Anti-diabetic effect of mulberry leaf polysaccharide by inhibiting pancreatic islet cell apoptosis and ameliorating insulin secretory capacity in diabetic rats

The regulatory mechanism of natural polysaccharides in type 2 diabetes mellitus treatment

Diabetes is a complex, multifactorial disease that is caused by a pathological combination of insulin resistance and pancreatic islet dysfunction. Polysaccharides are extensively dispersed in nature and have a very complicated structure with various biological properties. Natural polysaccharides have potentially extraordinary beneficial health effects on managing metabolic diseases such as diabetes, obesity and cardiovascular disease. Thus, a systematic review of the latest research into and possible regulatory mechanisms of natural polysaccharides for type 2 diabetes mellitus treatment is of great significance for a better understanding of their pharmaceutical value. We discuss the regulatory mechanisms of natural polysaccharides for the treatment of diabetes, and especially their role in reshaping dysfunctional gut microbiota. Natural polysaccharides could be developed as new and safe antidiabetic drugs, and detailed mechanistic studies could further clarify the molecular targets of polysaccharides in the treatment of diabetes.

Developments in the study of Chinese herbal medicine's assessment index and action mechanism for diabetes mellitus

In traditional Chinese medicine (TCM), based on various pathogenic symptoms and the 'golden chamber' medical text, Huangdi Neijing, diabetes mellitus falls under the category 'collateral disease'. TCM, with its wealth of experience, has been treating diabetes for over two millennia. Different antidiabetic Chinese herbal medicines reduce blood sugar, with their effective ingredients exerting unique advantages. As well as a glucose lowering effect, TCM also regulates bodily functions to prevent diabetes associated complications, with reduced side effects compared to western synthetic drugs. Chinese herbal medicine is usually composed of polysaccharides, saponins, alkaloids, flavonoids, and terpenoids. These active ingredients reduce blood sugar via various mechanism of actions that include boosting endogenous insulin secretion, enhancing insulin sensitivity and adjusting key enzyme activity and scavenging free radicals. These actions regulate glycolipid metabolism in the body, eventually achieving the goal of normalizing blood glucose. Using different animal models, a number of molecular markers are available for the detection of diabetes induction and the molecular pathology of the disease is becoming clearer. Nonetheless, there is a dearth of scientific data about the pharmacology, dose-effect relationship, and structure-activity relationship of TCM and its constituents. Further research into the efficacy, toxicity and mode of action of TCM, using different metabolic and molecular markers, is key to developing novel TCM antidiabetic formulations.

Anti-obesity and anti-diabetic bioactive peptides: A comprehensive review of their sources, properties, and techno-functional challenges

The scourge of obesity arising from obesogens and poor dieting still ravages our planet as half of the global population may be overweight and obese by 2035. This metabolic disorder is intertwined with type 2 diabetes (T2D), both of which warrant alternative therapeutic options other than clinically approved drugs like orlistat with their tendency of abuse and side effects. In this review, we comprehensively describe the global obesity problem and its connection to T2D. Obesity, overconsumption of fats, the mechanism of fat digestion, obesogenic gut microbiota, inhibition of fat digestion, and natural anti-obesity compounds are discussed. Similar discussions are made for diabetes with regard to glucose regulation, the diabetic gut microbiota, and insulinotropic compounds. The sources and production of anti-obesity bioactive peptides (AOBPs) and anti-diabetic bioactive peptides (ADBPs) are also described while explaining their structure-function relationships, gastrointestinal behaviors, and action mechanisms. Finally, the techno-functional applications of AOBPs and ADBPs are highlighted.

Structure-function relationship and biological activity of polysaccharides from mulberry leaves: A review

Mulberry (Latin name "Morus alba L.") is a perennial deciduous tree in the family of Moraceae, widely distributed around the world. In China, mulberry is mainly distributed in the south and the Yangtze River basin. Its leaves can be harvested 3-6 times a year, which has a great resource advantage. Mulberry leaves are regarded as the homology of medicine and food traditional Chinese medicine (TCM). Polysaccharides, as its main active ingredients, have various effects, such as antioxidant, hypoglycemic, hepatoprotective, and immunomodulatory. This review summarizes the research progress in the extraction, purification, structural characterization, and structure-function relationship of polysaccharides from mulberry leaves in the last decade, hoping to provide a reference for the subsequent development and market application of polysaccharides from mulberry leaves.

Extraction, purification, structural modification, activities and application of polysaccharides from different parts of mulberry

The mulberry plant is a member of the Moraceae family and belongs to the Morus genus. Its entire body is a treasure, with mulberries, mulberry leaves, and mulberry branches all suitable for medicinal use. The main active ingredient in mulberries is mulberry polysaccharide. Studies have shown that polysaccharides from different parts of mulberry exhibit antioxidant, antidiabetic, antibacterial, anti-inflammatory, and blood pressure-lowering properties. There are more studies on the biological activities, extraction methods, and structural characterization of polysaccharides from different parts of mulberry. However, the structural characterization of mulberry polysaccharides is mostly confined to the types and proportions of monosaccharides and the molecular weights of polysaccharides, and there are fewer systematic studies on polysaccharides from different parts of mulberry. In order to better understand the bioactive structure of mulberry polysaccharides, this article discusses the recent research progress in the extraction, separation, purification, bioactivity, structural modification, and application of polysaccharides from different parts of mulberry (mulberry leaves, mulberry fruits, and mulberry branches). It also delves into the pharmacological mechanisms of action of mulberry polysaccharides to provide a theoretical basis for further research on mulberry polysaccharides with a view to their deeper application in the fields of feed and nutraceuticals.

Mulberry leaf polysaccharide improves cyclophosphamide-induced growth inhibition and intestinal damage in chicks by modulating intestinal flora, enhancing immune regulation and antioxidant capacity

Polysaccharides are generally considered to have immune enhancing functions, and mulberry leaf polysaccharide is the main active substance in mulberry leaves, while there are few studies on whether mulberry leaf polysaccharide (MLP) has an effect on immunosuppression and intestinal damage caused by cyclophosphamide (CTX), we investigated whether MLP has an ameliorative effect on intestinal damage caused by CTX. A total of 210 1-day-old Mahuang cocks were selected for this experiment. Were equally divided into six groups and used to evaluate the immune effect of MLP. Our results showed that MLP significantly enhanced the growth performance of chicks and significantly elevated the secretion of cytokines (IL-1β, IL-10, IL-6, TNF-α, and IFN-γ), immunoglobulins and antioxidant enzymes in the serum of immunosuppressed chicks. It attenuated jejunal damage and elevated the expression of jejunal tight junction proteins Claudin1, Zo-1 and MUC2, which protected intestinal health. MLP activated TLR4-MyD88-NF-κB pathway and enhanced the expression of TLR4, MyD88 and NF-κB, which served to protect the intestine. 16S rDNA gene high-throughput sequencing showed that MLP increased species richness, restored CTX-induced gut microbiome imbalance, and enhanced the abundance of probiotic bacteria in the gut. MLP improves cyclophosphamide-induced growth inhibition and intestinal damage in chicks by modulating intestinal flora and enhancing immune regulation and antioxidant capacity. In conclusion, this study provides a scientific basis for MLP as an immune enhancer to regulate chick intestinal flora and protect chick intestinal mucosal damage.

Glucose-lowering effect of Reducose® enriched with 1-deoxynojirimycin and l-leucine: Studies on insulin secretion in INS-1 cells and reduction of blood glucose in diabetic rats

The extract of mulberry leaf and its active ingredients have already been reported to have anti-diabetic effects; however, further studies are required to obtain better quality extracts and higher yields of active ingredients. Reducose® is a commercially available aqueous extract of mulberry leaves with a high content of active ingredients. In this study, the biological activities of Reducose®, 1-deoxynojirimycin, and l-leucine were evaluated using a glucose-stimulated insulin secretion (GSIS) assay. The GSIS assay results were expressed as the glucose-stimulated index (GSI). Considering the pharmacological safety in pancreatic β-cells, the appropriate non-toxic concentrations were selected by screening for cytotoxicity of Reducose®, 1-deoxynojirimycin, and l-leucine before the GSIS assay. The effect of Reducose®, 1-deoxynojirimycin, and l-leucine on glucose-stimulated insulin secretion in INS-1 cells was compared. Reducose®, 1-deoxynojirimycin, and l-leucine increased the GSI values more effectively than gliclazide (positive control). This was associated with an increase in protein expression, such as peroxisome proliferator-activated receptor-γ, insulin receptor substrate-2, activated pancreatic and duodenal homeobox-1, which are related to the regulation of pancreatic β-cell function and survival. In order to elucidate the effect of Reducose® in anti-diabetic effects, blood glucose levels, insulin levels, and liver and lipid concentrations were investigated in a Sprague-Dawley rat model of high-fat diet/streptozotocin-induced diabetes. We observed that administration of Reducose® can decrease fasting blood glucose levels and reduce the production of AST, ALT, TG, and TC to a similar extent as metformin (positive control). These results suggested that Reducose® play a role in promoting GSIS but not enough to show that the content and proportion of 1-deoxynojirimycin and l-leucine play an important role in the GSIS activity of Reducose®.

Extraction, structural characterization and biological activities of polysaccharides from mulberry leaves: A review

In recent years, plant polysaccharides have garnered attention for their impressive biological activity. Mulberry leaves have a long history of medicinal and edible use in China, polysaccharide is one of the main active components of mulberry leaves, mainly consist of xylose, arabinose, fructose, galactose, glucose and mannose, etc. The extraction methods of mulberry leaves polysaccharides (MLPs) mainly include hot water extraction, microwave-assisted extraction, ultrasonic extraction, enzyme-assisted extraction, and co-extraction. The separation and purification of MLPs involve core steps such as decolorization, protein removal, and chromatographic separation. In terms of pharmacological effects, MLPs exhibit excellent activity in reducing blood glucose, anti-oxidation, immune regulation, anti-tumor, antibacterial, anti-coagulation, and regulation of gut microbiota. Currently, there is a considerable amount of research on MLPs, however, there is a lack of systematic summarization. This review summarizes the research progress on the extraction, structural characterization, and pharmacological activities of MLPs, and points out existing shortcomings and suggests reference solutions, aiming to provide a basis for further research and development of MLPs.

Mulberry Leaf Polysaccharides Attenuate Oxidative Stress Injury in Peripheral Blood Leukocytes by Regulating Endoplasmic Reticulum Stress

The present study assessed the protective effects and underlying mechanisms of mulberry leaf polysaccharides (MLPs) against hydrogen peroxide (H2O2)-induced oxidative stress injury in the peripheral blood leukocytes (PBLs) of Megalobrama amblycephala. Five treatment groups were established in vitro: the NC group (PBLs incubated in an RPMI-1640 complete medium for 4 h), the HP group (PBLs incubated in an RPMI-1640 complete medium for 3 h, and then stimulated with 100 μM of H2O2 for 1 h), and the 50/100/200-MLP pre-treatment groups (PBLs were pre-treated with MLPs (50, 100, and 200 μg/mL) for 3 h, and then stimulated with 100 μM of H2O2 for 1 h). The results showed that MLP pre-treatment dose-dependently enhanced PBLs' antioxidant capacities. The 200 μg/mL MLP pre-treatment effectively protected the antioxidant system of PBLs from H2O2-induced oxidative damage by reducing the malondialdehyde content and lactic dehydrogenase cytotoxicity, and increasing catalase and superoxide dismutase activities (p < 0.05). The over-production of reactive oxygen species, depletion of nicotinamide adenine dinucleotide phosphate, and collapse of the mitochondrial membrane potential were significantly inhibited in the 200-MLP pre-treatment group (p < 0.05). The expressions of endoplasmic reticulum stress-related genes (forkhead box O1α (foxO1α), binding immunoglobulin protein (bip), activating transcription factor 6 (atf6), and C/EBP-homologous protein (chop)), Ca2+ transport-related genes (voltage-dependent anion-selective channel 1 (vdac1), mitofusin 2 (mfn2), and mitochondrial Ca2+ uniporter (mcu)), and interleukin 6 (il-6) and bcl2-associated x (bax) were significantly lower in the 200-MLP pre-treatment group than in the HP group (p < 0.05), which rebounded to normal levels in the NC group (p > 0.05). These results indicated that MLP pre-treatment attenuated H2O2-induced PBL oxidative damage in the M. amblycephala by inhibiting endoplasmic reticulum stress and maintaining mitochondrial function. These findings also support the possibility that MLPs can be exploited as a natural dietary supplement for M. amblycephala, as they protect against oxidative damage.

Carboxymethyl cellulose based films enriched with polysaccharides from mulberry leaves (Morus alba L.) as new biodegradable packaging material

The objective of this study was to determine the properties of a new active packaging film developed by the addition of mulberry leaves polysaccharides (MLP) into carboxymethyl cellulose (CMC). Biodegradable CMC-MLP films were fabricated by casting method with various concentrations of MLP (1, 5 and 10 % w/w). The addition of MLP into the CMC matrix resulted increased thickness (0.126 to 0.163 mm) and roughness of the films. Also, the decline in moisture content from 27.91 to 14.12 %, water vapor permeability from 8.95 to 5.21 × 10-10 g-1 s-1 Pa-1, and a swelling degree from 59.11 to 37.45 % were observed. With the increasing concentration of MLP, the mechanical properties of the films were improved and higher dispersion of UV light were noted. Fourier transform - infrared spectroscopy (FT-IR) and X-ray diffraction revealed good inter-molecular interaction between CMC matrix and MLP. The prepared films showed excellent thermal stability, antioxidant and antibacterial properties as well as susceptibility to biodegradation in the soil environment. Moreover, it was proved that the films have ability to retard oil oxidation. Overall, it was concluded that CMC-MLP films constitute a promising biomaterial that may be applied as active food packaging.

The Mechanism of Mori Folium and Eucommiae Cortex against Cyclophosphamide-Induced Immunosuppression Integrating Network Pharmacology, Molecular Docking, Molecular Dynamics Simulations, and Experimental Validation

It has been reported that Mori Folium (MF) and Eucommiae Cortex (EC) exhibit pharmacological effects in the treatment of immunosuppression. However, the mechanism of MF and EC against immunosuppression remains unclear. This study aims to explore the mechanism of action of MF and EC for the treatment of immunosuppression through network pharmacology, molecular docking, molecular dynamics simulations and animal experiments. As a result, 11 critical components, 9 hub targets, and related signaling pathways in the treatment of immunosuppression were obtained based on network pharmacology. The molecular docking suggested that 11 critical components exhibited great binding affinity to 9 hub targets of immunosuppression. The molecular dynamics simulations results showed that (-)-tabernemontanine-AR, beta-sitosterol-AR and Dehydrodieugenol-HSP90AA1 complexes are stably bound. Additionally, in the animal experiments, the treated group results compared to the control group suggest that MF and EC have a significant effect on the treatment of immunosuppression. Therefore, MF and EC treatment for immunosuppression may take effects in a multi-component, multi-target, and multi-pathway manner. The results herein may provide novel insights into the treatment of immunosuppression in humans.

Identifying potential therapeutic targets of mulberry leaf extract for the treatment of type 2 diabetes: a TMT-based quantitative proteomic analysis

BACKGROUND

Mulberry (Morus alba L.) leaf, as a medicinal and food homologous traditional Chinese medicine, has a clear therapeutic effect on type 2 diabetes mellitus (T2DM), yet its underlying mechanisms have not been totally clarified. The study aimed to explore the mechanism of mulberry leaf in the treatment of T2DM through tandem mass tag (TMT)-based quantitative proteomics analysis of skeletal muscle.

METHODS

The anti-diabetic activity of mulberry leaf extract (MLE) was evaluated by using streptozotocin-induced diabetic rats at a dose of 4.0 g crude drug /kg p.o. daily for 8 weeks. Fasting blood glucose, body weight, food and water intake were monitored at specific intervals, and oral glucose tolerance test and insulin tolerance test were conducted at the 7th and 8th week respectively. At the end of the experiment, levels of glycated hemoglobin A1c, insulin, free fat acid, leptin, adiponectin, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were assessed and the pathological changes of rat skeletal muscle were observed by HE staining. TMT-based quantitative proteomic analysis of skeletal muscle and bioinformatics analysis were performed and differentially expressed proteins (DEPs) were validated by western blot. The interactions between the components of MLE and DEPs were further assessed using molecular docking.

RESULTS

After 8 weeks of MLE intervention, the clinical indications of T2DM such as body weight, food and water intake of rats were improved to a certain extent, while insulin sensitivity was increased and glycemic control was improved. Serum lipid profiles were significantly reduced, and the skeletal muscle fiber gap and atrophy were alleviated. Proteomic analysis of skeletal muscle showed that MLE treatment reversed 19 DEPs in T2DM rats, regulated cholesterol metabolism, fat digestion and absorption, vitamin digestion and absorption and ferroptosis signaling pathways. Key differential proteins Apolipoprotein A-1 (ApoA1) and ApoA4 were successfully validated by western blot and exhibited strong binding activity to the MLE's ingredients.

CONCLUSIONS

This study first provided skeletal muscle proteomic changes in T2DM rats before and after MLE treatment, which may help us understand the molecular mechanisms, and provide a foundation for developing potential therapeutic targets of anti-T2DM of MLE.

Effects and Mechanistic Role of Mulberry Leaves in Treating Diabetes and its Complications

Diabetes mellitus (DM) has become a surge burden worldwide owing to its high prevalence and range of associated complications such as coronary artery disease, blindness, stroke, and renal failure. Accordingly, the treatment and management of DM have become a research hotspot. Mulberry leaves (Morus alba L.) have been used in Traditional Chinese Medicine for a long time, with the first record of its use published in Shennong Bencao Jing (Shennong's Classic of Materia Medica). Mulberry leaves (MLs) are considered highly valuable medicinal food homologs that contain polysaccharides, flavonoids, alkaloids, and other bioactive substances. Modern pharmacological studies have shown that MLs have multiple bioactive effects, including hypolipidemic, hypoglycemic, antioxidation, and anti-inflammatory properties, with the ability to protect islet [Formula: see text]-cells, alleviate insulin resistance, and regulate intestinal flora. However, the pharmacological mechanisms of MLs in DM have not been fully elucidated. In this review, we summarize the botanical characterization, traditional use, chemical constituents, pharmacokinetics, and toxicology of MLs, and highlight the mechanisms involved in treating DM and its complications. This review can provide a valuable reference for the further development and utilization of MLs in the prevention and treatment of DM.

Current progress in the hypoglycemic mechanisms of natural polysaccharides

Unhealthy dietary pattern-induced type 2 diabetes mellitus poses a great threat to human health all over the world. Accumulating evidence has revealed that the pathophysiology of type 2 diabetes mellitus is closely associated with the dysregulation of glucose metabolism and energy metabolism, serious oxidative stress, prolonged endoplasmic reticulum stress, metabolic inflammation and intestinal microbial dysbiosis. Most important of all, insulin resistance and insulin deficiency are two key factors inducing type 2 diabetes mellitus. Nowadays, natural polysaccharides have gained increasing attention owing to their numerous health-promoting functions, such as hypoglycemic, energy-regulating, antioxidant, anti-inflammatory and prebiotic activities. Therefore, natural polysaccharides have been used to alleviate diet-induced type 2 diabetes mellitus. Specifically, this review comprehensively summarizes the underlying hypoglycemic mechanisms of natural polysaccharides and provides a theoretical basis for the development of functional foods. For the first time, this review elucidates hypoglycemic mechanisms of natural polysaccharides from the perspectives of their regulatory effects on glucose metabolism, insulin resistance and mitochondrial dysfunction.

Evaluation of mulberry leaves’ hypoglycemic properties and hypoglycemic mechanisms

The effectiveness of herbal medicine in treating diabetes has grown in recent years, but the precise mechanism by which it does so is still unclear to both medical professionals and diabetics. In traditional Chinese medicine, mulberry leaf is used to treat inflammation, colds, and antiviral illnesses. Mulberry leaves are one of the herbs with many medicinal applications, and as mulberry leaf study grows, there is mounting evidence that these leaves also have potent anti-diabetic properties. The direct role of mulberry leaf as a natural remedy in the treatment of diabetes has been proven in several studies and clinical trials. However, because mulberry leaf is a more potent remedy for diabetes, a deeper understanding of how it works is required. The bioactive compounds flavonoids, alkaloids, polysaccharides, polyphenols, volatile oils, sterols, amino acids, and a variety of inorganic trace elements and vitamins, among others, have been found to be abundant in mulberry leaves. Among these compounds, flavonoids, alkaloids, polysaccharides, and polyphenols have a stronger link to diabetes. Of course, trace minerals and vitamins also contribute to blood sugar regulation. Inhibiting alpha glucosidase activity in the intestine, regulating lipid metabolism in the body, protecting pancreatic -cells, lowering insulin resistance, accelerating glucose uptake by target tissues, and improving oxidative stress levels in the body are some of the main therapeutic properties mentioned above. These mechanisms can effectively regulate blood glucose levels. The therapeutic effects of the bioactive compounds found in mulberry leaves on diabetes mellitus and their associated molecular mechanisms are the main topics of this paper’s overview of the state of the art in mulberry leaf research for the treatment of diabetes mellitus.

Managing metabolic diseases: The roles and therapeutic prospects of herb-derived polysaccharides

Metabolic diseases have become a public health problem worldwide. Effective, novel and natural therapies are urgently needed to treat metabolic diseases. As natural bioactive compounds, polysaccharides have many physiological and medicinal properties. Recently, herb-derived polysaccharides have shown beneficial effects in the treatment of metabolic diseases, but the underlying mechanisms remain unclear. This review comprehensively summarizes the pharmacological progress and clinical evidence of herb-derived polysaccharides in the treatment of three metabolic diseases, namely type 2 diabetes mellitus, nonalcoholic fatty liver disease and obesity, and more importantly, discusses the molecular mechanism involved. Existing evidence has proved that herb-derived polysaccharides can maintain glucose homeostasis, promote insulin secretion, improve insulin resistance, reduce weight gain and hepatic steatosis, inhibit lipogenesis, alleviate oxidative stress and inflammation, and improve gut microbiota disorders in rodents with metabolic diseases. Notably, so far, human clinical trials of herb-derived polysaccharides for these three metabolic diseases remain rare. All in all, herb-derived polysaccharides may have good potential as drug candidates for the prevention and management of metabolic diseases. More high-quality clinical trials are needed to further validate its effectiveness and safety in human subjects.

Mulberry (Morus alba L.) Leaf Extract and 1-Deoxynojirimycin Improve Skeletal Muscle Insulin Resistance via the Activation of IRS-1/PI3K/Akt Pathway in db/db Mice

Mulberry (Morus alba L.) leaves have been used to lower blood glucose in patients with diabetes. We evaluated the effects of mulberry leaves extract (MLE) and 1-deoxynojirimycin (1-DNJ) in improving insulin resistance through the activation of the IRS-1/PI3K/Akt pathway in the skeletal muscle of db/db mice. Histological analysis revealed an amelioration of muscle deformation and increased muscle fiber size. MLE and 1-DNJ positively raised the protein expression of related glucose uptake and increased the translocation of glucose transporter type 4 (GLUT4) to the membrane. Furthermore, MLE and 1-DNJ activated the IRS-1/PI3K/Akt pathway in the skeletal muscle and, subsequently, modulated the protein levels of glycogen synthase kinase-3beta (GSK-3β) and glycogen synthase (GS), leading to elevated muscle glycogen content. These findings suggest that MLE and 1-DNJ supplementation improves insulin resistance by modulating the insulin signaling pathway in the skeletal muscle of db/db mice.

IGF-1R/YAP signaling pathway is involved in collagen V-induced insulin biosynthesis and secretion in rat islet INS-1 cells

PURPOSE

Type V collagen (collagen V) is one of the important components of extracellular matrix (ECM) in pancreas. We previously reported that pre-coating collagen V on the culture dishes enhanced insulin production in INS-1 rat pancreatic β cells. In this study, we investigate the underlying mechanism.

RESULTS

Insulin biosynthesis and secretion are both increased in INS-1 cells cultured on collagen V-coated dishes, accompanied by the reduced nuclear translocation of Yes-associated protein (YAP), a transcriptional co-activator. YAP, the downstream effector of Hippo signaling pathway, plays an important role in the development and function of pancreas. Inhibition of YAP activation by verteporfin further up-regulates insulin biosynthesis and secretion. Silencing large tumor suppressor (LATS), a core component of Hippo pathway which inhibits activity of YAP by phosphorylation, by siRNA transfection inhibits both insulin biosynthesis and secretion. In the present study, the protein level of insulin-like growth factor 1 receptor (IGF-1 R), detected as the upstream molecule of YAP, is reduced in the INS-1 cells cultured on the dishes coated with collagen V. The silencing of IGF-1 R by siRNA transfection further enhances insulin biosynthesis and secretion. IGF-1 treatment reduces collagen V-induced up-regulation of insulin biosynthesis and secretion, accompanying the increased nuclear YAP.

CONCLUSION

Inhibition of IGF-1 R/YAP signal pathway is involved in collagen V-induced insulin biosynthesis and secretion in INS-1 cells.

Morus Alba leaf extract affects metabolic profiles, biomarkers inflammation and oxidative stress in patients with type 2 diabetes mellitus: A double-blind clinical trial

INTRODUCTION

Morus Alba extract, despite its special properties, has been less studied in terms of its effects on metabolic profiles in patients with type 2 diabetes mellitus (T2DM). This study was carried out to determine the effects of Morus Alba extract, known as white mulberry, on liver enzymes, biomarkers of inflammation and oxidative stress, insulin metabolism and lipid profiles in patients with T2DM.

METHODS

The current randomized, double-blind, placebo-controlled trial was conducted among 60 patients with T2DM. Subjects were randomly divided into 2 groups to receive either Morus Alba extract (300 mg) (n = 30) or placebo (n = 30) twice a day. Fasting blood samples were collected at the baseline and 12 weeks after intervention to quantify related markers.

RESULTS

Morus Alba extract intake significantly decreased insulin (P = 0.026) and malondialdehyde (MDA) (P < 0.001), and significantly increased HDL-cholesterol concentrations (P = 0.001) compared with the placebo. However, Morus Alba extract intake did not affect other metabolic profiles.

CONCLUSIONS

The results of this study shown that the 12-week administration of Morus Alba extract among subjects with T2DM had beneficial effects on HDL-cholesterol, insulin and MDA levels, but did not affect other metabolic profiles. The present study was registered in the Iranian website for clinical trials as http://www.irct.ir: IRCT2016081312438N21.

Morus alba L. water extract changes gut microbiota and fecal metabolome in mice induced by high-fat and high-sucrose diet plus low-dose streptozotocin

Gut microbiota plays a key role in the pathophysiology of type 2 diabetes mellitus (T2D). Mulberry leaf has a hypoglycemic effect, but the potential mechanism is not fully understood. This study aimed to explore the influences and potential mechanisms of mulberry leaf water extract (MLWE) intervention on mice with T2D induced through a high-fat and high-sucrose diet combined with streptozotocin by the combination of fecal metabolomics and gut microbiota analysis. Results showed that MLWE could decrease fasting blood glucose and body weight while ameliorating lipid profiles, insulin resistance, liver inflammation, and the accumulation of lipid droplets in T2D mice. MLWE could reverse the abundances of the phyla Actinobacteria and Bacteroidetes and the ratio of Firmicutes/Bacteroidetes, and increase the abundances of the phyla Cyanobacteria and Epsilonbacteraeota in the feces of T2D mice. The abundances of genera Alloprevotella, Parabacteroides, Muribaculaceae, and Romboutsia in the feces of T2D mice could be reversed, while Oscillatoriales_cyanobacterium and Gastranaerophilales could be reinforced by MLWE supplementation. The levels of nine metabolites in the feces of T2D mice were improved, among which glycine, Phe-Pro, urocanic acid, phylloquinone, and lactate were correlated with Romboutsia and Gastranaerophilales. Taken together, we conclude that MLWE can effectively alleviate T2D by mediating the host-microbial metabolic axis.

Mulberry leaves ameliorate diabetes via regulating metabolic profiling and AGEs/RAGE and p38 MAPK/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry leaves have been used as traditional hypoglycemic medicine-food plant for thousand years in China. According to traditional Chinese medicine theory, type 2 diabetes mellitus (T2DM) belongs to the category of XiaoKe. Presently, the research of mulberry leaf hypoglycemic and lipid-lowering direction is mature, but the curative effects of alkaloids, flavonoids, polysaccharides, and other bioactive ingredients and the related mechanism is still unclear.

AIM OF THE STUDY

This paper aims to study the efficacy and mechanism of alkaloids, flavonoids, polysaccharides, and other bioactive components in mulberry leaves in the treatment of T2DM individually.

MATERIALS AND METHODS

The determination of levels of fasting blood glucose (FBG), triglyceride (TG) and total cholesterol (T-Cho), and pyruvate kinase (PK), hexokinase (HK), and alanine aminotransferase (ALT/GPT) of in plasma of diabetic mice. Urine metabolomics was analyzed by UPLC-QTOF/MS to evaluate differential metabolites from multiple metabolic pathways. The glucose uptake of HepG2 cells and 3T3-L1 cells. Expression of Caspase-3 and caspase-9, inflammatory injury and p38MAPK/NF-κB signaling pathway in GLUTag cells.

RESULTS

Our study revealed alkaloids, flavonoids, and polysaccharides in mulberry leaf could increase the levels of PK, HK, and ALT/GPT, and decrease the levels of TG and T-Cho significantly, and regulate glucose, amino acid, and lipid metabolism. Furthermore, 1-deoxynojirimycin (DNJ) and isoquercitrin (QG) both could increase glucose uptake and promote differentiation of HepG2 cells, increase PPARγ, C/EBPα and SREBP-l expression in 3T3-L1 cells, and inhibit AGEs-induced injury and apoptosis in GLUTag cells, reduce the expression of proteins related to AGEs/RAGE and p38MAPK/NF-κB pathway. Notably, isoquercitrin exhibited more pronounced anti-diabetic efficacy.

CONCLUSIONS

The alkaloids, flavonoids, and polysaccharides from mulberry leaf exhibited hypoglycemic activity through the regulation of glucose, amino acid, and lipid metabolism. 1-DNJ and QG increased glucose uptake and promoted differentiation of HepG2 cells, increased PPARγ, C/EBPα and SREBP-l expression in 3T3-L1 cells, and inhibited AGEs-induced injury and apoptosis in GLUTag cells via the AGEs/RAGE and p38 MAPK/NF-κB pathway.

Mulberry leaf (Morus alba L.): A review of its potential influences in mechanisms of action on metabolic diseases

The leaves of Morus alba L. (called Sangye in Chinese, ML), which belong to the genus Morus., are highly valuable edible plants in nutrients and nutraceuticals. In Asian countries including China, Japan and Korea, ML are widely used as functional foods including beverages, noodles and herbal tea because of its biological and nutritional value. Meanwhile, ML-derived products in the form of powders, extracts and capsules are widely consumed as dietary supplements for controlling blood glucose and sugar. Clinical studies showed that ML play an important role in the treatment of metabolic diseases including the diabetes, dyslipidemia, obesity, atherosclerosis and hypertension. People broadly use ML due to their nutritiousness, deliciousness, safety, and abundant active benefits. However, the systematic pharmacological mechanisms of ML on metabolic diseases have not been fully revealed. Therefore, in order to fully utilize and scale relevant products about ML, this review summarizes the up-to-date information about the ML and its constituents effecting on metabolic disease.

Pharmacological Investigations in Traditional Utilization of Alhagi maurorum Medik. in Saharan Algeria: In Vitro Study of Anti-Inflammatory and Antihyperglycemic Activities of Water-Soluble Polysaccharides Extracted from the Seeds

The anti-inflammatory and antihyperglycemic effects of polysaccharides extracted from Alhagi&nbsp;maurorum Medik. seeds, spontaneous shrub collected in Southern of Algerian Sahara were investigated. Their water extraction followed by alcoholic precipitation was conducted to obtain two water-soluble polysaccharides extracts (WSPAM1 and WSPAM2). They were characterized using Fourier transform infrared, ¹H/¹³C Nuclear Magnetic Resonance, Gas Chromatography-Mass Spectrometry and Size Exclusion Chromatography coupled with Multi-Angle Light Scattering. The capacity of those fractions to inhibit α-amylase activity and thermally induced Bovine Serum Albumin denaturation were also investigated. WSPAM1 and WSPAM2 were galactomannans with a mannose/galactose ratio of 2.2 and 2.4, respectively. The SEC-MALLS analysis revealed that WSPAM1 had a molecular weight of 1.4 × 10⁶ Da. The investigations highlighted antinflammatory and antihyperglycemic effects in a dose-dependant manner of WSPAM1 and WSPAM2.

Ethanol extract of mulberry leaves partially restores the composition of intestinal microbiota and strengthens liver glycogen fragility in type 2 diabetic rats

BACKGROUND

Mulberry leaf as a traditional Chinese medicine is able to treat obesity, diabetes, and dyslipidemia. It is well known that diabetes leads to intestinal microbiota dysbiosis. It is also recently discovered that liver glycogen structure is impaired in diabetic animals. Since mulberry leaves are able to improve the diabetic conditions through reducing blood glucose level, it would be interesting to investigate whether they have any positive effects on intestinal microbiota and liver glycogen structure.

METHODS

In this study, we first determined the bioactive components of ethanol extract of mulberry leaves via high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). Murine animal models were divided into three groups, normal Sprague-Dawley (SD) rats, high-fat diet (HFD) and streptozotocin (STZ) induced type 2 diabetic rats, and HFD/STZ-induced rats administered with ethanol extract of mulberry leaves (200 mg/kg/day). Composition of intestinal microbiota was analyzed via metagenomics by sequencing the V3-V4 region of 16S rDNAs. Liver glycogen structure was characterized through size exclusion chromatography (SEC). Both Student's t-test and Tukey's test were used for statistical analysis.

RESULTS

A group of type 2 diabetic rat models were successfully established. Intestinal microbiota analysis showed that ethanol extract of mulberry leaves could partially change intestinal microbiota back to normal conditions. In addition, liver glycogen was restored from fragile state to stable state through administration of ethanol extract of mulberry leaves.

CONCLUSIONS

This study confirms that the ethanol extract of mulberry leaves (MLE) ameliorates intestinal microbiota dysbiosis and strengthens liver glycogen fragility in diabetic rats. These finding can be helpful in discovering the novel therapeutic targets with the help of further investigations.

Recent advances on bioactive polysaccharides from mulberry

Mulberry (Moraceae family), commonly considered as a folk remedy, has a long history of usage in many regions of the world. Polysaccharides regarded as one of the major components in mulberry plants, and they possess antioxidant, antidiabetic, hepatoprotective, prebiotic, immunomodulatory and antitumor properties, among others. In recent decades, mulberry polysaccharides have been widely studied for their multiple health benefits and potential economic value. However, there are few reviews providing updated information on polysaccharides from mulberry. In this review, recent advances in the study of isolation, purification, structural characterization, biological activity and the structure-activity relationship of mulberry polysaccharides are summarized and discussed. Furthermore, a thorough analysis of the current trends and perspectives on mulberry polysaccharides is also proposed. Hopefully, these findings can provide a useful reference value for the development and application of natural polysaccharides in the field of functional food and medicine in the future.

Glucokinase activation as antidiabetic therapy: effect of nutraceuticals and phytochemicals on glucokinase gene expression and enzymatic activity

Diabetes represents an important public health problem. Recently, new molecular targets have been identified and exploited to treat this disease. Due to its pivotal role in glucose homeostasis, glucokinase (GCK) is a promising target for the development of novel antidiabetic drugs; however, pharmacological agents that modulate GCK activity have been linked to undesirable side-effects, limiting its use. Interestingly, plants might be a valuable source of new therapeutic compounds with GCK-activating properties and presumably no adverse effects. In this review, we describe biochemical characteristics related to the physiological and pathological importance of GCK, as well as the mechanisms involved in its regulation at different molecular levels. Posteriorly, we present a compendium of findings supporting the potential use of nutraceuticals and phytochemicals in the management of diabetes through modulation of GCK expression and activity. Finally, we propose critical aspects to keep in mind when designing experiments to evaluate GCK modulation properly.

Morus alba leaves ethanol extract protects pancreatic islet cells against dysfunction and death by inducing autophagy in type 2 diabetes

BACKGROUND

Protection of pancreatic islet cells against dysfunction or death by regulating autophagy is considered to be an effective method for treatment of type 2 diabetes mellitus (T2DM). Morus alba leaves (mulberry leaves), a popular herbal medicine, have been used for prevention of T2DM since ancient times.

PURPOSE

This study aimed to clarify whether Morus alba leaves ethanol extract (MLE) could protect islet cells in vivo and in vitro by regulating autophagy in T2DM, and explore the possible mechanism of action.

METHODS

The main chemical constituents in MLE were analyzed by HPLC. The T2DM rat model was induced via high-fat diet combined with peritoneal injection of low-dose streptozotocin, and MLE was administered by oral gavage. Fasting blood glucose (FBG) and plasma insulin were measured, and homeostatic model assessment of β cell function (HOMA-β) and insulin resistance (HOMA-IR) were determined. The histomorphology of pancreas islets was evaluated by haematoxylin and eosin staining. In palmitic acid (PA)-stressed INS-1 rat insulinoma cells, cell viability was assayed by an MTT method. Expression of the autophagy-related proteins LC3 I/II, p62, p-AMPK and p-mTOR in islet tissues and INS-1 cells was evaluated by western blotting or immunohistochemistry analysis.

RESULTS

The four main chemical constituents in MLE were identified as chlorogenic acid, rutin, isoquercitrin and quercitrin. MLE ameliorated hyperglycemia, insulin resistance and dyslipidemia of T2DM rats with prominent therapeutic effect. Further study indicated that MLE observably improved islet function, alleviated islet injury of T2DM rats, and inhibited PA-induced INS-1 cell death. On the other hand, MLE significantly induced autophagy in islet cells both in vivo and in vitro, and autophagy inhibitors abolished its therapeutic effect on T2DM rats and protective effect on islet cells. Apart from this, MLE markedly activated the AMPK/mTOR pathway in INS-1 cells, and the AMPK inhibitor prevented the autophagy induction ability of MLE.

CONCLUSION

Together, MLE could protect islet cells against dysfunction and death by inducing AMPK/mTOR-mediated autophagy in T2DM, and these findings provide a new perspective for understanding the treatment mechanism of Morus alba leaves against T2DM.

(-)-Leucophyllone, a Tirucallane Triterpenoid from Cornus walteri, Enhances Insulin Secretion in INS-1 Cells

Phytochemical examination of the MeOH extract from the stems and stem bark of Cornus walteri (Cornaceae) led to the isolation and verification of a tirucallane triterpenoid, (-)-leucophyllone, as a major component. Its structure was elucidated using NMR spectroscopy and liquid chromatography-mass spectrometry. The effect of (-)-leucophyllone on insulin secretion in INS-1 cells was investigated. (-)-Leucophyllone increased glucose-stimulated insulin secretion (GSIS) at concentrations showing no cytotoxic effect in rat INS-1 pancreatic β-cells. Moreover, we attempted to determine the mechanism of action of (-)-leucophyllone in the activation of insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3-kinase (PI3K), Akt, and pancreatic and duodenal homeobox-1 (PDX-1). Treatment of INS-1 cells with (-)-leucophyllone markedly increased the expression of these proteins. Our findings indicate the potential of (-)-leucophyllone as an antidiabetic agent.

The Effects of Major Mushroom Bioactive Compounds on Mechanisms That Control Blood Glucose Level

Diabetes mellitus is a life-threatening multifactorial metabolic disorder characterized by high level of glucose in the blood. Diabetes and its chronic complications have a significant impact on human life, health systems, and countries' economies. Currently, there are many commercial hypoglycemic drugs that are effective in controlling hyperglycemia but with several serious side-effects and without a sufficient capacity to significantly alter the course of diabetic complications. Over many centuries mushrooms and their bioactive compounds have been used in the treatment of diabetes mellitus, especially polysaccharides and terpenoids derived from various mushroom species. This review summarizes the effects of these main mushroom secondary metabolites on diabetes and underlying molecular mechanisms responsible for lowering blood glucose. In vivo and in vitro data revealed that treatment with mushroom polysaccharides displayed an anti-hyperglycemic effect by inhibiting glucose absorption efficacy, enhancing pancreatic β-cell mass, and increasing insulin-signaling pathways. Mushroom terpenoids act as inhibitors of α-glucosidase and as insulin sensitizers through activation of PPARγ in order to reduce hyperglycemia in animal models of diabetes. In conclusion, mushroom polysaccharides and terpenoids can effectively ameliorate hyperglycemia by various mechanisms and can be used as supportive candidates for prevention and control of diabetes in the future.

Mulberry leaf powder regulates antioxidative capacity and lipid metabolism in finishing pigs

This study evaluated the potential of mulberry leaf powder as an unconventional feed material for finishing pigs by assessing the growth performance, antioxidative properties, fatty acid profile, and lipid metabolism in 180 Xiangcun black pigs. Pigs with an initial body weight (BW) of 71.64 ± 1.46 kg were randomly assigned to 5 treatment groups, including the control diet and 4 experimental diets. The corn, soybean meal, and wheat bran in the control diet were partly replaced by 3%, 6%, 9%, or 12% mulberry leaf powder in experimental diets. There were 6 replicates (pens) of 6 pigs per replicate in each treatment. Blood and muscle samples were collected after the 50-day feed experiment. Compared with the control group, the 3%, 6%, and 9% mulberry diets had no adverse effect (P > 0.05) on the growth performance of pigs. The serum glutathione peroxidase activity and glutathione concentration increased linearly (P < 0.05) with the increase in dietary mulberry inclusion. There was no significant difference in the relative expression levels of antioxidant-related genes in muscle tissue between the control and mulberry groups. Inclusion of dietary mulberry powder increased (P < 0.05) the content of polyunsaturated fatty acids, especially in the longissimus dorsi (LD) muscle, up-regulated (P < 0.05) the relative mRNA expression level of uncoupling protein-3 in muscle tissue, but down-regulated (P < 0.05) the relative mRNA expression levels of hormone-sensitive lipase, acetyl CoA carboxylase α, lipoprotein lipase, and peroxisome proliferator-activated receptor γ in LD in a linear pattern. The nuclear respiratory factor 2 expression level in the LD muscle of pigs fed the 9% mulberry diet was higher (P < 0.01) than that in the other mulberry groups and control group. The inclusion of less than 12% dietary mulberry did not detrimentally affect the growth performance of Xiangcun black pigs, but enhanced the serum antioxidant property, increased the polyunsaturated fatty acid content, and inhibited lipid oxidation by regulating gene expression levels of lipid metabolism and mitochondrial uncoupling protein in muscle tissue. Mulberry leaves can be utilized as a forage crop in the diet of finishing pigs.

Mitigation mechanisms of Hizikia fusifarme polysaccharide consumption on type 2 diabetes in rats

The objective of current work was to explore the potential anti-diabetic mechanisms of Hizikia fusifarme polysaccharide (HFP) in type 2 diabetic rats. The carbohydrate loading experiment illustrated that HFP supplement could reduce blood sugar fluctuations caused by eating through inhibiting the hydrolysis of starch in mice. The analysis of typically diabetic symptoms and serum profiles showed that oral administration of HFP could mitigate hyperglycemia, insulin resistance, dyslipidemia, chronic inflammation and oxidative stress in rats. The 16s rRNA gene sequencing analysis indicated that HFP treatment could restore beneficial composition of gut flora in diabetic rats, and the correlation analysis revealed that the improvement of diabetes is closely related to the modification of gut flora by HFP intervention. Furthermore, the RT-qPCR and western blotting analysis clarified that HFP administration could increase glycogen storage in liver and skeletal muscle of diabetic rats through activating IRS/PI3K/AKT/GLUT signaling pathway and restrain gluconeogenesis via affecting the relative expression of Egr-1 and PEPCK genes.

Isolation and structure elucidation of polysaccharides from fruiting bodies of mushroom Coriolus versicolor and evaluation of their immunomodulatory effects

Coriolus versicolor is an edible medicinal mushroom in China. Two polysaccharides, named as CVPn and CVPa were separated from the dried fruiting bodies of Coriolus versicolor by water extraction and ethanol precipitation. Their chemical structures were well elucidated with overall consideration of monosaccharide composition, methylation analysis and 1D/2D-NMR spectra data. The bioactivities on RAW 264.7 macrophages cells were evaluated, and further structure-bioactivity relationships were concluded. With molecular weight of 29.7 kDa for CVPn and 50.8 kDa for CVPa, the two isolated polysaccharides were both composed of (l → 4)-β-/(1 → 3)-β-d-glucopyranosyl group as backbone with branches attached at O-6 site. Comparing to CVPn, CVPa with relative high molecular weight and less branches showed significant induction of NO production, obvious augmentation of iNOS and TNF-α mRNA expression level, and phagocytosis on RAW 264.7 cells. These results clarified that CVP polysaccharides with less branches and high molecular weight possessed enhanced immunomodulatory ability, and this finding could be a reference for the utilization of Coriolus versicolor.

Antidiabetic effects and underlying mechanisms of anti-digestive dietary polysaccharides from Sargassum fusiforme in rats

Sargassum fusiforme polysaccharides (SFP), an anti-digestive biologically active ingredient obtained from Sargassum fusiforme by ultrasound-assisted enzymatic extraction, have been proven to exhibit extremely strong alpha-glucosidase inhibitory activity. In the current research, the potential anti-diabetic effects and molecular mechanisms of SFP were investigated by classic biochemical analysis, high-throughput sequencing and molecular biology techniques in type 2 diabetic rats. The analysis of typical diabetic symptoms and serum profiles showed that oral administration of SFP could mitigate hyperglycemia, hyperinsulinemia, dyslipidemia and oxidative stress in diabetic rats. SFP also promoted glycogen synthesis in the liver and skeletal muscles. H&E staining observation confirmed that SFP intervention could partially repair liver and muscle injuries caused by diabetes. Moreover, 16S rRNA gene sequencing analysis indicated that SFP treatment could distinctly restore the beneficial composition of gut flora in diabetic rats. Furthermore, RT-qPCR analysis revealed that anti-diabetic effects of SFP may be closely related to accelerating the absorption and utilization of blood glucose in the liver and muscle and inhibiting hepatic glucose production. In short, this study demonstrated that SFP could be developed as functional foods or pharmaceutical supplements for the prevention or mitigation of diabetes and its complications.

Flavonoids Identification and Pancreatic Beta-Cell Protective Effect of Lotus Seedpod

Oxidative stress is highly associated with the development of diabetes mellitus (DM), especially pancreatic beta-cell injury. Flavonoids derived from plants have caused important attention in the prevention or treatment of DM. Lotus seedpod belongs to a traditional Chinese herbal medicine and has been indicated to possess antioxidant, anti-age, anti-glycative, and hepatoprotective activities. The purpose of this study was to demonstrate the pancreatic beta-cell protective effects of lotus seedpod aqueous extracts (LSE) against oxidative injury. According to HPLC/ESI-MS-MS method, LSE was confirmed to have flavonoids derivatives, especially quercetin-3-glucuronide (Q3G). In vitro, LSE dose-dependently improved the survival and function of rat pancreatic beta-cells (RIN-m5F) from hydrogen peroxide (H₂O₂)-mediated loss of cell viability, impairment of insulin secretion, and promotion of oxidative stress. LSE showed potential in decreasing the H₂O₂-induced occurrence of apoptosis. In addition, H₂O₂-triggered acidic vesicular organelle formation and microtubule-associated protein light chain 3 (LC3)-II upregulation, markers of autophagy, were increased by LSE. Molecular data explored that antiapoptotic and autophagic effects of LSE, comparable to that of Q3G, might receptively be mediated via phospho-Bcl-2-associated death promoter (p-Bad)/B-cell lymphoma 2 (Bcl-2) and class III phosphatidylinositol-3 kinase (PI3K)/LC3-II signal pathway. In vivo, LSE improved the DM symptoms and pancreatic cell injury better than metformin, a drug that is routinely prescribed to treat DM. These data implied that LSE induces the autophagic signaling, leading to protect beta-cells from oxidative stress-related apoptosis and injury.

Effect of the mixture of mulberry leaf powder and KGM flour on promoting calcium absorption and bone mineral density in vivo

BACKGROUND

In this paper, mulberry leaf powder (MLP) and konjac glucomannan (KGM) flour were used as raw materials, and animal experiments were designed to evaluate the effects of a mixture of MLP and KGM on bone density. The femoral bone microstructure of mice and pathological changes were observed by using micro-computed tomography) and haematoxylin and eosin (HE) staining methods, respectively. A three-point bending test was used to determine the biomechanical properties of the femur.

RESULTS

Results indicated that the calcium content of MLP was high, reaching 16 148.5 mg kg^-1 , and the total proportion of water-soluble calcium, calcium pectinate, and calcium carbonate accounted for about 60% of the total calcium content. Serum alkaline phosphatase (AKP) activity was significantly lower, and serum calcium content was significantly higher (P < 0.05), in the MLP + KGM group (KM) than in the low-calcium control group, whereas no significant difference (P > 0.05) was found for serum phosphorus content. KM had a longer femur length, a higher bone mineral density (BMD) (P > 0.05), and significantly greater femur diameter, dry weight, index and bone calcium content (P < 0.05). However, these parameters were not significantly different from those of the calcium carbonate control group (P > 0.05).

CONCLUSION

The results indicate that the MLP/KGM mixture can reduce the high rate of bone turnover and the corresponding loss of bone mass caused by calcium deficiency and is thus effective in enhancing bone density. © 2019 Society of Chemical Industry.

Antidiabetic Potential of Prosopis farcta Roots: In Vitro Pancreatic Beta Cell Protection, Enhancement of Glucose Consumption, and Bioassay-Guided Fractionation

By using the streptozotocin- (STZ-) induced cytotoxicity in β-TC3 cells as an assay model, a bioassay-guided fractionation study was employed to isolate and characterize the potential antidiabetic principles of roots of Prosopis farcta. A combination of open column chromatography on reverse-phase silica gel using a water-ethanol gradient (10 : 90 to 100 : 0) followed by HPLC-based fractionation led to an active compound that appears to be composed of carbohydrate/sugar. When cell viability under STZ was reduced to 49.8 ± 4% (mean ± SD), treatment with the active compound at the concentration of 0.5 mg/mL either as a coadministration or a pretreatment improved the viability to 93 ± 1.9% and 91.5 ± 7%, respectively. The reduction in the mitochondrial membrane potential by STZ (47.34 ± 8.9% of control) was similarly recovered to 84.5 ± 4.3 (coadministration) and 88 ± 5.5% (pretreatment) by the active fraction. The bioassay-guided fractionation, β-cell protective effect, and increased glucose consumption (up to 1.49-fold increase) in hepatocytes by the extracts and active fraction are also discussed.

The homogenous polysaccharide SY01-23 purified from leaf of Morus alba L. has bioactivity on human gut Bacteroides ovatus and Bacteroides cellulosilyticus

Function of mulberry leaf (Morus alba L.) polysaccharide has been reported on antitumor, immunostimulatory and anti-inflammatory effects. However, the bioactivity on human gut microbiota is unclear so far. Here, three homogenous polysaccharides named SY01-21, SY01-22, SY01-23 were isolated from mulberry leaf with molecular weight 57 kDa, 25 kDa and 7.2 kDa, respectively. The monosaccharide composition of SY01-21 contained rhamnose, galactose and arabinose in a molar ratio of 7.60:43.52:48.88. SY01-22 contained rhamnose, galacturonic acid, glucose, galactose, xylose and arabinose in a molar ratio of 14.61:9.06:1.35:34.65:2.99:37.34. SY01-23 contained rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose and arabinose in a molar ratio of 23.00:4.12:24.60:5.74:17.28:1.12:24.13. Bioactivity test showed SY01-21 promoted the growth of Bacteroides cellulosilyticus (BC) while SY01-22 benefited the growth of Bacteroides ovatus (BO). Interestingly, SY01-23 boosted the growth of both BO and BC. However, Bacteroides thetaiotamicron (BT) only grew on 5 mg/mL SY01-21. Intriguingly, the growth of co-culture of BT with BO or BC was better than monoculture. This suggested that cross-feeding might exist between them. Besides, we found BO and BC generated acetate and propionate by utilizing SY01-23. The above results suggested that SY01-23 might modify human gut microbiota by driving colonization of Bacteroides in the gut to improve wellness.

Tropisetron improves pancreas function and increases insulin synthesis and secretion in the STZ-induced diabetic rats: involvement of UCP2/ZnT8 pathway

OBJECTIVES

Diabetes mellitus is one of the most common metabolic diseases. Tropisetron, as a 5-HT3 receptor antagonist, has a considerable role in the inflammation and oxidative stress lowering. This study aimed to investigate the effect of this 5-HT3 receptor antagonist on insulin secretion in male diabetic rats and the possible mechanisms.

METHODS

Animals were divided into five equal groups; the control, tropisetron, diabetes, tropisetron-diabetes and glibenclamide-diabetes (7 in each group). Tropisetron and glibenclamide were administrated for 2 weeks after inducing type 1 diabetes.

KEY FINDINGS

We demonstrated that insulin secretion improved robustly in diabetes-tropisetron compared with the diabetic group. Oxidative stress biomarkers were lower in a diabetes-tropisetron group than in diabetic rats. Simultaneously, tropisetron administration promoted the expression of ZnT8 and GLUT2 and also beta-cell mass in pancreatic tissue, while the expression of uncoupling protein 2 (UCP2) was restrained. The histological evaluation confirmed our results. These effects were equipotent with glibenclamide, indicating that tropisetron can protect islets from the abnormal insulin secretion and morphological changes induced by type 1 diabetes.

CONCLUSIONS

This effect might be partly related to the modulated UCP2/ZnT8 signal pathway and improved oxidative stress-induced damage.

Flavonoids extracted from mulberry (Morus alba L.) leaf improve skeletal muscle mitochondrial function by activating AMPK in type 2 diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry (Morus alba L.) leaves have been widely applied to controlling blood glucose as a efficacious traditional Chinese medicine or salutary medical supplement. The extracts of mulberry leaf suppress inflammatory mediators and oxidative stress, protect the pancreatic β-cells and modulate glucose metabolism in diabetic rats. Our previous studies and others have shown that mulberry leaf extract has excellent therapeutic effects on type 2 diabetes mellitus (T2DM), however, the underlying mechanism remains to be studied.

AIM OF THE STUDY

Skeletal muscle insulin resistance (IR) plays an important role in the pathogenesis of T2DM. The aim of this study was to investigate the effects and mechanisms of Mulberry leaf flavonoids (MLF) in L6 skeletal muscle cells and db/db mice.

MATERIALS AND METHODS

L6 skeletal muscle cells were cultured and treated with/without MLF for in vitro studies. For in vivo studies, the db/db mice with/without MLF therapy were used. Coomassie brilliant blue staining and α-SMA immunofluorescence staining were used to identify the differentiated L6 cells. Glucose level and ATP level of L6 myotubes were performed by optical density detection and cell viability was performed by MTT method. Mitochondrial membrane potential of L6 myotubes was detected by JC-1 fluorescent staining. ROS level of L6 myotubes was detected by DCFH-DA fluorescent staining. The body weight, food intake, and blood glucose of the mice were measured in different treatment days. Oral glucose tolerance test (OGTT), starch glucose tolerance test (STT) and insulin tolerance test (ITT) were performed in mice. Glycated hemoglobin, glycated serum protein, insulin, liver and muscle glycogen, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c) of the mice were detected by corresponding kit. The pathologic change of pancreas and skeletal muscle of mice were performed by H & E staining. Immunohistochemistry staining was used to detect the GLUT4 and p-AMPK expressions in skeletal muscle in mice. GLUT4, CPT-1, NRF1, COXIV, PGC-1α, and p-AMPK expression levels in L6 cells and mice were detected by western bolt assay.

RESULTS

MLF and metformin significantly ameliorated muscle glucose uptake and mitochondrial function in L6 muscle cells. MLF also increased the phosphorylation of AMPK and the expression of PGC-1α, and up-regulated the protein levels of m-GLUT4 and T-GLUT4. These effects were reversed by the AMPK inhibitor compound C. In db/db mice, MLF improve diabetes symptoms and insulin resistance. Moreover, MLF elevated the levels of p-AMPK and PGC-1α, raised m-GLUT4 and T-GLUT4 protein expression, and ameliorated mitochondrial function in skeletal muscle of db/db mice.

CONCLUSIONS

MLF significantly improved skeletal muscle insulin resistance and mitochondrial function in db/db mice and L6 myocytes through AMPK-PGC-1α signaling pathway, and our findings support the therapeutic effects of MLF on type 2 diabetes.

Polysaccharide from Rosa roxburghii Tratt Fruit Attenuates Hyperglycemia and Hyperlipidemia and Regulates Colon Microbiota in Diabetic db/db Mice

This study was aimed at investigating the hypoglycemic and hypolipidemic effects of a polysaccharide (RTFP) isolated from Rosa roxburghii Tratt fruit on type-2 diabetic db/db mice. The results indicated that the oral administration of RTFP could significantly decrease the body weight, fat, and liver hypertrophy and the levels of fasting blood glucose, serum insulin, and serum lipids of the db/db mice. Histopathological observation showed that RTFP could effectively protect the pancreas, liver, and epididymal fat against damage and dysfunction. Real-time quantitative polymerase chain reaction analysis confirmed that the gene expression levels of peroxisome proliferator-activated receptors-γ (PPAR-γ), sterol regulatory element-binding protein-1 (SREBP-1c), acetyl-CoA carboxylase-1 (ACC-1), fatty acid synthase (FAS), and glucose-6-phosphatase (G6 Pase) were significantly down-regulated in the liver of db/db mice after treatment with RTFP. Moreover, RTFP treatment reversed gut dysbiosis by lowering the Firmicutes-to-Bacteroidetes ratio and enhancing the relative abundances of beneficial bacteria including Bacteroidaceae, Bacteroidaceae S24-7 group, and Lactobacillaceae. These findings suggest that RTFP can be used as a promising functional supplement for the prevention and treatment of type-2 diabetes mellitus.

Extended Intake of Mulberry Leaf Extract Delayed Metformin Elimination via Inhibiting the Organic Cation Transporter 2

Diabetes mellitus (DM) has become a major health problem in most countries of the world. DM causes many complications, including hyperglycemia, diabetic ketoacidosis, and death. In Asia, mulberry has been used widely in the treatment of DM. Combination of drugs with herbal medicine may reduce the unwanted side effects caused by drugs. In this study, the influence of extended mulberry leaves extract (MLE) intake on metformin (Met) was evaluated in terms of pharmacokinetics and pharmacodynamics in DM-induced rats. Three week-treatment of MLE alone produced the anti-hyperglycemic effect (around 24%) if compared to the control. Interestingly, Met administration after MLE treatment for 3 weeks enhanced about 49% of the anti-hyperglycemic effect of Met. In addition, the extended intake of MLE potentiated the anti-hyperglycemic effect of Met on various concentrations. This potentiated anti-hyperglycemic effect of Met appears to be due to the pharmacokinetic change of Met. In this study, 3 week-treatment of MLE reduced the elimination of Met in DM-induced rats. In addition, MLE reduced the human organic cation transporter 2 (hOCT2) activity in a concentration-dependent manner. Thus, these findings suggest that MLE lowered the elimination of Met via inhibiting the hOCT2.

Glucose-lowering effect of Gryllus bimaculatus powder on streptozotocin-induced diabetes through the AKT/mTOR pathway

This study was carried out to elucidate the antidiabetic effects of Gryllus bimaculatus powder using a streptozotocin (STZ)-induced rat model of type I diabetes. Administration of the insect powder significantly rescued representative diabetes markers (i.e., insulin and C-peptide) in STZ-treated rats. Improved glucose tolerance test (GTT) and insulin tolerance test (ITT) results were also observed, indicating that Gryllus bimaculatus powder exerts antidiabetic effects. Gryllus bimaculatus powder administration rescued STZ-induced alterations in both islet morphology and insulin staining patterns. The extract increased antiapoptotic Bcl2 expression and decreased proapoptotic Bax and active caspase 3 expressions. In addition, the Gryllus bimaculatus powder supplementation enhanced AKT/mTOR pathway, a key marker of the state of anabolic metabolism, and its downstream effector, mTOR. Collectively, our results suggest that Gryllus bimaculatus contributes to the maintenance of pancreatic β-cell function and morphology against a diabetic state through the regulations against apoptosis and anabolic metabolism.

Antioxidative and Hypoglycemic Effect of Ta-ermi Extracts on Streptozotocin-Induced Diabetes

INTRODUCTION

The purpose of the present study was to reveal the potential positive effect of the Ta-ermi extracts on oxidative stress and streptozotocin (STZ)-diabetic mice and rats treated with Ta-ermi water- and alcohol-extracts.

METHODS

The study was carried out using three experimental model: 1) in vitro experiments whereby Ta-ermi extracts were incubated with free radical generators such as 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) to evaluate Ta-ermi's antioxidant effects; 2) testing the hypoglycemic effects of Ta-ermi extracts in streptozotocin (STZ)-induced diabetic mice; and 3) testing the beneficial effects of Ta-ermi extracts on mitochondrial complex I function using STZ-diabetic rats.

RESULTS

In vitro antioxidant experiments showed that both of the extracts could scavenge free radicals and exhibited inhibitory effects on glucosidase and aldose reductase with differential effects between water extract and alcohol extract. In the STZ mouse diabetic model, both the water- and alcohol-extracts attenuated body weight decrease, decreased blood glucose levels in a concentration-dependent manner, improved insulin sensitivity, and increased oral glucose tolerance ability. In the STZ-diabetic rat model, both the water- and alcohol-extracts were found to be able to lower blood glucose levels in the diabetic animals with no effects on body weight changes. Moreover, in the STZ-diabetic rats, both the water- and alcohol-extracts of Ta-ermi could inhibit the increase of mitochondrial NADH/ubiquinone oxidoreductase (complex I) activity in the pancreas and enhanced complex I activity in the liver but showed no effect on lung or kidney mitochondrial complex I.

DISCUSSION

The present study points to the potential medicinal value of Ta-ermi's water and alcohol extracts in lowering blood glucose and decreasing diabetic oxidative stress. One limitation of our study is that the compound or compounds that actually have this beneficial effect in the extracts remain unknown at this time. Therefore, the future studies should be focused on the identification of the components in the extracts that exhibit anti-oxidative and hypoglycemic effects.

CONCLUSION

Taken together, our studies using different experimental paradigms indicate that Ta-ermi extracts possess antioxidant and anti-diabetic properties and may be employed as functional food ingredients for the remission of diabetes.

Anti-Diabetic Effects and Mechanisms of Dietary Polysaccharides

Diabetes mellitus is a multifactorial, heterogeneous metabolic disorder, causing various health complications and economic issues, which apparently impacts the human's life. Currently, commercial diabetic drugs are clinically managed for diabetic treatment that has definite side effects. Dietary polysaccharides mainly derive from natural sources, including medicinal plants, grains, fruits, vegetables, edible mushroom, and medicinal foods, and possess anti-diabetic potential. Hence, this review summarizes the effects of dietary polysaccharides on diabetes and underlying molecular mechanisms related to inflammatory factors, oxidative stress, and diabetes in various animal models. The analysis of literature and appropriate data on anti-diabetic polysaccharide from electronic databases was conducted. In vivo and in vitro trials have revealed that treatment of these polysaccharides has hypoglycemic, hypolipidemic, antioxidant, and anti-inflammatory effects, which enhance pancreatic β-cell mass and alleviates β-cell dysfunction. It enhances insulin signaling pathways through insulin receptors and activates the PI3K/Akt pathway, and eventually modulates ERK/JNK/MAPK pathway. In conclusion, dietary polysaccharides can effectively ameliorate hyperglycemia, hyperlipidemia, low-grade inflammation, and oxidative stress in type 2 diabetes mellitus (T2DM), and, thus, consumption of polysaccharides can be a valuable choice for diabetic control.

The mechanism of mulberry leaves against renal tubular interstitial fibrosis through ERK1/2 signaling pathway was predicted by network pharmacology and validated in human tubular epithelial cells

Mulberry leaf was reported that it has antidiabetic activity, although the mechanisms underlying the function have not been fully elucidated. In the present study, the results of network pharmacology suggested that mulberry leaves could regulate key biological process in development of diabetes, and the process implicates multiple signaling pathways, such as JAK-STAT, MAPK, VEGF, PPAR, and Wnt. Then, the research in vitro indicated that mulberry leaves remarkably ameliorated high glucose-induced epithelial to mesenchymal transition, which was characterized with significant reduction of intracellular reactive oxygen species (ROS) levels as well as downregulation of NADPH oxidase subunits NOX1, NOX2, and NOX4, and it was found to be connected with the ERK1/2 signaling pathway in human tubular epithelial cells (HK-2). Moreover, the results of bioinformatics and the dual luciferase report showed that ZEB1 might be a target gene of miR-302a; decreased miR-302a and increased ZEB1 expressions could significantly promote epithelial to mesenchymal transition. However, mulberry leaves could reverse these modulations. Our results demonstrated that network pharmacology could provide a guidance role for traditional Chinese medicine research, and mulberry leaves could be of benefit in preventing high glucose-induced EMT in HK-2 cells, which proved that it was related to the upregulation of miR-302a by targeting ZEB1 and the inhibition of NADPH oxidase/ROS/ERK1/2 pathway.