Enrichment of the Glycyrrhizic Acid from Licorice Roots (Glycyrrhiza glabra L.) by Isoelectric Focused Adsorptive Bubble Chromatography

Isolating and Purification Technologies for Glycyrrhizic Acid

Glycyrrhizic acid (GA) is the primary active component of the traditional Chinese medicinal herb licorice. It possesses antimicrobial, anti-inflammatory, and antitumor activities. In addition, due to its unique sweetness, it can also be used as a food additive. Traditional Chinese medicines are typically used directly as drugs. However, the chemical composition of Chinese medicinal materials such as licorice is complex, containing not only effective components but also ineffective and even toxic substances. To efficiently exert their medicinal value and minimize the side effects of harmful substances, the extraction and separation of the active components is an important means to achieve the modernization of traditional Chinese medicine utilization. This article focuses on the extraction of GA, summarizes the current technologies related to the extraction and separation of GA, reveals the underlying chemical principles, and evaluates the advantages and disadvantages of the corresponding technologies. On this basis, it proposes challenges faced in the separation of GA and provides corresponding solutions. The author believes that with the continuous introduction of precise chemical synthesis and other methods in separation, the extraction and separation of the active substance will become greener and more efficient. It will also provide a reference for the extraction of other effective components of traditional Chinese medicine.

Anti-Diabetic Activity of Glycyrrhetinic Acid Derivatives FC-114 and FC-122: Scale-Up, In Silico, In Vitro, and In Vivo Studies

Type 2 diabetes (T2D) is one of the most common diseases and the 8th leading cause of death worldwide. Individuals with T2D are at risk for several health complications that reduce their life expectancy and quality of life. Although several drugs for treating T2D are currently available, many of them have reported side effects ranging from mild to severe. In this work, we present the synthesis in a gram-scale as well as the in silico and in vitro activity of two semisynthetic glycyrrhetinic acid (GA) derivatives (namely FC-114 and FC-122) against Protein Tyrosine Phosphatase 1B (PTP1B) and α-glucosidase enzymes. Furthermore, the in vitro cytotoxicity assay on Human Foreskin fibroblast and the in vivo acute oral toxicity was also conducted. The anti-diabetic activity was determined in streptozotocin-induced diabetic rats after oral administration with FC-114 or FC-122. Results showed that both GA derivatives have potent PTP1B inhibitory activity being FC-122, a dual PTP1B/α-glucosidase inhibitor that could increase insulin sensitivity and reduce intestinal glucose absorption. Molecular docking, molecular dynamics, and enzymatic kinetics studies revealed the inhibition mechanism of FC-122 against α-glucosidase. Both GA derivatives were safe and showed better anti-diabetic activity in vivo than the reference drug acarbose. Moreover, FC-114 improves insulin levels while decreasing LDL and total cholesterol levels without decreasing HDL cholesterol.

Dynamic interfacial properties and foam behavior of licorice root extract solutions

Licorice (Glycyrrhiza glabra) is a useful plant of the family Fabaceae, with sweet-tasting roots. The root extract of this plant is rich in saponins, so it can be considered a source of natural surfactants. This research provides some applicable information about the dynamic surface tension and foam behavior of aqueous solutions of licorice root extract (LRE). The pendant drop shape analysis was utilized to study the surface tension and dilational surface rheology of LRE at the water/air interface. The Bikerman type experiment was used to measure foamability and foam stability of aqueous LRE solutions. The equilibrium surface tensions reveal that the LRE contains surface-active components and is capable of reducing the surface tension by 25 mN/m at the critical aggregation concentration (CAC). The surface dilational visco-elasticity measurements proved that the adsorption layers are predominantly of elastic nature. Also the foamability and foam stability show a meaningful correlation with the dynamic surface properties. This study aims to contribute to the development of appropriate utilization of the benefits provided by a biosurfactant source in foam-related commercial applications.

Indole- and Pyrazole-Glycyrrhetinic Acid Derivatives as PTP1B Inhibitors: Synthesis, In Vitro and In Silico Studies

Regulating insulin and leptin levels using a protein tyrosine phosphatase 1B (PTP1B) inhibitor is an attractive strategy to treat diabetes and obesity. Glycyrrhetinic acid (GA), a triterpenoid, may weakly inhibit this enzyme. Nonetheless, semisynthetic derivatives of GA have not been developed as PTP1B inhibitors to date. Herein we describe the synthesis and evaluation of two series of indole- and N-phenylpyrazole-GA derivatives (4a-f and 5a-f). We measured their inhibitory activity and enzyme kinetics against PTP1B using p-nitrophenylphosphate (pNPP) assay. GA derivatives bearing substituted indoles or N-phenylpyrazoles fused to their A-ring showed a 50% inhibitory concentration for PTP1B in a range from 2.5 to 10.1 µM. The trifluoromethyl derivative of indole-GA (4f) exhibited non-competitive inhibition of PTP1B as well as higher potency (IC₅₀ = 2.5 µM) than that of positive controls ursolic acid (IC₅₀ = 5.6 µM), claramine (IC₅₀ = 13.7 µM) and suramin (IC₅₀ = 4.1 µM). Finally, docking and molecular dynamics simulations provided the theoretical basis for the favorable activity of the designed compounds.

Anti-ulcer effect and potential mechanism of licoflavone by regulating inflammation mediators and amino acid metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza is the dry root and rhizome of the leguminous plant, Glycyrrhiza uralensis Fisch., Glycyrrhiza inflata Bat. or Glycyrrhiza glabra L., which was firstly cited in Shennong's Herbal Classic in Han dynasty and was officially listed in the Chinese Pharmacopoeia, has been widely used in China during the past millennia. Licoflavone is the major component of Glycyrrhiza with anti-ulcer activity. The present study is based on clarifying the anti-ulcer effect of licoflavone, aiming at elucidating the possible molecule mechanisms of its action for treating gastric ulcer rats induced by acetic acid.

MATERIALS AND METHODS

Rats were divided into 7 groups, and drugs were administered from on the day after the onset of gastric ulcer (day 3) until day 11 of the experiment once daily continuously. The plasma were analyzed by high-performance liquid chromatography combined with time-of-flight mass spectrometry (HPLC/ESI-TOF-MS), significant different metabolites were investigated to explain its therapeutic mechanism. Furthermore, quantitative real time polymerase chain reaction (RT-PCR) analysis was performed to detect the expression of RNA in stomach tissue for verifying the above results.

RESULTS

Licoflavone can effectively cure the gastric ulcer, particularly the middle dose group. According to the statistical analysis of the plasma different metabolites from each groups and the expression of genes in tissues, sixteen significant different metabolites, including histamine, tryptophan, arachidonic acid, phingosine-1-phosphate etc., contributing to the treatment of gastric ulcer were discovered and identified. In RT-PCR analysis, the results of the expression of RNA were corresponded with what we discovered.

CONCLUSIONS

Our study indicated licoflavone plays the role of treating gastric ulcer by regulating inflammation mediators and amino acid metabolism. We demonstrated that metabolomics technology combined with gene technology is a useful tool to search different metabolites and to dissect the potential mechanisms of traditional Chinese medicine (TCM) in treating gastric ulcer.