Structure-function relationship of licorice (Glycyrrhiza glabra) root extract-xanthan/guar gum mixture in a high sugar content system

BACKGROUND

Foam-gels are one of the most important multicomponent-model systems in aerated confectionery, and an investigation of their microstructure is desirable. In this research, the structure-function relationship of xanthan gum/guar gum (XG/GG) and licorice (Glycyrrhiza glabra) root extract powder (LEP) was investigated in a high-sugar medium. Foam-gel systems were prepared at 4:10% to 8:20% ratios of LEP to biopolymer.

RESULTS

The results show that increasing the LEP content reduced both the melting point and enthalpy, probably due to higher overrun and weaker junctions. Boosting the XG/GG ratio led the enhancement of mechanical properties, whereas increasing the LEP concentration weakened all textural parameters, which could be due to the poor structure of the network in the presence of the foaming agent, increased moisture content and overrun. In the whipped mixture samples containing 10 g kg^-1 XG/GG, higher foaming capacity was observed. By increasing the level of biopolymers, smaller and more uniform air cells were formed according to a scanning electron microscopical study. At higher concentration of LEP, smaller bubbles and increased porosity were seen, which could be attributed to the availability of surfactant in the interfacial layer.

CONCLUSION

Maximum structural strength was achieved at a 4:20 ratio of LEP to XG/GG. In rheological experiments, pseudoplastic behavior was seen in all samples. Generally, this model system can be simulated for other herbal extracts containing natural surfactants such as saponins. Achieving a more detailed understanding of these structures and their interactions could help in formulating novel food products. © 2021 Society of Chemical Industry.

Glycyrrhizic acid ameliorates submandibular gland oxidative stress, autophagy and vascular dysfunction in rat model of type 1 diabetes

The burden of diabetes mellitus (DM) and associated complications is increasing worldwide, affecting many organ functionalities including submandibular glands (SMG). The present study aims to investigate the potential ameliorative effect of glycyrrhizic acid (GA) on diabetes-induced SMG damage. Experimental evaluation of GA treatment was conducted on a rat model of type I diabetes. Animals were assigned to three groups; control, diabetic and GA treated diabetic groups. After 8 weeks, the SMG was processed for assessment of oxidative stress markers, autophagy related proteins; LC3, Beclin-1 and P62, vascular regulator ET-1, aquaporins (AQPs 1.4 and 5), SIRT1 protein expressions in addition to LC3 and AQP5 mRNA expressions. Also, parenchymal structures of the SMG were examined. GA alleviated the diabetes-induced SMG damage via restoring the SMG levels of oxidative stress markers and ET-1 almost near to the normal levels most probably via regulation of SIRT1, AQPs and accordingly LC-3, P62 and Beclin-1levels. GA could be a promising candidate for the treatment of diabetes-induced SMG damage via regulating oxidative stress, autophagy and angiogenesis.

Gegen Qinlian Decoction ameliorates type 2 diabetes osteoporosis via IGFBP3/MAPK/NFATc1 signaling pathway based on cytokine antibody array

BACKGROUND

Osteoporosis affects more than half the patients with type 2 diabetes mellitus (T2DM). Up to data, there is no effective clinical practice in managing type 2 diabetes osteoporosis (T2DOP) because of its complex pathogenesis. Gegen Qinlian Decoction (GQD) has been used for the long-term management of T2DM. However, the underlying mechanism of GQD in the treatment of T2DOP remains unknown.

PURPOSE

To reveal the role of GQD in T2DOP and its potential therapeutic targets in the management of T2DOP.

STUDY DESIGN

The effect of GQD on T2DOP was observed in db/db mice in four groups: model group, GQD low-dose group (GQD-L), GQD high-dose group (GQD-H), and metformin (positive control) group. C57BL/6J mice were used as the negative control group.

METHODS

Quantitative phytochemical analysis of GQD was performed using high-performance liquid chromatography (HPLC). Micro-CT and hematoxylin-eosin (H&E) staining were used to evaluate bone histomorphometry. To screen for candidate targets of GQD, a cytokine antibody array was used, followed by bioinformatics analysis. Quantitative real-time PCR (qRT-PCR) and western blotting (WB) were used to determine expression levels.

RESULTS

The major active components of GQD were confirmed by HPLC. Micro-CT and H&E staining showed that bone mass was significantly increased in the GQD-H group compared with the model group. Antibody arrays revealed that the expression of insulin-like growth factor binding protein 3 (IGFBP3) was elevated in the GQD-H group. The MAPK pathway was identified using bioinformatics analysis. Additionally, the levels of osteoclastogenesis-related genes, including cathepsin K (Ctsk), acid phosphatase 5 (Acp5), matrix metallopeptidase 9 (Mmp9), and ATPase H+ transporting V0 subunit D2 (Atp6v0d2) were significantly decreased in the GQD-H group. Compared with the model group, high-dosage GQD inhibited phosphorylation of extracellular signal-regulated kinases (ERKs) and P38 mitogen-activated protein kinase (MAPK) and the expression of c-Fos and nuclear factor of activated T cells 1 (NFATc1).

CONCLUSION

GQD plays a protective role in T2DOP by upregulating IGFBP3 expression and downregulating the IGFBP3/MAPK/NFATc1 signaling pathway. IGFBP3 in serum may also be a novel biomarker in the treatment of T2DOP. Our current findings not only expand the application of GQD, but also provide a theoretical basis and guidance for T2DOP.

Exploring the Pivotal Immunomodulatory and Anti-Inflammatory Potentials of Glycyrrhizic and Glycyrrhetinic Acids

Licorice extract is a Chinese herbal medication most often used as a demulcent or elixir. The extract usually consists of many components but the key ingredients are glycyrrhizic (GL) and glycyrrhetinic acid (GA). GL and GA function as potent antioxidants, anti-inflammatory, antiviral, antitumor agents, and immuneregulators. GL and GA have potent activities against hepatitis A, B, and C viruses, human immunodeficiency virus type 1, vesicular stomatitis virus, herpes simplex virus, influenza A, severe acute respiratory syndrome-related coronavirus, respiratory syncytial virus, vaccinia virus, and arboviruses. Also, GA was observed to be of therapeutic valve in human enterovirus 71, which was recognized as the utmost regular virus responsible for hand, foot, and mouth disease. The anti-inflammatory mechanism of GL and GA is realized via cytokines like interferon-γ, tumor necrotizing factor-α, interleukin- (IL-) 1β, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, and IL-17. They also modulate anti-inflammatory mechanisms like intercellular cell adhesion molecule 1 and P-selectin, enzymes like inducible nitric oxide synthase (iNOS), and transcription factors such as nuclear factor-kappa B, signal transducer and activator of transcription- (STAT-) 3, and STAT-6. Furthermore, DCs treated with GL were capable of influencing T-cell differentiation toward Th1 subset. Moreover, GA is capable of blocking prostaglandin-E2 synthesis via blockade of cyclooxygenase- (COX-) 2 resulting in concurrent augmentation nitric oxide production through the enhancement of iNOS2 mRNA secretion in Leishmania-infected macrophages. GA is capable of inhibiting toll-like receptors as well as high-mobility group box 1.

The anti-diabetic activity of licorice, a widely used Chinese herb

ETHNOPHARMACOLOGICAL RELEVANCE

A great deal of valuable experience has been accumulated in the traditional Chinese medicine (TCM) system for the treatment of "Xiaoke" disease which is known as diabetes mellitus now. As the most-commonly used Chinese herb, licorice has been used in TCM for more than two thousand years. It is often used in combination with other herbs to treat metabolic disorders, especially diabetes mellitus.

AIM OF THE STUDY

To summarize the characteristics, mechanisms, and clinical use of licorice and its active components for treating diabetes mellitus.

METHODS

PubMed, Web of Science, Research Gate, Science Direct, Google Scholar, and Academic Journals were used as information sources by the inclusion of the search terms 'diabetes', 'licorice', 'licorice extracts', 'flavonoids', 'triterpenoids', and their combinations, mainly from 2005 to 2019.

RESULTS

Licorice extracts, five flavonoids and three triterpenoids isolated from licorice possess great antidiabetic activities in vivo and in vitro. This was done by several mechanisms such as increasing the appetency and sensitivity of insulin receptor site to insulin, enhancing the use of glucose in different tissues and organs, clearing away the free radicals and resist peroxidation, correcting the metabolic disorder of lipid and protein, and improving microcirculation in the body. Multiple signaling pathways, including the PI3K/Akt, AMPK, AGE-RAGE, MAPK, NF-кB, and NLRP3 signaling pathways, are targets of the licorice compounds.

CONCLUSION

Licorice and its metabolites have a great therapeutic potential for the treatment of diabetes mellitus. However, a better understanding of their pharmacological mechanisms is needed for evaluating its efficacy and safety.

Network pharmacology and metabolomics study on the intervention of traditional Chinese medicine Huanglian Decoction in rats with type 2 diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

Type 2 diabetes mellitus (T2DM) is currently one of the most prominent and global chronic conditions. Huanglian Decoction (HLD) is a traditional Chinese medicine (TCM) preparation that has been used to treat T2DM for thousands of years in China. However, its mechanism of action at the metabolic level is still unclear. The purpose of this work is to study the mechanism of HLD in treating T2DM based on metabolomics and network pharmacology.

MATERIALS AND METHODS

In this study, metabolomics combined with network pharmacology was used to elucidate the therapeutic mechanism of HLD in T2DM. Serum samples were collected from rats with T2DM, induced by a high-sugar and high-fat diet combined with streptozotocin (STZ), to measure the levels of biochemical markers. Urinary metabolomics-based analysis using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) was conducted to evaluate the differential metabolites from multiple metabolic pathways.

RESULTS

After treatment with HLD for 4 weeks, biochemical indicators, including fasting blood glucose (FBG), blood lipid, fasting insulin (FINS), insulin sensitivity index (ISI), and homeostasis model assessment of insulin resistance (HOMA-IR), were significantly improved. Metabolomics results revealed that HLD regulated the biomarkers, such as cytosine, L-carnitine, betaine, phenylalanine, glucose, citrate, phenylpyruvate, and hippuric acid in glyoxylate and dicarboxylate metabolism, phenylalanine metabolism, and tricarboxylic acid (TCA) cycle. The combination of network pharmacology, metabolomics, western blot, and PCR showed that HLD can treat T2DM by enhancing the gene and protein expression levels of glucose transporter 4 (GLUT4), insulin receptor (INSR), and mitogen-activated protein kinase 1 (MAPK1) to interfere with glyoxylate and dicarboxylate metabolism.

CONCLUSIONS

The study based on metabolomics and network pharmacology indicated that HLD can improve T2DM through multiple targets and pathways, and it may be a useful alternative therapy for the treatment of T2DM.

Herbal Medicine of the 21st Century: A Focus on the Chemistry, Pharmacokinetics and Toxicity of Five Widely Advocated Phytotherapies

Widely advocated for their health benefits worldwide, herbal medicines (HMs) have evolved into a billion dollar generating industry. Much is known regarding their wellness inducing properties, prophylactic and therapeutic benefits for the relief of both minor to chronic ailment conditions given their long-standing use among various cultures worldwide. On the other hand, their equally meaningful chemistry, pharmacokinetic profile in humans, interaction and toxicity profile have been poorly researched and documented. Consequently, this review is an attempt to highlight the health benefits, pharmacokinetics, interaction, and toxicity profile of five globally famous HMs. A systematic literature search was conducted by browsing major scientific databases such as Bentham Science, SciFinder, ScienceDirect, PubMed, Google Scholar and EBSCO to include 196 articles. In general, ginsenosides, glycyrrhizin and curcumin demonstrate low bioavailability when orally administered. Ginkgo biloba L. induces both CYP3A4 and CYP2C9 and alters the AUC and Cmax of conventional medications including midazolam, tolbutamide, lopinavir and nifedipine. Ginsenosides Re stimulates CYP2C9, decreasing the anticoagulant activity of warfarin. Camellia sinensis (L.) Kuntze increases the bioavailability of buspirone and is rich in vitamin K thereby inhibiting the activity of anticoagulant agents. Glycyrrhiza glabra L. displaces serum bound cardiovascular drugs such as diltiazem, nifedipine and verapamil. Herbal medicine can directly affect hepatocytes leading to hepatoxicity based on both intrinsic and extrinsic factors. The potentiation of the activity of concurrently administered conventional agents is potentially lethal especially if the drugs bear dangerous side effects and have a low therapeutic window.

Glycyrrhizin Protects the Diabetic Retina against Permeability, Neuronal, and Vascular Damage through Anti-Inflammatory Mechanisms

Damage associated molecular pattern (DAMPs), such as high mobility group box 1 (HMGB1), may be involved in retinal inflammation in response to high glucose. To test whether HMGB1 inhibition could protect the diabetic retina, C57BL/6J mice were made diabetic and treated with glycyrrhizin, a HMGB1 inhibitor, for up to six months. Measurements of permeability, neuronal, and vascular changes were done, as well as assessments of HMGB1, tumor necrosis factor alpha (TNFα), and interleukin-1-beta (IL1β) levels. Retinal endothelial cells (REC) treated with glycyrrhizin had reduced IL1β and cleaved caspase 3 levels. Data also demonstrate that glycyrrhizin effectively reduced HMGB1 levels throughout the retina, as well as maintained normal retinal permeability and retinal capillary coverage. Glycyrrhizin maintained normal cell numbers in the ganglion cell layer and prevented thinning of the retina at two months. These histological changes were associated with reduced reactive oxygen species, as well as reduced HMGB1, TNFα, and IL1β levels. The data strongly imply that HMGB1 inhibition prevented diabetic retinal changes through anti-inflammatory pathways.

Protective effect of glycyrrhizin on myocardial ischemia/reperfusion injury-induced oxidative stress, inducible nitric oxide synthase and inflammatory reactions through high-mobility group box 1 and mitogen-activated protein kinase expression

Glycyrrhizin, which is a type of perennial leguminous caudex, has been used in various Asian countries, including P.R. China, India and Japan, for thousands of years. The present study was designed to investigate the protective effect of glycyrrhizin on myocardial ischemia/reperfusion (I/R) injury through oxidative stress, inducible nitric oxide synthase (iNOS), and inflammatory reactions via high-mobility group box 1 (HMGB1) and mitogen-activated protein kinase (MAPK) expression. Sprague-Dawley rats were divided into five groups: Sham; myocardial I/R injury + non-treated; myocardial I/R injury + 2 mg/kg glycyrrhizin; myocardial I/R injury + 4 mg/kg glycyrrhizin; and myocardial I/R injury + 10 mg/kg glycyrrhizin. Pre-treatment with glycyrrhizin significantly reduced infarct size and inhibited creatine kinase, creatine kinase-MB, lactate dehydrogenase and cardiac troponin T activities in rats with myocardial I/R injury. Furthermore, glycyrrhizin treatment significantly suppressed oxidative stress, iNOS protein expression and inflammatory reactions in rats with myocardial I/R injury. Additionally, treatment with glycyrrhizin significantly decreased the release of HMGB1 from the cerebral cortex into the serum in rats with myocardial I/R injury. Notably, glycyrrhizin significantly suppressed p-ERK, p-p38 MAPK and p-c-Jun N-terminal kinase protein expressions, and promoted extracellular signal-regulated kinase protein expression in rats with myocardial I/R injury. Collectively, the present study indicates that the protective effect of glycyrrhizin may reduce myocardial I/R injury through oxidative stress, iNOS and inflammatory reactions, via HMGB1 and MAPK expression.

Glycyrrhizic Acid Prevents Diabetic Nephropathy by Activating AMPK/SIRT1/PGC-1α Signaling in db/db Mice

Diabetic nephropathy (DN) is a major cause of end-stage renal disease (ESRD). Glycyrrhizic acid (GA) is an effective inhibitor of reactive oxygen species (ROS) production. We investigated the role of GA in the progression of renal injury in DN. Albumin (Alb)/creatinine (crea) levels were significantly lower, and renal histopathology was attenuated in the diabetic db/db mice that were treated with GA (15 mg/kg via intraperitoneal injection) once per day for eight weeks. These changes were associated with significantly lower levels of α-smooth muscle actin (α-SMA) and transforming growth factor β1 (TGF-β1) expression. Additionally, diabetic db/db mice displayed more terminal deoxynucleotidyl transferase-mediated nick-end labeling- (TUNEL-) positive nuclei and diabetes-induced ROS production in the kidneys, and these effects were attenuated by the treatment with GA, which activated adenosine monophosphate-activated protein kinase (AMPK)/silent information regulator 1 (SIRT1)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) signaling in the kidneys. In summary, in diabetic db/db mice, the effect of GA on DN involved, in part, the inhibition of ROS and the activation of AMPK/SIRT1/PGC-1α signaling in the kidneys. GA, therefore, shows therapeutic potential for preventing and treating DN.

Glycyrrhizic acid prevents enteritis through reduction of NF‑κB p65 and p38MAPK expression in rat

Glycyrrhizic acid has a variety of biological properties, including a protective function in the liver, and anti‑inflammatory, anti‑ulcer, anti‑anaphylaxis, anti‑oxidant, immunoregulatory, antiviral and anticancer activities. The efficacy of glycyrrhizic acid can be increased when combined with other medicines. In the present study, the potential protective effects of glycyrrhizic acid against enteritis in rats, and its role in regulating anti‑inflammation, anti‑oxidation, angiogenic and apoptotic mechanisms were investigated using enzyme‑linked immunosorbent and bicinchoninic acid assays, and reverse transcription‑quantitative polymerase chain reaction and western blotting analyses. Adult male Sprague‑Dawley rats were injected with 20 mg/kg methotrexate (MTX) to establish enteritis. Additionally, rats with MTX‑induced enteritis were peritoneally injected with 200 mg glycyrrhizic acid for 9 weeks. The current study demonstrated that glycyrrhizic acid could alleviate MTX‑induced increases of tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6 levels, and raise IL‑10 levels, in rats with enteritis. Treatment with glycyrrhizic acid significantly reduced D‑lactate and intercellular adhesion molecule‑1 gene expression (P<0.01), but did not inhibit diamine oxidase activity in MTX‑induced enteritis. Pretreatment with glycyrrhizic acid significantly suppressed the promotion of p38 mitogen‑activated protein kinase (p38MAPK), nuclear factor‑κB p65 (NF‑κB p65) protein expression, interferon‑γ protein concentration, and caspase‑3 and cycloxygenase‑2 activity in MTX‑induced enteritis (P<0.01). The findings of the current study suggest that glycyrrhizic acid may prevent enteritis by reducing NF‑κB p65 and p38MAPK expression levels, which may inform future therapeutic strategies for the treatment of enteritis.

Inhibitory effects and actions of pentacyclic triterpenes upon glycation

Pentacyclic triterpenic compounds including asiatic, betulinic, maslinic, oleanolic and ursolic acid occur naturally in many herbs and plant foods. It is well known that these triterpenoids possess anti-oxidative and anti-inflammatory activities. Furthermore, recent in vitro and in vivo researches indicated that these compounds could inhibit the production of advanced glycation end-products (AGEs). The impact of these triterpenes upon the activity and protein expression of enzymes involved in polyol pathway including aldose reductase and sorbitol dehydrogenase has been examined, and positive results are reported. These studies suggest that certain triterpenes are potent anti-glycative agents, and may benefit the prevention and/or therapy of glycation-related diseases such as diabetes mellitus and Alzheimer’s disease. In this review article, the anti-glycative activity and action mode of certain triterpenes are highlighted. These information may promote the anti-glycative application of these natural compounds.

Renal Protective Effects of a Diet and Exercise Intervention in Type 2 Diabetic Rats

Purpose:

Diabetic nephropathy (DN) is one of the most common diabetic microvascular complications. Inflammatory factors participate in each stage of DN, and nuclear factor (NF)-κB and monocyte chemoattractant protein-1(MCP-1) play important mediation roles. The purpose of this study was to investigate the renal protective effects of a diet and exercise intervention in a rat model of Type 2 diabetes mellitus (T2DM).

Method:

Control rats (Group A, n = 10) were fed a normal diet, while 30 rats were fed a high-glucose, high-fat diet and given an intraperitoneal injection of streptozocin to establish the T2DM model. Model rats ( n = 8 per group) were randomized into Groups B, C, and D. Groups C and D were treated with glibenclamide, and Group D received an 8-week diet and exercise intervention. Blood, 12-hr urine, and kidney tissue samples were collected postintervention for detecting blood glucose and lipid levels, expression of MCP-1 and NF-κB, and renal function indices.

Results:

Postintervention, blood glucose, and lipid levels in Groups C and D were lower than those in Group B, with decreases in Group D significantly greater than in Group C. Every index of renal protection showed greater improvement in Group D than in Group C ( p < .05). The expression of NF-κB and MCP-1 was lower in Group D than in Group C ( p < .05).

Conclusions:

The diet and exercise intervention reduced the inflammatory reaction and delayed T2DM and DN progression by inhibiting the activation of NF-κB and downregulating the expression of MCP-1.