Frondosa Polysaccharide Research Articles

Optimization of Extraction Technology, Structure, and Antioxidant Activity of Polysaccharide from Grifola frondosa

AbstractUsing DMSO as solvent, ultrasonic‐assisted extraction of polysaccharides from Grifola frondosa is studied. The effects of different extraction conditions on the yield of polysaccharides are investigated. The optimal extraction conditions are found by a Box‐Behnken design. The results showed that the yield of Grifola frondosa polysaccharide can reach 6.94% under the following conditions: liquid–solid ratio of 33.8 mL g‐1, ultrasonic power of 104.6 W, extraction temperature of 35.6°C, and extraction time of 4.7 h. The structure of the polysaccharides is investigated by infrared spectroscopy, nuclear magnetic resonance, molecular weight, monosaccharide composition, and methylation. The purified polysaccharides are found to have good antioxidant activity in vitro.

The polysaccharides from the Grifola frondosa fruiting body prevent lipopolysaccharide/D-galactosamine-induced acute liver injury via the miR-122-Nrf2/ARE pathways.

Polysaccharides can be used as a potential hepatoprotective agent in the treatment of acute liver injury. However, the underlying mechanism governing how polysaccharides protect against acute liver injury induced by lipopolysaccharide/d-galactosamine (LPS/d-GalN) remains unclear. To investigate the mechanism, the anti-oxidative and anti-inflammatory action and pathways were determined. In this study, we investigated the hepatoprotective effects of Grifola frondosa polysaccharides (GFP), which are obtained from the fruiting body of Grifola frondosa, on (LPS/d-GalN)-induced liver injury in mice. Histopathological analyses showed that GFP protected against LPS/d-GalN-induced lung inflammation. The activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the levels of the inflammatory mediators tumor necrosis factor-α (TNF-α), interleukin (IL)-2, IL-6, and monocyte chemoattractant protein-1 (MCP-1) were inhibited by GFP. The LPS/d-GalN-induced myeloperoxidase (MPO) activity and malondialdehyde (MDA) content were inhibited by GFP. The levels of superoxide dismutase (SOD) and glutathione (GSH) were upregulated by GFP. The GFP-treated group showed reduced expression levels of miR-122 in liver tissue. Nrf2 has been identified as a potential target of miR-122. The western blotting results showed that GFP attenuates LPS/d-GalN-induced acute liver injury via upregulating transcription factors Nrf2, Nqo-1, and HO-1 and downregulating transcription factor Keap-1 in the Nrf2/ARE signaling pathway. In conclusion, these results indicated that GFP was highly effective in inhibiting liver injury and may be a promising potential therapeutic reagent for liver injury treatment. GFP exerts protective effects against LPS/d-GalN-induced liver injury in mice, which may be related to the regulation of the miR-122-Nrf2/ARE pathways.

The role of Rho1 gene in the cell wall integrity and polysaccharides biosynthesis of the edible mushroom Grifola frondosa

Grifola frondosa polysaccharides, especially β-glucans, showed the significant antitumor, hypoglycemic, and immune-stimulating activities. In the present study, a predominant regulatory subunit gfRho1p of β-1,3-glucan synthase in G. frondosa was identified with a molecular weight of 20.79 kDa and coded by a putative 648-bp small GTPase gene gfRho1. By constructing mutants of RNA interference and over-expression gfRho1, the roles of gfRho1 in the growth, cell wall integrity and polysaccharide biosynthesis were well investigated. The results revealed that defects of gfRho1 slowed mycelial growth rate by 22% to 33%, reduced mycelial polysaccharide and exo-polysaccharide yields by 4% to 7%, increased sensitivity to cell wall stress, and down-regulated gene transcriptions related to PKC-MAPK signaling pathway in cell wall integrity. Over-expression of gfRho1 improved mycelial growth rate and polysaccharide production of G. frondosa. Our study supports that gfRho1 is an essential regulator for polysaccharide biosynthesis, cell growth, cell wall integrity and stress response in G. frondosa.

Investigation of the uptake and transport of polysaccharide from Se-enriched Grifola frondosa in Caco-2 cells model

A variety of beneficial pharmacological activities have been reported for Se-enriched Grifola frondosa polysaccharides. However, little has been reported on its absorption, and its intestinal uptake and transport profiles remain unknown. Based on our previous research, the aim of this study was to investigate its absorption from two aspects - the polysaccharides and selenium of Se-enriched Grifola frondosa polysaccharides (Se-GFP-22) across Caco-2 cells in vitro. The Caco-2 cells monolayer culture model was successfully constructed to study the transport and uptake of Se-GFP-22. The results revealed that the uptake and transport of Se-GFP-22 were time- and concentration- dependent. Transport studies illustrated that Se-GFP-22 could penetrate Caco-2 cells, mainly mediated through the same routes as endocytosis and selenium in the organic selenium (Se-GFP-22) was more easily absorbed than that in the inorganic selenium control group (sodium selenite). The uptake of Se-GFP-22 may be a macropinocytosis pathway, which was an accumulation from cytoplasm to nucleus process. Se-GFP-22 was a moderately absorbed biological macromolecule testified by the apparent permeability coefficients (Papp) value and transport rates. This work illustrates the characteristics on uptake and transport of Se-GFP-22 and all these results may help to explore the mechanism of polysaccharide absorption in vitro.

Meta-analysis on effect of Grifola frondosa polysaccharide in regulating in vivo immunoregulatory function on animal disease models

The study aimed to explore the in vivo immunoregulatory function of Grifola frondosa polysaccharide( GFP) on animal disease models. Databases of PubMed,Embase,Web of Scinece,CNKI,CBM and Wan Fang Data were searched from the date of their establishment to February 2018. Two reviewers independently screened included studies and evaluated their quality by using SYRCLE's risk of bias tool. R software was used to analyze the data. Finally,20 animal experiment studies were included. According to Metaanalysis. For cellular immunity,GFP could effectively enhance the proliferation of effect or T cells,natural killer cells and macrophages in mice. The percentage of CD4+T cells( MD = 1. 89,95% CI [0. 94,2. 83],P < 0. 000 1),CD8+T cells( MD = 8. 46,95% CI[5. 93,11. 00],P<0. 000 1),NK cells( MD= 2. 67,95% CI [0. 23,5. 11],P= 0. 03),and macrophages( MD= 14. 09,95% CI[0. 84,27. 34],P= 0. 04) were all higher than those in control group. For humoral immunity,GFP could increase the secretion of TNF-α and INF-γ． The secretion of TNF-α( SMD = 15. 92,95% CI [9. 07,22. 76],P<0. 000 1) and INF-γ( SMD = 5. 34,95% CI[3. 42,7. 26],P<0. 000 1) were all higher than those in control group. In conclusion,GFP could regulate immunologic function by enhancing the proliferation activity of immune cells( CD4+T cells,CD8+T cells,NK cells and macrophages) and the secretion of immune factors( TNF-α and INF-γ) ． However,it is necessary to further standardize the selection of specific surface markers of immune cells and the administration of GFP,in order to reduce the heterogeneity among the studies. At the same time,more attention shall be paid to experimental design,implementation and full report,especially to the establishment and implementation of animal experimental registration system,so as to improve the transparency and quality of the whole process of animal experimental research,enhance the value of basic research ultimately,and provide a reliable theoretical basis for the transformation of basic research into clinical research.

Hypoglycemic and hypolipidemic activities of Grifola frondosa polysaccharides and their relationships with the modulation of intestinal microflora in diabetic mice induced by high-fat diet and streptozotocin

This study aimed to investigate the hypoglycemic and hypolipidemic activities of polysaccharides from Grifola frondosa (GFP) in diabetic mice induced by high-fat diet (HFD) and streptozotocin (STZ). Results showed that oral administration of GFP markedly reduced the serum levels of fasting blood glucose (FBG), oral glucose tolerance (OGT), cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C), and significantly decreased the hepatic levels of TC, TG and free fatty acids (FFA). Meanwhile, high-dose of GFP supplementation (900 mg/kg day) also showed powerful effects on moderating the composition of intestinal microflora in diabetic mice, especially altering the functionally relevant intestinal microbial phylotypes. Spearman’s correlation network analysis revealed that key microbial phylotypes responding to GFP intervention were strongly correlated with the glucose and lipid metabolic disorders associated parameters. Moreover, GFP treatment regulated mRNA expression levels of the genes responsible for hepatic glucose and lipid metabolism. It is noteworthy that GFP treatment markedly increased mRNA expression of cholesterol 7α-hydroxylase (CYP7A1) and bile salt export pump (BSEP), suggesting an enhancement of bile acids (BAs) synthesis and excretion in liver. These findings demonstrated that GFP could prevent hyperglycemia and hyperlipidemia in diabetic mice by altering gut microbiota and regulating hepatic glycolipid metabolism related genes, and therefore could be used as potential functional food ingredients for the prevention or treatment of hyperglycemia and hyperlipidemia.

Hypoglycemic activity and gut microbiota regulation of a novel polysaccharide from Grifola frondosa in type 2 diabetic mice

GFP-N, a novel heteropolysaccharide with a molecular weight of 1.26 × 107 Da, was isolated from maitake mushroom and purified by anion-exchange chromatography on a DEAE cellulose-52 column and gel-filtration chromatography on a Sephadex G-100 column. Its structure was characterized by Fourier transform infrared spectroscopy and one-dimensional (1H- and 13C-) NMR spectra, 1H1H correlation spectroscopy, and 1H13C heteronuclear single-quantum coherence spectroscopy. The structure of GFP-N consisted of L-arabinose, D-mannose and D-glucose and mainly contained three kinds of linkage type units as →2,6)-α-D-Manp-(1 → 4, α-L-Araf-C1→, and →3,6)-β-D-Glcp-(1 → . GFP-N could activate insulin receptor substrate 1, phosphatidylinositol-3-kinase, and glucose transporter 4 and inhibit c-Jun N-terminal kinase 1/2 for hypoglycemic effects in diabetic mouse livers. This is also the first report of the regulatory efficacy of Grifola frondosa polysaccharide on intestinal microflora in vivo using single-molecule real-time sequencing. These results indicated that polysaccharide from maitake mushroom could be as an enhancer to improve type 2 diabetes and a healthy food option to help regulate gut microbiota in diabetic individuals.

The biological activities of the antitumor drug Grifola frondosa polysaccharide.

Grifola frondosa, a polypore fungus that grows at the base of trees, is an edible and medicinal mushroom with a large fruiting body characterized by overlapping caps. Japanese scholars found that Grifola frondosa polysaccharide or D-fraction is the major biologically active ingredient, which is a protein-bound glucan or proteoglucan, consisting of β-glucan (either β-1,6-linked glucan with β-1,3 branches or β-1,3-linked glucan branched with β-1,6 glucosides, but it also contains d-xylose, d-fucose, d-mannose, l-arabinose, uronic acid, and galactose with largely unknown linkages. The Grifola frondosa polysaccharides with different molecular weight and monosaccharide compositions can be obtained by using different extraction methods, such as hot water extraction, acid or alkaline extraction, or microwave extraction methods from the fruiting bodies, mycelia or the fermentation broth. Grifola frondosa polysaccharide-based drug was developed in China and approved as an adjunctive therapeutic drug for cancer treatment by the State Food and Drug Administration (SFDA) in 2010. There are eight fungal glycan-based drugs, some of them have to be injected in order to be effective in vivo but the Grifola frondosa polysaccharide-based drug can be taken either orally or by injection. In this article, based on the search results of Chinese VIP, CNKI, Wanfang database and PubMed database, 108 independent studies were summarized. The chemical structure, the antitumor, immunomodulatory, anti-diabetic, anti-hyperlipidemia, and antiviral activity and molecular mechanisms of GFP are reviewed and discussed. Our goal is to provide a molecular picture that would allow in-depth evaluation of Grifola frondosa polysaccharide as an adjunctive drug for cancer therapy.

Effect of Grifola frondosa polysaccharide on anti-tumor activity in combination with 5-Fu in Heps-bearing mice

GP11 had been reported to have effectively anti-tumor activity by improving the immune function in our previous study. To avoid drawbacks of the 5-Fu, GP11 in combination with 5-Fu was investigated in this study. The results demonstrated that such synergism displayed enhance the anti-tumor activity of 5-Fu. Additionally, a strength effect was also observed in regulating immune function of GP11 and 5-Fu simultaneous administration, such as enhancing serum interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-α) secretion, and increasing immune organs weights. Moreover, GP11 could improve the haematological and biochemical parameters deterioration, superoxide dismutase (SOD) activities reduction and malondialdehyde (MDA) levels enhancement in non-immune organs induced by 5-Fu. All these results illustrated that GP11 exhibited attenuated and synergized effect on 5-Fu by improving the immune function. It could be developed as an auxiliary preparation for chemotherapeutic drugs.

Anti-Diabetic and Anti-Nephritic Activities of Grifola frondosa Mycelium Polysaccharides in Diet-Streptozotocin-Induced Diabetic Rats Via Modulation on Oxidative Stress.

Grifola frondosa is an edible fungus with a variety of potential pharmacological activities. This study investigates the hypoglycemic, anti-diabetic nephritic, and antioxidant properties of G. frondosa polysaccharides in diet-streptozotocin-induced diabetic rats. After a 4-week treatment with 100mg/kg of metformin and 200mg/kg of one of four different G. frondosa polysaccharide mixtures (especially GFPS3 and GFPS4), diabetic rats had enhanced body weight and suppressed plasma glucose, indicating the hypoglycemic activities of the G. frondosa polysaccharides. G. frondosa polysaccharides regulated the level of serum creatinine, blood urea nitrogen, N-acetyl-β-D-glucosaminidase, and albuminuria; inhibited the serum levels of interleukin (IL)-2, IL-6, and TNF-α; and enhanced the serum levels of matrix metalloproteinase 9 and interferon-α, confirming their anti-diabetic nephritic activities. G. frondosa polysaccharides ameliorated the pathological alterations in the kidneys of diabetic rats. Moreover, G. frondosa polysaccharides modulated the serum levels of oxidant factors such as superoxide dismutase, glutathione peroxidase, catalase, malondialdehyde, and reactive oxygen species, revealing their antioxidant properties. Furthermore, the administration of G. frondosa polysaccharides inhibited nuclear factor kappa B activities in the serum and kidneys. All of the data revealed that the activation of nuclear factor kappa B plays a central role in G. frondosa polysaccharide-mediated anti-diabetic and anti-nephritic activities.

Se-enriched G. frondosa polysaccharide protects against immunosuppression in cyclophosphamide-induced mice via MAPKs signal transduction pathway

To assess the immunomodulatory and antioxidant activities of a Se-polysaccharide from Se-enriched G. frondosa (Se-GFP-22), immunosuppressed mice models were generated by cyclophosphamide (CTX) administration and then treated with Se-GFP-22. Results showed that Se-GFP-22 could increase thymus and spleen indices, phagocytic index, co-mitogenic (ConA- or LPS-stimulated) activities on splenocytes, DTH reaction, serum hemolysin formation and immunoglobulin (Ig G, Ig A and Ig M) levels in CTX-treated mice. Se-GFP-22 significantly enhanced the antioxidant activity in CTX-treated mice, as shown by the evaluation of GSH-Px, SOD and CAT activities, as well as MDA levels in serum, liver and kidney. Se-GFP-22 strongly stimulated inflammatory cytokines (IL-2 and IFN-γ) and NO productions by up-regulating mRNA expressions of IL-2, IFN-γ and iNOS. Se-GFP-22 possessed the immunomodulatory activity by up-regulating various transcription factors (JNK, ERK, and p38) in MAPKs signaling pathways. This study suggested that Se-GFP-22 may provide an alternative strategy in lessening chemotherapy-induced immunosuppression.

A novel iron supplements preparation from Grifola frondosa polysaccharide and assessment of antioxidant, lymphocyte proliferation and complement fixing activities

Grifola frondosa polysaccharide-iron (III) complex (GFP-iron) was synthesized and characterized. Based on single factor and orthogonal optimization experiments of GFP-iron (III) complex synthesis, the optimum conditions were the reaction temperature 80°C, pH 8, reaction time 90min and ratio of catalyst to GFP 1:1.0gg−1. The iron content of GFP-iron (III) complex reached 24.15% under the optimums and characterized by fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-Ray Diffraction (XRD), thermogravimetry (TG) and iron release in vitro assay.By 5-axe cobweb charts, the antioxidant activity of GFP-iron (III) complex was comprehensively evaluated. The results showed GFP-iron (III) complex retained a certain antioxidant activity. The lymphocytes proliferation of GFP-iron (III) complex was increased by 61.68% comparing with that of GFP at the sample concentration of 62.5μg/mL. At giving 50% haemolysis, the concentration of GFP-iron (III) complex was 0.261mg/mL. Therefore, GFP-iron (III) complex would be expected to exploit into a new-type comprehensive iron supplements.

A water-soluble polysaccharide from Grifola frondosa induced macrophages activation via TLR4-MyD88-IKKβ-NF-κB p65 pathways.

Here, the immunomodulatory effects of water-soluble polysaccharide from Grifola frondosa on RAW264.7 macrophages and its molecular mechanisms were investigated. G. frondosa polysaccharide could obviously enhance immunostimulatory activity such as the release of nitric oxide and cytokine production. Western blotting results showed that G. frondosa polysaccharide elevated the TLR4, which might act as an upstream regulator of MyD88 induced G. frondosa polysaccharide. MyD88 promoted IKKβ in endochylema and translocate NF-κB p65 subunit into the nucleus which increased the NO production and cytokine/chemokines level. The results suggested that G. frondosa polysaccharide activated macrophages through TLR4-MyD88-IKKβ-NF-κBp65 signaling pathways.

Grifola frondosa polysaccharides induce breast cancer cell apoptosis via the mitochondrial-dependent apoptotic pathway.

Grifola frondosa, a type of food and medical fungus, has been shown to exhibit various pharmacological activities, including anticancer effects. As the most typical cancer diagnosed among female patients, breast cancer remains a huge concern threatening human health globally. In the present study, the anti-breast cancer effects of Grifola frondosa polysaccharides (GFPs) and the underlying mechanisms were investigated in MCF-7 and MDA-MB-231 cells, as well as in nude mice bearing MCF-7 tumor xenografts. GFPs exerted cytotoxic effects on the cells, as indicated by a decrease in cell viability, and an increase in the apoptototic rate, lactate dehydrogenase release and reactive oxygen species accumulation, inducing mitochondrial dysfunction. The increased expression of Bax, cleaved caspase-3 and caspase-8, and the reduced levels of B-cell lymphoma 2 (Bcl-2) and Bcl-extra large (Bcl-xL) were observed in the cells incubated with GFPs and in the tumor tissues of the mice treated with GFPs. Moreover, the GFPs significantly suppressed the phosphorylation of AKT/glycogen synthase kinase-3β and extracellular signal-regulated kinases in a time-dependent manner. Finally, the inhibition of MCF-7 tumor xenograft growth further confirmed the anti-breast cancer effects of GFPs. All these findings revealed that GFPs induced human breast cancer cell apoptosis via the mitochondrial-dependent apoptotic pathway, and provide experimental evidence to support the use of Grifola frondosa as a potential treatment for breast cancer.

Structural elucidation and antioxidant activity a novel Se-polysaccharide from Se-enriched Grifola frondosa

Se-GFP-22, a heteropolysaccharide, with a weight-average Mw of 4.13×106Da, was purified from the crude Se-polysaccharide (Se-GFP) isolated from fruit bodies of Se-enriched Grifola frondosa. Selenium was accumulated efficiently in Grifola frondosa during cultivation with Na2SeO3. The structure was investigated through FT-IR, GC, GC–MS, NMR, HPSEC-MALL-RI, particle size, Conge-red test, CD, AFM and SEM. Se-GFP-22 was deduced as a backbone chain of 1,4-α-d-Glcp units with a branched point at C6 of both 1,3,6-β-d-Manp and 1,4,6-α-d-Galp units. A typical absorption for selenium ester was existed in Se-GFP-22. Se-GFP-22 adopted as a spherical conformation with random coils. A novel Se-polysaccharide of different monosaccharide constituents, molecular weight, linkage types and high content of selenium has been isolated from G. frondosa. The antioxidant effect of Se-GFP-22 was more potent than that of G. frondosa polysaccharide (GFP-22), which may be influenced by the co-effect of polysaccharide and Se, molecular weight, degree of branching and configuration.

Structure and immunomodulatory activity of extracellular polysaccharide from Grifola frondosa

We aimed at analyzing the structure of extracellular polysaccharide A from Grifola frondosa (EXGFP-A) and testing its immunomodulatory activity. Structural analysis shows that EXGFP-A was a contained α-D-glucoside bond and pyranose ring. GC analysis reveals that EXGFP-A was mainly composed of rhamnose, arabinose, xylose, mannose, glucose, galactose, by the molar ratio of 0.28:0.31:0.30:0.06:7.98:0.61. The results of MTT(3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay indicates when EXGFP-A was at a concentration of 80 μg/mL and treatment time of 48 h, RAW264.7 cells proliferation index reached a maximum of 137.5%. Meanwhile, the AO staining showed that EXGFP-A activated RAW264.7 cells and improved the level of intracellular nucleic acid metabolism. In addition, in a certain range of concentration, EXGFP-A was able to increase the release of NO in RAW264.7 cells, and upregulate the mRNA expression of immunological factor TNF-α, IL-1β, IL-6, IL-12, IFN-γ and iNOS of RAW264.7 cells. Our results confirm that EXGFP-A had immunomodulatory activity. Our findings provided scientific basis for the structural analysis and application of Grifola frondosa polysaccharide.

Structural characterization and immunomodulatory activity of Grifola frondosa polysaccharide via toll-like receptor 4-mitogen-activated protein kinases-nuclear factor κB pathways.

We isolated a neutral polysaccharide from the fruiting body of a mushroom Grifola frondosa (GFP-A). The aim of this study was to characterize a neutral α-d-polysaccharide derived from G. frondosa and evaluate its immunomodulatory effect on toll-like receptor 4, mitogen-activated protein kinases and nuclear factor κB pathways of protein expression in macrophages. The structural features of GFP-A were characterized by physicochemical and instrumental analyses. Its molecular weight was found to be 8.48 × 10(2) kDa. The main chain of GFP-A consisted of (1 → 4)-linked and (1 → 6)-linked α-d-glucopyranosyl, and (1 → 3,6)-linked α-d-mannopyranosyl residues, which branched at C-3. The branches consisted of (1 → 6)-linked α-d-galactopyranosyl and t-l-rhamnopyranosyl residues. An in vitro immunomodulatory assay for pro-inflammatory cytokines (interleukin-1β, interleukin-2, tumor necrosis factor alpha, etc.) using the macrophage cell line, RAW 264.7, revealed that GFP-A exhibited significant immunomodulatory activity by stimulating the toll-like receptor 4, mitogen-activated protein kinases to nuclear factor κB/pathway.

Structural characterization and antiviral activity of a novel heteropolysaccharide isolated from Grifola frondosa against enterovirus 71

A novel heteropolysaccharide from Grifola frondosa mycelia was extracted and purified using DEAE Sephadex A-50 and Sephadex G-200 chromatography. Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopy were used to decipher the structure of the purified G. frondosa polysaccharide (GFP1). Chemical and spectral analysis revealed that GFP1, with an average molecular weight of 40.5kDa, possessed a 1,6-β-d-glucan backbone with a single 1,3-α-d-fucopyranosyl side-branching unit. Enterovirus 71 (EV71) is the causative pathogen of hand-foot-and-mouth disease. GFP1 was tested for its anti-EV71 activity in cultured cells, which showed that EV71 viral replication was blocked and viral VP1 protein expression and genomic RNA synthesis were suppressed. Moreover, GFP1 exhibited apoptotic and other activities by suppressing the EV71-induced caspase-3 cleavage and IκBα down regulation. Our results demonstrate that the novel G. frondosa polysaccharide has antiviral activity, which could be valuable as a potentially new anti-EV71 therapeutic compound.

Hypoglycemic effects of Grifola frondosa (Maitake) polysaccharides F2 and F3 through improvement of insulin resistance in diabetic rats

Our laboratory has previously demonstrated that Grifola frondosa polysaccharides (GFPs) showed hypoglycemic effects. This study aimed to investigate which polysaccharide-enriched fractions of GFPs were the main active constituents, and to disclose their hypoglycemic mechanism. F2 and F3 were obtained from GFPs and their hypoglycemic effects were investigated. Fasting serum glucose (FSG) levels, fasting serum insulin (FSI) levels and a homeostasis model assessment of insulin resistance (HOMA-IR) were measured, and the hepatic mRNA levels of insulin receptor (IR), insulin receptor substrate-1 (IRS-1), protein tyrosine phosphatase-1B (PTP1B), phosphatidylinositol 3-kinase (PI3K) and Akt/protein kinase B (PKB) were determined by a quantitative polymerase chain reaction (qPCR). The activity of IR and IRS-1 were determined by an enzyme-linked immunosorbent assay (ELISA), and their phospho-protein levels were analyzed with western blotting. F2 and F3 significantly decreased the levels of FSG, FSI and HOMA-IR compared with a diabetic control group (P < 0.05). F2 and F3 increased the activity and mRNA levels of IR, and the latter also increased the mRNA levels of IRS-1. As for the protein levels of phospho-IR and IRS-1, both F2 and F3 increased the protein levels of IR (Try 1361), but decreased IRS-1 (Ser307). In the PI3K/Akt pathway, F3 increased the mRNA levels of PI3K and Akt, however, F2 inhibited PTP1B expression. F2 and F3 are presumed to cause an improvement in insulin resistance, triggered by the reactivation of IR and IRS-1.

CHITOSAN/SULFATED GRIFOLA FRONDOSA POLYSACCHARIDE HYBRID SPONGE ACCELERATED WOUND HEALING

The essential role and function of a dressing is to provide an environment that promotes wound healing. In this study, the development and characterization of novel polymer hybrid sponge based on chitosan-Grifola frondosa polysaccharide and cross-linked by freeze-thaw method for possible use in a variety of biomedical application is reported. A water-soluble sulfated derivative G. frondosa polysaccharide was obtained from G. frondosa polysaccharide with 98% of concentrated sulfuric acid. To make effective wound healing accelerator, a chitosan/sulfated G. frondosa polysaccharides hybrid sponge was prepared. To evaluate the wound healing effect, full thickness skin excision was performed on the backs of the rats and then the sponge was applied in the wounds, respectively. After 7 days and 14 days, gross and histological examination was performed. Grossly, untreated control group revealed that the wound had well-defined margin and was covered by crust. The testing group treated with sponge appeared to be nearly completely healed. Histology of each group was well correlated to gross findings. The testing group shows nearly complete regeneration of appendage structure similar to normal in the dermis in contrast to control group with absence and less number of skin appendages. It hints that the sponge can accelerate wound healing. The result indicates that the chitosan/sulfated G. frondosa polysaccharide hybrid sponge is a promising dressing for wound healing.