Anti-diabetic effects of polysaccharides from Talinum triangulare in streptozotocin (STZ)-induced type 2 diabetic male mice

Isolation, structural, biological activity and application of Gleditsia species seeds galactomannans

Gleditsia fruits have been known as a valuable traditional Chinese herb for tens of centuries. Previous studies showed that the galactomannans are considered as one of the major bioactive components in Gleditsia fruits seeds (GSGs). Here, we systematically review the major studies of GSGs in recent years to promote their better understanding. The extraction methods of GSGs mainly include hot water extraction, microwave-assisted extraction, ultrasonic extraction, acid extraction, and alkali extraction. The analysis revealed that GGSs exhibited in the form of semi-flexible coils, and its molecular weight ranged from 0.018 × 103 to 2.778 × 103 KDa. GSGs are composed of various monosaccharide constituents such as mannose, galactose, glucose, and arabinose. In terms of pharmacological effects, GSGs exhibit excellent activity in antioxidation, hypoglycemic, hypolipidemic, anti-inflammation. Moreover, GSGs have excellent bioavailability, biocompatibility, and biodegradability, which make them used in food additives, food packaging, pharmaceutical field, industry and agriculture. Of cause, the shortcomings of the current research and the potential development and future research are also highlighted. We believe our work provides comprehensive knowledge and underpinnings for further research and development of GSGs.

A Review on Bioactive Compounds, Ethnomedicinal Importance and Pharmacological Activities of Talinum triangulare (Jacq.) Willd

Talinum triangulare (Jacq.) Willd. is a traditional leafy vegetable used by tribal communities for ethnomedicinal and ethnoculinary preparations. This article reviews the current knowledge of its multiple uses, including pharmacological activities and nutritional composition. The literature survey shows that it has been traditionally useful in the treatment of several diseases, such as anaemia, diabetes, measles, and ulcers and the preparation of various traditional foods. Analysis of the literature on its phytochemicals shows its richness in bioactive compounds. Further, research also shows that this plant has antidiabetic, antiobesity, antitumor, antiulcer, hepatoprotective, and neuroprotective activities besides anti-inflammatory and antioxidant properties. Nutrient analysis of the plant reveals the presence of Ca, Zn, Fe, vitamins C and E, dietary fibre and protein in considerable quantities. The results of the pharmacological studies on the antidiabetic, antiulcer and anti-anaemic activities provide support in favour of its ethnomedicinal uses. The presence of bioactive compounds and pharmacological activities show the usefulness of this plant as a functional food.

Structural characterization of Hericium erinaceus polysaccharides and the mechanism of anti-T2DM by modulating the gut microbiota and metabolites

A low molecular weight polysaccharides of HEP-1, with molecular weights of 1.67 × 10⁴ Da and composition of →6)-β-D-Glcp-(1→, →3)-β-D-Glcp-(1→, β-D-Glcp-(1→ and →3,6)-β-D-Glcp-(1→, was isolated and characterized from the fruiting body of Hericium erinaceus. The results indicated that HEP-1 showed potential effects against T2DM-induced imbalance of glucose and lipid metabolism by promoting the serum glucose uptake by hepatic glycogen synthesis via activating the IRS/PI3K/AKT signaling pathway, and inhibiting fatty acid synthesis and reducing hepatic lipid accumulation via activating the AMPK/SREBP-1c signaling pathways. Besides, HEP-1 promoted the production of beneficial bacteria in the gut, and increased the beneficial metabolites in liver through the gut-liver axis, consequently, resisting the occurrence of T2DM.

Mulberry extract ameliorates T2DM-related symptoms via AMPK pathway in STZ-HFD-induced C57BL/6J mice

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry (Morus alba L.) is not only a tasty food but also a beneficial medicinal substance that has been historically used to treat diabetes, as recorded in Tang Ben Cao. Recent research on animal models has shown that the ethyl acetate extract of Morus alba L. fruits (EMF) has hypoglycemic and hypolipidemic properties. However, there is a lack of documentation on the specific mechanisms through which EMF exerts its hypoglycemic effects.

OBJECTIVE OF THE STUDY

This study aimed to investigate the impact of EMF on L6 cells and C57/BL6J mice and to elucidate the potential mechanisms underlying its effects. The findings of this study can contribute to the existing evidence for the application of EMF as a therapeutic drug or dietary supplement in the management of type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

The UPLC-Q-TOF-MS technique was utilized to gather MS data. Masslynx 4.1 software in conjunction with the SciFinder database and other relevant references were used to analyze and identify the chemical composition of EMF. A series of in vitro investigations including MTT assay, glucose uptake assay and Western blot analysis were performed using an L6 cell model stably expressing IRAP-mOrange after EMF treatment. In vivo investigations were performed on a STZ-HFD co-induced T2DM mouse model, which included assessments of body composition, biochemical tests, histopathological analysis, and Western blot analysis.

RESULTS

MTT results revealed that EMF had no toxic effects on the cells at various concentrations. When EMF was administered to L6 cells, there was an increase in glucose transporter type 4 (GLUT4) translocation activity and a significant dose-dependent enhancement of glucose uptake by L6 myotubes. EMF treatment led to a marked increase in P-AMPK levels and GLUT4 expression in the cells, but these effects were reversed by an AMPK inhibitor (Compound C). In diabetic mice with STZ-HFD-induced diabetes, EMF treatment improved oral glucose tolerance, hyperglycemia, and hyperinsulinemia. Furthermore, EMF supplementation significantly reduced insulin resistance (IR) in diabetic mice, as evaluated using a steady-state model of the insulin resistance index. Histopathological sections demonstrated that acute EMF treatment reduced hepatic steatosis, pancreatic damage, and adipocyte hypertrophy. Western blot analysis demonstrated that EMF treatment also reduced abnormally high PPARγ expression, elevated the level of p-AMPK and p-ACC, and augmented the abundance of GLUT4 in insulin-sensitive peripheral tissues.

SUMMARY

The results suggest that EMF may exert beneficial effects on T2DM through the AMPK/GLUT4 and AMPK/ACC pathways, as well as by regulating PPARγ expression.

Pumpkin Polysaccharide Extracted by Subcritical Water: Physicochemical Characterization and Anti-Diabetic Effects in T2DM Rats

SCOPE

This study aims to optimize the extraction of pumpkin polysaccharide by subcritical water, investigates the physicochemical properties and biological activities of pumpkin polysaccharide.

METHODS AND RESULTS

Subcritical water is used to extract pumpkin polysaccharide. The structure and composition of pumpkin polysaccharide are analyzed by infrared spectroscopy, gel filtration chromatography, and high-performance liquid chromatography. The hypoglycemic and hypolipidemic potential of pumpkin polysaccharide aere determined by the physicochemical indexes, pathological, and immunohistochemical analysis in T2DM rats induced by STZ + high-fat diet. The optimal conditions for subcritical water are 1:15, 150°C, and 10 min. Pumpkin polysaccharide has α-configurations and are mainly composed of seven different monosaccharides, and it exhibits good free-radical scavenging ability and inhibition of α-amylase, α-glucosidase, and pancreatic lipase activities. Pumpkin polysaccharide treatment in T2DM rats significantly decreases the concentrations of blood glucose, insulin, TC, TG, LDL-C, and MDA; increases the levels of HDL-C; and enhances the antioxidant enzymes activities (SOD and CAT). Histopathology and immunohistochemical analyses reveal that pumpkin polysaccharide has protective effects on kidney and pancreatic organs in T2DM rats.

CONCLUSION

Pumpkin polysaccharide extracted by SWE shows great potential as functional food ingredients and candidates for T2DM treatment.

Effects of Auricularia auricula Polysaccharides on Gut Microbiota Composition in Type 2 Diabetic Mice

In previous studies, Auriculariaauricula polysaccharides (AAP) has been found to improve type 2 diabetes mellitus, but its mechanism remains unclear. In this study, we sought to demonstrate that AAP achieves remission by altering the gut microbiota in mice with type 2 diabetes. We successfully constructed a type 2 diabetes mellitus (T2DM) model induced by a high-fat diet (HFD) combined with streptozotocin (STZ), following which fasting blood glucose (FBG) levels and oral glucose tolerance test (OTGG) were observed to decrease significantly after 5 weeks of AAP intervention. Furthermore, AAP enhanced the activities of total superoxide dismutase (T-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), and reduced the content of malondialdehyde (MDA) to alleviate the oxidative stress injury. AAP-M (200 mg/kg/d) displayed the best improvement effect. Moreover, 16S rRNA results showed that AAP decreased the abundance of Firmicutes and increased that of Bacteroidetes. The abundance of beneficial genera such as Faecalibaculum, Dubosiella, Alloprevotella, and those belonging to the family Lachnospiraceae was increased due to the intake of AAP. AAP could reduced the abundance of Desulfovibrio, Enterorhabdus, and Helicobacter. In all, these results suggest that AAP can improve the disorders of glucose and lipid metabolism by regulating the structure of the gut microbiota.

Cashew Gum: A Review of Brazilian Patents and Pharmaceutical Applications with a Special Focus on Nanoparticles

Natural polysaccharides are structures composed of highly diversified biological macromolecules whose properties have been exploited by a diversity of industries. Until 2018, the polysaccharides market raised more than US $ 12 billion worldwide, while an annual growth forecast of 4.8% is expected by 2026. The food industry is largely responsible for the consumption of this plant-source material, produced by microbiological fermentation. Among the used polysaccharides, gums are hydrocolloids obtained from a variety of sources and in different forms, being composed of salts of calcium, potassium, magnesium and sugar monomers. Their non-toxicity, hydrophilicity, viscosity, biodegradability, biocompatibility and sustainable production are among their main advantages. Although Brazil is amongst the largest producers of cashew gum, reaching 50 tons per year, the polysaccharide is not being used to its full potential, in particular, with regard to its uses in pharmaceuticals. Cashew gum (CG), obtained from Anacardium occidentale L., caught the attention of the industry only in 1970; in 1990, its production started to grow. Within the Brazilian academy, the groups from the Federal University of Ceará and Piauí are devoting the most efforts to the study of cashew gum, with a total of 31 articles already published. The number of patents in the country for innovations containing cashew tree gum has reached 14, including the technological process for the purification of cashew tree gum, comparison of physical and chemical methods for physicochemical characterizations, and optimum purification methodology. This scenario opens a range of opportunities for the use of cashew gum, mainly in the development of new pharmaceutical products, with a special interest in nanoparticles.

Characterization of Anoectochilus roxburghii polysaccharide and its therapeutic effect on type 2 diabetic mice

Anoectochilus roxburghii is a traditional herb in China that can be potentially used to treat diabetes. A novel polysaccharide ARLP-W was isolated from Anoectochilus roxburghii by chromatography on DEAE-52 cellulose. Chemical analysis indicated that ARLP-W (8.1 × 10⁴ Da) was mainly composed of mannose and glucose. The main linkages of glycosidic bonds of ARLP-W were β-1, 4-Manp and α-1, 4-Glcp. The terminal Glcp was connected to Manp-via O-3. RT-qPCR and western blotting analysis showed that ARLP-W caused a significant reduction in the levels of the key gluconeogenesis enzymes phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase) in the liver. The results of the insulin resistance tests indicated that ARLP-W increased glucose absorption. These results indicate that ARLP-W has a good therapeutic effect on type 2 diabetes and can assist with further development and application treatment of diabetes.

Purification and Characterization of Fractions Containing Polysaccharides from Talinum triangulare and Their Immunomodulatory Effects

Previous studies identified that extracts of Talinum triangulare rich in flavonoids and phenolic acids showed antioxidative and immunomodulatory activities. In this study, the L9 orthogonal array was used to determine the optimal extraction conditions for water-extracted polysaccharides of T. triangulare (TTP) by hot reflux extraction and ultrasonic assisted extraction (UAE) methods. Results showed that while both extraction methods obtained a maximum polysaccharide yield of 3.1%, the optimal conditions for obtaining TTP was by UAE method. TTP was separated into large (LTTP) and small (STTP) molecular weights by dialysis. Since LTTP showed better effects than STTP in inducing macrophages to produce nitric oxide (NO) and indirectly inhibiting human cervical cancer HeLa cells, six different LTTP fractions were separated using anion-exchange chromatography. Contents of polysaccharides, triterpenoids, polyphenols, and proteins and molecular weights of major polysaccharide in each fraction were analyzed. The F1 fraction of LTTP, which showed the highest inducing ability of mouse RAW264.7 macrophages to secrete NO and tumor necrosis factor-α, showed the most significant indirect inhibitory effect of human colon cancer SW620 cells. These results suggest that LTTP, especially the F1 fraction, of T. triangulare may be used in health foods or Chinese medicine for its immunomodulatory potential.

Antidiabetic Effects of Arginyl-Fructosyl-Glucose, a Nonsaponin Fraction from Ginseng Processing in Streptozotocin-Induced Type 2 Diabetic Mice through Regulating the PI3K/AKT/GSK-3β and Bcl-2/Bax Signaling Pathways

Streptozotocin- (STZ-) induced type 2 diabetes mellitus (T2DM) caused insulin secretion disorder and hyperglycemia, further causing tissue and organ damage. In recent years, studies on ginseng (Panax ginseng C. A. Meyer) and its saponins (Ginsenosides) have proved to possess antidiabetic pharmacological activities, but the mechanism of nonsaponins on STZ-induced T2DM is still unclear. Arginyl-fructosyl-glucose (AFG) is a representative nonsaponin component produced in the processing of red ginseng. The present study was designed to assess the possible healing consequence of AFG on STZ-induced T2DM in mice and also to explore its fundamental molecular contrivances. T2DM-related indexes, fasting blood glucose levels, and body weight, histological changes, biochemical considerations, biomarkers, the mRNA countenance intensities of inflammatory facts, and variations in correlated protein manifestation in adipose tissue and liver tissue were calculated. Consequences specified that AFG usage successfully amends STZ-induced insulin conflict and liver grievance in T2DM. Systematically, AFG action diminished STZ-induced oxidative stress and inflammatory responses in the liver. In addition, we demonstrated that AFG also attenuates apoptosis and insulin secretion disorders in T2DM by adjusting the PI3K/AKT/GSK3β signaling pathway. At the end, these discoveries recommend that AFG averts the development of T2DM through numerous types of machinery and proposes that AFG can also be used in order to treat T2DM in the future.

Beneficial effects of Aronia melanocarpa berry extract on hepatic insulin resistance in type 2 diabetes mellitus rats

We aimed to investigate) the effects of Aronia melanocarpa berry extract (AMBE) on hepatic insulin resistance and its mechanism at the molecular level in high-fat diet (HFD)- and streptozotocin (STZ)-induced type 2 diabetes mellitus (T2DM) rats. The rats were supplemented with AMBE at doses of 100 and 400 mg/kg body weight (bw) daily for 8 weeks. AMBE significantly reduced blood glucose and serum insulin levels and the homeostatic model assessment for insulin resistance score; improved glucose tolerance; increased hepatic glycogen content; and regulated glucose metabolism enzyme activity, including glucokinase, pyruvate kinase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase in the liver. AMBE also reduced lipid accumulation and oxidative stress along with inflammation in the hepatic tissue of T2DM rats and improved hepatic function. The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was activated by AMBE through the elevation of insulin receptor substrate-2, PI3K, Akt, and glycogen synthase kinase-3β phosphorylation and glucose transporter 2, which might contribute to the promotion of glycogen synthesis and improvement of hepatic insulin resistance. AMBE shows promise as an ingredient of functional foods for alleviating hepatic insulin resistance in T2DM. PRACTICAL APPLICATION: The extract from the berries of Aronia melanocarpa (Michx.) Elliott (AMBE), with its relatively high content of polyphenolic compounds, has been shown to exert hypoglycemic effects in animal models of diabetes. Our findings support the use of A. melanocarpa as a functional food additive for the alleviation of hepatic insulin resistance and the management of glucose homeostasis in T2DM.

Evidence of anti-inflammatory activity of Schizandrin A in animal models of acute inflammation

Schisandrin A (Sch A) is a lignin extracted from the fruit of Schisandra chinensis, which has potential anti-inflammatory properties and is used for treating various inflammatory diseases. In this study, we aimed to evaluate the anti-inflammatory effects of Sch A and the underlying mechanisms in animal models of acute inflammation. First, the anti-inflammatory effects of Sch A were evaluated preliminarily in an animal model of xylene-induced ear edema. Sch A pretreatment significantly decreased the degree of edema and inhibited telangiectasia in the ear. Second, a mouse model of paw edema was used to investigate the anti-inflammatory effects and mechanisms of Sch A. Pretreatment with Sch A significantly inhibited carrageenan-induced paw edema in mice. Hematoxylin-eosin (HE) staining of paw tissues demonstrated that Sch A inhibited the infiltration of inflammatory cells in the mouse model of paw edema. Enzyme-linked immunosorbent assay (ELISA) results indicated that the levels of inflammatory factors decreased. The western blot and immunohistochemical assay results revealed that the toll-like receptor 4/nuclear factor kappa-B (TLR4/NF-κB) pathway could play a role in the anti-inflammatory functions of Sch A. The findings demonstrated that Sch A exerts anti-inflammatory effects and may provide possible strategies for the treatment of inflammatory diseases.

Oleoylethanolamide Increases Glycogen Synthesis and Inhibits Hepatic Gluconeogenesis via the LKB1/AMPK Pathway in Type 2 Diabetic Model

Oleoylethanolamide (OEA) is an endogenous peroxisome proliferator-activated receptor α (PPARα) agonist that acts on the peripheral control of energy metabolism. However, its therapeutic potential and related mechanisms in hepatic glucose metabolism under type 2 diabetes mellitus (T2DM) are not clear. Here, OEA treatment markedly improved glucose homeostasis in a PPARα-independent manner. OEA efficiently promoted glycogen synthesis and suppressed gluconeogenesis in mouse primary hepatocytes and liver tissue. OEA enhanced hepatic glycogen synthesis and inhibited gluconeogenesis via liver kinase B1 (LKB1)/5' AMP-activated protein kinase (AMPK) signaling pathways. PPARα was not involved in the roles of OEA in the LKB1/AMPK pathways. We found that OEA exerts its antidiabetic effect by increasing glycogenesis and decreasing gluconeogenesis via the LKB1/AMPK pathway. The ability of OEA to control hepatic LKB1/AMPK pathways may serve as a novel therapeutic approach for the treatment of T2DM. SIGNIFICANCE STATEMENT: Oleoylethanolamide (OEA) exerted a potent antihyperglycemic effect in a peroxisome proliferator-activated receptor α-independent manner. OEA played an antihyperglycemic role primarily via regulation of hepatic glycogen synthesis and gluconeogenesis. The main molecular mechanism of OEA in regulating liver glycometabolism is activating the liver kinase B1/5' AMP-activated protein kinase signaling pathways.

Distinct cardiac energy metabolism and oxidative stress adaptations between obese and non-obese type 2 diabetes mellitus

Background: Little is known about the pathophysiological diversity of myocardial injury in type 2 diabetes mellitus (T2DM), but analyzing these differences is important for the accurate diagnosis and precise treatment of diabetic cardiomyopathy. This study aimed to elucidate the key cardiac pathophysiological differences in myocardial injury between obese and non-obese T2DM from mice to humans.

Methods: Obese and non-obese T2DM mouse models were successfully constructed and observed until systolic dysfunction occurred. Changes in cardiac structure, function, energy metabolism and oxidative stress were assessed by biochemical and pathological tests, echocardiography, free fatty acids (FFAs) uptake fluorescence imaging, transmission electron microscopy, etc. Key molecule changes were screened and verified by RNA sequencing, quantitative real-time polymerase chain reaction and western blotting. Further, 28 human heart samples of healthy population and T2DM patients were collected to observe the cardiac remodeling, energy metabolism and oxidative stress adaptations as measured by pathological and immunohistochemistry tests.

Results: Obese T2DM mice exhibited more severe cardiac structure remodeling and earlier systolic dysfunction than non-obese mice. Moreover, obese T2DM mice exhibited severe and persistent myocardial lipotoxicity, mainly manifested by increased FFAs uptake, accumulation of lipid droplets and glycogen, accompanied by continuous activation of the peroxisome proliferator activated receptor alpha (PPARα) pathway and phosphorylated glycogen synthase kinase 3 beta (p-GSK-3β), and sustained inhibition of glucose transport protein 4 (GLUT4) and adipose triglyceride lipase (ATGL), whereas non-obese mice showed no myocardial lipotoxicity characteristics at systolic dysfunction stage, accompanied by the restored PPARα pathway and GLUT4, sustained inhibition of p-GSK-3β and activation of ATGL. Additionally, both obese and non-obese T2DM mice showed significant accumulation of reactive oxygen species (ROS) when systolic dysfunction occurred, but the NF-E2-related factor 2 (Nrf2) pathway was significantly activated in obese mice, while was significantly inhibited in non-obese mice. Furthermore, the key differences found in animals were reliably verified in human samples.

Conclusion: Myocardial injury in obese and non-obese T2DM may represent two different types of complications. Obese T2DM individuals, compared to non-obese individuals, are more prone to develop cardiac systolic dysfunction due to severe and persistent myocardial lipotoxicity. Additionally, anti-oxidative dysfunction may be a key factor leading to myocardial injury in non-obese T2DM.

Effect of polysaccharides from adlay seed on anti-diabetic and gut microbiota

Diabetes is a chronic metabolic disease characterized by elevated blood glucose levels due to insulin resistance and β-cell dysfunction. This study aims to examine the effects of polysaccharides from adlay seeds (PAS) on hyperglycemia and gut microbiota in streptozocin (STZ)-induced diabetic mice. The administration of PAS in diabetic mice caused a significant decrease in the glucose level and serum levels of glycosylated hemoglobin (HbA1c). Similarly, PAS also showed decreased total cholesterol (TC) and triglyceride (TG) concentrations. Furthermore, a significant increase in the concentrations of glucagon-like peptide 1 (GLP-1) was observed. Unexpectedly, PAS reduced the concentrations of anti-amyloid beta (Aβ1-42) protein. Also, histopathological examination showed that PAS contributed to the reduction of STZ-lesioned pancreatic cells. Metformin treatment significantly reduced the diversity of the gut microbiota, while PAS treatment altered the diversity and composition of the microbiota. Collectively, our findings demonstrate that the hypoglycemic effects of PAS in type-2 diabetic mice (T2D) may be associated with the regulation of the intestinal microbiota and its metabolic pathways.

Jiaogulan tea (Gpostemma pentaphyllum) potentiates the antidiabetic effect of white tea via the AMPK and PI3K pathways in C57BL/6 mice

The use of plant-based beverages to interfere with the onset of diabetes may be a promising approach towards type 2 diabetes mellitus (T2DM).

Antihyperglycemic activity of Porphyridium cruentum biomass and extra-cellular polysaccharide in streptozotocin-induced diabetic rats

Porphyridium cruentum, known as red microalga, is able to produce extra-cellular polysaccharides (EPs) that have beneficial health effects. In this study, the effect of P. cruentum biomass and EPs with various doses was studied in streptozotocin (STZ)-induced diabetic rats to determine their antihyperglycemic activity and its potential mechanism. The doses of biomass were 600, 1200 and 1800 mg/kg body weight (BW) while the doses of EPs were 150, 300 and 450 mg/kg BW. P. cruentum biomass and EPs could slightly reduce food intake in STZ-diabetic rats as compared with diabetic group. After a 14-day treatment, P. cruentum EPs could decrease blood glucose levels of STZ-induced diabetic rats while P. cruentum biomass at all doses could not. P. cruentum EPs was as effective as glibenclamide in lowering blood glucose levels of diabetic rats. In addition, P. cruentum EPs could significantly increase (p < 0.05) Langerhans islets areas, the number of β-cells and the height of intestinal villi. Treatment with 450 mg/kg BW of EPs resulted in the most effective antihyperglycemic activity. Thus, P. cruentum has the potential to resolve hyperglycemic and diabetic problems.

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.

Antioxidant and Anti-Diabetic Activities of Polysaccharides from Guava Leaves

Guava (Psidium guajava L., Myrtaceae) leaves have been used as a folk herbal tea to treat diabetes for a long time in Asia and North America. In this study, we isolated polysaccharides from guava leaves (GLP), and evaluated its antioxidant activity in vitro and anti-diabetic effects on diabetic mice induced by streptozotocin combined with high-fat diet. The results indicated that GLP exhibited good DPPH, OH, and ABTS free-radical scavenging abilities, and significantly lowered fasting blood sugar, total cholesterol, total triglycerides, glycated serum protein, creatinine, and malonaldehyde. Meanwhile, it significantly increased the total antioxidant activity and superoxide dismutase (SOD) enzyme activity in diabetic mice, as well as ameliorated the damage of liver, kidney, and pancreas. Thus, polysaccharides from guava leaves could be explored as a potential antioxidant or anti-diabetic agents for functional foods or complementary medicine.

Antidiabetic activity of a polysaccharide-protein complex from Asian Clam (Corbicula fluminea) in streptozotoxin-induced diabetic rats and its underlying mechanism

Antidiabetic activity of a polysaccharide-protein complex from Asian Clam (Corbicula fluminea) in streptozotoxin-induced diabetic rats and its underlying mechanism.

Hypolipidemic activities of partially deacetylated α-chitin nanofibers/nanowhiskers in mice

Partially deacetylated α-chitin nanofibers/nanowhiskers mixtures (DEChNs) were prepared by 35% sodium hydroxide (NaOH) treatment followed by disintegration in water at pH 3-4. The aim of this study was to investigate the hypolipidemic effects of DEChNs at different dosage levels in male Kunming mice. The male mice were randomly separated into five groups, that is, a normal diet group, a high-fat diet group, and three DEChN groups that were treated with different doses of DEChN dispersions (L: low dose, M: medium dose, H: high dose). Primarily, the DEChNs significantly decreased body weight (BW) gain and adipose tissue weight (ATW) gain of mice. Meanwhile, the decreasing extent of weight ratios between ATW and BW was dependent on the dose of DEChNs. Moreover, the DEChNs prevented an increase in plasma lipids (cholesterol and triacylglycerol) in mice when they were fed a high-fat diet. Histopathological examination of hepatocytes revealed that the DEChNs were effective in decreasing the accumulation of lipids in the liver and preventing the development of a fatty liver. The results suggested that the DEChNs reduced the absorption of dietary fat and cholesterol in vivo and could effectively reduce hypercholesterolemia in mice.

A novel PPARα/γ agonist, propane-2-sulfonic acid octadec-9-enyl-amide, ameliorates insulin resistance and gluconeogenesis in vivo and vitro

Peroxisome proliferator-activated receptor alpha/gamma (PPARα/γ) agonists have emerged as important pharmacological agents for improving insulin action. Propane-2-sulfonic acid octadec-9-enyl-amide (N15) is a novel PPARα/γ dual agonist synthesized in our laboratory. The present study investigates the efficacy and safety of N15 on insulin resistance regulation in high fat diet (HFD)-and streptozotocin (STZ)-induced diabetic mice and in palmitic acid (PA)-induced HepG2 cells. Our results showed that N15 remarkably ameliorated insulin resistance and dyslipidemia in vivo, as well as rectified the glucose consumption and gluconeogenesis in vitro. Moreover, the glucose-lowering effect of N15 was associated with PPARγ mediated up-regulation of hepatic glucose consumption and down-regulation of gluconeogenesis. Meanwhile, N15 exerted advantageous effects on glucose and lipid metabolism without triggering weight gain and hepatotoxicity in mice. In conclusion, our data demonstrated that by alleviating glucose and lipid abnormalities, N15 could be used as a potential prophylactic and therapeutic agent against type 2 diabetes and related metabolic disorders.

Biological activities and pharmaceutical applications of polysaccharide from natural resources: A review

Pharmacotherapy using natural substances can be currently regarded as a very promising future alternative to conventional therapy. As biological macromolecules, polysaccharide together with protein and polynucleotide, are extremely important biomacromoleules which play important roles in the growth and development of living organism. Polysaccharide is important component of higher plants, membrane of the animal cell and the cell wall of microbes. It is also closely related to the physiological functions. Recently, increasing attention has been paid on polysaccharides as an important class of bioactive natural products. Numerous researches have demonstrated the bioactivities of natural polysaccharides, which lead to the application of polysaccharides in the treatment of disease. In this paper, the various aspects of the investigation results of the bioactivities of polysaccharides were summarized, including its diversity pharmacological applications, such as immunoregulatory, anti-tumor, anti-virus, antioxidation, and hypoglycemic activity, and their application of polysaccharides in the treatment of disease are also discussed. We hope this review can offer some theoretical basis and inspiration for the mechanism study of the bioactivity of polysaccharides.

Antidiabetic activities of polysaccharides separated from Inonotus obliquus via the modulation of oxidative stress in mice with streptozotocin-induced diabetes

This study evaluated the effects of Inonotus obliquus polysaccharides (IOs) on diabetes and other underlying mechanisms related to inflammatory factors and oxidative stress in a mouse model of streptozotocin (STZ)-induced diabetes. Four weeks administration of metformin (120 mg/kg) and IO1-4 (50%-80% alcohol precipitation), or IO5 (total 80% alcohol precipitation) at doses of 50 mg/kg reverses the abnormal changes of bodyweights and fasting blood glucose levels of diabetic mice. IOs significantly increased the insulin and pyruvate kinase levels in serum, and improved the synthesis of glycogen, especially for IO5. IOs restored the disturbed serum levels of superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde. The down-regulation of interleukin-2 receptor, matrix metalloproteinase-9, and the enhancement of interleukin-2 in serum of diabetic mice were significantly attenuated by IOs. Histologic and morphology examinations showed that IOs repaired the damage on kidney tissues, inhibited inflammatory infiltrate and extracellular matrix deposit injuries in diabetic mice. Compared with untreated diabetic mice, IOs decreased the expression of phosphor-NF-κB in the kidneys. These results show that IOs treatment attenuated diabetic and renal injure in STZ-induced diabetic mice, possibly through the modulation of oxidative stress and inflammatory factors. These results provide valuable evidences to support the use of I. obliquus as a hypoglycemic functional food and/or medicine.

Hypoglycemic and hypolipidemic effects of a polysaccharide from Lachnum YM240 and its derivatives in mice, induced by a high fat diet and low dose STZ

Carboxymethylated and sulfated polysaccharides (CLEP and SLEP) were prepared from an exopolysaccharide previously obtained from Lachnum YM240 (LEP) by chemical modifications. Two doses (50 mg kg-1 and 200 mg kg-1 b. w.) of LEP, CLEP and SLEP were orally administered to normal mice and type 2 diabetic mice (T2DM) that were induced by streptozotocin (STZ) and a high fat diet, respectively. The hypoglycemic effect was evaluated by testing the oral glucose tolerance, fasting blood glucose (FBG) levels, fasting serum insulin (FINS), glycosylated hemoglobin A1c (HbA1c), and the hypolipidemic effect was evaluated by the body, spleen, pancreas, liver and kidney weights, as well as serum triglycerides (TG), cholesterol (TC) and free fatty acids (FFA). After four weeks of administration, LEP, CLEP and SLEP showed a marked FBG fall rate of 11.2%, 44.0% and 42.5% for the high-dose and 7.43%, 38.5% and 33.1% for the low-dose, respectively, as compared to the DC group. Moreover, compared with DC mice, TC concentrations in the high-dose groups of LEP, CLEP and SLEP were significantly decreased by 29.6%, 38.7% (P < 0.05), 33.0% (P < 0.05), and TG concentrations decreased by 18.9%, 43.9% (P < 0.01), 29.0% (P < 0.05), respectively. In addition, LEP and the derivatives significantly upregulated the expression of glucokinase (GK) and adenosine monophosphate-activated protein kinase (AMPK) in the liver, AMPK and glucose transporter 4 (Glut4) in skeletal muscle and peroxysome proliferator-activated receptor (PPAR-γ) in adipose tissue, whereas downregulated the expression of glucose-6-phosphatase (G6P) in the liver; these were examined using ELISA detection kits. These results for FBG and serum lipids indicate that LEP and its derivatives possess significant hypoglycemic and hypolipidemic effects and carboxymethylation improved the hypoglycemic and hypolipidemic effects more effectively than sulfation. Therefore, the carboxymethylated and sulfated modifications were effective ways to enhance the hypoglycemic and hypolipidemic activities of polysaccharides.

Anti-hyperglycemic activity of polysaccharides from calyx of Physalis alkekengi var. franchetii Makino on alloxan-induced mice

The present study was undertaken to investigate the hypoglycemic effect of polysaccharides (PPSC) isolated from calyx of Physalis alkekengi var. franchetii Makino in alloxan-induced diabetic mice. Seven polysaccharide fractions were obtained through a DEAE-52 column and Sephadex G-100 gel column and they were the main composes of PPSC. The PPSC treatment could prevent the loss of body weight in diabetic mice and result in a decrease of fasting blood glucose (FBG) and glycated serum protein (GSP) and an increase of fasting serum insulin in a dose-dependent manner. The histopathological examination of pancreas revealed the ability of PPSC to protect and reverse β-cells from necrosis due destruction of alloxan in diabetic mice. Furthermore, oral PPSC upregulated the expression of PI3K, Akt and GLUT4 mRNA in skeletal muscles and adipose tissues. The results suggest that PPSC possess significant anti-diabetic activity, as evaluated using alloxanised diabetic mice model. Consequently, PPSC might be a promising candidate for the development of a new anti-diabetic agent.

Applicability of Isolates and Fractions of Plant Extracts in Murine Models in Type II Diabetes: A Systematic Review

Type II diabetes mellitus is one of the most common public health problems worldwide. Its increasing prevalence in several countries and the difficult metabolic control of individuals with the disease justify studying strategies for primary prevention. The population has sought alternative and cheaper ways to treat the disease, including the use of plants considered medicinal by the population. In this study, we carried out a systematic review on the applicability of isolates and fractions of plant extracts in animal models in type II diabetes. A literature search was performed in MEDLINE/PubMed and Scopus databases. Studies using other experimental animals (horses, rabbits, and monkeys) and humans as well as articles in Chinese, German, and Russian were excluded. We assessed the quality of the studies included by using the criteria described in the ARRIVE guidelines. In general, the animals that received fractions or isolates presented reduced blood glucose levels, normalization of body weight and plasma insulin levels, and reduced total triglycerides and cholesterol. In addition, we observed wide variation among the analyzed parameters, which hindered comparison between the studies found. In further studies, standardized reports and experimental design would help to establish comparable study groups and advance the overall knowledge, thus facilitating translatability from animal data to human clinical conditions.

Anti-diabetic polysaccharides from natural sources: A review

Diabetes mellitus (DM) is a metabolic disease attracted worldwide concerns, which severely impairs peoples' quality of life and is attributed to several life-threatening complications, including atherosclerosis, nephropathy and retinopathy. The current therapies for DM include mainly oral anti-diabetic drugs and insulin. However, continuous use of these causes insulin resistance and side-effects, and the demand of effective, nontoxic and affordable drugs for DM patients is eager. Several previous studies have shown that non-toxic biological macromolecules, mainly polysaccharides, possess prominent efficacies on DM. Based on these encouraging observations, a great deal of efforts have been focused on discovering anti-diabetic polysaccharides for the development of effective therapeutics for DM. This review focuses on the advancements in the anti-diabetic efficacy of various natural polysaccharides and polysaccharide complexes from 2010 to 2015.