US Food and Drug Administration guidance, which is based on changes in the AUC of each probe substrate drug, the investigated licorice extract should not cause any clinically relevant pharmacokinetic interactions with respect to CYP3A4/5, CYP2C9, CYP2D6, or CYP1A2. SIGNIFICANCE STATEMENT: Despite generally-recognized-as-safe status, the licorice species Glycyrrhiza glabra has been associated with some toxicity. Preclinical studies suggest that G. glabra might cause pharmacokinetic drug interactions by inhibiting several cytochrome P450 enzymes. This phase 1 clinical study addressed these concerns by evaluating clinically relevant effects with respect to CYP3A4/5, CYP2C9, CYP2D6, and CYP1A2. These results showed that a standardized G. glabra extract did not cause any clinically relevant pharmacokinetic drug interactions with four major cytochrome P450 enzymes.

Investigating the Effect of Hydroalcoholic Extract of Licorice Root to Prevent Ovariectomy-Mediated Complications

Introduction. The importance of women’s health and the quality of life after menopause is a critical issue. To prevent disability and menopause complications as well as avoid the side effects of hormone replacement therapy (HRT), in this study, licorice hydroalcoholic extract (Glycyrrhiza uralensis roots) was evaluated as a natural remedy. Methods. Seventy-two female Sprague-Dawley rats were divided into six groups: control group, Sham-operated group, Glycyrrhiza (Gly) 30% group, and ovariectomized group as well as two ovariectomized groups treated with Gly 10% and Gly 30%. Normal saline and different treatments were administered orally for 8 weeks. At the end of the study, calcium, alkaline phosphatase, estrogen, and progesterone levels in the ovariectomized rats were determined. Moreover, the stereological and histopathological changes in uterine tissue in all groups were determined. Phytochemical analyses were also performed to determine the total phenolic content and antioxidant potential of the extract. Result. The hydroalcoholic extract of licorice root exhibited considerable effect to improve calcium, estrogen, and progesterone levels in the ovariectomized rats. Also, hydroalcoholic extract of licorice root successfully decreases the amount of alkaline phosphatase (ALP) level. The stereological and histopathological findings confirmed the therapeutic potential of this extract. The considerable effects of hydroalcoholic extract of licorice root could be due to high amounts of phytoestrogens with similar estrogen-like structures. Considerable total phenolic content and antioxidant activity were also seen in licorice root extract. Conclusion. Hydroalcoholic extract of licorice root due to containing high amounts of phytoestrogens with similar chemical structures to estradiol notably improves biochemical parameters as well as stereological and histopathological markers of uterine tissues in ovariectomy rats, so it could be a potential agent for prevention and/or treatment as hormone replacement therapy in healthy middle-aged and/or older women.

Virtual screening by targeting proteolytic sites of furin and TMPRSS2 to propose potential compounds obstructing the entry of SARS-CoV-2 virus into human host cells

BACKGROUND AND AIM

The year 2020 begins with the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that cause the disease COVID-19, and continue till today. As of March 23, 2021, the outbreak has infected 124,313,054 worldwide with a total death of 2,735,707. The use of traditional medicines as an adjuvant therapy with western drugs can lower the fatality rate due to the COVID-19. Therefore, in silico molecular docking study was performed to search potential phytochemicals and drugs that can block the entry of SARS-CoV-2 into host cells by inhibiting the proteolytic cleavage activity of furin and TMPRSS2.

EXPERIMENTAL PROCEDURE

The protein-protein docking of the host proteases furin and TMPRSS2 was carried out with the virus spike (S) protein to examine the conformational details and residues involved in the complex formation. Subsequently, a library of 163 ligands containing phytochemicals and drugs was virtually screened to propose potential hits that can inhibit the proteolytic cleavage activity of furin and TMPRSS2.

RESULTS AND CONCLUSION

The phytochemicals like limonin, gedunin, eribulin, pedunculagin, limonin glycoside and betunilic acid bind at the active site of both furin and TMPRSS2. Limonin and gedunin found mainly in the citrus fruits and neem showed the highest binding energy at the active site of furin and TMPRSS2, respectively. The polyphenols found in green tea can also be useful in suppressing the furin activity. Among the drugs, the drug nafamostat may be more beneficial than the camostat in suppressing the activity of TMPRSS2.

Magnesium isoglycyrrhizinate inhibits airway inflammation in rats with chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is a kind of chronic lung diseases with the characteristics of airway remodeling and airflow obstruction. Magnesium isoglycyrrhizinate (MgIG) is an anti-inflammatory glycyrrhizic acid preparation for treating hepatitis. However, whether MgIG can treat other diseases and its action mechanism is still obscure. In this study, we evaluated the anti-inflammatory effect of MgIG in rats with COPD and investigated the underlying mechanisms.

Methods

Rat model of COPD was constructed by endotracheal-atomized lipopolysaccharide exposure and cigarette smoke induction. Rats were randomly divided into 5 groups: control group, COPD model group, salmeterol fluticasone comparator group, low dose of MgIG group, and high dose of MgIG group. Except for normal control group, the other four groups received sensitization treatment by cigarette smoking and endotracheal-atomization of endotoxin lipopolysaccharide to construct COPD rats model. After model established successfully, the COPD rats in each group received corresponding dose of endotracheal-atomized normal saline, salmeterol fluticasone, and MgIG every day prior to exposure of cigarette smoke from days 30 to 45. Normal control group were treated with normal saline. Finally, All rats were euthanatized. Pulmonary function was measured. Cells in bronchoalveolar lavage fluid were classified, inflammatory factors IL-6 and TNF-α were determined, histopathological analysis was performed by HE staining, and expression of NLRP3 and cleaved caspase-1 in the lung tissue was also determined by Western blotting.

Results

It showed that MgIG treatment (0.40 or 0.80 mg/kg/day) could recover the weight and the clinical symptoms of rats with COPD, accompanied with lung inflammation infiltration reduction, airway wall attenuation, bronchial mucus secretion reduction. Additionally, MgIG administration reduced inflammatory cells (white blood cells, neutrophils, lymphocytes and monocytes) accumulation in bronchoalveolar lavage fluid and decreased IL-6 and TNF-α production in the serum of COPD rats. Furthermore, MgIG treatment also reduced the expression level of NLRP3 and cleaved caspase-1.

Conclusion

It indicate that MgIG might be an alternative for COPD treatment, and its mechanism of action might be related to the suppression of NLRP3 inflammasome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01745-7.