Isolation, structural characterization and immunomodulatory activity on RAW264.7 cells of a novel exopolysaccharide of Dictyophora rubrovalvata.

Fungal polysaccharides have been explored by many for both structural studies and biological activities, but few studies have been done on the extracellular polysaccharides of Dictyophora rubrovalvata, so a new exopolysaccharide was isolated from Dictyophora rubrovalvata and its structure and its immunological activity were investigated. The crude exopolysaccharide (EPS) was purified by DEAE52 cellulose and Sephadex G-200 to obtain a new acidic polysaccharide (DR-EPS). DR-EPS (2.66 × 103 kDa) was consisted mainly of mannose, glucose, galactose and glucuronic acid with a molar ratio of 1: 0.86: 0.20: 0.01. In addition, DR-EPS increased the phagocytic activity of RAW264.7 cells up to 2.67 times of the blank control group. DR-EPS improved intracellular nucleic acid and glycogen metabolism as observed by AO and PAS staining. DR-EPS(40 µg/mL) promoted NO production up to 30.66 µmol, enhanced acid phosphatase (ACP) and superoxide dismutase (SOD) activities, with activity maxima of 660 U/gprot and 96.27 U/mgprot, respectively, and DR-EPS (160 µg / mL) significantly increased the lysozyme content as 2.73 times of the control group. The good immunological activity of extracellular polysaccharides of Dictyophora rubrovalvata provides directions for the use of fermentation broths.

Hovenia dulcis Fruit Peduncle Polysaccharides Reduce Intestinal Dysbiosis and Hepatic Fatty Acid Metabolism Disorders in Alcohol-Exposed Mice.

Alcohol abuse can lead to alcoholic liver disease, becoming a major global burden. Hovenia dulcis fruit peduncle polysaccharides (HDPs) have the potential to alleviate alcoholic liver injury and play essential roles in treating alcohol-exposed liver disease; however, the hepatoprotective effects and mechanisms remain elusive. In this study, we investigated the hepatoprotective effects of HDPs and their potential mechanisms in alcohol-exposed mice through liver metabolomics and gut microbiome. The results found that HDPs reduced medium-dose alcohol-caused dyslipidemia (significantly elevated T-CHO, TG, LDL-C), elevated liver glycogen levels, and inhibited intestinal-hepatic inflammation (significantly decreased IL-4, IFN-γ and TNF-α), consequently reversing hepatic pathological changes. When applying gut microbiome analysis, HDPs showed significant decreases in Proteobacteria, significant increases in Firmicutes at the phylum level, increased Lactobacillus abundance, and decreased Enterobacteria abundance, maintaining the composition of gut microbiota. Further hepatic metabolomics analysis revealed that HDPs had a regulatory effect on hepatic fatty acid metabolism, by increasing the major metabolic pathways including arachidonic acid and glycerophospholipid metabolism, and identified two important metabolites-C00157 (phosphatidylcholine, a glycerophospholipid plays a central role in energy production) and C04230 (1-Acyl-sn-glycero-3-phosphocholine, a lysophospholipid involved in the breakdown of phospholipids)-involved in the above metabolism. Overall, HDPs reduced intestinal dysbiosis and hepatic fatty acid metabolism disorders in alcohol-exposed mice, suggesting that HDPs have a beneficial effect on alleviating alcohol-induced hepatic metabolic disorders.

Isolation and structural characterization of exopolysaccharide from the Cordyceps cicadae and the immunomodulatory activity on RAW264.7 cells.

A new exopolysaccharide component named as PC-EPS was isolated from Cordyceps cicadae, and its structure was determined. PC-EPS was identified to be constituted of mannose, glucose, and galactose (28.84:1:19.42), with an average molecular weight of 3.72 × 106  Da, according to the results of monosaccharide composition, Fourier transform infrared, nuclear magnetic resonance, periodate oxidation and Smith degradation, and methylation studies. According to structural characterization, PC-EPS's connection type was made up of →6) -α-d-Manp (1→, →2) -ß-d-Manp (1→, →4) -α-d-Manp (1→, →2) -α-d-Galf (1→, and →4) -α-d-Galp (1→. PC-EPS may significantly increase phagocytosis and RAW264.7 cell proliferation. Additionally, by boosting intracellular lysozyme, cellular acid phosphatase, and cellular superoxide dismutase enzyme concentrations, as well as by promoting the generation of cellular NO, it is the potential to regulate the immunological activity of RAW264.7 cells. Additionally, the effects of PC-EPS on RAW264.7 cells increased their capacities to create tumor necrosis factor-α and interleukin 6 cytokines, all of which suggested that PC-EPS had the potential to improve immunomodulatory activity.

Tremella fuciformis Polysaccharide Induces Apoptosis of B16 Melanoma Cells via Promoting the M1 Polarization of Macrophages.

Anti-tumor activity of Tremella fuciformis polysaccharides (TFPS) has been widely reported, but its mechanism remains poorly understood. In this study, we established an in vitro co-culture system (B16 melanoma cells and RAW 264.7 macrophage-like cells) to explore the potential anti-tumor mechanism of TFPS. Based on our results, TFPS exhibited no inhibition on the cell viability of B16 cells. However, significant apoptosis was observed when B16 cells were co-cultured with TFPS-treated RAW 264.7 cells. We further found that mRNA levels of M1 macrophage markers including iNOS and CD80 were significantly upregulated in TFPS-treated RAW 264.7 cells, while M2 macrophage markers such as Arg-1 and CD 206 remained unchanged. Besides, the migration, phagocytosis, production of inflammatory mediators (NO, IL-6 and TNF-α), and protein expression of iNOS and COX-2 were markedly enhanced in TFPS-treated RAW 264.7 cells. Network pharmacology analysis indicated that MAPK and NF-κB signaling pathways may be involved in M1 polarization of macrophages, and this hypothesis was verified by Western blot. In conclusion, our research demonstrated that TFPS induced apoptosis of melanoma cells by promoting M1 polarization of macrophages, and suggested TFPS may be applied as an immunomodulatory for cancer therapy.

Transcriptome analysis reveals key metabolic pathways and gene expression involving in cell wall polysaccharides-disassembling and postharvest fruit softening in custard apple (Annona squamosa L.).

This study aimed to investigate the effect of custard apple cell wall polysaccharides-disassembling on postharvest fruit softening and to explore its key metabolic pathways and gene expression. Custard apple fruit was stored at 15 ± 0.5 °C for 12 days, it was found that the decreased significantly in fruit firmness, contents of Na2CO3-soluble pectin, hemicellulose and cellulose, and the increased significantly in water-soluble pectin and CDTA-soluble pectin. The activities of cell wall-degrading relevant enzymes in fruit were improved significantly during storage, including cellulase, polygalacturonase, pectin methyl esterase, neutral xylanase, ß-galactosidase, and ß-D-glucosidase. The RNA sequencing results revealed 41,545 nonredundant unigenes and 7571 differentially expressed genes (DEGs) in custard apple fruit samples. Functional annotation and DEGs data revealed cell wall degradation potentially involved in starch and sucrose metabolism, amino sugar and nucleotide sugar metabolism, galactose metabolism, pentose and glucuronate interconversions. Specifically, two EG and six ß-Glc genes controlled the cellulose decomposition, and one ß-xyl and one GATU genes involved in the degradation of hemicellulose, and two PME, one Pel, and four PG genes were the major regulators of pectin disassembling. These results provide a molecular foundation for explaining fruit softening and extending shelf life of custard apple.

Preparation, structural characterization and neuroprotective effects to against H2O2-induced oxidative damage in PC12 cells of polysaccharides from Pleurotus ostreatus.

Pleurotus ostreatus is one of the most common edible and medicinal fungi in life, and its polysaccharide has been a hot research topic in recent years. In this paper, a new intracellular polysaccharide component named P. ostreatus polysaccharide (POP-W) was obtained from the mycelium of P. ostreatus, and its structure was analyzed. The results showed that its molecular weight was Mw = 3.034 × 103 kDa, and it did not contain protein and nucleic acid. POP-W was composed of mannose, glucose, galactose and xylose in a molar ratio of 40.34:47.60:7.97:4.09. The backbone of POP-W was α-D-Glcp(1→,→3,4)-α-D-Glcp(1→, →3,4)-α-D-Manp(1→,→3)-α -D-Galp(1→, →4)-α-D-Glcp(1→, →3)-α-D-Glcp(1→, →2)-ß-D-Manp(1→, →4) -ß-D-Xylp(1 â†’. SEM and TGA analysis showed the structure of POP-W and good thermal stability. In addition, POP-W showed significant antioxidant activity in vitro. More importantly, POP-W protected PC12 cells induced by H2O2 by inhibiting the contents of lactate dehydrogenase (LDH) and malondialdehyde (MDA) and increasing the levels of superoxide dismutase (SOD) and reduced glutathione (GSH). Western blot detection of Caspase-3, BAX, Bcl-2, PI3K/Akt protein expression. The results showed that POP-W inhibited the expression of caspase-3 and BAX, while promoting the expression of Bcl-2. In addition, POP-W can also promote the phosphorylation of Akt. In conclusion, POP-W pretreatment can protect PC12 cells from H2O2-induced oxidative damage through PI3K/Akt signaling pathway and regulation of apoptosis-related pathway proteins. It provided a theoretical basis for the practical application of the polysaccharide of P. ostreatus in production.

Trichoderma asperellum as a novel source to prepare chitooligosaccharides by enzymatic hydrolysis and its antimicrobial activity.

Chitooligosaccharides (COS), an important biological functional component, are mainly extracted from marine products, but its raw materials are currently facing challenges such as marine resources pollution and demineralization. This study aimed to explore Trichoderma asperellum as a novel source to prepare COS. The COS were prepared by the enzymatic degradation of chitosan from T. asperellum, and single factor experiment and orthogonal designs were used to optimize the enzymatic conditions for the preparation of COS. The composition of COS was performed by thin-layer chromatography, high-performance liquid chromatography, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The results showed that the degree of deacetylation of T. asperellum chitosan was 87.59%, and its enzymatic hydrolysis yield was 89.37 % under optimized extraction conditions. Moreover, the composition of COS in T. asperellum included chitotriose, chitopentaose, and chitohexaose. Compared with shrimp shells, COS prepared from T. asperellum showed stronger antibacterial properties against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Salmonella bacilli.

Preparation and antibacterial effect of chitooligosaccharides monomers with different polymerization degrees from crab shell chitosan by enzymatic hydrolysis.

This study aimed to explore the structure and antibacterial properties of chitooligosaccharide monomers with different polymerization degrees and to provide a theoretical basis for inhibiting Salmonella infection. Chitosan was used as a raw material to prepare and separate low-molecular-weight chitooligosaccharides. Chitobiose, chitotriose, and chitotetraose were obtained by gradient elution with cation exchange resin. The molecular weights and acetyl groups of the three monomers were determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) and nuclear magnetic resonance (NMR), respectively. Three chitooligosaccharide monomers were used to explore the antibacterial effect on Salmonella. The results showed that the degree of deacetylation of chitosan was 92.6%, and the enzyme activity of chitosanase was 102.53 U/g. Within 18 h, chitosan was enzymatically hydrolyzed to chitooligosaccharides containing chitobiose, chitotriose, and chitotetraose, which were analyzed by thin-layer chromatography (TLC) and MALDI-TOF. MALD-TOF and TLC showed that the separation of monomers with ion exchange resins was effective, and NMR showed that there was no acetyl group. Chitobiose had a poor inhibitory effect on Salmonella, and chitotriose and chitotetraose had equivalent antibacterial effects.

Biosorption Characteristic and Cytoprotective Effect of Pb2+, Cu2+ and Cd2+ by a Novel Polysaccharide from Zingiber strioatum.

The pollution of heavy metal ions can cause damage to the human body through food, so developing a new biocompatible material that can remove the damage of heavy metal ions has a good application prospect. In this study, we obtained a new homogeneous polysaccharide composed of seven monosaccharides from Zingiber strioatum by using the method of separation and purification of polysaccharide. The results of adsorption behavior showed that the concentration, temperature and pH value could affect the adsorption effect of Zingiber strioatum polysaccharide (ZSP). Through model fitting of the data of adsorption time and metal concentration, the pseudo second-order kinetic model can well describe the kinetics of the adsorption process, and the adsorption isotherm data fit well with the Langmuir model. In the preliminary research results of adsorption mechanism, SEM showed the appearance of ZSP as flake and porous surface; EDX analysis confirmed the metal adsorption capacity of ZSP. Meanwhile, XPS and FT-IR further clarified the adsorption based on functional groups composed of C and O. The cells preprotected by ZSP can resist heavy metal ions. The above results show that ZSP can be used as a new macromolecule to bind heavy metal ions, which can broaden the research scope of polysaccharides in contaminated food systems.

Structural characterization of a polysaccharide from Abelmoschus esculentus L. Moench (okra) and its hypoglycemic effect and mechanism on type 2 diabetes mellitus.

A novel acidic polysaccharide named AeP-P-1 was prepared from Abelmoschus esculentus L. Moench (okra). AeP-P-1 is a heteropolysaccharide with a molecular weight of 3.02 × 103 kDa and is composed of L-rhamnose, D-galactose, and D-galacturonic acid in the ratio 1.87 : 3.58 : 1.00. Structural characterization based on methylation and 1D/2D NMR analyses indicated that AeP-P-1 is composed of T-linked-Rhap, T-linked-Galp, 1,2,4-linked-Rhap, 1,4-linked-Galp, 1,6-linked-Galp, and 1,3,4-linked-Galp in a molar ratio of 2.42 : 3.36 : 6.46 : 13.31 : 3.12 : 1, respectively. The hypoglycemic effect and mechanism of AeP-P-1 on type 2 diabetes mellitus were also explored. Firstly, AeP-P-1 can reduce blood lipids and liver and kidney damage caused by T2DM. Finally, AeP-P-1 induces the phosphorylation of GSK3ß, maintains the activity of glycogen synthase (GCS), and promotes glycogen synthesis by regulating the expression of insulin/PI3K/Akt pathway proteins. These results indicated that AeP-P-1 could be developed as a potential ingredient in immunostimulatory agents.

Structural characteristics of polysaccharide from Zingiber striolatum and its effects on gut microbiota composition in obese mice.

To investigate a polysaccharide from Zingiber striolatum favorably modulates gut microbiota in mice fed a high-fat diet. Z. striolatum was utilized to extract the crude polysaccharide CZSP, which was subsequently refined using DEAE-52 cellulose and Sephadex G-150 to yield the novel polysaccharide Zingiber strioatum pure polysaccharide-1 (ZSPP-1). ZSPP-1 was an acidic heteroglycan made up of galactose, mannose, glucose, xylose, arabinose, glucuronic acid, and galacturonic acid with an average molecular weight of 1.57 × 106 Da. The structure of ZSPP-1 was investigated by FT-IR, methylation and NMR analysis, and the results denoted that the linkage structure types include T-Manp-linked, ß-Xylp-(1,2)-linked, ß-Galp-(1,4)-linked, α-GlcpA-(1,6)-linked, ß-Arap-(1,4)-linked, α-Glcp-(1,3,4,6)-linked, α-Glcp-(1,2)-linked, and ß-T-Xylp-linked, in which ß-Galp-(1,4)-linked and α-GalpA-(1,4)-linked might be the main linkage. The results of the intervention experiments showed that ZSPP-1 changed the intestinal flora structure of the Firmicutes and Bacteroidetes in obese mice, and promoted the growth of beneficial bacteria such as Akkermansia, Lactobacillus, and Bacteroides in the intestine. It also restored the imbalanced flora structure due to high-fat diet to normal. It also restored the imbalanced flora structure due to high-fat diet to normal. Z. striolatum polysaccharides presented a considerable advantage in alleviating high-fat diet induced obesity, which indicates that it can be further exploited as a natural functional food resource.

Dendrobium candidum polysaccharide reduce atopic dermatitis symptoms and modulate gut microbiota in DNFB-induced AD-like mice.

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a high prevalence worldwide. Increasing evidence suggests that the gut microbiota plays an important role in the pathogenesis of AD. In this study, we sought to verify the effect of Dendrobium candidum polysaccharides (DCP) on AD induced by 2,4-Dinitrofluorobenzene (DNFB) in Balb/c mice regarding its impact on the intestinal microbiome. We found that 2-week oral administration of DCP improved AD-like symptoms and histological damage of skin, reduced mast cell infiltration, down-regulated the level of serum total IgE and the expression of pro-inflammatory cytokines such as TNF-α, IFN-γ, IL-4 and IL-6, and increased the expression level of anti-inflammatory cytokine IL-10. The beneficial effect of DCP was attributed to the restoration of the intestinal microbiome composition and the unbalance of the intestinal homeostasis. Our results indicated that DCP might be used as a promising novel microbiota-modulating agent for the treatment of AD.

Tremella fuciformis polysaccharides alleviate induced atopic dermatitis in mice by regulating immune response and gut microbiota.

Atopic dermatitis (AD), characterized by severe pruritus, immune imbalance, and skin barrier dysfunction, has a high incidence worldwide. Recent evidence has shown that the modulation of gut microbiota is crucial for alleviating clinical symptoms of AD. Tremella fuciformis polysaccharides (TFPS) have been demonstrated to have a variety of biological activities such as immunomodulatory, anti-tumor, antioxidant, anti-inflammatory, neuroprotective, hypoglycemic and hypolipidemic effects. However, their effects on AD treatment have never been investigated. In this study, we compared the therapeutic effects of topical or oral administration of TFPS on AD in dinitrofluorobenzene (DNFB)-induced AD mice. Both topical application and oral administration of TFPS led to improvement on transdermal water loss, epidermal thickening, and ear edema in AD mice, but the oral administration showed significantly better efficacy than the topical application. The TFPS treatment increased the proportion of CD4 (+) CD25 (+) Foxp3 (+) regulatory T cells in mesenteric lymph nodes. Additionally, the non-targeted metabolomics and sequencing of 16S rDNA amplicons were performed, revealing metabolite modulation in feces and changed composition of gut microbiota in mice, which were induced for AD-like disorder and treated by oral administration of TFPS. Collectively, these data suggest that the oral administration of TFPS may constitute a novel effective therapy for AD, with underlying mechanisms associated with the regulation of immune response, and improvement of both metabolism and the composition of intestinal microbiota.

Comparison of structural and antioxidant activity of polysaccharide extracted from truffles.

As the main component of truffles, polysaccharides have a variety of biological activities such as anti-oxidation, anti-tumor, and hypoglycemic activity, and these activities are closely related to its structure. In this study, Tuber Aestivum crude polysaccharide (TACP) and Tuber Melanosporum crude polysaccharide (TMCP) were obtained from Tuber Aestivum and Tuber Melanosporum by using microwave-assisted hot water, and then the Sephadex G-200 column was utilized to further separate and purify Tuber Aestivum polysaccharide (TAP) and Tuber Melanosporum polysaccharide (TMP) from TACP and TMCP. The structural characterization results showed that the molecular weight of TAP was 2.18 × 104  kDa, while TMP was 8.79 × 103  kDa. Although the two polysaccharide components were mainly composed of mannose (Man) and glucose (Glc), the molar ratio of Man and Glc in TAP was 14.76: 12.31, with a molar ratio of 5.43:10.94 in TMP. Furthermore, the antioxidant activity of two polysaccharide components was evaluated. TAP and TMP could protect porcine jejunal epithelial (IPEC-J2) cells from oxidative damage by H2 O2 , but TAP exhibited stronger antioxidant effects. It was mainly reflected that TAP could increase the secretion level of intracellular antioxidant enzymes (superoxide dismutase and catalase) in IPEC-J2 cells, and had a significant effect on the total antioxidant capacity of cells. The reactive oxygen species and malondialdehyde had better scavenging ability at the concentration of 20 µg/ml. The difference between TAP and TMP may be due to the dissimilar structure. Its structure-activity relationship needs further study. PRACTICAL APPLICATION: The structure of TAP and TMP were different, and TAP had higher molecular weight. Besides, TAP and TMP can protect IPEC-J2 cells from oxidative stress, providing a theoretical basis for developing potential antioxidant drugs of practical significance.

Rheological properties of polysaccharides from Pholiota nameko with different temperature extraction: Concentration, pH, temperature, and saltion.

Cold and hot water extracted polysaccharides (CW-PNPs and HW-PNPs) were isolated from Pholiota nameko. The rheological properties of PNPs were investigated by steady shear and oscillatory rheological measurements. The PNPs exhibited typical non-Newtonian and shear-thinning behavior, which are affected by PNP concentration, temperature, pH value, salt ion, and concentration. Specifically, the apparent viscosity of the two PNPs solutions at concentration of 1% (w/w) was shown as HW-PNPs > CW-PNPs. The apparent viscosity of PNPs decreases under acidic and alkaline conditions and when the temperature rises; K+ and Na+ cause the apparent viscosity of CW-PNPs to decrease, while Ca2+ and Al3+ are opposite. The addition of four different salt ions all caused the apparent viscosity of the HW-PNPs to decrease. The results of dynamic rheological experiments show that G' and G″ showed slightly frequency dependency with G' exceeding G″ throughout the accessible range of frequency for CW-PNPs and HW-PNPs.

Structural characterization and protective effect on PC12 cells against H2O2-induced oxidative damage of a polysaccharide extracted from mycelia of Lactarius deliciosus Gray.

The crude polysaccharide LDP was extracted from mycelia of Lactarius deliciosus Gray and then purified by DEAE-52 cellulose and Sephadex G-200 to obtain a novel polysaccharide named LDP-CP. LDP-CP was mainly composed of mannose, glucose and galactose with an average molecular weight of 2.33 × 103 kDa. The structure of LDP-CP was determined by FT-IR, methylation and NMR analysis, and the results showed that the sugar linkage units of LDP-CP were composed of (1 â†’ 3)-linked ß-D-Manp, (1 â†’ 2,4)-linked α-D-Manp, (1→)-linked α-D-Manp, (1 â†’ 4)-linked ß-D-Glcp, (1 â†’ 2)-linked ß-D-Manp, (1 â†’ 4,6)-linked α-D-Manp, (1 â†’ 4)-linked α-D-Galp, (1 â†’ 2,3)-linked α-D-Glcp and (1→)-linked α-D-Glcf. The protective effects of LDP and LDP-CP on PC12 cells against H2O2-induced oxidative injury were exhibited by enhancing cell viability and morphological protection. The improvement to the level of LDH, SOD and GSH further indicated that LDP and LDP-CP had ability to alleviate H2O2-induced oxidative damage on PC12 cells. The polysaccharides in Lactarius deliciosus Gray mycelia exhibited the great advantages in the management of oxidative toxicity, which indicated that the polysaccharides can be further developed in application of natural functional food source.

Structural characterization and prebiotic potential of an acidic polysaccharide from Imperial Chrysanthemum.

A novel water-soluble polysaccharide, named ICP-1, was isolated and purified by Sephadex G-200 after extracting the crude polysaccharide (ICP) from Imperial Chrysanthemum. The structural characterization of ICP-1 was determined by physical and chemical methods, FT-IR, NMR, SEM, HPGPC, periodate oxidation, Smith degradation, methylation and Congo red test. Then, acid production and proliferation of lactic acid bacteria and the tolerance tests of simulated gastrointestinal fluid were measured to investigate the activity of prebiotic potential. The results showed that ICP-1 was an acidic hetero-polysaccharide with an average molecular weight of 2.98 × 103 kDa and a specific optical rotation of +155°. The glycosyl residues of ICP-1 were composed of (1→), (1→4) and (1→6) glucose, (1→5) arabinose, (1→4) galacturonic acid and (1→3,6) mannose. Besides, ICP-1 can speed up the acid production of lactic acid bacteria and promote the growth and proliferation of lactic acid bacteria effectively.

Structure, antioxidant property and protection on PC12 of a polysaccharide isolated and screened from Abelmoschus esculentus L.Moench (okra).

AeP-P-2, a pectic polysaccharide, was extracted from the fruit pod of okra. It composed of rhamnose (Rha), arabinose (Ara), glucose (Glc), galactose (Gal) and galacturonic acid (GalA) with the ratio of 4.75:2.01:1.00:4.91:7.24. The main structural feature of AeP-P-2 are 1,4-linked galacturonan units (homogalacturonan backbone) and (1 → 2) and (1 → 2,4) linked Rha (rhamnogalacturonan I region). And the other side chains contained →1)-linked Ara, (1 → 5)-linked Ara, (1 → 4)-linked Glc, (1 → 6)-linked Gal, (1 → 4)-linked Rha, (1 → 2,4)-linked Rha, →1)-linked Ara and →1)-linked Gal. When the concentration of AeP-P-2 was 3.2 mg/mL, the scavenging rates on DPPH·, ABTS, O2-· and ·OH reached to 61.88%, 87.10%, 52.17% and 60.32%, respectively. AeP-P-2 also could protect PC12 cells from the damage of H2O2 and reduce apoptosis caused by oxidative damage by decreasing the level of ROS. The findings indicated that okra was a functional vegetable and AeP-P-2 was worth studying and developing into antioxidant component.

Effect of steam explosion pretreatment on the structure and bioactivity of Ampelopsis grossedentata polysaccharides.

Steam explosion (SE) was a friendly environmentally pretreatment method. In this study, the effect of steam explosion (SE) pretreatment on structure and α-glucosidase inhibitory activity of Ampelopsis grossedentata polysaccharides was evaluated. Two novel polysaccharides (AGP and AGP-SE) were extracted, isolated, purified and analyzed by NMR, FT-IR and methylation. The results indicated that AGP mainly consisted of Rha, Xyl, Glc, and Ara with a molecular weight of 2.74 × 103 kDa and AGP-SE mainly consisted of Man, Ara, and Gal with a molecular weight of 2.14 × 103 kDa. Furthermore, the backbone of AGP and AGP-SE were mainly composed of 5)-Araf-(1→, -Glcp-(1→, 6)-Glcp-(1→, 6)-Galp-(1→, 3,6)-Manp-(1→, and 2,3,6)-Glcp-(1→. Finally, we demonstrated that all polysaccharides exhibited obviously α-glucosidase inhibition activity and mixed type inhibition. AGP-SE had better α-glucosidase inhibition activity and the binding affinity KD on α-glucosidase by using Surface Plasmon Resonance (SPR) than AGP. Overall, SE pretreatment is an effective method for extracting polysaccharide and provides a new idea into the improvement of biological activity.

Structure analysis and antioxidant activity of polysaccharide-iron (III) from Cordyceps militaris mycelia.

Iron-enriched Cordyceps militaris was obtained by adding FeSO4 solution to the mycelia for biotransformation. The polysaccharide-iron (III) was extracted by water extraction and alcohol precipitation. High performance liquid chromatography showed that the crude polysaccharide-iron (III) had three components. The second component was purified by Sephadex G-150 and named as CPS-iron-II. The average molecular weight of CPS-iron-II was 44.136 kDa. The content of iron was 2.73%. The monosaccharide composition analysis indicated that the CPS-iron-II was composed of rhamnose, arabinose, galactose, glucose, mannose, galacturonic acid with percentage ratio of 0.94:3.12:27.01:36.62:30.20:2.12. The results of methylation analysis revealed that the CPS-iron-II was made of →2)-ß-D-Glcp-(1→, with →2, 4)-α-D-Glcp-(1→ highly branched. Congo-red test showed that CPS-iron-II can cause flocculation of Congo red solution. The anti-oxidative analysis showed that antioxidant activity of CPS-iron-II was almost equal to that of Vc. The manuscript provided a new way for the preparation of polysaccharide-iron(III) from Cordyceps militaris.