Wogonin ameliorates hyperglycemia and dyslipidemia via PPARα activation in db/db mice

Exploring the mechanism of Jinlida granules against type 2 diabetes mellitus by an integrative pharmacology strategy

Jinlida granule (JLD) is a Traditional Chinese Medicine (TCM) formula used for the treatment of type 2 diabetes mellitus (T2DM). However, the mechanism of JLD treatment for T2DM is not fully revealed. In this study, we explored the mechanism of JLD against T2DM by an integrative pharmacology strategy. Active components and corresponding targets were retrieved from Traditional Chinese Medicine System Pharmacology (TCMSP), SwissADME and Bioinformatics Analysis Tool for Molecular Mechanisms of Traditional Chinese Medicine Database (BATMAN-TCM) database. T2DM-related targets were obtained from Drugbank and Genecards databases. The protein-protein interaction (PPI) network was constructed and analyzed with STRING (Search Toll for the Retrieval of Interacting Genes/proteins) and Cytoscape to get the key targets. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) enrichment analyses were performed with the Database for Annotation, Visualization and Integrated Discovery (DAVID). Lastly, the binding capacities and reliability between potential active components and the targets were verified with molecular docking and molecular dynamics simulation. In total, 185 active components and 337 targets of JLD were obtained. 317 targets overlapped with T2DM-related targets. RAC-alpha serine/threonine-protein kinase (AKT1), tumor necrosis factor (TNF), interleukin-6 (IL-6), cellular tumor antigen p53 (TP53), prostaglandin G/H synthase 2 (PTGS2), Caspase-3 (CASP3) and signal transducer and activator of transcription 3 (STAT3) were identified as seven key targets by the topological analysis of the PPI network. GO and KEGG enrichment analyses showed that the effects were primarily associated with gene expression, signal transduction, apoptosis and inflammation. The pathways were mainly enriched in PI3K-AKT signaling pathway and AGE-RAGE signaling pathway in diabetic complications. Molecular docking and molecular dynamics simulation verified the good binding affinity between the key components and targets. The predicted results may provide a theoretical basis for drug screening of JLD and a new insight for the therapeutic effect of JLD on T2DM.

Screening of CPT1A-Targeting Lipid Metabolism Modulators Using Mitochondrial Membrane Chromatography

Carnitine palmitoyltransferase 1A (CPT1A), which resides on the mitochondrial outer membrane, serves as the rate-limiting enzyme of fatty acid β-oxidation. Identifying the compounds targeting CPT1A warrants a promising candidate for modulating lipid metabolism. In this study, we developed a CPT1A-overexpressed mitochondrial membrane chromatography (MMC) to screen the compounds with affinity for CPT1A. Cells overexpressing CPT1A were cultured, and subsequently, their mitochondrial membrane was isolated and immobilized on amino-silica gel cross-linked by glutaraldehyde. After packing the mitochondrial membrane column, retention components of MMC were performed with LC/MS, whose analytic peaks provided structural information on compounds that might interact with mitochondrial membrane proteins. With the newly developed MMC-LC/MS approach, several Chinese traditional medicine extracts, such as Scutellariae Radix and Polygoni Cuspidati Rhizoma et Radix (PCRR), were analyzed. Five noteworthy compounds, baicalin, baicalein, wogonoside, wogonin, and resveratrol, were identified as enhancers of CPT1A enzyme activity, with resveratrol being a new agonist for CPT1A. The study suggests that MMC serves as a reliable screening system for efficiently identifying modulators targeting CPT1A from complex extracts.

Overview of Natural Supplements for the Management of Diabetes and Obesity

Bioactive compounds found in various natural sources, such as fruits, vegetables, and herbs, have been studied for their potential benefits in managing obesity and diabetes. These compounds include polyphenols, flavonoids, other antioxidants, fiber, and certain fatty acids. Studies have found that these compounds may improve insulin sensitivity, regulate blood sugar levels, and promote weight loss. However, the effects of these compounds can vary depending on the type and amount consumed, as well as individual factors, such as genetics and lifestyle. Nutraceutical substances have multifaceted therapeutic advantages, and they have been reported to have disease-prevention and health-promoting properties. Several clinically used nutraceuticals have been shown to target the pathogenesis of diabetes mellitus, obesity, and metabolic syndrome and their complications and modulate various clinical outcomes favorably. This review aims to highlight and comment on some of the most prominent natural components used as antidiabetics and in managing obesity.

In-silico, in-vitro and in-vivo Biological Activities of Flavonoids for the Management of Type 2 Diabetes

In spite of the fact that many medicinal plants have been truly utilized for the management of diabetes all through the world, very few of them have been reported scientifically. Recently, a diverse variety of animal models have been established to better understand the pathophysiology of diabetes mellitus, and new medications to treat the condition have been introduced in the market. Flavonoids are naturally occurring substances that can be found in plants and various foods and may have health benefits in the treatment of neuropathic pain. Flavonoids have also been shown to have an anti-inflammatory impact that is significant to neuropathic pain, as indicated by a decrease in several pro-inflammatory mediators such TNF-, NF-B IL-6, and IL-1. Flavonoids appear to be a viable novel therapy option for macrovasular complications in preclinical models; however, human clinical data is still inadequate. Recently, several in silico, in-vitro and in-vivo aproaches were made to evaluate mechanisms associated with the pathogenesis of diabetes in a better way. Screening of natural antidiabetic agents from plant sources can be analysed by utilizing advanced in-vitro techniques and animal models. Natural compounds, mostly derived from plants, have been studied in diabetes models generated by chemical agents in the majority of research. The aim of this work was to review the available in silico, in-vitro and animal models of diabetes for screening of natural antidiabetic agents. This review contributes to the scientist's design of new methodologies for the development of novel therapeutic agents having potential antihyperglycemic activity.

Lonicera Caerulea Juice Alleviates Alcoholic Liver Disease by Regulating Intestinal Flora and the FXR-FGF15 Signaling Pathway

Alcoholic liver disease (ALD) is a growing public health issue with high financial, social, and medical costs. Lonicera caerulea, which is rich in polyphenolic compounds, has been shown to exert anti-oxidative and anti-inflammatory effects. This study aimed to explore the effects and mechanisms of concentrated Lonicera caerulea juice (LCJ) on ALD in mice. ALD was established in mice via gradient alcohol feeding for 30 days. The mice in the experimental group were given LCJ by gavage. The reduction of aspartate transaminase (AST) and alanine transaminase (ALT) in the serum of mice indicated that LCJ has a liver-protective effect. LCJ improved the expression of AMPK, PPARα, and CPT1b in ALD mice to reduce the liver lipid content. Additionally, LCJ increased the expression of farnesoid X receptor (FXR), fibroblast growth factor 15 (FGF15), and fibroblast growth factor receptor 4 (FGFR4), which lowers the expression of cytochrome P450 7A1 (CYP7A1) and lessens bile acid deposition in the liver. In mice, LCJ improved the intestinal barrier by upregulating the expression of mucins and tight junction proteins in the small intestine. Moreover, it accelerated the restoration of microbial homeostasis in both the large and small intestines and increased short-chain fatty acids in the cecum. In conclusion, LCJ alleviates ALD by reducing liver and serum lipid accumulation and modulating the FXR-FGF15 signaling pathway mediated by gut microbes.

Gut Microbiome: The Interplay of an "Invisible Organ" with Herbal Medicine and Its Derived Compounds in Chronic Metabolic Disorders

Resembling a concealed "organ" in a holobiont, trillions of gut microbes play complex roles in the maintenance of homeostasis, including participating in drug metabolism. The conventional opinion is that most of any drug is metabolized by the host and that individual differences are principally due to host genetic factors. However, current evidence indicates that only about 60% of the individual differences in drug metabolism are attributable to host genetics. Although most common chemical drugs regulate the gut microbiota, the gut microbiota is also known to be involved in drug metabolism, like the host. Interestingly, many traditional herbal medicines and derived compounds are biotransformed by gut microbiota, manipulating the compounds' effects. Accordingly, the gut microbiota and its specified metabolic pathways can be deemed a promising target for promoting drug efficacy and safety. However, the evidence regarding causality and the corresponding mechanisms concerning gut microbiota and drug metabolism remains insufficient, especially regarding drugs used to treat metabolic disorders. Therefore, the present review aims to comprehensively summarize the bidirectional roles of gut microbiota in the effects of herbal medicine in metabolic diseases to provide vital clues for guiding the clinical application of precision medicine and personalized drug development.

An Overview on Plant Derived Phenolic Compounds and Their Role in Treatment and Management of Diabetes

Objectives

In recent decades, the trend for treating diabetes mellitus (DM) has shifted toward alternative medicines that are obtained from plant sources. Existing literature suggests that phenolic compounds derived from plants possess promising health-promoting properties. This study aimed to discuss the role of plant-derived phenolic compounds in the effective treatment and management of diabetes.

Methods

Information about plant secondary metabolites, phenolic compounds, and their role in the treatment and management of diabetes was collected from different databases, such as Pubmed, ScienceDirect, Scopus, and Google Scholar. Keywords like secondary metabolites, phenolic compounds, simple phenol, flavonoids, lignans, stilbenes, and diabetes were searched. Research and review articles with relevant information were included in the study.

Results

Anti-diabetic studies of the four major classes of phenolic compounds were included in this review. The plant-derived phenolic compounds were reported to have potent anti-diabetic activities. However, each class of phenolic compounds was found to behave differently according to various mechanisms.

Conclusion

The obtained results suggest that phenolic compounds derived from natural sources display promising anti-diabetic activities. Based on the available information, it can be concluded that phenolic compounds obtained from various natural sources play key roles in the treatment and management of diabetes.

Wogonin, a Compound in Scutellaria baicalensis, Activates ATF4–FGF21 Signaling in Mouse Hepatocyte AML12 Cells

Fibroblast growth factor 21 (FGF21), which is mainly synthesized and secreted by the liver, plays a crucial role in systemic glucose and lipid metabolism, ameliorating metabolic diseases. In this study, we screened the WAKANYAKU library derived from medicinal herbs to identify compounds that can activate Fgf21 expression in mouse hepatocyte AML12 cells. We identified Scutellaria baicalensis root extract and one of its components, wogonin, as an activator of Fgf21 expression. Wogonin also enhanced the expression of activating transcription factor 4 (ATF4) by a mechanism other than ER stress. Knockdown of ATF4 by siRNA suppressed wogonin-induced Fgf21 expression, highlighting its essential role in wogonin’s mode of action. Thus, our results indicate that wogonin would be a strong candidate for a therapeutic to improve metabolic diseases by enhancing hepatic FGF21 production.

Characterization of the mechanism of Scutellaria baicalensis on reversing radio-resistance in colorectal cancer

Scutellaria baicalensis (SB) has been shown to improve the therapeutic effects of colorectal cancer (CRC) and perform well for reversing radio-resistance in different cancers. However, its potential function and mechanism related to radio-resistance in CRC has not been explored. A radio-resistant human CRC cell line (HCT116R) was applied. A network pharmacological analysis was performed to reveal the potential mechanism of SB for reversing radio-resistance in CRC, and computational pathological analysis was applied to indicate the clinicopathological significance of the key targets. Then, our hypothesis was further verified by molecular docking. The network pharmacology analysis showed that wogonin is the key compound of SB for reversing the radio-resistance of CRC. A Kyoto Encyclopedia of Genes and Genomes analysis showed that the genes for SB that reverse radio-resistance in CRC are mainly involved in steroid hormone biosynthesis. An enrichment analysis pointed out that Sulfotransferase family 2B member 1 (SULT2B1) is a potentially vital gene. SULT2B1 was demonstrated as being highly expressed in CRC and upregulated in radio-resistant rectal tissues or cell lines. A CCK-8 and clone formation test showed that the viability and clone formation ability of HCT116R were significantly decreased by wogonin combined with radiotherapy, compared to radiotherapy alone. By contrast, flow cytometry revealed that the apoptosis of HCT116R was significantly increased when wogonin treatment combined with radiotherapy, compared with radiotherapy alone. Molecular docking verification indicated that SULT2B1 and wogonin have a good binding ability. Taken together, SULT2B1 may be the potential drug target in treating radio-resistant CRC. Wogonin may be the core compound of SB for reversing radio-resistance in CRC by targeting SULT2B1.

Wogonin Ameliorated Obesity-Induced Lipid Metabolism Disorders and Cardiac Injury via Suppressing Pyroptosis and Deactivating IL-17 Signaling Pathway

Obesity leads to structural and functional changes in the heart and has become a global burden of disease. Wogonin is a natural flavonoid which possesses cardioprotective, neuroprotective, and anti-cancer properties. However, the effects of wogonin on obesity-induced cardiac injury remain unclear. In this study, the high-fat diet (HFD)-induced obese mice model was successfully established. Moreover, HFD induced a fat mass and cardiac injury in mice. More importantly, wogonin treatment reduced fat mass and improved cardiac function of HFD mice. Consistently, wogonin ameliorated myocardial lipid metabolism in HFD-induced obese mice by reducing triglyceride (TC), total cholesterol (TG), and non-esterified fatty acid (NEFA) levels in serum, as well as the TG and free fatty acids (FFA) levels in heart tissues. Interestingly, wogonin treatment alleviated myocardial pyroptosis in HFD-induced obese mice. Through bioinformatic analysis, the IL-17 signaling pathway was predicted to be modulated by wogonin. Results showed that wogonin deactivated the IL-17 signaling pathway in HFD mice. These findings suggested that wogonin ameliorated obesity-induced disorders of lipid metabolism and cardiac injury via suppressing pyroptosis and deactivating the IL-17 signaling pathway, which provided a novel therapeutic strategy for HFD-induced cardiac injury.

Exploring Compounds to be used as Cosmetic Agents that Activate Peroxisome Proliferator-Activated Receptor Alpha

OBJECTIVE

The human epidermis is formed by the proliferation and differentiation of keratinocytes adjacent to the basement membrane. The outermost layer, the stratum corneum, is equipped with a barrier function that prevents water evaporation, and intercellular lipids play an important role in this barrier function. When the barrier is functioning normally, evaporation is prevented; however, when barrier function is impaired, moisture evaporates, resulting in dry and rough skin. Therefore, maintenance of normal barrier function is critical for maintaining normal skin function. Peroxisome proliferator-activated receptor α (PPARα) is mainly involved in lipid metabolism in the liver but is also expressed in the epidermis and is involved in inducing keratinocyte differentiation, promoting lipid production, maintaining barrier function, and suppressing skin inflammation. Hence, compounds that activate PPARα are expected to control skin function. Therefore, we identified PPARα activators from among extracts of natural resources that have been approved for use in humans and analyzed the effects of these extracts on skin function.

METHODS

First, extracts of 474 natural resources were screened using a PPARα activator screening cell line independently constructed in our laboratory. Next, reporter assays were performed using the Gal4-chimera system to evaluate whether these extracts act as ligands for PPARα. We then analyzed their effect on primary normal human epidermal keratinocyte cells by using real-time RT-PCR. Finally, we evaluated PPARα activation effect by the combination of these extracts.

RESULTS

We identified 36 extracts having the effect of activating PPARα. In particular, #419, a Typha angustifolia spike extract, showed concentration-dependent transcriptional activation through PPARα-LBD and was considered to be likely to contain a compound that is a ligand of PPARα. #419 increased the expression of PPARα target genes as well as genes related to skin function in primary cultured human epidermal keratinocytes. Finally, the use of #419 in combination with nine extracts increased PPAR activity more than twice as much as #419 alone treatment.

CONCLUSIONS

These results showed that the reporter cell line could be useful for discovering extracts of natural resources and that the identified Typha angustifolia spike extract could be used in cosmetics that activate PPARα, which expected to improve skin function.

Effects of wogonin on the growth and metastasis of colon cancer through the Hippo signaling pathway

Wogonin is an effective component of Scutellaria baicalensis Georgi, which exhibits anti-tumor activity. The aim of this study was to explore the effects of wogonin on colon cancer (CC). Human CC cell lines, SW480 and HCT116, were cultured, and MTT assay was performed to detect cell survival. RT-qPCR and Western blotting were used to measure mRNA and protein expression, respectively. The migration and invasion abilities of the CC cells were determined by a transwell assay. Immunofluorescence staining was performed to determine the localization of IRF3. Xenograft mice were used to investigate the effects of wogonin on CC in vivo. Wogonin inhibited the survival and metastasis of CC cells. In addition, wogonin suppressed epithelial-mesenchymal transition (EMT). Furthermore, the protein expression of YAP1 and IRF3 was downregulated, and p-YAP1 was upregulated after wogonin treatment. Wogonin also suppressed IRF3 expression in the nuclei of CC cells and overexpression of YAP1 reversed the effects of wogonin in CC cells. Finally, wogonin inhibited the tumor growth in the mice and overexpression of YAP1 reversed the wogonin effects. Thus, these results showed that wogonin relieved the carcinogenic behaviors and EMT of CC cells via the IRF3-mediated Hippo signaling pathway.

Wogonin and alleviation of hyperglycemia via inhibition of DAG mediated PKC expression. A brief insight

Protein kinase C (PKC) is a family of protein kinase enzymes that can phosphorylate other proteins and influence their functions, such as signal transduction, cell survival, and death. Increased diacylglycerol (DAG) concentrations, which are typically observed raised in hyperglycemic situations such as diabetes mellitus, can also activate PKC enzymes (DM). On the other hand, PKC isomers have been shown to play an essential role in diabetes and many hyperglycemic complications, most importantly atherosclerosis and diabetic cardiomyopathy (DCM). As a result, blocking PKC activation via DAG can prevent hyperglycemia and related consequences, such as DCM. Wogonin is a herbal medicine which has anti-inflammatory properties, and investigations show that it scavenge oxidative radicals, attenuate nuclear factor-kappa B (NF-κB) activity, inhibit several essential cell cycle regulatory genes, block nitric oxide (NO) and suppress cyclooxygenase-2 (COX-2). Furthermore, several investigations show that wogonin also attenuates diacylglycerol DAG levels in diabetic mice. Since the DAG-PKC pathway is linked with hyperglycemia and its complications, Wogonin-mediated DAG-PKC attenuation can help treat hyperglycemia and its complications.

Network Pharmacology-Based Analysis and Experimental Exploration of Antidiabetic Mechanisms of Gegen Qinlian Decoction

Type-2 diabetes mellitus (T2DM) and therapy options have been studied increasingly due to their rising incidence and prevalence. The trend of applying traditional Chinese medicine (TCM) to treat T2DM is increasing as a crucial medical care for metabolic dysfunctions. Gegen Qinlian decoction (GQL), a well-known classical TCM formula used in China, has been clinically applied to treat various types of chronic metabolic diseases. However, antidiabetic effects of GQL administration during T2DM have never been studied systematically. We assessed physiological and molecular targets associated with therapeutic effects of GQL by evaluating network topological characteristics. The GQL-related biological pathways are closely associated with antidiabetic effects, including the TNF and PI3K–AKT signaling pathways. Associated primary biological processes such as RNA polymerase II promoter transcription participate in the inflammatory response, oxidative stress reduction, and glucose metabolic process, thereby exerting multiple biological effects on the antidiabetic mechanism. Furthermore, our results showed that GQL can affect blood glycemic levels and ameliorate inflammatory symptoms, and liver and pancreas tissue injury in high-fat diet plus streptozotocin-induced diabetic mice. In vivo and in vitro experiments confirmed that antidiabetic effects of GQL were associated with a modulation of the TNF and PI3K–AKT–MTOR pathways.

Metabonomic Study on the Plasma of High-Fat Diet-Induced Dyslipidemia Rats Treated with Ge Gen Qin Lian Decoction by Ultrahigh-Performance Liquid Chromatography-Mass Spectrometry

Gegen Qinlian decoction (GGQLD) has a definite effect on T2DM in clinic, and it has the effect of lowering blood sugar, improving insulin resistance, and improving the blood lipid level of rats with dyslipidemia, but the intervention mechanism of GGQLD on dyslipidemia has not been clarified. The changes in endogenous metabolites in the plasma of high-fat diet-induced dyslipidemia rats treated with Ge Gen Qin Lian Decoction (GGQLD) were studied to elucidate the therapeutic effects and mechanism of action of GGQLD in dyslipidemia. Based on ultrahigh-performance liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS), the metabolic profiles of rat serum samples were collected. The rat model of dyslipidemia was induced by a 60% fat-fed high-fat diet. After feeding the rats with a high-fat diet for 4 weeks, dyslipidemia appeared. After 5 weeks of GGQLD (14.85 g kg⁻¹) administration, the metabonomics of rats' plasma samples in the normal group, model group, and administration group were analyzed. Mass profiler professional (MPP), SIMCA-P 14.1, and Graphpad prism 6.0 software were used combined with METLIN biological database and human metabolite database HMDB to screen and identify endogenous biomarkers. Metaboanalyst 4.0 software was used by combining with HMDB and KEGG databases; the enrichment and metabolic pathway of biomarkers were analyzed to explore the metabolic mechanism of dyslipidemia rats induced by high-fat diet and the intervention mechanism of Gegen Qinlian decoction. After 5 weeks of administration of GGQLD, the levels of serum TC and TG were significantly decreased (P < 0.05, P < 0.01), while HDL-C and LDL-C were not significantly affected. After administration, the food intake of rats in the administration group decreased gradually, and the change trend of body weight gradually slowed down. The metabonomics of rat plasma samples results showed that 23 potential biomarkers including α-linolenic acid, arachidonic acid, and lysophosphatidylcholine were significantly changed in positive ion mode. Studies have shown that GGQLD has a significant lipid-lowering effect on dyslipidemia rats induced by a high-fat diet, and its preventive mechanism is related to tryptophan metabolism, fatty acid biosynthesis, α-linolenic acid metabolism, arachidonic acid, and glycerophosphatidyl metabolism pathway.

High phosphate impairs arterial endothelial function through AMPK-related pathways in mouse resistance arteries

AIMS

In patients with renal disease, high serum phosphate shows a relationship with cardiovascular risk. We speculate that high phosphate (HP) impairs arterial vasodilation via the endothelium and explore potential underlying mechanisms.

METHODS

Isolated vessel relaxation, endothelial function, glomerular filtration rate (GFR), oxidative stress status and protein expression were assessed in HP diet mice. Mitochondrial function and protein expression were assessed in HP-treated human umbilical vein endothelial cells (HUVECs).

RESULTS

High phosphate (1.3%) diet for 12 weeks impaired endothelium-dependent relaxation in mesenteric arteries, kidney interlobar arteries and afferent arterioles; reduced GFR and the blood pressure responses to acute administration of acetylcholine. The PPARα/LKB1/AMPK/eNOS pathway was attenuated in the endothelium of mesenteric arteries from HP diet mice. The observed vasodilatory impairment of mesenteric arteries was ameliorated by PPARα agonist WY-14643. The phosphate transporter PiT-1 knockdown prevented HP-mediated suppression of eNOS activity by impeding phosphorus influx in HUVECs. Endothelium cytoplasmic and mitochondrial reactive oxygen species (ROS) were increased in HP diet mice. Moreover HP decreased the expression of mitochondrial-related antioxidant genes. Finally, mitochondrial membrane potential and PGC-1α expression were reduced by HP treatment in HUVECs, which was partly restored by AMPKα agonist.

CONCLUSIONS

HP impairs endothelial function by reducing NO bioavailability via decreasing eNOS activity and increasing mitochondrial ROS, in which the AMPK-related signalling pathways may play a key role.

Effect of Quercetin on Lipids Metabolism Through Modulating the Gut Microbial and AMPK/PPAR Signaling Pathway in Broilers

The present study was conducted to investigate effects and mechanism of quercetin on lipids metabolism in broilers. 480 AA broilers were randomly allotted to four treatments (0, 0.2, 0.4, and 0.6 g/kg quercetin) for 42 days. Compared with the control, 0.6 g/kg quercetin significantly decreased percentage of abdominal fat (P < 0.05); 0.2, 0.4, and 0.6 g/kg quercetin significantly decreased relative abundance of Lachnospiraceae and Desulfovibrionaceae (P < 0.05, P < 0.05, P < 0.01; P < 0.01, P < 0.01, P < 0.01); 0.2 g/kg quercetin significantly increased mRNA expression of PI3K, AMPKα1, AMPKα2, AMPKβ2, LKB1 (P < 0.01, P < 0.01, P < 0.05, P < 0.01, P < 0.05), and significantly reduced mRNA expression of SREBP1 and PPARγ (P < 0.01, P < 0.05); 0.4 g/kg quercetin significantly increased mRNA expression of LKB1 and PKB (P < 0.05, P < 0.01) and significantly reduced mRNA expression of ACC, HMGR, PPARγ, and SREBP1 (P < 0.05, P < 0.01, P < 0.01, P < 0.01); 0.6 g/kg quercetin significantly increased mRNA expression of AMPKγ, LKB1, CPT1, PPARα, PKB (P < 0.01, P < 0.01, P < 0.01, P < 0.05, P < 0.05), and significantly reduced the mRNA expression of PI3K, ACC, HMGR, PPARγ, SREBP1 (P < 0.05, P < 0.05, P < 0.01, P < 0.01, P < 0.01); 0.2 g/kg quercetin significantly increased protein expression of AMPK (P < 0.01); 0.6 g/kg quercetin significantly increased protein expression of LKB1 (P < 0.01), 0.2 and 0.6 g/kg quercetin significantly increased protein expression of PI3K, PKB, CPT1 (P < 0.05, P < 0.01, P < 0.05, P < 0.01, P < 0.01, P < 0.01), and significantly reduced protein expression of ACC and SREBP1 (P < 0.01, P < 0.01, P < 0.01, P < 0.01). In conclusion, quercetin improved lipid metabolism by modulating gut microbial and AMPK/PPAR signaling pathway in broilers.

The main bioactive compounds of Scutellaria baicalensis Georgi. for alleviation of inflammatory cytokines: A comprehensive review

Scutellaria baicalensis Georgi., a plant used in traditional Chinese medicine, has multiple biological activities, including anti-inflammatory, antiviral, antitumor, antioxidant, and antibacterial effects, and can be used to treat respiratory tract infections, pneumonia, colitis, hepatitis, and allergic diseases. The main active substances of S. baicalensis, baicalein, baicalin, wogonin, wogonoside, and oroxylin A, can act directly on immune cells such as lymphocytes, macrophages, mast cells, dendritic cells, monocytes, and neutrophils, and inhibit the production of the inflammatory cytokines IL-1β, IL-6, IL-8, and TNF-α, and other inflammatory mediators such as nitric oxide, prostaglandins, leukotrienes, and reactive oxygen species. The molecular mechanisms underlying the immunomodulatory and anti-inflammatory effects of the active compounds of S. baicalensis include downregulation of toll-like receptors, activation of the Nrf2 and PPAR signaling pathways, and inhibition of the nuclear thioredoxin system and inflammation-associated pathways such as those of MAPK, Akt, NFκB, and JAK-STAT. Given that in addition to the downregulation of cytokine production, the active constituents of S. baicalensis also have antiviral and antibacterial effects, they may be more promising candidate therapeutics for the prevention of infection-related cytokine storms than are drugs having only antimicrobial or anti-inflammatory activities.

Wogonin Ameliorates Renal Inflammation and Fibrosis by Inhibiting NF-κB and TGF-β1/Smad3 Signaling Pathways in Diabetic Nephropathy

Introduction

Diabetic nephropathy (DN) has become an increasing threat to health, and inflammation and fibrosis play important roles in its progression. Wogonin, a flavonoid, has been proven to suppress inflammation and fibrosis in various diseases, including acute kidney injury. This study aimed at investigating the effect of wogonin on diabetes-induced renal inflammation and fibrosis.

Materials and Methods

Streptozotocin (STZ)-induced diabetic mouse models received gavage doses of wogonin (10, 20, and 40 mg/kg) for 12 weeks. Metabolic indices from blood and urine and pathological damage of glomerulus in the diabetic model were assessed. Glomerular mesangial cells SV40 were cultured in high glucose (HG) medium containing wogonin at concentrations of 1.5825, 3.125, and 6.25 μg/mL for 24 h. Inflammation and fibrosis indices were evaluated by histopathological, Western blotting, and PCR analyses.

Results

Wogonin treatment ameliorated albuminuria and histopathological lesions in diabetic mice. Inflammatory cytokines, such as monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and related signaling pathway NF-κB were downregulated after the administration of wogonin in vivo and in vitro. Furthermore, wogonin reduced the expression of extracellular matrix (ECM), including fibronectin (FN), collagen IV (Col-IV), α-smooth muscle actin (α-SMA), and transforming growth factor-β1 (TGF-β1) in the kidneys of diabetic mice and HG-induced mesangial cells. Moreover, the inhibition of TGF-β1/Smad3 pathway might be responsible for these changes.

Conclusion

Wogonin may ameliorate renal inflammation and fibrosis in diabetic nephropathy by inhibiting the NF-κB and TGF-β1/Smad3 signaling pathways.

Combination of Scutellaria baicalensis and Metformin Ameliorates Diet-Induced Metabolic Dysregulation in Mice via the Gut-Liver-Brain Axis

Scutellaria baicalensis (SB), a herbal medicine, is commonly used to treat metabolic diseases, while Metformin (MF) is a widely used drug for type 2 diabetes. The purpose of this study was to investigate whether co-treatment of SB with MF could produce a potential therapeutic effect on high-fat and high-fructose diet (HFFD)-induced metabolic dysregulation. First, we optimized the dose of SB (100, 200, 400, and 800[Formula: see text]mg/kg) with MF (200[Formula: see text]mg/kg) in HFFD-induced C57BL6J mice. Next, the optimized dose of SB (400[Formula: see text]mg/kg) was co-administered with MF (50, 100, and 200[Formula: see text]mg/kg) in a similar animal model to find the effective combinations of SB and MF. Metabolic markers were determined in serum and tissues using different assays, histology, gene expression, and gut microbial population. The SB and MF co-treatment significantly decreased the body, liver, and VAT weights. The outcome of OGTT was improved, and the fasting insulin, HbA1c, TG, TC, LDL-c, AST, and ALT were decreased, while HDL-c was significantly increased. Histological analyses revealed maintained the integrity of liver, adipose tissue, and intestine prevented lipid accumulation in the liver and intestine and combated neuronal damage in the brain. Importantly, controlled the expression of PPAR[Formula: see text], and IL-6 genes in the liver, and expression of BDNF, Glut1, Glut3, and Glut4 genes in the brain. Treatment-specific gut microbial segregation was observed in the PCA chart. Our findings indicate that SB and MF co-treatment is an effective therapeutic approach for HFFD-induced metabolic dysregulation which is operated through the gut-liver-brain axis.

Neohesperidin attenuates obesity by altering the composition of the gut microbiota in high-fat diet-fed mice

Obesity and related metabolic disorders are associated with intestinal microbiota dysbiosis, disrupted intestinal barrier, and chronic inflammation. Neohesperidin (Neo), a natural polyphenol abundant in citrus fruits, is known for its preventative and therapeutic effects on numerous diseases. Here, we report that Neo administration attenuates weight gain, low-grade inflammation, and insulin resistance in mice fed high-fat diet (HFD). Also, Neo administration substantially restores gut barrier damage, metabolic endotoxemia, and systemic inflammation. Sequencing of 16S rRNA genes in fecal samples revealed that Neo administration reverses HFD-induced intestinal microbiota dysbiosis: an increase in the diversity of gut microbiota and alteration in the composition of intestinal microbiota (particularly in the relative abundances of Bacteroidetes and Firmicutes). Furthermore, systemic antibiotic treatment abolishes the beneficial effects of Neo in body weight control, suggesting that the effect of Neo on obesity attenuation largely depends on the gut microbiota. More importantly, we demonstrate that the impact of Neo on the regulation of obesity could be transferred from Neo-treated mice to HFD-fed mice via fecal microbiota transplantation. Collectively, our data highlight the efficacy of Neo as a prebiotic agent for attenuating obesity, implying a potential mechanism for gut microbiota mediated the beneficial effect of Neo.

Flavonoids and type 2 diabetes: Evidence of efficacy in clinical and animal studies and delivery strategies to enhance their therapeutic efficacy

Diabetes mellitus type 2 (T2DM) is a metabolic disorder develops due to the overproduction of free radicals where oxidative stress could contribute it. Possible factors are defective insulin signals, glucose oxidation, and degradation of glycated proteins as well as alteration in glutathione metabolism which induced hyperglycemia. Previous studies revealed a link between T2DM with oxidative stress, inflammation and insulin resistance which are assumed to be regulated by numerous cellular networks such as NF-κB, PI3K/Akt, MAPK, GSK3 and PPARγ. Flavonoids are ubiquitously present in the nature and classified according to their chemical structures for example, flavonols, flavones, flavan-3-ols, anthocyanidins, flavanones, and isoflavones. Flavonoids indicate poor bioavailability which could be improved by employing various nano-delivery systems against the occurrences of T2DM. These bioactive compounds exert versatile anti-diabetic activities via modulating targeted cellular signaling networks, thereby, improving glucose metabolism, α -glycosidase, and glucose transport or aldose reductase by carbohydrate metabolic pathway in pancreatic β-cells, hepatocytes, adipocytes and skeletal myofibres. Moreover, anti-diabetic properties of flavonoids also encounter diabetic related complications. This review article has designed to shed light on the anti-diabetic potential of flavonoids, contribution of oxidative stress, evidence of efficacy in clinical, cellular and animal studies and nano-delivery approaches to enhance their therapeutic efficacy. This article might give some new insights for therapeutic intervention against T2DM in near future.

Targeting Foam Cell Formation in Atherosclerosis: Therapeutic Potential of Natural Products

Foam cell formation and further accumulation in the subendothelial space of the vascular wall is a hallmark of atherosclerotic lesions. Targeting foam cell formation in the atherosclerotic lesions can be a promising approach to treat and prevent atherosclerosis. The formation of foam cells is determined by the balanced effects of three major interrelated biologic processes, including lipid uptake, cholesterol esterification, and cholesterol efflux. Natural products are a promising source for new lead structures. Multiple natural products and pharmaceutical agents can inhibit foam cell formation and thus exhibit antiatherosclerotic capacity by suppressing lipid uptake, cholesterol esterification, and/or promoting cholesterol ester hydrolysis and cholesterol efflux. This review summarizes recent findings on these three biologic processes and natural products with demonstrated potential to target such processes. Discussed also are potential future directions for studying the mechanisms of foam cell formation and the development of foam cell-targeted therapeutic strategies.

Dietary plant flavonoids in prevention of obesity and diabetes

Obesity and diabetes are the most prevailing chronic metabolic diseases worldwide from mainly lipid and glucose metabolic dysfunctions and their incidence is increasing at an alarming high rate. Obesity is characterized by excess fat accumulation in WAT and liver and is the central player of insulin resistance in the peripheral tissues from chronic inflammation, lipotoxicity and gut dysbiosis, and plays a key role for development of type 2 diabetes (T2DM) and vascular diseases. Diabetes mellitus, known as diabetes, is chiefly characterized by hyperglycaemia from impaired insulin secretion and insulin resistance. Several identified mutant genes in insulin secretion and resistance and various environmental factors are considered responsible for the onset of this disease. Currently available oral synthetic drugs, biguanides, incretin mimetic, GLP-1R and PPAR agonists and DPP-4 inhibitors for management of obesity and diabetes have several adverse effects in patients on long-term use. Emerging evidence supports the efficacy of dietary plant flavonoids in prevention and attenuation of obesity and diabetes by the protection and proliferation of pancreatic beta-cells and improvement of their insulin secretory function via activation of cAMP/PKA signaling pathway as well as in the improvement of insulin sensitivity in the peripheral metabolic tisssues for glucose uptake and utilization via inhibition of inflammation, lipotoxicity and oxidative stress. These flavonoids improve GLUT-4 expression and translocation to plasma membrane by activation of insulin-sensitive PI3K/Akt signaling and insulin-independent AMPK, SIRT-1 and MOR activation pathways for regulation of glucose homeostasis, and improve fat oxidation and reduce lipid synthesis by regulation of related genes for lipid homeostasis in the body of obese diabetic animals. In this chapter, we have highlighted all these beneficial anti-obesity and antidiabetic potentials of some dietary plant flavonoids along with their molecular actions, bioavailability and pharmacokinetics. In addition, the present understanding and management of obesity and diabetes are also focused.

Wogonin Alleviates Hyperglycemia Through Increased Glucose Entry into Cells Via AKT/GLUT4 Pathway

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Insulin resistance and type 2 Diabetes mellitus resulting in chronic hyperglycemia is a major health problem in the modern world. Many drugs have been tested to control hyperglycemia which is believed to be the main factor behind many of the diabetes-related late-term complications. Wogonin is a famous herbal medicine which has been shown to be effective in controlling diabetes and its complications. In our previous work, we showed that wogonin is beneficial in many ways in controlling diabetic cardiomyopathy. In this review, we mainly explained wogonin anti-hyperglycemic property through AKT/GLUT4 pathway. Here we briefly discussed that wogonin increases Glut4 trafficking to plasma membrane which allows increased entry of glucose and thus alleviates hyperglycemia.

Conclusion:

Wogonin can be used as an anti-diabetic and anti-hyperglycemic drug and works via AKT/GLUT4 pathway.

Flavonoids and Their Anti-Diabetic Effects: Cellular Mechanisms and Effects to Improve Blood Sugar Levels

Diabetes mellitus (DM) is a prevailing global health metabolic disorder, with an alarming incidence rate and a huge burden on health care providers. DM is characterized by the elevation of blood glucose due either to a defect in insulin synthesis, secretion, binding to receptor, or an increase of insulin resistance. The internal and external factors such as obesity, urbanizations, and genetic mutations could increase the risk of developing DM. Flavonoids are phenolic compounds existing as secondary metabolites in fruits and vegetables as well as fungi. Their structure consists of 15 carbon skeletons and two aromatic rings (A and B) connected by three carbon chains. Flavonoids are furtherly classified into 6 subclasses: flavonols, flavones, flavanones, isoflavones, flavanols, and anthocyanidins. Naturally occurring flavonoids possess anti-diabetic effects. As in vitro and animal model's studies demonstrate, they have the ability to prevent diabetes and its complications. The aim of this review is to summarize the current knowledge addressing the antidiabetic effects of dietary flavonoids and their underlying molecular mechanisms on selected pathways: Glucose transporter, hepatic enzymes, tyrosine kinase inhibitor, AMPK, PPAR, and NF-κB. Flavonoids improve the pathogenesis of diabetes and its complications through the regulation of glucose metabolism, hepatic enzymes activities, and a lipid profile. Most studies illustrate a positive role of specific dietary flavonoids on diabetes, but the mechanisms of action and the side effects need more clarification. Overall, more research is needed to provide a better understanding of the mechanisms of diabetes treatment using flavonoids.

Anti-Diabetic Effect of a Shihunine-Rich Extract of Dendrobium loddigesii on 3T3-L1 Cells and db/db Mice by Up-Regulating AMPK-GLUT4-PPARα

The stems of Dendrobium loddigesii, a Chinese herb, are often used to treat diabetes and its polar extract is rich in shihunine, a water-soluble Orchidaceae alkaloid, but little is known about the anti-diabetes effects and mechanism of shihunine. This study investigated the anti-diabetic effect of a shihunine-rich extract of D. loddigesii (DLS) based on 3T3-L1 cells and db/db mice. The underlying mechanisms were primarily explored using Western blot analysis and immunohistochemical staining. The 3T3-L1 cell experiments showed that DLS can reduce the intracellular accumulation of oil droplets as well as triglycerides (p < 0.001) and promote the 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2deoxyglucose (2-NBDG) uptake of 3T3-L1 cells (p < 0.001). The animal experiments confirmed that after 8 weeks of DLS treatment, the body weight, fasting blood sugar, and serum lipid levels of mice were significantly lowered, and the oral glucose tolerance test and serum insulin level were significantly improved compared to the no-treatment diabetes mellitus group. Further histomorphology observation led to the conclusion that the quantities of islet cells were significantly increased and the increase in adipose cell size was significantly suppressed. The immunohistochemical test of pancreatic tissue revealed that DLS inhibited the expression of cleaved cysteine aspartic acid-specific protease 3 (cleaved caspase-3). Western blot experiments showed that DLS had agonistic effects on adenosine monophosphate (AMP)-activated protein kinase phosphorylation (p-AMPK) and increased the expression levels of peroxisome proliferator-activated receptor α (PPARα) and glucose transporter 4 (GLUT4) in liver or adipose tissues. These data suggest that the shihunine-rich extract of D. loddigesii is an anti-diabetic fraction of D. loddigesii. Under our experimental condition, DLS at a dose of 50 mg/kg has good anti-diabetic efficacy.

Efficacy of traditional Chinese medication Tangminling pill in Chinese patients with type 2 diabetes

The morbidity of type 2 diabetes mellitus (T2DM) has been increasing rapidly worldwide. Tangminling pill, consisting of ten Chinese herbal medications, is usually prescribed for T2DM in mainland China. Whether treatment with Tangminling can improve clinical outcomes of T2DM patients was still debated. Four studies comparing Tangminling vs. placebo treatment in T2DM patients were included and 767 T2DM patients were enrolled in our analyses. Tangminling treatment exhibited better efficacy than placebo in reducing hemoglobin A1c (HbA1c) (1.11 vs. 0.32%; pooled weighted mean difference [WMD]: 0.80; 95% confidence interval [CI]: 0.65–0.96; P<0.001), fasting plasma glucose (0.82 vs. −0.40 mM; WMD: 1.10; 95% CI: 0.56–1.64; P<0.001), 2-h postprandial glucose (2-hr PG) (2.81 vs. 1.11 mM; WMD: 1.80; 95% CI: 1.72–1.88; P<0.001), homeostatic model assessment-β level (4.28 vs. 0.41; WMD: 0.44; 95% CI: 0.27–0.61; P<0.001), waist circumference (WC) (1.04 vs. 0.36 cm; WMD: 0.78; 95% CI: 0.37–1.19; P<0.001) and body weight index (0.37 vs. 0.11 kg/m²; WMD: 0.30; 95% CI: −0.00 to 0.61; P=0.05). Tangminling pill might reduce glucose level and body weight and improve β-cell function in T2DM patients. Our study highlights the important role of Tangminling pill in the management of T2DM.

Aryl hydrocarbon receptor agonist indigo protects against obesity-related insulin resistance through modulation of intestinal and metabolic tissue immunity

Background/objectives

Low-grade chronic inflammation in visceral adipose tissue and the intestines are important drivers of obesity associated insulin resistance. Bioactive compounds derived from plants are an important source of potential novel therapies for the treatment of chronic diseases. In search for new immune based treatments of obesity associated insulin resistance, we screened for tissue relevant anti-inflammatory properties in 20 plant-based extracts.

Methods

We screened 20 plant-based extracts to assess for preferential production of IL-10 compared to TNFα, specifically targetting metabolic tissues, including the visceral adipose tissue. We assessed the therapeutic potential of the strongest anti-inflammatory compound, indigo, in the C57BL/6J diet-induced obesity mouse model with supplementation for up to 16 weeks by measuring changes in body weight, glucose and insulin tolerance, and gut barrier function. We also utilized flow cytometry, quantitative PCR, enzyme-linked immunosorbent assay (ELISA), and histology to measure changes to immune cells populations and cytokine profiles in the intestine, visceral adipose tissue (VAT), and liver. 16SrRNA sequencing was performed to examine gut microbial differences induced by indigo supplementation.

Results

We identifed indigo, an aryl hydrocarbon receptor (AhR) ligand agonist, as a potent inducer of IL-10 and IL-22, which protects against high-fat diet (HFD)-induced insulin resistance and fatty liver disease in the diet-induced obesity model. Therapeutic actions were mechanistically linked to decreased inflammatory immune cell tone in the intestine, VAT and liver. Specifically, indigo increased Lactobacillus bacteria and elicited IL-22 production in the gut, which improved intestinal barrier permeability and reduced endotoxemia. These changes were associated with increased IL-10 production by immune cells residing in liver and VAT.

Conclusions

Indigo is a naturally occurring AhR ligand with anti-inflammatory properties that effectively protects against HFD-induced glucose dysregulation. Compounds derived from indigo or those with similar properties could represent novel therapies for diseases associated with obesity-related metabolic tissue inflammation.

Scutellaria baicalensis Alleviates Insulin Resistance in Diet-Induced Obese Mice by Modulating Inflammation

Insulin resistance is strongly associated with the metabolic syndrome, and chronic inflammation is known to be a major mechanism of insulin resistance and is a therapeutic target. This study was designed to evaluate the effect of Scutellaria baicalensis (SB) in high-fat diet (HFD)-induced insulin-resistant mice and to investigate its mechanism based on inflammatory responses. Mice were fed a HFD to induce insulin resistance and then administered SB for nine weeks. Body weight, glucose, lipid, insulin, epididymal fat pad and liver weights, and histologic characteristics were evaluated to determine the effect on insulin resistance. In order to evaluate the effects on the inflammatory process, we analyzed the proportions of macrophages in liver and epididymal fat and measured inflammatory gene expression. Fasting and postprandial glucose, fasting insulin, HOMA-IR, triglycerides, and low density lipoprotein cholesterol levels were significantly decreased by SB administration. The epididymal fat and liver showed significant weight decreases and histological improvements. Total adipose tissue macrophages (ATMs) decreased (27.71 ± 3.47% vs. 45.26 ± 7.26%, p < 0.05), M2 ATMs increased (47.02 ± 6.63% vs. 24.28 ± 8.00%, p < 0.05), and CD11b⁺ Kupffer cells decreased. The expression levels of tumor necrosis factor alpha and F4/80 in the liver were significantly decreased (12.03 ± 1.47% vs. 25.88 ± 4.57%, p < 0.05) compared to HFD group. These results suggest that SB improved insulin resistance through inhibition of macrophage-mediated inflammation.

Synergistic Effect of Bupleuri Radix and Scutellariae Radix on Adipogenesis and AMP-Activated Protein Kinase: A Network Pharmacological Approach

Obesity has become a major health threat in developed countries. However, current medications for obesity are limited because of their adverse effects. Interest in natural products for the treatment of obesity is thus rapidly growing. Korean medicine is characterized by the wide use of herbal formulas. However, the combination rule of herbal formulas in Korean medicine lacks experimental evidence. According to Shennong's Classic of Materia Medica, the earliest book of herbal medicine, Bupleuri Radix (BR) and Scutellariae Radix (SR) possess the Sangsoo relationship, which means they have synergistic features when used together. Therefore these two are frequently used together in prescriptions such as Sosiho-Tang. In this study, we used the network pharmacological method to predict the interaction between these two herbs and then investigated the effects of BR, SR, and their combination on obesity in 3T3-L1 adipocytes. BR, SR, and BR-SR mixture significantly decreased lipid accumulation and the expressions of two major adipogenic factors, peroxisome proliferator-activated receptor-gamma (PPARγ) and CCAAT/enhancer-binding protein-alpha (C/EBPα), and their downstream genes, Adipoq, aP2, and Lipin1 in 3T3-L1 cells. In addition, the BR-SR mixture had synergistic effects compared with BR or SR on inhibition of adipogenic-gene expressions. BR and SR also inhibited the protein expressions of PPARγ and C/EBPα. Furthermore, the two extracts successfully activated AMP-activated protein kinase alpha (AMPK α), the key regulator of energy metabolism. When compared to those of BR or SR, the BR-SR mixture showed higher inhibition rates of PPARγ and C/EBPα, along with higher activation rate of AMPK. These results indicate a new potential antiobese pharmacotherapy and also provide scientific evidence supporting the usage of herbal combinations instead of mixtures in Korean medicine.

Immune and Metabolic Regulation Mechanism of Dangguiliuhuang Decoction against Insulin Resistance and Hepatic Steatosis

Dangguiliuhuang decoction (DGLHD) is a traditional Chinese medicine (TCM) formula, which mainly consists of angelica, radix rehmanniae, radix rehmanniae praeparata, scutellaria baicalensis, coptis chinensis, astragalus membranaceus, and golden cypress, and used for the treatment of diabetes and some autoimmune diseases. In this study, we explored the potential mechanism of DGLHD against insulin resistance and fatty liver in vivo and in vitro. Our data revealed that DGLHD normalized glucose and insulin level, increased the expression of adiponectin, diminished fat accumulation and lipogenesis, and promoted glucose uptake. Metabolomic analysis also demonstrated that DGLHD decreased isoleucine, adenosine, and cholesterol, increased glutamine levels in liver and visceral adipose tissue (VAT) of ob/ob mice. Importantly, DGLHD promoted the shift of pro-inflammatory to anti-inflammatory cytokines, suppressed T lymphocytes proliferation, and enhanced regulatory T cells (Tregs) differentiation. DGLHD also inhibited dendritic cells (DCs) maturation, attenuated DCs-stimulated T cells proliferation and secretion of IL-12p70 cytokine from DCs, and promoted the interaction of DCs with Tregs. Further studies indicated that the changed PI3K/Akt signaling pathway and elevated PPAR-γ expression were not only observed with the ameliorated glucose and lipid metabolism in adipocytes and hepatocytes, but also exhibited in DCs and T cells by DGLHD. Collectively, our results suggest that DGLHD exerts anti-insulin resistant and antisteatotic effects by improving abnormal immune and metabolic homeostasis. And DGLHD may be a novel approach to the treatment of obesity-related insulin resistance and hepatic steatosis.

Wogonin mitigates nonalcoholic fatty liver disease via enhancing PPARα/AdipoR2, in vivo and in vitro

Wogonin has been reported to attenuate hyperglycemia in diabetic mice via anti-adipogenic effect on adipocytes. The potential therapeutic role of wogonin in nonalcoholic fatty liver disease (NAFLD) remains obscure. The aim of the present study was to explore the protective effect of wogonin on NAFLD mice and cultured NCTC 1469 cells exposed to palmitate. Wogonin supplementation significantly improved metabolic parameters in NAFLD mice, including body weight, blood glucose, insulin resistance, adiponectin, blood lipids, aminotransferases and hepatic histopathology. Further research in liver tissues from NAFLD mice and NCTC 1469 cells stressed by lipotoxicity showed wogonin treatment reduced inflammatory response by lowering interleukin-6 (IL-6) and tumor necrosis factor α (TNFα), alleviated oxidative stress by preventing the accumulation of oxidative product malondialdehyde (MDA) and strengthening the anti-oxidative capacity of glutathione (GSH), Superoxide Dismutase (SOD) and Glutathione Peroxidase (GPX). In addition, wogonin repaired the lipotoxicity-induced decline of peroxisome proliferator- activated receptor α (PPARα) and adiponectin receptor 2 (AdipoR2) in hepatocytes, in vivo and in vitro. Knock-down of PPARα abolished the protective effect of wogonin on NCTC 1469 cells, including the up-regulation of AdipoR2. Taken together, the current study demonstrated wogonin might be a potential therapeutic agent for NAFLD via up-regulation of hepatic PPARα/AdipoR2.

Wogonin enhances intracellular adiponectin levels and suppresses adiponectin secretion in 3T3-L1 adipocytes

As an insulin sensitizer and modulator of inflammatory responses, adiponectin has become a therapeutic target for insulin resistance, diabetes, and diabetes-related complications. Wogonin possesses anti-oxidative, anti-inflammatory, and anti-diabetic abilities. However, its effect on generation and secretion of adiponectin is ill-defined in adipocytes. Here, we demonstrated that wogonin administration augmented intracellular adiponectin levels and attenuated adiponectin release in a dose- and time-dependent manner in mature 3T3-L1 adipocytes, along with a suppression of PKCδ phosphorylation. Wogonin treatment also prevented PKCδ overexpression-induced reduction of intracellular adiponectin levels and enhancement of adiponectin release. In addition, wogonin supplementation dramatically increased AMPK phosphorylation and SirT1 expression. Inhibition of either AMPK or SirT1 mitigated wogonin action on adiponectin production and release. Furthermore, inhibition of AMPK by its specific inhibitor markedly reduced wogonin-enhanced mRNA and protein expressions of SirT1. These results suggested that wogonin regulated expression and secretion of adiponectin via PKCδ/AMPK/SirT1 signaling pathway in mature 3T3-L1 adipocytes.

Hypolipidemic effects of HVC1 in a high cholesterol diet‑induced rat model of hyperlipidemia

HVC1, a novel formation containing four herbs, was developed and its hypolipidemic effects in rats with high cholesterol diet (HCD)-induced hyperlipidemia were investigated. The rats were given a HCD for 8 weeks. The HVC1-treated groups were orally administered HVC1 at doses of 10, 50 or 250 mg/kg, respectively, and the simvastatin group was treated at a dose of 10 mg/kg. The normal diet and HCD control groups were administered with physiological saline. Oral administration of HVC1 (10, 50 or 250 mg/kg) significantly reduced the body weight of rats with hyperlipidemia and regulated the total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels in the serum. In addition, tissue analysis revealed that lipid accumulation in the liver and aorta was reduced by HVC1 administration. Furthermore, HVC1 significantly reduced the mRNA expression of peroxisome proliferator-activated receptor-γ, 3-hydroxy-3-methylglutaryl-CoA reductase and low-density lipoprotein receptor, as well as the protein level of 5′ adenosine monophosphate-activated protein kinase in the liver. The results clearly demonstrate that HVC1 has a potent hypolipidemic effect, and suggest that HVC1 should be evaluated as a potential treatment for hyperlipidemia.

The Effects of Chunghyul-Dan (A Korean Medicine Herbal Complex) on Cardiovascular and Cerebrovascular Diseases: A Narrative Review

Chunghyul-dan (CHD) is a herbal complex containing 80% ethanol extract and is composed of Scutellariae Radix, Coptidis Rhizoma, Phellodendri Cortex, Gardeniae Fructus, and Rhei Rhizoma. We have published several experimental and clinical research articles on CHD. It has shown antilipidemic, antihypertensive, antiatherosclerotic, and inhibitory effects on ischemic stroke recurrence with clinical safety in the previous studies. The antilipidemic effect of CHD results from 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase and pancreatic lipase-inhibitory activity. The antihypertensive effect likely results from the inhibitory effect on endogenous catecholamine(s) release and harmonization of all components showing the antihypertensive effects. Furthermore, anti-inflammatory and antioxidant effects on endothelial cells are implicated to dictate the antiatherosclerotic effects of CHD. It also showed neuroprotective effects on cerebrovascular and parkinsonian models. These effects of CHD could be helpful for the prevention of the recurrence of ischemic stroke. Therefore, we suggest that CHD could be a promising medication for treating and preventing cerebrovascular and cardiovascular diseases. However, to validate and better understand these findings, well-designed clinical studies are required.

Wogonin attenuates diabetic cardiomyopathy through its anti-inflammatory and anti-oxidative properties

Among diabetic cardiovascular complications cardiomyopathy is major event which if not well controlled culminates in cardiac failure. Wogonin from the root of Scutellaria baicalensis Georgi has shown specific anti-diabetes bioactivity. However, its effect on diabetic complications remains unclear. The main purpose of this study is to investigate the potential effects of wogonin on diabetic cardiomyopathy and to figure out its underlying mechanism. We found that wogonin administration suppressed hyperglycemia, improved cardiac function, and mitigated cardiac fibrosis in STZ-induced diabetic mice. Wogonin supplementation also attenuated diabetic-induced cardiomyocyte apoptosis and necrosis. In addition, wogonin treatment exhibited the properties of anti-oxidative stress and anti-inflammation in STZ diabetic mice, evidenced by improved activities of anti-oxidases including SOD1/2 and CAT, decreased ROS and MDA production, suppressed expression of inflammation factors such as IL-1β, IL-6, TNFα, and PAI-1, and inhibited NF-κB signaling. These results suggested that wogonin potentially mitigate hyperglycemia-related cardiomyocyte impairment through inhibiting inflammation and oxidative stress.

Molecular Mechanisms of the Anti-Obesity and Anti-Diabetic Properties of Flavonoids

Obesity and diabetes are the most prevailing health concerns worldwide and their incidence is increasing at a high rate, resulting in enormous social costs. Obesity is a complex disease commonly accompanied by insulin resistance and increases in oxidative stress and inflammatory marker expression, leading to augmented fat mass in the body. Diabetes mellitus (DM) is a metabolic disorder characterized by the destruction of pancreatic β cells or diminished insulin secretion and action insulin. Obesity causes the development of metabolic disorders such as DM, hypertension, cardiovascular diseases, and inflammation-based pathologies. Flavonoids are the secondary metabolites of plants and have 15-carbon skeleton structures containing two phenyl rings and a heterocyclic ring. More than 5000 naturally occurring flavonoids have been reported from various plants and have been found to possess many beneficial effects with advantages over chemical treatments. A number of studies have demonstrated the potential health benefits of natural flavonoids in treating obesity and DM, and show increased bioavailability and action on multiple molecular targets. This review summarizes the current progress in our understanding of the anti-obesity and anti-diabetic potential of natural flavonoids and their molecular mechanisms for preventing and/or treating obesity and diabetes.

Antidiabetic properties of dietary flavonoids: a cellular mechanism review

Background

Natural food products have been used for combating human diseases for thousands of years. Naturally occurring flavonoids including flavones, flavonols, flavanones, flavonols, isoflavones and anthocyanidins have been proposed as effective supplements for management and prevention of diabetes and its long-term complications based on in vitro and animal models.

Aim

To summarize the roles of dietary flavonoids in diabetes management and their molecular mechanisms.

Findings

Tremendous studies have found that flavonoids originated from foods could improve glucose metabolism, lipid profile, regulating the hormones and enzymes in human body, further protecting human being from diseases like obesity, diabetes and their complications.

Conclusion

In the current review, we summarize recent progress in understanding the biological action, mechanism and therapeutic potential of the dietary flavonoids and its subsequent clinical outcomes in the field of drug discovery in management of diabetes mellitus.

Wogonin suppresses osteopontin expression in adipocytes by activating PPARα

AIM

Wogonin (5,7-dihydroxy-8-methoxyflavone), a major bioactive compound of the flavonoid family, is commonly extracted from the traditional Chinese medicine Scutellaria baicalensis and possesses antioxidant and anti-inflammatory activities and is assumed to have anti-diabetes function. Indeed, a current study has shown that it can possibly treat metabolic disorders such as those found in db/db mice. However, the underlying molecular mechanism remains largely unclear. The aim of this study was to investigate the impact of wogonin on osteopontin (OPN) expression in adipose tissue from type 1 diabetic mice and in 3T3-L1 adipocytes.

METHODS

Type 1 diabetes was induced by streptozotocin (STZ) injection. 3T3-L1 preadipocytes were converted to 3T3-L1 adipocytes through treatment with insulin, dexamethasone, and 3-isobutyl-1-methylxanthine (IBMX). Western blot analysis and RT-PCR were performed to detect protein expression and mRNA levels, respectively.

RESULTS

Wogonin treatment suppressed the increase in serum OPN levels and reduced OPN expression in adipose tissue from STZ-induced type 1 diabetic mice. Administration of wogonin enhanced PPARα expression and activity. Silencing of PPARα diminished the inhibitory effects of wogonin on OPN expression in 3T3-L1 adipocytes. Furthermore, the levels of c-Fos and phosphorylated c-Jun were reduced in wogonin-treated adipose tissue and 3T3-L1 adipocytes. In addition, wogonin treatment dramatically mitigated p38 MAPK phosphorylation. Pharmacological inhibition of p38 MAPK by its specific inhibitor SB203580 increased PPARα activity and decreased OPN expression.

CONCLUSION

Our results suggest that wogonin downregulated OPN expression in adipocytes through the inhibition of p38 MAPK and the sequential activation of the PPARα pathway. Given the adverse effects of high OPN levels on metabolism, our results provide evidence for the potential administration of wogonin as a treatment for diabetes.

The effect of quercetin and kaempferol aglycones and glucuronides on peroxisome proliferator-activated receptor-gamma (PPAR-γ)

Quercetin and kaempferol increase PPAR-γ mediated gene expression without acting as agonistic ligands; glucuronidation reduces their activity in cell-based assays.

Natural Flavonoids as Potential Herbal Medication for the Treatment of Diabetes Mellitus and its Complications

Diabetes mellitus, together with its various complications, is becoming a serious threat to human health. Natural products are secondary metabolites widely distributed in plants, having a broad range of biological activities. The development of antidiabetic medication from natural products, especially those originating from plants with a traceable folk-usage history in treating diabetes, is receiving more attention. Many studies highlighted not only the benefits of natural flavonoids with hypoglycemic effects, but also their importance in the management of diabetic complications. This review describes selected natural flavonoids that have been validated for their hypoglycemic properties, together with their mechanisms of action. Also discussed are their activities in the treatment of diabetic complications demonstrated via laboratory diabetic animal models, in vitro and clinical trials using human subjects. Published papers from 2000 to date on flavonoids and diabetes were covered through accessing Web of Science and multiple databases for biomedical sciences. The major potential benefits of natural flavonoids discussed in this review clearly suggest that these substances are lead compounds with sufficient structural diversity of great importance in the antidiabetic drug developing process.