Antidiabetic activity of polysaccharides from Suillellus luridus in streptozotocin-induced diabetic mice

An Overview on Mushroom Polysaccharides: Health-promoting Properties, Prebiotic and Gut Microbiota Modulation Effects and Structure-function Correlation

Mushroom polysaccharides are recognized as "biological response modifiers". Besides several bioactivities, a growing interest in their prebiotic potential has been raised due to the gut microbiota modulation potential. This review comprehensively summarizes mushroom polysaccharides' biological properties, structure-function relationship, and underlying mechanisms. It provides a recent overview of the key findings in the field (2018-2024). Key findings and limitations on structure-function correlation are discussed. Although most studies focus on β-glucans or extracts, α-glucans and chitin have gained interest. Prebiotic capacity has been associated with α-glucans and chitin, while antimicrobial and wound healing potential is attributed to chitin. However, further research is of utmost importance. Human fecal fermentation is the most reported approach to assess prebiotic potential, indicating impacts on intestinal biological, mechanical, chemical and immunological barriers. Gut microbiota dysbiosis has been directly connected with intestinal, cardiovascular, metabolic, and neurological diseases. Concerning gut microbiota modulation, animal experiments have suggested proinflammatory cytokines reduction and redox balance re-establishment. Most literature focused on the anticancer and immunomodulatory potential. However, anti-inflammatory, antimicrobial, antiviral, antidiabetic, hypocholesterolemic, antilipidemic, antioxidant, and neuroprotective properties are discussed. A significant overview of the gaps and research directions in synergistic effects, underlying mechanisms, structure-function correlation, clinical trials and scientific data is also given.

The function and application of edible fungal polysaccharides

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

Chemical characterisation and appraisal of antidiabetic potential of Terminalia citrina extract in streptozotocin induced hyperglycaemia in Wistar rats

The current research was aimed to evaluate the antidiabetic activity of Terminalia citrina methanolic extract (TCME) by streptozotocin-induced diabetes in male Wistar rats. TCME exhibited better in-vitro antioxidant and alpha-amylase inhibitory activity as compared to other tested extracts. TCME at 250, 500, and 750 mg/kg showed notable (p < .05) antidiabetic potential by lowering fasting blood glucose level, restoring lipid level, serum amylase, HbA1c, kidney, and liver function tests as coevidenced from histological findings of the liver, pancreas, and kidney. TCME remarkably reinstated the antioxidant enzymatic activities (CAT: 0.181 ± 0.011 IU/mg protein, SOD: 21.45 ± 1.53 IU/mg protein) and reduced lipid peroxidation level (40.60 ± 2.41 µM/mg protein) in the liver and kidney tissue of diabetic rats at 750 mg/kg dose. The acute and subacute oral toxicity study of TCME exhibited no clinical toxicity signs and mortality. Its GC-MS spectrum unveiled the existence of 10-octadecenoic acid and other compounds which might have contributed to antidiabetic potential.

Anti-Hyperglycemic Effect of the Brown Slime Cap Mushroom Chroogomphus rutilus (Agaricomycetes) Crude Polysaccharide In Vitro and In Vivo

The prevalence of diabetes is increasing worldwide, and it is very important to study new hypoglycemic active substances. In this study, we investigated the hypoglycemic effect of Chroogomphus rutilus crude polysaccharide (CRCP) in HepG2 cells and streptozotocin-induced diabetic mice. A glucose consumption experiment conducted in HepG2 cells demonstrated the in vitro hypoglycemic activity of CRCP. Furthermore, CRCP exhibited significant hypoglycemic effects and effectively ameliorated insulin resistance in insulin resistant HepG2 cells. In high-fat diet and streptozotocin-induced diabetic mice, after 4 weeks of CRCP administration, fasting blood glucose, fasting serum insulin, triglyceride, total cholesterol, low-density lipoprotein cholesterol, glutamate transaminase, alanine transaminase, and insulin resistance index significantly decreased, while high-density lipoprotein cholesterol and insulin sensitivity index (ISI) were markedly increased. Moreover, hematoxylin-eosin (HE) staining and immunofluorescence labeling of tissue sections indicated that CRCP attenuated the pathological damage of liver and pancreas in diabetic mice. These results indicate that CRCP is a potential hypoglycemic agent.

Characterization and comparison of cardiomyocyte protection activities of non-starch polysaccharides from six ginseng root herbal medicines

Ginseng is rich of polysaccharides, however, the evidence supporting polysaccharides to distinguish various ginseng species is rarely reported. Focusing on six root ginseng (e.g., Panax ginseng-PG, P. quinquefolius-PQ, P. notoginseng-PN, red ginseng-RG, P. japonicus-PJ, and P. japonicus var. major-PJM), the contained non-starch polysaccharides (NPs) were structurally characterized and compared by both the chemical and biological evaluation. Holistic fingerprinting at three levels (the NPs and the acid hydrolysates involving oligosaccharides and monosaccharides) utilized various chromatography methods, and the treatment of H9c2 cells with the NPs by OGD and H2O2-induced injury models was used to assess the protective effect. NPs from six Panax herbal medicines occupied about 20 % of the total polysaccharides, which were of the highest content in RG and the lowest in PN. NPs from six ginseng exhibited weak differentiations in the molecular weight distribution, while marker oligosaccharides were found to distinguish PN and RG from the others. Glc and GalA were more abundant in the NPs for PG and RG, respectively. NPs from PQ (100/200 μg/mL) showed significant cardiomyocyte protection effect by regulating the mitochondrial functions. This work further testifies the role of polysaccharides in quality control of herbal medicine, with new markers discovered beneficial to distinguish the ginseng.

Polysaccharides from natural resource: ameliorate type 2 diabetes mellitus via regulation of oxidative stress network

Diabetes mellitus (DM) is a group of metabolic diseases characterized by hyperglycemia that can occur in children, adults, elderly people, and pregnant women. Oxidative stress is a significant adverse factor in the pathogenesis of DM, especially type 2 diabetes mellitus (T2DM), and metabolic syndrome. Natural polysaccharides are macromolecular compounds widely distributed in nature. Some polysaccharides derived from edible plants and microorganisms were reported as early as 10 years ago. However, the structural characterization of polysaccharides and their therapeutic mechanisms in diabetes are relatively shallow, limiting the application of polysaccharides. With further research, more natural polysaccharides have been reported to have antioxidant activity and therapeutic effects in diabetes, including plant polysaccharides, microbial polysaccharides, and polysaccharides from marine organisms and animals. Therefore, this paper summarizes the natural polysaccharides that have therapeutic potential for diabetes in the past 5 years, elucidating their pharmacological mechanisms and identified primary structures. It is expected to provide some reference for the application of polysaccharides, and provide a valuable resource for the development of new diabetic drugs.

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.

Purification and Structure Characterization of the Crude Polysaccharide from the Fruiting Bodies of Butyriboletus pseudospeciosus and Its Modulation Effects on Gut Microbiota

Polysaccharides from the species of Boletaceae (Boletales, Agaricomycetes, Basidiomycota) are economically significant to both functional foods and medicinal industries. The crude polysaccharide from Butyriboletus pseudospeciosus (BPP) was prepared, and its physicochemical properties were characterized through the use of consecutive experimental apparatus, and its impact on the gut microbiota of Kunming mice was evaluated. Analyses of the structure characteristics revealed that BPP was mainly composed of Man, Glc, and Gal, possessing the pyranose ring and β/α-glycosidic linkages. TG analysis exhibited that BPP had great heat stability. The SEM observation performed demonstrated that BPP appeared with a rough, dense, and porous shape. Through the BPP intervention, the serum and fecal biochemical index in mice can be improved obviously (p < 0.05). The abundance of beneficial microbiota in the BPP-treated group was significantly increased, while the abundance of harmful microbiota was significantly decreased (p < 0.05). Based on the Tax4Fun, we also revealed the relationship between the species of gut microbiota and showed that the high dose of BPP has significantly changed the functional diversities compared with those in other groups (p < 0.05). The results suggest that B. pseudospeciosus could serve as potential functional food or medicine.

Isolation, structural and bioactivities of polysaccharides from Anoectochilus roxburghii (Wall.) Lindl.: A review

Anoectochilus roxburghii (Wall.) Lindl. (A. roxburghii), a valuable herbal medicine in China, has great medicinal and edible value. Polysaccharides, as one of the main active components of A. roxburghii, comprise glucose, arabinose, xylose, galactose, rhamnose, and mannose in different molar ratios and glycosidic bond types. By varying the sources and extraction methods of A. roxburghii polysaccharides (ARPS), different structural characteristics and pharmacological activities can be elucidated. ARPS has been reported to exhibit antidiabetic, hepatoprotective, anti-inflammatory, antioxidant, antitumor, and immune regulation activities. This review summarizes the available literature on the extraction and purification methods, structural features, biological activities, and applications of ARPS. The shortcomings of the current research and potential focus in future studies are also highlighted. This review provides systematic and current information on ARPS to promote their further exploitation and application.

The antihyperglycemic effect of pulsed electric field-extracted polysaccharide of Kaempferia elegans officinale on streptozotocin induced diabetic mice

Kaempferia elegans polysaccharide (KEP) was extracted using a high-voltage pulsed electric field-assisted hot water method. Its physicochemical properties, in vitro activity and hypoglycemic effect was investigated. Experiments were undertaken with diabetic mice models and the potential mechanism of KEP to improve blood glucose levels was unveiled through measurements of relevant indicators in the serum and liver of the mice. Results showed that KEP is mainly composed of glucose, rhamnose, arabinose, and galactose. It has certain DPPH and ABTS free radical scavenging ability and good α-glucosidase inhibitory ability, indicating that KEP has the potential to improve blood glucose levels in diabetes patients. The experimental results of KEP treatment on mice showed that KEP could control the continuous increase of fasting blood glucose levels. The potential mechanisms behind this blood glucose level control composes of (1) increasing the glucokinase and C peptide levels and decreasing Glucose-6-phosphatase content for improving key enzyme activity in the glucose metabolism pathway. This promotes the consumption of blood glucose during glycolysis, thereby inhibiting the production of endogenous glucose in gluconeogenesis pathway; (2) reducing triglyceride, total cholesterol, low density lipoprotein cholesterol, and increasing high density lipoprotein cholesterol content, for regulating blood lipid indicators to normal levels; and (3) by improving the activities of catalase, glutathione peroxidase, and antioxidant enzymes superoxide dismutase for further improving the antioxidant defense system in the body to reduce blood glucose.

A Review of Development and Utilization for Edible Fungal Polysaccharides: Extraction, Chemical Characteristics, and Bioactivities

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Because of their distinctive flavor and exceptional nutritional and medicinal value, they have been a frequent visitor to people’s dining tables and have become a hot star in the healthcare, pharmaceutical, and cosmetics industries. Edible fungal polysaccharides (EFPs) are an essential nutrient for edible fungi to exert bioactivity. They have attracted much attention because of their antioxidant, immunomodulatory, antitumor, hypoglycemic, and hypolipidemic bioactivities. As a result, EFPs have demonstrated outstanding potential over the past few decades in various disciplines, including molecular biology, immunology, biotechnology, and pharmaceutical chemistry. However, the complexity of EFPs and the significant impact of mushroom variety and extraction techniques on their bioactivities prevents a complete investigation of their biological features. Therefore, the authors of this paper thoroughly reviewed the comparison of different extraction methods of EFPs and their advantages and disadvantages. In addition, the molecular weight, monosaccharide composition, and glycosidic bond type and backbone structure of EFPs are described in detail. Moreover, the in vitro and in vivo bioactivities of EFPs extracted by different methods and their potential regulatory mechanisms are summarized. These provide a valuable reference for improving the extraction process of EFPs and their production and development in the pharmaceutical field.

The HbA1c and blood glucose response to selenium-rich polysaccharide from Fomes fomentarius loaded solid lipid nanoparticles as a potential antidiabetic agent in rats

Fomes fomentarius is a medicinal fungus used in traditional Chinese medicine to treat various illnesses. Antidiabetic effects of F. fomentarius extracts have been reported recently. In this study, F. fomentarius extracellular polysaccharide (PS) was prepared, and then to enhance its antidiabetic effects, Na₂SeO₃ was added to the culture medium, and selenium-polysaccharide (PS-Se) was obtained. Also, solid lipid nanoparticles containing PS (SLN-PS) and PS-Se (SLN-PS-Se) were synthesized by the microemulsion method to compare their effects with free polysaccharides in streptozotocin (STZ) diabetic rats. Optimized SLNs had a size of 170.5 nm and drug loading of 9.27 %. EDS analysis confirmed that Se presence in PS-Se. Characterization analyses such as FTIR, DSC, TGA, and XRD suggested that SLNs have good thermal stability and crystalline nature. Release of PS from SLNs demonstrated sustained profile, and MTT assay proved that PSs and SLNs have no cytotoxicity. Furthermore, oral administration of PS, PS-Se, SLN-PS, and SLN-PS-Se for 28 days to diabetic rats significantly declined blood glucose by 48.24 %, 49.96 %, 55.50 %, and 60.47 %, respectively. Also, insulin secretion and body weight improved, and HbA1c levels decreased. Treatment by PS, PS-Se, SLN-PS, and SLN-PS-Se alleviated lipid profiles, liver enzymes, and serum proteins. Liver anti-oxidant parameters and histopathological observation of the liver, pancreas, and kidney confirmed that F. fomentarius PSs and SLNs have antidiabetic impacts. Moreover, supplementation of PS with selenium improves its anti-hyperglycemic effects. Finally, SLN-PS and SLN-PS-Se showed a higher antidiabetic impact than free PS and PS-Se.

Neocornuside A–D, Four Novel Iridoid Glycosides from Fruits of Cornus officinalis and Their Antidiabetic Activity

Four previously undescribed iridoid glycosides neocornuside A–D (1–4), along with six known ones (5–10), were isolated from Cornus officinalis fruit. Their structures were elucidated by extensive spectroscopic (NMR, UV, IR, and MS) analysis and comparison with data reported in the literature. All isolates were assessed for their antidiabetic activity on the relative glucose consumption in insulin-induced insulin-resistant HepG2 cells. The results showed that compounds 1, 3, and 7 exhibited significant antidiabetic activities with EC50 values of 0.582, 1.275, and 0.742μM, respectively. Moreover, compounds 1, 3, and 7 could improve the ability of 2-NBDG uptake of insulin-induced HepG2 cells.

Hypoglycemic effect of a novel polysaccharide from Lentinus edodes on STZ-induced diabetic mice via metabolomics study and Nrf2/HO-1 pathways

With the increased worldwide prevalence of diabetes, more and more attentions are focused on the natural drug candidate who could treat diabetes with high efficacy but without undesired side effect....

Bioactive components of mushrooms: Processing effects and health benefits

Mushrooms have been recognized for their culinary attributes for long and were relished in the most influential civilizations in history. Currently, they are the focus of renewed research because of their therapeutic abilities. Nutritional benefits from mushrooms are in the form of a significant source of essential proteins, dietary non-digestible carbohydrates, unsaturated fats, minerals, as well as various vitamins, which have enhanced its consumption, and also resulted in the development of various processed mushroom products. Mushrooms are also a crucial ingredient in traditional medicine for their healing potential and curative properties. The literature on the nutritional, nutraceutical, and therapeutic potential of mushrooms, and their use as functional foods for the maintenance of health was reviewed, and the available literature indicates the enormous potential of the bioactive compounds present in mushrooms. Future research should be focused on the development of processes to retain the mushroom bioactive components, and valorization of waste generated during processing. Further, the mechanisms of action of mushroom bioactive components should be studied in detail to delineate their diverse roles and functions in the prevention and treatment of several diseases.

Delineating the inherent functional descriptors and biofunctionalities of pectic polysaccharides

Pectin is a plant-based heteropolysaccharide macromolecule predominantly found in the cell wall of plants. Pectin is commercially extracted from apple pomace, citrus peels and sugar beet pulp and is widely used in the food industry as a stabilizer, emulsifier, encapsulant, and gelling agent. This review highlights various parameters considered important for describing the inherent properties and biofunctionalities of pectins in food systems. These inherent descriptors include monosaccharide composition, galacturonic acid content, degree of esterification, molecular weight, structural morphology, functional group analysis, and functional properties, such as water and oil holding capacity, emulsification, foaming capacity, foam stability, and viscosity. In this study, we also delineate their potential as a nutraceutical, prebiotic, and carrier for bioactive compounds. The biofunctionalities of pectin as an anticancer, antioxidant, lipid-lowering, and antidiabetic agent are also conceptually elaborated in the current review. The multidimensional characteristics of pectin make it a potential candidate for use in food and biomedical science.

Sargassum fusiforme polysaccharide partly replaces acarbose against type 2 diabetes in rats

The objective of present research was to explore whether Sargassum fusiforme polysaccharide (SFP) could partly replace acarbose against type 2 diabetes in rats. Results indicated that SFP co-administered with low-dose acarbose intervention typically mitigated diabetic symptoms and serum profiles and exhibited better anti-diabetic effects than single acarbose treatment in controlling fasting blood glucose, improving insulin resistance and mitigating kidney injuries. The RT-qPCR analysis indicated that SFP co-administered with low-dose acarbose administration distinctly activated the IRS/PI3K/AKT signaling pathway compared with single acarbose treatment. Moreover, the co-administration also restrained liver fat accumulation via affecting the expression of HMGCR and SREBP-1c genes. In addition, the 16S rRNA gene sequencing analysis indicated that SFP co-administered with low-dose acarbose significantly restored beneficial composition of gut flora in diabetic rats, such as the increase of Muribaculaceae, Lachnospiraceae, Bifidobacterium, Ruminococcaceae_UCG-014, Ruminococcus_1, Romboutsia, Eggerthellaceae, Alistipes and Faecalibaculum, and the decrease of Escherichia-Shigella. These results suggested that SFP, the novel natural adjuvant of acarbose, displayed the desirable benefits in minimizing the dose of drug, while improving the anti-diabetic efficiency.

Structural characterization of a polysaccharide from Suillellus luridus and its antidiabetic activity via Nrf2/HO-1 and NF-κB pathways

A heteropolysaccharide designated SLPC-1S with the Mw of 9.4 kDa was purified from the caps of Suillellus luridus. Monosaccharide composition analysis revealed that SLPC-1S was composed of galactose, glucose, arabinose and mannose in a molar ratio of 44.9:27.6:14.7:12.8. Structural characterization indicated that SLPC-1S had a backbone principally composed of 1,3 linked α-D-Galp, 1,3 linked β-D-Glcp and 1,6 linked β-D-Glcp with the branches mainly composed of 1,3 linked β-D-Glcp, 1,3 linked α-L-Arap, 1,3 linked α-D-Manp and T-linked α-D-Galp. Furthermore, SLPC-1S exhibited excellent antidiabetic activities in the streptozotocin-induced diabetic mice. Protein expression and mRNA levels in NF-kB and Nrf2/HO-1 signaling pathways were detected by western blots and real-time polymerase chain reaction (RT-PCR), respectively. The results strongly proved that SLPC-1S can be treated as a potential agent for preventing and treating diabetes via regulating Nrf2-mediated oxidative stress and NF-κB-mediated inflammatory responses.

A novel polysaccharide from Castanea mollissima Blume: Preparation, characteristics and antitumor activities in vitro and in vivo

A new water-soluble polysaccharide, CMP90, with a molecular weight of 23.9 kDa was isolated from Castanea mollissima Blume and the preliminary structural characteristics and antitumor effects of CMP90 in vitro and in vivo were investigated in the research. CMP90 consists of arabinose, galactose, glucose, xylose and mannose (molar ratio: 0.08:0.11:5.14:0.12:0.08) with α- and β-anomeric units. The results of in vitro experiments indicated that CMP90 exhibited a significant inhibitory effect on the proliferation of HL-60 cells with typical apoptotic characteristics by inducing cell cycle arrested at G1/M phase. Additionally, the results in vivo suggested CMP90 was able to inhibit the growth of S180 solid tumors via protecting immune organs, improving the levels of serum cytokines (TNF-α, IL-2 and IFN-γ), enhancing the activities of immune cells (macrophages, lymphocytes and NK cells) and inducing cell apoptosis or death. Taken together, these combined data clearly indicated that CMP90 may be used as a potential candidate agent for cancer therapy.

Adjuvant Therapy With Mushroom Polysaccharides for Diabetic Complications

Background

Diabetic complications seriously endanger the health of most diabetic patients around the world. Most chemical hypoglycemic agents have adverse effects and are unable to improve the progression of diabetic complications. In recent years, a number of medicinal herbs have become increasingly popular for the treatment of diabetic complications due to their relative safety. Polysaccharides extracted from medicinal herbs with multiple pharmacological activities and low toxicity have been reported to be useful in the treatment of diabetic complications.

Methods

Primary studies with keywords including polysaccharide and diabetic complications were retrieved from the Web of Science and NCBI databases and were read and analyzed.

Results

Mushroom polysaccharides were proven to have positive effects on diabetic complications.

Conclusions

We studied the effects of mushroom polysaccharides on hyperglycemia and as adjuvant therapies for diabetic complications and summarized the applications and limitations of mushroom polysaccharides to better understand their application for the treatment of diabetic complications.

The purification, structural characterization and antidiabetic activity of a polysaccharide from Anoectochilus roxburghii

Anoectochilus roxburghii, a traditional Chinese medicinal herb, has been widely used for treating numerous chronic diseases.

Anti-Diabetic Nephropathy Activities of Polysaccharides Obtained from Termitornyces albuminosus via Regulation of NF-κB Signaling in db/db Mice

Termitornyces albuminosus is a kind of traditional Chinese edible fungus rich in nutrients and medicinal ingredients, and it has anti-oxidative, analgesic and anti-inflammatory effects. However, the hypoglycemic and nephroprotective effects of polysaccharides separated from T. albuminosus (PTA) have not been reported. The properties of PTA were analyzed in a BKS.Cg-Dock7^m +/+ Lepr^db/JNju (db/db) mouse model of diabetes. After the administration of PTA for eight weeks, the hypoglycemic and hypolipidemic activities of PTA in the db/db mice were assessed. The results of a cytokine array combined with an enzyme-linked immunosorbent assay confirmed the anti-oxidative and anti-inflammatory activities of PTA. An eight-week administration of PTA caused hypoglycemic and hypolipidemic functioning, as indicated by suppressed plasma glucose levels, as well as the modulation of several cytokines related to glycometabolism, in the sera and kidneys of the mice. PTA treatment also had a protective effect on renal function, restoring renal structures and regulating potential indicators of nephropathy. In the kidneys of the db/db mice, PTA treatment reduced the activation of protein kinase B, the inhibitor of κB kinase alpha and beta, and the inhibitor of κB alpha and nuclear factor-κB (NF-κB). We establish the hypoglycemic, hypolipidemic, and anti-diabetic nephropathy effects of PTA, and we find that the renal protection effects of PTA may be related to anti-inflammatory activity via the regulation of NF-κB signaling.

Glucose-lowering and hypolipidemic activities of polysaccharides from Cordyceps taii in streptozotocin-induced diabetic mice

Background

Hyperglycemia and dyslipidemia are classic features of patients with diabetes mellitus (DM). Cordyceps taii, a folk medicinal fungus native to southern China, possesses various pharmacological activities. This study aimed to assess the glucose-lowering and hypolipidemic effects of polysaccharides from C. taii (CTP) in streptozotocin (STZ)-induced diabetic mice.

Methods

Kunming mice were intraperitoneally injected with STZ at a dose of 100 mg/kg body weight. After induction of diabetes, diabetic mice were randomly divided into five groups: diabetic mellitus group (DM), metformin-treated group, low, medium, and high-dose CTP-treated group (CTP-L, CTP-M, and CTP-H). Normal mice served as the control group. After treatment for 28 days, body weight, fasting serum insulin (FSI), fasting blood glucose (FBG), homeostasis model assessment-insulin resistance (HOMA-IR), triglyceride (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and C-reactive protein (CRP) levels were measured. Histological analysis of pancreatic tissue and immune organ indices was also performed to evaluate the anti-diabetes effect of CTP. SPSS (version 21.0) software was used for statistical analysis, and statistical differences were considered significant at p < 0.05.

Results

Compared with the DM group, the body weight and FSI level of CTP-H group increased by 36.13 and 32.47%, whereas the FBG and HOMA-IR decreased by 56.79 and 42.78%, respectively (p < 0.05). Histopathological examination of the pancreas revealed that CTP improved and repaired the impaired islet β-cells in pancreatic tissue. Compared with the DM group, the levels of TC, TG, and LDL-C decreased by 13.84, 31.87, and 36.61%, whereas that of HDL-C increased by 28.60% in CTP-H (p < 0.05). Further study showed that the thymus index in CTP-H was elevated by approximately 54.96%, and the secretion of pro-inflammatory cytokines TNF-α, IL-6, and CRP was inhibited by approximately 19.97, 34.46, and 35.41%, respectively (p < 0.05).

Conclusion

The anti-diabetes effect of CTP is closely associated with immunoregulation and anti-inflammation, and CTP may be considered as a therapeutic drug or functional food for DM intervention.

Structural characterization and determination of biological activities for different polysaccharides extracted from tree mushroom species

Chemical composition and structural characterization of polysaccharides of Fomes fomentarius (FF), Fuscoporia torulosa, Ganoderma adspersum, Ganoderma applanatum (GAP), Ganoderma lucidum, Phellinus igniarius, Pleurotus ostreatus (PO), and Porodaedalea pini (PP) tree mushrooms with antioxidant and anticholinesterase activities were determined in this research. Total carbohydrate contents of the polysaccharides were ranged between 65.06 ± 6.76 and 88.27 ± 5.15 µg/mg and total protein contents were ranged between 3.18 ± 0.72 and 6.56 ± 1.25 µg/mg. Galactose, glucose, and mannose were identified as major monosaccharides in all polysaccharides using gas chromatography-mass spectrometry. FT-IR analysis showed the characteristic peaks of the polysaccharides and high performance liquid chromatography-diode array detection was used to determine the molecular weight of the polysaccharides. In β-carotene-linoleic acid assay FF (IC₅₀ : 2.55 ± 0.40 µg/ml) displayed the highest antioxidant activity, whereas GAP indicated the highest antioxidant activity in cupric reducing antioxidant capacity (A_0.50 :59.90 ± 0.53 μg/ml), ABTS^•+ (IC₅₀ : 16.62 ± 0.31 μg/ml), and DPPH^• (IC₅₀ : 45.58 ± 0.21 μg/ml) assays. In cholinesterase inhibitory activity test, PO (56.31±0.0.74%) showed significant inhibitory activity against butyrylcholinesterase enzyme. PRACTICAL APPLICATIONS: Polysaccharides from mushrooms are the major class of bioactive compounds with various biological activities. Several studies were performed on the biological activity of the polysaccharide extracts from different mushrooms. However, to our knowledge, this is the first report on the chemical composition, structural characterization, antioxidant, and anticholinesterase activities of extracted polysaccharides from studied mushrooms in detail. This investigation shows that polysaccharide extracts obtained from tree mushrooms show a significant bioactivity and these polysaccharides might be used as bioactive natural sources in the pharmaceutical, food, and cosmetic industries.