Glycyrrhizic acid: A promising carrier material for anticancer therapy

Extraction, physicochemical properties, bioactivities and application of natural sweeteners: A review

Natural sweeteners generally refer to a sweet chemical component directly extracted from nature or obtained through appropriate modifications, mainly secondary metabolites of plants. Compared to the first-generation sweeteners represented by sucrose and the second-generation sweeteners represented by sodium cyclamate, natural sweeteners usually have high sweetness, low-calorie content, good solubility, high stability, and rarely toxic side effects. Historically, researchers mainly focus on the function of natural sweeteners as substitutes for sugars in the food industry. This paper reviews the bioactivities of several typical natural sweeteners, including anti-cancer, anti-inflammatory, antioxidant, anti-bacterial, and anti-hyperglycemic activities. In addition, we have summarized the extraction, physicochemical properties, and application of natural sweeteners. The article aimed to comprehensively collate vital information about natural sweeteners and review the potentiality of tapping bioactive compounds from natural products. Hopefully, this review provides insights into the further development of natural sweeteners as therapeutic agents and functional foods.

The State-of-the-Art Antibacterial Activities of Glycyrrhizin: A Comprehensive Review

Licorice (Glycyrrhiza glabra) is a plant of the genus Glycyrrhiza in the family Fabaceae/Leguminosae and is a renowned natural herb with a long history of medicinal use dating back to ancient times. Glycyrrhizin (GLY), the main active component of licorice, serves as a widely utilized therapeutic agent in clinical practice. GLY exhibits diverse medicinal properties, including anti-inflammatory, antibacterial, antiviral, antitumor, immunomodulatory, intestinal environment maintenance, and liver protection effects. However, current research primarily emphasizes GLY's antiviral activity, while providing limited insight into its antibacterial properties. GLY demonstrates a broad spectrum of antibacterial activity via inhibiting the growth of bacteria by targeting bacterial enzymes, impacting cell membrane formation, and altering membrane permeability. Moreover, GLY can also bolster host immunity by activating pertinent immune pathways, thereby enhancing pathogen clearance. This paper reviews GLY's inhibitory mechanisms against various pathogenic bacteria-induced pathological changes, its role as a high-mobility group box 1 inhibitor in immune regulation, and its efficacy in combating diseases caused by pathogenic bacteria. Furthermore, combining GLY with other antibiotics reduces the minimum inhibitory concentration, potentially aiding in the clinical development of combination therapies against drug-resistant bacteria. Sources of information were searched using PubMed, Web of Science, Science Direct, and GreenMedical for the keywords "licorice", "Glycyrrhizin", "antibacterial", "anti-inflammatory", "HMGB1", and combinations thereof, mainly from articles published from 1979 to 2024, with no language restrictions. Screening was carried out by one author and supplemented by others. Papers with experimental flaws in their experimental design and papers that did not meet expectations (antifungal papers, etc.) were excluded.

Microbial β-Glucuronidase Hydrogel Beads Activate Chemotherapeutic Prodrug

Bacteria-assisted chemotherapeutics have been highlighted as an alternative or supplementary approach to treating cancer. However, dynamic cancer-microbe studies at the in vitro level have remained a challenge to show the impact and effectiveness of microbial therapeutics due to the lack of relevant coculture models. Here, we demonstrate a hydrogel-based compartmentalized system for prodrug activation of a natural ingredient of licorice root, glycyrrhizin, by microbial β-glucuronidase (GUS). Hydrogel containment with Lactococcus lactis provides a favorable niche to encode GUS enzymes with excellent permeability and can serve as an independent ecosystem in the transformation of pro-apoptotic materials. Based on the confinement system of GUS expressing microbes, we quantitatively evaluated chemotherapeutic effects enhanced by microbial GUS enzyme in two dynamic coculture models in vitro (i.e., 2D monolayered cancer cells and 3D tumor spheroids). Our findings support the processes of prodrug conversion mediated by bacterial GUS enzyme which can enhance the therapeutic efficacy of a chemotherapy drug under dynamic coculture conditions. We expect our in vitro coculture platforms can be used for the evaluation of pharmacological properties and biological activity of xenobiotics as well as the potential impact of microbes on cancer therapeutics.

Bio-soft matter derived from traditional Chinese medicine: Characterizations of hierarchical structure, assembly mechanism, and beyond

Structural and functional explorations on bio-soft matter such as micelles, vesicles, nanoparticles, aggregates or polymers derived from traditional Chinese medicine (TCM) has emerged as a new topic in the field of TCM. The discovery of such cross-scaled bio-soft matter may provide a unique perspective for unraveling the new effective material basis of TCM as well as developing innovative medicine and biomaterials. Despite the rapid rise of TCM-derived bio-soft matter, their hierarchical structure and assembly mechanism must be unambiguously probed for a further in-depth understanding of their pharmacological activity. In this review, the current emerged TCM-derived bio-soft matter assembled from either small molecules or macromolecules is introduced, and particularly the unambiguous elucidation of their hierarchical structure and assembly mechanism with combined electron microscopic and spectroscopic techniques is depicted. The pros and cons of each technique are also discussed. The future challenges and perspective of TCM-derived bio-soft matter are outlined, particularly the requirement for their precise in situ structural determination is highlighted.

Glycyrrhizic acid attenuates sorafenib resistance by inducing ferroptosis via targeting mTOR signaling in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the most malignant cancer worldwide. Sorafenib (SRF) is a common therapeutic drug used for patients with advanced HCC. Nevertheless, drug resistance frequently occurs in patients treated with sorafenib. Glycyrrhizic acid (GRA) is a natural compound that is identified to exhibit anti-cancer effects. In this work, we aimed to investigate the effects of GRA on SRF-resistant HCC cells and the potential regulatory mechanisms.

METHODS

We established SRF-resistant HCC cell lines and administrated GRA treatment. We performed CCK-8 and colony formation experiments to detect cell proliferation. The accumulation of lipid reactive oxygen species (ROS) and iron levels were measured to evaluate ferroptosis. The protein levels of ferroptosis suppressor glutathione peroxidase 4 (GPX4) and SLC7A11, and the activation of AKT and mTOR were measured with western blotting assay.

RESULTS

GRA treatment notably suppressed the viability and proliferation of SRF-resistant HCC cells. SRF-resistant HCC cells exhibited repressed ferroptosis level activated AKT/mTOR cascade, and GRA treatment reversed these effects. Inhibition of ferroptosis and activation of mTOR reversed the anti-proliferation effects of GRA on SRF-resistant HCC cells.

CONCLUSION

Treatment with GRA could effectively reverse the SRF resistance of HCC cells via inducing ferroptosis and inactivating the AKT/mTOR cascade.

Salvia miltiorrhiza Bunge (Danshen) based nano-delivery systems for anticancer therapeutics

BACKGROUND

The ancient Chinese herb Salvia miltiorrhiza Bunge (Danshen), plays the important role in cardiovascular and cerebrovascular disease. Furthermore, Danshen could also be used for curing carcinogenesis. Up to now, the anti-tumor effects of the main active constituents of Danshen have made great progress. However, the bioavailability of the active constituents of Danshen were restricted by their unique physical characteristics, like low oral bioavailability, rapid degradation in vivo and so on.

PURPOSE

With the leap development of nano-delivery systems, the shortcomings of the active constituents of Danshen have been greatly ameliorated. This review tried to summarize the recent progress of the active constituents of Danshen based delivery systems used for anti-tumor therapeutics.

METHODS

A systematic literature search was conducted using 5 databases (Embase, Google scholar, PubMed, Scopus and Web of Science databases) for the identification of relevant data published before September 2023. The words "Danshen", "Salvia miltiorrhiza", "Tanshinone", "Salvianolic acid", "Rosmarinic acid", "tumor", "delivery", "nanomedicine" and other active ingredients contained in Danshen were searched in the above databases to gather information about pharmaceutical decoration for the active constituents of Danshen used for anti-tumor therapeutics.

RESULTS

The main extracts of Danshen could inhibit the proliferation of tumor cells effectively and a great deal of studies were conducted to design drug delivery systems to ameliorate the anti-tumor effect of the active contents of Danshen through different ways, like improving bioavailability, increasing tumor targeting ability, enhancing biological barrier permeability and co-delivering with other active agents.

CONCLUSION

This review systematically represented recent progress of pharmaceutical decorations for the active constituents of Danshen used for anti-tumor therapeutics, revealing the diversity of nano-decoration skills and trying to inspire more designs of Danshen based nanodelivery systems, with the hope that bringing the nanomedicine of the active constituents of Danshen for anti-tumor therapeutics from bench to bedside in the near future.

Introducing the glycyrrhizic acid and glabridin rich genotypes from the cultivated Iranian licorice (Glycyrrhiza glabra L.) populations to exploit in production systems

Currently, the stable, uniform, and highly efficient production of raw materials for pharmaceutical companies has received special attention. To meet these criteria and reduce harvesting pressure on the natural habitats of licorice (Glycyrrhiza glabra L.), cultivation of this valuable plant is inevitable. In the present study, to introduce the glycyrrhizic acid (GA)- and glabridin-rich genotypes from cultivated Iranian licorice, forty genotypes from eight high-potential wild populations were cultivated and evaluated under the same environmental conditions. The GA content varied from 5.00 ± 0.04 mg/g DW (TF2 genotype) to 23.13 ± 0.02 mg/g DW (I5 genotype). The highest and lowest glabridin content were found in the K2 (0.72 ± 0.021 mg/g DW) and M5 (0.02 ± 0.002 mg/g DW) genotypes, respectively. The rutin content in the leaves of the studied genotypes varied from 1.27 ± 0.02 mg/g DW in E4 to 3.24 ± 0.02 mg/g DW in BO5 genotypes. The genotypes from the Ilam population were characterized by higher vegetative growth and yield traits in the aerial parts and roots. The average root dry yield was 2.44 tons per hectare (t/ha) among the studied genotypes and a genotype from Ilam (I5) yielded the maximum value (3.08 ± 0.034 t/ha). The highest coefficient of variation among the genotypes was observed for leaf width (CV = 34.9%). The GA and glabridin-rich genotypes introduced in this study can be used in the future breeding programs to release new bred licorice cultivars.

Copper Ion-Inspired Dual Controllable Drug Release Hydrogels for Wound Management: Driven by Hydrogen Bonds

Bacterial infections and inflammation progression yield huge trouble for the management of serious skin wounds and burns. However, some hydrogel dressing exhibit poor wound-healing capabilities. Additionally, little information is given on the molecular theory of hydrogel gelation mechanisms and drug release performance from drug-polymer network in the water environment. Herein, cationic guar gum (CG) is first mixed with dipotassium glycyrrhizinate (DG), and then crosslinked Cu2+ to strengthen the mechanical strength followed by encapsulating mussel adhesive protein (MAP) as composite dressings. Intriguingly, CG-Cu2+ 0.5-DG10 possessed proper rheological properties and mechanical strength predominantly driven by strong CG-H2O-Cu2+ and Cu2+-CG hydrogen bonding interaction. Weak DG-CG hydrogen bonding only controlled DG release in the initial 4 h, while strong hydrogen bonding is the main force regulating the sustained release of Cu2+ within 48 h. The incorporation of MAP further loosened the tight crosslinking of CG-Cu2+ 0.5-DG10. The screened CG-Cu2+ 0.5-DG10/MAP possessed excellent self-healing, injectability, antibacterial, anti-inflammatory, cell proliferation-promotion activities with high biocompatibility. Therefore, CG-Cu2+ 0.5-DG10/MAP hydrogel expedited wound closure on S. aureus-infected full-thickness skin wound model and lowered necrosis progression to the unburned interspaces on a rat burn model. The results highlight the promising translational potential of Cu2+-inspired hydrogels for the management of burns and infected wounds.

So Shiho Tang Reduces Inflammation in Lipopolysaccharide-Induced RAW 264.7 Macrophages and Dextran Sodium Sulfate-Induced Colitis Mice

So Shiho Tang (SSHT) is a traditional herbal medicine commonly used in Asian countries. This study evaluated the anti-inflammatory effect of SSHT and the associated mechanism using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and murine dextran sodium sulfate (DSS)-induced ulcerative colitis models. Pre-treatment of RAW 264.7 macrophages with SSHT significantly reduced LPS-induced inflammation by decreasing nitrite production and regulating the mitogen-activated protein kinase pathway. Meanwhile, in mice, DSS-induced colitis symptoms, including colon shortening and body weight loss, were attenuated by SSHT. Moreover, representative compounds of SSHT, including glycyrrhizic acid, ginsenoside Rb1, baicalin, saikosaponin A, and saikosaponin B2, were quantified, and their effects on nitrite production were measured. A potential anti-inflammatory effect was detected in LPS-induced RAW 264.7 cells. Our findings suggest that SSHT is a promising anti-inflammatory agent. Its representative components, including saikosaponin B2, ginsenoside Rb1, and baicalin, may represent the key active compounds responsible for eliciting the anti-inflammatory effects and can, therefore, serve as quality control markers in SSHT preparations.

Self-assembled nanodrug delivery systems for anti-cancer drugs from traditional Chinese medicine

Traditional Chinese medicine (TCM) is a combination of raw herbs and herbal extracts with a plethora of documented beneficial bioactivities, which has unique advantages in anti-tumor therapy, and many of its major bioactive molecules have been identified in recent years due to advances in chemical separation and structural analysis. However, the major chemical classes of plant-derived bioactive compounds frequently possess chemical properties, including poor water solubility, stability, and bioavailability, that limit their therapeutic application. Alternatively, natural small molecules (NSMs) containing these components possess modifiable groups, multiple action sites, hydrophobic side chains, and a rigid skeleton with self-assembly properties that can be exploited to construct self-assembled nanoparticles with therapeutic effects superior to their individual constituents. For instance, the construction of a self-assembled nanodrug delivery system can effectively overcome the strong hydrophobicity and poor in vivo stability of NSMs, thereby greatly improving their bioavailability and enhancing their anti-tumor efficacy. This review summarizes the self-assembly methods, mechanisms, and applications of a variety of NSMs, including terpenoids, flavonoids, alkaloids, polyphenols, and saponins, providing a theoretical basis for the subsequent research on NSMs and the development of SANDDS.

Biosynthesis of Chryseno[2,1,c]oxepin-12-Carboxylic Acid from Glycyrrhizic Acid in Aspergillus terreus TMZ05-2, and Analysis of Its Anti-inflammatory Activity

Glycyrrhizic acid, glycyrrhetinic acid, and their oxo, ester, lactone, and other derivatives, are known for their anti-inflammatory, anti-oxidant, and hypoglycemic pharmacological activities. In this study, chryseno[2,1-c]oxepin-12-carboxylic acid (MG) was first biosynthesized from glycyrrhizic acid through sequential hydrolysis, oxidation, and esterification using Aspergillus terreus TMZ05-2, providing a novel in vitro biosynthetic pathway for glycyrrhizic acid derivatives. Assessing the influence of fermentation conditions and variation of strains during culture under stress-induction strategies enhanced the final molar yield to 88.3% (5 g/L glycyrrhizic acid). CCK8 assays showed no cytotoxicity and good cell proliferation, and anti-inflammatory experiments demonstrated strong inhibition of NO release (36.3%, low-dose MG vs. model), transcriptional downregulation of classical effective cellular factors tumor necrosis factor-α (TNF-α; 72.2%, low-dose MG vs. model), interleukin-6 (IL-6; 58.3%, low-dose MG vs. model) and interleukin-1β (IL-1β; 76.4%, low-dose MG vs. model), and decreased abundance of P-IKK-α, P-IKB-α, and P-P65 proteins, thereby alleviating inflammatory responses through the NF-κB pathway in LPS-induced RAW264.7 cells. The findings provide a reference for the biosynthesis of lactone compounds from medicinal plants.

Pectin-based double network hydrogels as local depots of celastrol for enhanced antitumor therapy

In this study, A double-network (DN) hydrogel composed of a physical glycyrrhizic acid (GA) network and a chemically crosslinked pectin-based network was fabricated as a local depot of celastrol (CEL) for cancer treatment. The obtained DN hydrogel possessed excellent mechanical performance, flexibility, biocompatibility, biodegradability and self-healing property. Furthermore, the release profile of CEL loaded DN hydrogel maintained a controlled and sustained release of CEL for a prolonged period. Finally, in vivo animal experiments demonstrated that the DN hydrogel could significantly enhance the therapeutic efficiency of CEL in CT-26 tumor-bearing mice upon intratumoral injection while effectively alleviate the toxicity of the CEL. In summary, this injectable pectin-based double network hydrogels are ideal delivery vehicle for tumor therapy.

Glycyrrhizic acid enhances the anticancer activity of cisplatin in the human ovarian cancer cell line

This study aimed to investigate the effects of glycyrrhizic acid (GL) on the anticancer activity of cisplatin in A2780 ovarian cancer cells. Cultured A2780 cells were treated with different concentrations of GL and cisplatin individually and in combination. The MTT assay, flow cytometry, wound-healing, and clonogenic assay, were used to determine cell viability, apoptosis, migration, and colony formation, respectively. The effects on superoxide dismutase (SOD) activity were also evaluated. QPCR was used to study the effects of individual and combined treatments with GL and cisplatin on the expression levels of migration genes (MMP2 and MMP9), and some apoptosis pathway genes (caspase-3, -8, -9, and BCL2). A synergistic effect was observed between GL and cisplatin (CI < 1). Combination therapy was significantly more effective in reducing cell viability, suppressing migration and colony formation, inducing apoptosis, and altering gene expression compared to single therapies. GL significantly increased SOD activity. The relative expression of caspase -3, -8, and - 9 increased significantly, and the expression levels of MMP2 and MMP9 decreased significantly in the treated cells. Our results indicate that GL enhances the anticancer activity of cisplatin in the A2780 cell line. Therefore, the combination of GL and cisplatin can be proposed as a promising therapeutic strategy for ovarian cancer.

Site-specific crosslinking and assembly of tetrameric β-glucuronidase improve glycyrrhizin hydrolysis

In this study, eight nonconserved residues with exposed surfaces and flexible conformations of the homotetrameric PGUS (β-glucuronidase from Aspergillus oryzae Li-3) were identified. Single-point mutation into cysteine enabled the thiol-maleimide reaction and site-specific protein assembly using a two-arm polyethylene glycol (PEG)-maleimide crosslinker (Mal2 ). The Mal2 (1k) (with 1 kDa PEG spacer)-crosslinked PGUS assemblies showed low crosslinking efficiency and unimproved thermostability except for G194C-Mal2 (1k). To improve the crosslinking efficiency, a lengthened crosslinker Mal2 (2k) (with 2 kDa PEG spacer) was used to produce PGUS assembly and a highly improved thermostability was achieved with a half-life of 47.2-169.2 min at 70°C, which is 1.04-3.74 times that of wild type PGUS. It is found that the thermostability of PGUS assembly was closely associated with the formation of inter-tetramer assembly and intratetramer crosslinking, rather than the PEGylation of the enzyme. Therefore, the four-arm PEG-maleimide crosslinker Mal4 (2k) (with 2 kDa PEG spacer) was employed to simultaneously increase the inter-tetramer assembly and intratetramer crosslinking, and the resulting PGUS assemblies showed further improved thermostabilities compared with Mal2 (2k)-crosslinked assemblies. Finally, the application of PGUS assemblies with significantly improved thermostability to the bioconversion of GL proved that the PGUS assembly is a strong catalyst for glycyrrhizin (GL) hydrolysis in industrial applications.

Microbial fortification of pharmacological metabolites in medicinal plants

Medicinal plants are rich in secondary metabolites with beneficial pharmacological effects. The production of plant secondary metabolites is subjected to the influences by environmental factors including the plant-associated microbiome, which is crucial to the host's fitness and survival. As a result, research interests are increasing in exploiting microbial capacities for enhancing plant production of pharmacological metabolites. A growing body of recent research provides accumulating evidence in support of developing microbe-based tools for achieving this objective. This mini review presents brief summaries of recent studies on medicinal plants that demonstrate microbe-augmented production of pharmacological terpenoids, polyphenols, and alkaloids, followed by discussions on some key questions beyond the promising observations. Explicit molecular insights into the underlying mechanisms will enhance microbial applications for metabolic fortification in medicinal plants.

All-Natural, Robust, and pH-Responsive Glycyrrhizic Acid-Based Double Network Hydrogels for Controlled Nutrient Release

Supramolecular hydrogels self-assembled from naturally occurring small molecules (e.g., glycyrrhizic acid, GA) are promising materials for controlled bioactive delivery due to their facile fabrication processes, excellent biocompatibility, and versatile stimuli-responsive behaviors. However, most of these natural hydrogels suffer from poor mechanical strength and processability for practical applications. In this work, through adopting a multicomponent gel approach, we developed a novel mechanically robust GA-based hydrogel with an interpenetrating double network (DN) that is composed of a Ca2+-enhanced hydrogen-bond supramolecular GA nanofibril (GN) network and a Ca2+cross-linked natural polysaccharide sodium alginate (ALG) network. Compared to the single GN network (SN) hydrogel, the GN-ALG hybrid hydrogels (GN-ALG-DN) with the hierarchical double-network structure possess excellent mechanical properties and shaping adaptation, encouraging small and large amplitude oscillatory shear (SAOS and LAOS) rheological performances, better thermal stability, higher resistance to large compression deformations, and lower swelling behaviors. Furthermore, the GN-ALG-DN hydrogels exhibit a pH-responsive and sustained release behavior of nutrients (i.e., vitamin B12, VB12), showing a faster VB12 release rate with a higher swelling ratio in an alkaline condition (pH 7.5) than in an acidic condition (pH 2.5). This is ascribed to the fact that the higher dissociation degree of carboxylic groups in GA and ALG molecules in an alkaline environment induces the erosion and looseness of the self-assembled GN network and the ionic-cross-linked ALG network, which can lead to the decomposition of the hybrid hydrogels and thereby increases the release of nutrients. Cytotoxicity tests further demonstrate the excellent biocompatibility of the GN-ALG-DN hydrogels. This study highlights the design of robust shaped and structured supramolecular hydrogels from natural herb small molecules, which can serve as solid, edible, and stimuli-responsive active cargo delivery platforms for food, biomedical, and sustainable applications.

Advances in the roles of glycyrrhizic acid in cancer therapy

Since the first 70 years of reporting cancer chemotherapy, malignant tumors have been the second most common cause of death in children and adults. Currently, the commonly used anti-cancer methods include surgery, chemotherapy, radiotherapy, and immunotherapy. Although these treatment methods could alleviate cancer, they lead to different forms of side effects and have no particularly significant effect on prolonging the patients' life span. Glycyrrhizic acid (GL), a native Chinese herbal extract, has a wide range of pharmacological effects, such as anti-cancer, anti-inflammatory, antioxidant, and immune regulation. In this review, the anti-cancer effects and mechanisms of GL are summarized in various cancers. The inhibition of GL on chemotherapy-induced side effects, including hepatotoxicity, nephrotoxicity, genotoxicity, neurotoxicity and pulmonary toxicity, is highlighted. Therefore, GL may be a promising and ideal drug for cancer therapy.

Antibacterial and Antihemolytic Activity of New Biomaterial Based on Glycyrrhizic Acid and Quercetin (GAQ) against Staphylococcus aureus

The goal of this study is to obtain and characterize the complex of quercetin with glycyrrhizic acid, which is known to serve as a drug delivery system. Quercetin is a flavonoid with a wide range of biological activities, including an antimicrobial effect. However, quercetin instability and low bioavailability that limits its use in medical practice makes it necessary to look for new nanoformulations of it. The formation of the GAQ complex (2:1) was confirmed by using UV and FT-IR spectroscopies. It was found that the GAQ exhibited antimicrobial and antihemolytical activities against S. aureus bacteria and its main virulent factor-α-hemolysin. The IC₅₀ value for the antihemolytical effect of GAQ was 1.923 ± 0.255 µg/mL. Using a fluorescence method, we also showed that the GAQ bound tightly to the toxin that appears to underlie its antihemolytic activity. In addition, another mechanism of the antihemolytic activity of the GAQ against α-hemolysin was shown, namely, its ability to increase the rigidity of the outer layer of the erythrocyte membrane and thus inhibit the incorporation of α-hemolysin into the target cells, increasing their resistance to the toxin. Both of these effects of GAQ were observed at concentrations below the MIC value for S. aureus growth, indicating the potential of the complex as an antivirulence agent.

Glycyrrhizic acid glycosides reduces extensive tripterygium glycosides-induced lipid deposition in hepatocytes

Aim

Tripterygium glycosides (TG) extracted from the plant Tripterygium wilfordii Hook F has been used to treat chronic kidney diseases for many years. However, hepatotoxicity limits its clinical application. Glycyrrhizic acid glycosides (GA) can reduce TG hepatotoxicity, however, further investigation into the underlying molecular mechanisms by which GA attenuates TG-induced hepatotoxicity is required.

Methods

Sprague‒Dawley rats were randomly divided into the control group, the TG groups (TG189 mg/kg group, TG472.5 mg/kg group), and the TG + GA groups (TG189 mg/kg + GA20.25 mg/kg group, TG472.5 mg/kg + GA20.25 mg/kg group). After 21 consecutive days of intragastric administration, structural and molecular changes in hepatocytes were detected.

Results

After 21 days of TG treatment, the serum level of the total bilirubin, triglyceride, total cholesterol, and low-density lipoprotein cholesterol increased in the TG189 mg/kg and TG472.5 mg/kg groups when compared to the control group. High-density lipoprotein cholesterol levels were reduced in both TG groups. The ultrastructure of hepatocytes and the structural integrity of the liver were compromised. In addition, the relevant molecular level of the peroxisome proliferators-activated receptor α (PPARα) and acyl-CoA synthetase long-chain family members (ACSLs) pathway was modulated. With the addition of 20.25 mg/kg GA, the serum biochemical indexes and liver tissue structure ultrastructure of hepatocytes were improved, and the PPARα-ACSLs pathway was corrected.

Conclusion

The combined application of GA and TG improved abnormal lipid metabolism, repaired liver structure, reduced lipid deposition in hepatocytes, and reduced TG-induced hepatotoxicity.

The Endless World of Carotenoids-Structural, Chemical and Biological Aspects of Some Rare Carotenoids

Carotenoids are a large and diverse group of compounds that have been shown to have a wide range of potential health benefits. While some carotenoids have been extensively studied, many others have not received as much attention. Studying the physicochemical properties of carotenoids using electron paramagnetic resonance (EPR) and density functional theory (DFT) helped us understand their chemical structure and how they interact with other molecules in different environments. Ultimately, this can provide insights into their potential biological activity and how they might be used to promote health. In particular, some rare carotenoids, such as sioxanthin, siphonaxanthin and crocin, that are described here contain more functional groups than the conventional carotenoids, or have similar groups but with some situated outside of the rings, such as sapronaxanthin, myxol, deinoxanthin and sarcinaxanthin. By careful design or self-assembly, these rare carotenoids can form multiple H-bonds and coordination bonds in host molecules. The stability, oxidation potentials and antioxidant activity of the carotenoids can be improved in host molecules, and the photo-oxidation efficiency of the carotenoids can also be controlled. The photostability of the carotenoids can be increased if the carotenoids are embedded in a nonpolar environment when no bonds are formed. In addition, the application of nanosized supramolecular systems for carotenoid delivery can improve the stability and biological activity of rare carotenoids.

Immune Exosomes Loading Self-Assembled Nanomicelles Traverse the Blood-Brain Barrier for Chemo-immunotherapy against Glioblastoma

Effective drug delivery and prevention of postoperative recurrence are significant challenges for current glioblastoma (GBM) treatment. Poor drug delivery is mainly due to the presence of the blood-brain barrier (BBB), and postoperative recurrence is primarily due to the resistance of GBM cells to chemotherapeutic drugs and the presence of an immunosuppressive microenvironment. Herein, a biomimetic nanodrug delivery platform based on endogenous exosomes that could efficiently target the brain without targeting modifications and co-deliver pure drug nanomicelles and immune adjuvants for safe and efficient chemo-immunotherapy against GBM is prepared. Inspired by the self-assembly technology of small molecules, tanshinone IIA (TanIIA) and glycyrrhizic acid (GL), which are the inhibitors of signal transducers and activators of transcription 3 from traditional Chinese medicine (TCM), self-assembled to form TanIIA-GL nanomicelles (TGM). Endogenous serum exosomes are selected to coat the pure drug nanomicelles, and the CpG oligonucleotides, agonists of Toll-like receptor 9, are anchored on the exosome membrane to obtain immune exosomes loaded with TCM self-assembled nanomicelles (CpG-EXO/TGM). Our results demonstrate that CpG-EXO/TGM can bind free transferrin in blood, prolong blood circulation, and maintain intact structures when traversing the BBB and targeting GBM cells. In the GBM microenvironment, the strong anti-GBM effect of CpG-EXO/TGM is mainly attributed to two factors: (i) highly efficient uptake by GBM cells and sufficient intracellular release of drugs to induce apoptosis and (ii) stimulation of dendritic cell maturation and induction of tumor-associated macrophages polarization by CpG oligonucleotides to generate anti-GBM immune responses. Further research found that CpG-EXO/TGM can not only produce better efficacy in combination with temozolomide but also prevent a postoperative recurrence.

Tetramerization of GH2 β-Glucuronidases is Essential for Catalyzing the Hydrolysis of the Large Substrate Glycyrrhizin

In this study, structural analysis was employed to identify three hotspot residues that contribute most to the tetramer formation of a glycoside hydrolase family 2 (GH2) β-glucuronidase (GUS) from Aspergillus oryzae Li-3. Single-point mutation at these sites completely disrupted the tetramer structure and abolished the glycyrrhizin (GL)-hydrolyzing activity. Then, the W522A dimer was refactored into a tetramer by disulfide bonding, and partial GL activity was restored. Further saturated mutation showed a strong correlation between the GL activity of the mutants and their tetramer ratios. Molecular simulations were employed to illustrate the critical role of the tetramer interface in maintaining a functional active-site structure. The three highly conserved tetramer-forming residues were finally applied to two other GH2 GUSs for tetramer dissociation and demonstrated the significance of the homotetramerization for GL-hydrolyzing activity of GH2 GUSs. This study lays foundation for engineering GL-hydrolyzing GUSs at the quaternary structure level for function regulations.

Licorice (Glycyrrhiza glabra L.)-Derived Phytochemicals Target Multiple Signaling Pathways to Confer Oncopreventive and Oncotherapeutic Effects

Cancer is a highly lethal disease, and its incidence has rapidly increased worldwide over the past few decades. Although chemotherapeutics and surgery are widely used in clinical settings, they are often insufficient to provide the cure for cancer patients. Hence, more effective treatment options are highly needed. Although licorice has been used as a medicinal herb since ancient times, the knowledge about molecular mechanisms behind its diverse bioactivities is still rather new. In this review article, different anticancer properties (antiproliferative, antiangiogenic, antimetastatic, antioxidant, and anti-inflammatory effects) of various bioactive constituents of licorice (Glycyrrhiza glabra L.) are thoroughly described. Multiple licorice constituents have been shown to bind to and inhibit the activities of various cellular targets, including B-cell lymphoma 2, cyclin-dependent kinase 2, phosphatidylinositol 3-kinase, c-Jun N-terminal kinases, mammalian target of rapamycin, nuclear factor-κB, signal transducer and activator of transcription 3, vascular endothelial growth factor, and matrix metalloproteinase-3, resulting in reduced carcinogenesis in several in vitro and in vivo models with no evident toxicity. Emerging evidence is bringing forth licorice as an anticancer agent as well as bottlenecks in its potential clinical application. It is expected that overcoming toxicity-related obstacles by using novel nanotechnological methods might importantly facilitate the use of anticancer properties of licorice-derived phytochemicals in the future. Therefore, anticancer studies with licorice components must be continued. Overall, licorice could be a natural alternative to the present medication for eradicating new emergent illnesses while having just minor side effects.

Recent advances in medicinal chemistry of oleanolic acid derivatives

Oleanolic acid (OA), a ubiquitous pentacyclic oleanane-type triterpene isolated from edible and medicinal plants, exhibits a wide spectrum of pharmacological activities and tremendous therapeutic potential. However, the undesirable pharmacokinetic properties limit its application and development. Numerous researches on structural modifications of OA have been carried out to overcome this limitation and improve its pharmacokinetic and therapeutic properties. This review aims to compile and summarize the recent progresses in the medicinal chemistry of OA derivatives, especially on structure-activity relationship in the last few years (2010-2021). It gives insights into the rational design of bioactive derivatives from OA scaffold as promising therapeutic agents.

Radix Glycyrrhizae Preparata Induces Cell Cycle Arrest and Induced Caspase-Dependent Apoptosis in Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is a highly aggressive and devastating brain tumor characterized by poor prognosis and high rates of recurrence. Despite advances in multidisciplinary treatment, GBM constinues to have a poor overall survival. The Radix Glycyrrhizae Preparata (RGP) has been reported to possess anti-allergic, neuroprotective, antioxidative, and anti-inflammatory activities. However, it not clear what effect it may have on tumorigenesis in GBM. This study demonstrated that RGP reduced glioma cell viability and attenuated glioma cell locomotion in GBM8401 and U87MG cells. RGP treated cells had significant increase in the percentage of apoptotic cells and rise in the percentage of caspase-3 activity. In addition, the results of study’s cell cycle analysis also showed that RGP arrested glioma cells at G₂/M phase and Cell failure pass the G2 checkpoint by RGP treatment in GBM8401 Cells. Based on the above results, it seems to imply that RGP activated DNA damage checkpoint system and cell cycle regulators and induce apoptosis in established GBM cells. In conclusion, RGP can inhibit proliferation, cell locomotion, cell cycle progression and induce apoptosis in GBM cells in vitro.

New Aspects of the Antioxidant Activity of Glycyrrhizin Revealed by the CIDNP Technique

Electron transfer plays a crucial role in ROS generation in living systems. Molecular oxygen acts as the terminal electron acceptor in the respiratory chains of aerobic organisms. Two main mechanisms of antioxidant defense by exogenous antioxidants are usually considered. The first is the inhibition of ROS generation, and the second is the trapping of free radicals. In the present study, we have elucidated both these mechanisms of antioxidant activity of glycyrrhizin (GL), the main active component of licorice root, using the chemically induced dynamic nuclear polarization (CIDNP) technique. First, it was shown that GL is capable of capturing a solvated electron, thereby preventing its capture by molecular oxygen. Second, we studied the effect of glycyrrhizin on the behavior of free radicals generated by UV irradiation of xenobiotic, NSAID—naproxen in solution. The structure of the glycyrrhizin paramagnetic intermediates formed after the capture of a solvated electron was established from a photo-CIDNP study of the model system—the dianion of 5-sulfosalicylic acid and DFT calculations.

Development of Green and Efficient Extraction of Bioactive Ginsenosides from Panax ginseng with Deep Eutectic Solvents

The extraction of active constituents from natural sources in a green and efficient manner is considered an important field in the pharmaceutical industry. In recent years, deep eutectic solvents (DESs), a new type of green solvent, have attracted increasing attention. Therefore, we aimed to establish a green and high-efficiency extraction method for ginsenosides based on DESs. This study takes Panax ginseng as a model sample. Eighteen different DESs were produced to extract polar ginsenosides. Ultrasound-assisted extraction (UAE) was applied for simplicity and efficiency. A binary DES synthesized using choline chloride and urea at a proportion of 1:2 prepared by a heating stirring method is proven to be more effective than other solvents, such as the widely used 70% ethanol for the extraction of ginsenosides. Three variables that might affect the extraction, including the DES content in the extraction solvent, liquid/solid ratio, and ultrasound extraction time, were evaluated for optimization. The optimum extraction conditions for ginsenosides were determined as follows: DES water content of 20 wt%, liquid/solid ratio of 15 mL g⁻¹, and an ultrasonic extraction time of 15 min. The extraction yield for the optimized method is found to be 31% higher than that for 70% ethanol, which achieves efficient extraction. This study shows that DESs are available to extract ginsenosides for use in traditional Chinese medicine. The discovery also contributes to further research into the green extraction of ginsenosides.

Glycyrrhizic Acid Inhibits Core Fucosylation Modification Modulated EMT and Attenuates Bleomycin-Induced Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal and incurable chronic interstitial lung disease with an unknown etiology. Recent evidence suggests that epithelial-mesenchymal transition (EMT) is one of the possible factors in the pathogenesis of pulmonary fibrosis. Glycyrrhizic acid (GA) is a natural active ingredient extracted from the root of the traditional Chinese herb licorice, which has been shown in previous studies to have the effect of alleviating lung injury. In this study, our objective was to investigate whether GA could ameliorate pulmonary fibrosis by altering EMT, as well as the therapeutic potential of changing core fucosylation (CF) to target EMT-related pathways. First, we verified that GA partially reverses EMT in a rat model of bleomycin-induced lung interstitial fibrosis, alleviating pulmonary fibrosis, and implying that GA has antifibrotic potential. Next, we discovered that GA attenuated lung interstitial fibrosis by reducing CF modifications to some extent. Interestingly, we found that GA therapy reduced the expression of phosphorylated Smad2/3 (p-Smad2/3) and β-catenin in the EMT pathway and that GA inhibited the modification of TGF-βR and WNT receptor proteins by CF, suggesting that GA may interfere with the EMT process by modulating TGF-βR, WNT core fucosylation modifications to attenuate pulmonary fibrosis. In conclusion, these findings indicate that GA could be a potential therapeutic agent for IPF, and further support the idea that targeting CF alterations could be a novel technique for the treatment of diseases involving EMT.

Mechanochemical preparation of triptolide-loaded self-micelle solid dispersion with enhanced oral bioavailability and improved anti-tumor activity

Triptolide (TP), a compound isolated from a Chinese medicinal herb, possesses potent anti-tumor, immunosuppressive, and anti-inflammatory properties, but was clinically limited due to its poor solubility, bioavailability, and toxicity. Considering the environment-friendly, low-cost mechanochemical techniques and potential dissolution enhancement ability of Na₂GA, an amorphous solid dispersion (Na₂GA&TP-BM) consisting of TP and Na₂GA were well-prepared to address these issues. The performance of Na₂GA&TP-BM was improved through ball milling, such as from crystalline state to an amorphous solid dispersion, suitable nano micelle size and surface potential, and increased solubility. This change had a significant improvement of pharmacokinetic behavior in mice and could be able to extend the blood circulation time of the antitumor drug. Moreover, in vitro and in vivo anti-tumor study showed that Na₂GA&TP-BM displayed more potent cytotoxicity to tumor cells. The work illustrated an environment-friendly and safe preparation of the TP formulation, which was promising to enhance the oral bioavailability and antitumor ability of TP, might be considered for efficient anticancer therapy.

Bacillus amyloliquefaciens Rescues Glycyrrhizic Acid Loss Under Drought Stress in Glycyrrhiza uralensis by Activating the Jasmonic Acid Pathway

Drought is a major factor limiting the production of the perennial medicinal plant Glycyrrhiza uralensis Fisch. (Fabaceae) in Northwest China. In this study, 1-year-old potted plants were inoculated with the strain Bacillus amyloliquefaciens FZB42, using a gradient of concentrations (CFU), to test for microbe-induced host tolerance to drought condition treatments in a greenhouse experiment. At the concentration of 10⁸ CFU ml^-1, FZB42 had significant growth-promoting effect on G. uralensis: the root biomass was 1.52, 0.84, 0.94, and 0.38 times that under normal watering and mild, moderate, and severe drought stress conditions, respectively. Under moderate drought, the positive impact of FZB42 on G. uralensis growth was most pronounced, with both developing axial and lateral roots strongly associated with indoleacetic acid (IAA) accumulation. An untargeted metabolomic analysis and physiological measurements of mature roots revealed that FZB42 improved the antioxidant system of G. uralensis through the accumulation of proline and sucrose, two osmotic adjustment solutes, and by promoting catalase (CAT) activity under moderate drought stress. Furthermore, significantly higher levels of total flavonoids, liquiritin, and glycyrrhizic acid (GA), the pharmacologically active substances of G. uralensis, were found in the roots of inoculated plants after FZB42 inoculation under all imposed drought conditions. The jasmonic acid (JA) content, which is closely related to plant defense responses and secondary metabolites' production, was greatly increased in roots after the bacterial inoculations, indicating that FZB42 activated the JA pathway. Taken together, our results demonstrate that inoculation with FZB42 alleviates the losses in production and pharmacological metabolites of G. uralensis caused by drought via the JA pathway's activation. These results provide a developed prospect of a microbial agent to improve the yield and quality of medical plants in arid and semi-arid regions.

Oncopreventive and oncotherapeutic potential of licorice triterpenoid compound glycyrrhizin and its derivatives: Molecular insights

Licorice (Glycyrrhiza glabra) is a well-known natural herb used to treat different ailments since ancient times. Glycyrrhizin (GL), which is the primary triterpenoid compound of licorice extract, has been known to have broad-spectrum pharmacological effects. GL is cleaved into glucuronide and the aglycone, glycyrrhetinic acid (GA), which exists in two stereoisomeric forms: 18α- and 18β-GA. It is well documented that GL and GA have great potential as anti-inflammatory, anticancer, antiviral, anti-diabetic, antioxidant, and hepatoprotective agents. Studies undertaken during the coronavirus disease 2019 pandemic suggest that GL is effective at inhibiting the viral replication of severe acute respiratory syndrome coronavirus 2. The anticancer effects of GL and GA involve modulating various signaling pathways, such as the phosphatase and tensin homolog/phosphatidylinositol 3-kinase/protein kinase B pathway, the mitogen-activated protein kinase, and the mammalian target of rapamycin/signal transducer and activator of transcription 3, which are mainly involved in regulating cancer cell death, oxidative stress, and inflammation. The potential of GL and GA in preventing cancer development and suppressing the growth and invasion of different cancer types has been reviewed in this paper. This review also provides molecular insights on the mechanism of action for the oncopreventive and oncotherapeutic effects of GL and its derivative, GA, which could help develop more specific forms of these agents for clinical use.

Elaborated survey in the scope of nanocarriers engineering for boosting chemotherapy cytotoxicity: A meta-analysis study

Cancer is the prime cause of mortality throughout the world. Although the conventional chemotherapeutic agents damage the cancerous cells, they exert prominent injury to the normal cells owing to their lack of specificity. With advances in science, many research studies have been established to boost the cytotoxic effect of the chemotherapeutic agents via innovating novel nano-formulations having different variables. In the current meta-analysis study, combined data from different research articles were gathered for the evidence-based proof of the superiority of drug loaded nanocarriers over their corresponding conventional solutions in boosting the cytotoxic effect of chemotherapy in terms of IC50 values. The meta-analysis was subdivided into three subgroups; nanoparticles versus nanofibers, surface functionalized nanocarriers versus naked ones, and protein versus non-protein-based platforms. The different subgroups interestingly showed distinct scoring outcome data paving the road for cytotoxicity enhancement of the anti-cancer drugs in an evidence-based manner.

Mechanism of the enhancing effect of glycyrrhizin on nifedipine penetration through a lipid membrane

The saponin glycyrrhizin from liquorice root shows the ability to enhance the therapeutic activity of other drugs when used as a drug delivery system. Due to its amphiphilic properties, glycyrrhizin can form self-associates (dimers, micelles) and supramolecular complexes with a wide range of hydrophobic drugs, which leads to an increase in their solubility, stability and bioavailability. That is why the mechanism of the biological activity of glycyrrhizin is of considerable interest and has been the subject of intensive physical and chemical research in the last decade. Two mechanisms have been proposed to explain the effect of glycyrrhizin on drug bioavailability, namely, the increase in drug solubility in water and enhancement of the membrane permeability. Interest in the membrane-modifying ability of glycyrrhizic acid (GA) is also growing at present due to its recently discovered antiviral activity against SARS-CoV-2 Bailly and Vergoten (2020) [1]. In the present study, the passive permeability of the DOPC lipid membrane for the calcium channel blocker nifedipine was elucidated by parallel artificial membrane permeability assay (PAMPA) and full atomistic molecular dynamics (MD) simulation with free energy calculations. PAMPA experiments show a remarkable increase in the amount of nifedipine (NF) permeated with glycyrrhizin compared to free NF. In previous studies, we have shown using MD techniques that glycyrrhizin molecules can integrate into the lipid bilayer. In this study, MD simulation demonstrates a significant decrease in the energy barrier of NF penetration through the lipid bilayer in the presence of glycyrrhizin both in the pure DOPC membrane and in the membrane with cholesterol. This effect can be explained by the formation of hydrogen bonds between NF and GA in the middle of the bilayer.

Tailoring structure and properties of long-lived emulsion foams stabilized by a natural saponin glycyrrhizic acid: Role of oil phase

Novel supramolecular nanofibrils assembled from food-grade saponin glycyrrhizic acid (GA) are effective building blocks to make complex multiphase systems, e.g., emulsion foams. In this work, the effects of different oil phases (castor oil, sunflower oil, dodecane, and limonene) on the formation, stability and structural properties of long-lived emulsion foams prepared by GA nanofibrils (GNs) were investigated. The obtained results showed that soft-solid emulsion foams (4 wt% GNs) can be fabricated, independently of oil phase, and their structural properties, viscoelasticity, and tribological properties can be well tuned by oil phase polarity. Compared to the GNs aqueous foams, the presence of jammed emulsion droplets in the liquid channels and at the surfaces of bubbles can provide a higher bubble stability for emulsion foams. For more polar oil phase (castor oil), GNs showed a higher affinity to the oil-water interface with a lower interfacial tension, thus forming smaller oil droplets and bubbles, which leads to the higher mechanical strength, denser network microstructures, and lower friction coefficients of emulsion foams. However, the limonene foam exhibited weak storage stability and rheological properties, as well as the relatively low lubrication, which may be related to the formation of oil droplet aggregates and clusters induced by the volatility of limonene. GN-based emulsion foams are thermoresponsive, independently of oils, and the temperature-switchable process for the destabilization and regeneration of foams can be controlled and repeated. These emulsion foams based on natural saponin nanofibrils with tunable properties have potential sustainable applications in foods, pharmaceuticals, and personal care products.

Glycyrrhiza acid micelles loaded with licochalcone A for topical delivery: Co-penetration and anti-melanogenic effect

The co-penetration of micellar vehicles and the encapsulated drugs into the skin layers, as well as the mechanisms underlying the penetration enhancement have not been clearly elucidated. We developed licochalcone A (LA)-loaded glycyrrhiza acid (GA) (GA+LA) micelles for topical delivery of LA into the epidermis. The in vitro co-penetration, penetration pathways, mechanism of interaction between skin and the micelles, and the in vitro and in vivo whitening effect of GA+LA micelles were evaluated. Co-penetration and penetration pathways were visualized on the abdominal skin of rats model with confocal laser scanning microscopy (CLSM) using a nile blue A-labeled GA (GA-NB). We found that GA significantly increased the transport of LA into the skin predominantly via the hair follicles and GA mainly accumulated in the SC and epidermis, while LA was localized in the epidermis and dermis. Moreover, 73.4% of the LA deposited into the epidermis within 12 h and approximately 9.32% of the LA permeated across the SC in the form of entire micelles within 24 h. GA-NB+LA micelles disaggregated and accumulated in the specific skin layers, and the LA released from the carrier penetrated into deeper layers. Moreover, the GA+LA micelles promoted drug penetration via intracellular or intercellular routes by loosening the skin surface and enhancing fluidization through lipid distortion and keratin denaturation. Furthermore, GA+LA micelles exhibited synergistic whitening effect on B16 cells and UVB-exposed C57BL/6 mice. Collectively, GA micelles can enhance penetration of LA to the epidermis mainly via the hair follicles following topical application, and reduce skin pigmentation.

Glycyrrhizin as a Nitric Oxide Regulator in Cancer Chemotherapy

Simple Summary

Glycyrrhizin (GL) has anti-cancer, anti-inflammatory, anti-viral, and anti-oxidant activity. In particular, GL reduces multidrug resistance (MDR) in cancer cells, which is a major obstacle to chemotherapy. Nitric oxide (NO) also plays an important role in MDR, and GL affects NO concentration in the tumor microenvironment. However, the effects of GL and NO interaction on MDR have not been reviewed. Here, we review the role of GL as an NO regulator in cancer cells and its subsequent anti-MDR effect and posit that GL is a promising MDR inhibitor for cancer chemotherapy.

Abstract

Chemotherapy is used widely for cancer treatment; however, the evolution of multidrug resistance (MDR) in many patients limits the therapeutic benefits of chemotherapy. It is important to overcome MDR for enhanced chemotherapy. ATP-dependent efflux of drugs out of cells is the main mechanism of MDR. Recent studies have suggested that nitric oxide (NO) can be used to overcome MDR by inhibiting the ATPase function of ATP-dependent pumps. Several attempts have been made to deliver NO to the tumor microenvironment (TME), however there are limitations in delivery. Glycyrrhizin (GL), an active compound of licorice, has been reported to both reduce the MDR effect by inhibiting ATP-dependent pumps and function as a regulator of NO production in the TME. In this review, we describe the potential role of GL as an NO regulator and MDR inhibitor that efficiently reduces the MDR effect in cancer chemotherapy.

Glycyrrhizic Acid Scavenges Reactive Carbonyl Species and Attenuates Glycation-Induced Multiple Protein Modification: An In Vitro and In Silico Study

The current study is aimed at studying the inhibitory effect of glycyrrhizic acid (GA) on D-ribose-mediated protein glycation via various physicochemical analyses and in silico approaches. Being a potent free radical scavenger and a triterpenoid saponin, GA plays a vital role in diminishing the oxidative stress and thus could be an effective inhibitor of the nonenzymatic glycation process. Our data showed that varying concentrations of GA inhibited the in vitro BSA-AGEs via inhibiting the formation of fructosamines, fluorescent AGEs, scavenging protein carbonyl and hydroxymethyl furfural (HMF) content, and protection against D-ribose-induced modification of BSA as evident by increased free Arg and Lys residues in GA-treated Gly-BSA samples. Moreover, GA also attenuated D-ribose-induced alterations in the secondary structure of BSA by protecting the α-helix and β-sheet conformers and amide-I band delocalization. In addition, GA attenuated the modification in β-cross amyloid structures of BSA and in silico molecular interaction study too showed strong binding of GA with higher number of Lys and Arg residues of BSA and binding energy (ΔG) of -8.8 Kcal/mol, when compared either to reference standard aminoguanidine (AG)-BSA complex (ΔG: -4.3 Kcal/mol) or D-ribose-BSA complex (ΔG: -5.2 Kcal/mol). Therefore, GA could be a new and favorable inhibitor of the nonenzymatic glycation process that ameliorates AGEs-related complications via attenuating the AGE formation and glycation-induced multiple protein modifications with a reduced risk of adverse effects on protein structure and functionality; hence, it could be investigated at further preclinical settings for the treatment and management of diabetes and age-associated complications.

Glycyrrhizic Acid and Its Hydrolyzed Metabolite 18β-Glycyrrhetinic Acid as Specific Ligands for Targeting Nanosystems in the Treatment of Liver Cancer

Glycyrrhizic acid and its hydrolyzed metabolite 18β-glycyrrhetinic acid, obtained from the plant Glycyrrhiza glabra, have numerous pharmacological activities, such as anti-inflammatory, anti-ulcerative, antiallergic, immunomodulatory, antiviral, antitumor, hepatoprotective, and antioxidant effects, and others. In addition to the pharmacological activities, in the 1980s, an interaction and uptake of these molecules by the liver was verified, which was later confirmed by other studies through the discovery of specific receptors in the hepatocytes. The presence of these specific receptors in the liver led to vectorization and delivery of drugs, by the introduction of glycyrrhizic acid or glycyrrhetinic acid on the surface of nanosystems, for the treatment of liver diseases. This review describes experimental evidence of vectorization by conjugating glycyrrhizic acid or glycyrrhetinic acid to nanosystems and delivery of antitumor drugs for the treatment of liver cancer and also describes the techniques used to perform this conjugation. We have shown that due to the existence of specific receptors for these molecules, in addition to the targeting of nanosystems to hepatocytes, nanosystems having glycyrrhizic acid or glycyrrhetinic acid on their surface had the same therapeutic effect in a significantly lower dose compared to the free drug and unconjugated nanosystems, with consequent reduction of side effects and toxicity.

Plant-microbial interaction: The mechanism and the application of microbial elicitor induced secondary metabolites biosynthesis in medicinal plants

Plants and microbes interact with each other via different chemical signaling pathways. At the risophere level, the microbes can secrete molecules, called elicitors, which act on their receptors located in plant cells. The so-called elicitor molecules as well as their actions differ according to the mcirobes and induce different bilogical responses in plants such as the synthesis of secondary metabolites. Microbial compounds induced phenotype changes in plants are known as elicitors and signaling pathways which integrate elicitor's signals in plants are called elicitation. In this review, the impact of microbial elicitors on the synthesis and the secretion of secondary metabolites in plants was highlighted. Moreover, biological properties of these bioactive compounds were also highlighted and discussed. Indeed, several bacteria, fungi, and viruses release elicitors which bind to plant cell receptors and mediate signaling pathways involved in secondary metabolites synthesis. Different phytochemical classes such as terpenoids, phenolic acids and flavonoids were synthesized and/or increased in medicinal plants via the action of microbial elicitors. Moreover, these compounds compounds exhibit numerous biological activities and can therefore be explored in drugs discovery.

Piperine-Loaded Glycyrrhizic Acid- and PLGA-Based Nanoparticles Modified with Transferrin for Antitumor : Piperine-Loaded Glycyrrhizic Acid- and PLGA-Based Nanoparticles

The purpose of this study was to enhance the antitumor effect of piperine by constructing the nanoparticles modified with transferrin (Tf-PIP-NPs) and evaluating their efficacy in vitro and in vivo. The Tf-PIP-NPs were prepared by the solvent evaporation method, and their properties were characterized. The effects of Tf-PIP-NPs on cytotoxicity, cell uptake, apoptosis, and mitochondrial membrane potential were evaluated in HepG2 cells, MDA-MB-231 cells, and 4T1 cells. In a 4T1 tumor-bearing mouse model, the antitumor efficacy of Tf-PIP-NPs was assessed in terms of tumor volumes, changes in body weight, HE staining, and immunohistochemical analysis. With a mean particle size of 112.2 ± 1.27 nm, the zeta potential of (- 28.0 ± 1.6 mV) Tf-PIP-NPs were rapidly internalized by tumor cells after 1 h through the transferrin receptor (TfR)-mediated endocytosis pathway, significantly inducing cellular apoptosis and mitochondrial membrane potential loss. Although Tf-PIP-NPs had no significant difference with PIP-NPs in tumor volume inhibition due to the presence of tumor microenvironment, it could significantly upregulate the expression of related pro-apoptotic proteins and induce tumor necrosis. We used the self-assembly properties of glycyrrhizic acid (GL) and polymer-PLGA to encapsulate piperine and modified with the transferrin, which provided a promising approach to improve the antitumor efficacy for anticarcinogen.

Evaluating the mucoprotective effects of glycyrrhizic acid-loaded polymeric nanoparticles in a murine model of 5-fluorouracil-induced intestinal mucositis via suppression of inflammatory mediators and oxidative stress

OBJECTIVES

5-Fluorouracil (5-FU), a chemotherapeutic drug, has severe deteriorating effects on the intestine, leading to mucositis. Glycyrrhizic acid is a compound derived from a common herbal plant Glycyrrhiza glabra, with mucoprotective, antioxidant and anti-inflammatory actions, however, associated with poor pharmacokinetics. Owing to the remarkable therapeutic action of glycyrrhizic acid-loaded polymeric nanocarriers in inflammatory bowel disease, we explored their activity against 5-FU-induced intestinal mucositis in mice. Polymeric nanocarriers have proven to be efficient drug delivery vehicles for the long-term treatment of inflammatory diseases, but have not yet been explored for 5-FU-induced mucositis. Therefore, this study aimed to produce glycyrrhizic acid-loaded polylactic-co-glycolic acid (GA-PLGA) nanoparticles to evaluate their protective and therapeutic effects in a 5-FU-induced mucositis model.

METHODS

GA-PLGA nanoparticles were prepared using a modified double emulsion method, physicochemically characterized, and tested for in vitro drug release. Thereafter, mucositis was induced by 5-FU (50 mg/kg; IP) administration to the mice for the first 3 days (day 0, 1, 2), and mice were treated orally with GA-PLGA nanoparticles for 7 days (day 0-6).

RESULTS

GA-PLGA nanoparticles significantly reduced mucositis severity measured by body weight, diarrhea score, distress, and anorexia. Further, 5-FU induced intestinal histopathological damage, altered villi-crypt length, reduced goblet cell count, elevated pro-inflammatory mediators, and suppressed antioxidant enzymes, all of which were reversed by GA-PLGA nanoparticles.

CONCLUSION

Morphological, behavioral, histological, and biochemical results suggested that GA-PLGA nanoparticles were efficient, biocompatible, targeted, and sustained release drug delivery nano-vehicle for enhanced mucoprotective, anti-inflammatory, and antioxidant effects in 5-FU-induced intestinal mucositis.

Stable DOPG/Glycyrrhizin Vesicles with a Wide Range of Mixing Ratios: Structure and Stability as Seen by Scattering Experiments and Cryo-TEM

Phosphatidylglycerols represent a large share of the lipids in the plasmamembrane of procaryotes. Therefore, this study investigates the role of charged lipids in the plasma membrane with respect to the interaction of the antiviral saponin glycyrrhizin with such membranes. Glycyrrhizin is a natural triterpenic-based surfactant found in licorice. Vesicles made of 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1’-glycerol) (DOPG)/glycyrrhizin are characterized by small-angle scattering with neutrons and X-rays (SANS and SAXS). Small-angle scattering data are first evaluated by the model-independent modified Kratky–Porod method and afterwards fitted by a model describing the shape of small unilamellar vesicles (SUV) with an internal head-tail contrast. Complete miscibility of DOPG and glycyrrhizin was revealed even at a ratio of lipid:saponin of 1:1. Additional information about the chain-chain correlation distance of the lipid/saponin mixtures in the SUV structures is obtained from wide-angle X-ray scattering (WAXS).

Glycyrrhetinic acid: a promising scaffold for the discovery of anticancer agents

INTRODUCTION

Oleanane-type pentacyclic triterpenes named glycyrrhetinic acids (GAs) featuring a C-30 carboxylic acid group, are extracted from the licorice (Glycyrrhiza uralensis). Numerous biological properties of GA have been reported and have attracted researchers from all over the world in recent years due to the peculiar GA scaffold-based semisynthetic cytotoxic effects.

AREAS COVERED

This review represents the applications of semisynthetic derivatives of GA for the development of future cancer treatments. Included in the review are important structural features of the semisynthetic GAs crucial for cytotoxic effects.

EXPERT OPINION

Numerous semisynthetic GA derivatives illustrated excellent cytotoxic effects toward various cancer cells. Notably the C-₃(OH) at ring A along with C_30-CO₂H at ring E as vital structural features, make GA very appealing as a lead scaffold for medicinal chemistry, since these two groups permit the creation of further chemical diversity geared toward improved cytotoxic effects. Furthermore, numerous GA derivatives have been synthesized and indicate that compounds featuring cyanoenone moieties in ring A, or compounds having the amino group or nitrogen comprising heterocycles and hybrids thereof, illustrate more potent cytotoxicity. Furthermore, GA has a great capability to be conjugated with other anticancer molecules to synergistically enhance their combined cytotoxicity.

Preclinical Evidence for the Pharmacological Actions of Glycyrrhizic Acid: A Comprehensive Review

Glycyrrhiza glabra L. (Family: Fabaceae) is one of the important traditional medicinal plant used extensively in folk medicine. It is known for its ethnopharmacological value in curing a wide variety of ailments. Glycyrrhizin, an active compound of G. glabra, possesses anti-inflammatory activity due to which it is mostly used in traditional herbal medicine for the treatment and management of chronic diseases. The present review is focused extensively on the pharmacology, pharmacokinetics, toxicology, and potential effects of Glycyrrhizic Acid (GA). A thorough literature survey was conducted to identify various studies that reported on the GA on PubMed, Science Direct and Google Scholar.

Glycyrrhizin Derivatives Suppress Cancer Chemoresistance by Inhibiting Progesterone Receptor Membrane Component 1

Progesterone receptor membrane component 1 (PGRMC1) is highly expressed in various cancer cells and contributes to tumor progression. We have previously shown that PGRMC1 forms a unique heme-stacking functional dimer to enhance EGF receptor (EGFR) activity required for cancer proliferation and chemoresistance, and the dimer dissociates by carbon monoxide to attenuate its biological actions. Here, we determined that glycyrrhizin (GL), which is conventionally used to ameliorate inflammation, specifically binds to heme-dimerized PGRMC1. Binding analyses using isothermal titration calorimetry revealed that some GL derivatives, including its glucoside-derivative (GlucoGL), bind to PGRMC1 potently, whereas its aglycone, glycyrrhetinic acid (GA), does not bind. GL and GlucoGL inhibit the interaction between PGRMC1 and EGFR, thereby suppressing EGFR-mediated signaling required for cancer progression. GL and GlucoGL significantly enhanced EGFR inhibitor erlotinib- or cisplatin (CDDP)-induced cell death in human colon cancer HCT116 cells. In addition, GL derivatives suppressed the intracellular uptake of low-density lipoprotein (LDL) by inhibiting the interaction between PGRMC1 and the LDL receptor (LDLR). Effects on other pathways cannot be excluded. Treatment with GlucoGL and CDDP significantly suppressed tumor growth following xenograft transplantation in mice. Collectively, this study indicates that GL derivatives are novel inhibitors of PGRMC1 that suppress cancer progression, and our findings provide new insights for cancer treatment.