DEAE-Sepharose Fast Flow Column Research Articles

Structural characteristics and antioxidant activity of a low-molecular-weight jujube polysaccharide by ultrasound assisted metal-free Fenton reaction

This study used an ultrasonically accelerated metal-free Fenton (H2O2-Vc system) reaction to promote water-extracted degrading polysaccharides from Ziziphus Jujuba cv. Muzao (DZMP). A novel jujube polysaccharide (DPZMP3) was obtained by degradation using DEAE-Sepharose Fast Flow and Sephacryl S-100 column chromatography. Methylation analysis, HPGPC, ion chromatography, FT-IR, and NMR spectroscopies were used to clarify the chemical structures of DPZMP3. Monosaccharide compositional analysis of DPZMP3 revealed the presence of Rha, Ara, Gal, and GalA at a molar ratio of 1.00:1.49:1.60:7.68, and the HPGPC data demonstrated the average Mw of 34.3 kDa. Based on the structural and linkage research using NMR spectroscopy and GC–MS, it was determined that DPZMP3 was a homogalacturonan pectic polysaccharide with a (1 → 4)-Galp branch at C-6 and a small amount of Araf and Rhap residues. The ultrasonic-aided Fenton treatment did not significantly alter the structure of DPZMP3. It may also be useful for DZMP and enhancing their antioxidant activity in vitro. The current study's findings could pave the way for the food sector to use jujube polysaccharides obtained by degradation as a functional food component.

Characterization of a novel antioxidant exopolysaccharide from an intestinal-originated bacteria Bifidobacterium pseudocatenulatum Bi-OTA128

Microbial exopolysaccharides (EPSs) have attracted extensive attention for their biological functions in antioxidant activities. In this study, we characterized a novel EPS produced by Bifidobacterium pseudocatenulatum Bi-OTA128 which exhibited the highest antioxidant capacity compared to nine other ropy bacterial strains, achieving 76.50 % and 93.84 % in DPPH· and ABTS·+ scavenging activity, and ferric reducing power of 134.34 μM Fe2+. Complete genomic analysis identified an eps gene cluster involved in the EPS biosynthesis of Bi-OTA128 strain, which might be responsible for its ropy phenotype. The EPS was then isolated and purified by a DEAE-Sepharose Fast Flow column. A single elution part EPS128 was obtained with a recovery rate of 43.5 ± 1.78 % and a total carbohydrate content of 93.6 ± 0.76 %. Structural characterization showed that EPS128 comprised glucose, galactose, and rhamnose (molar ratio 4.0:1.2:1.1), featuring a putative complex backbone structure with four branched chains and an unusual acetyl group at O-2 of terminal rhamnose. Antioxidant assay in vitro indicated that EPS128 exhibited antioxidant potential with 50.52 % DPPH· and 65.40 % ABTS·+ scavenging activities, reaching 54.3 % and 70.44 % of the efficacy of standard Vitamin C at 2.0 mg/L. Furthermore, EPS128 showed protective effects against H2O2-induced oxidative stress in HepG2 cells by reducing cellular reactive oxygen species (ROS) and increasing cell viability. These findings present the first comprehensive report of an antioxidant EPS from B. pseudocatenulatum, highlighting its potential as a natural antioxidant for applications in the food industry and clinical settings.

Isolation and purification of bovine N‐glycans from whey protein concentrate (WPC 70)

N‐glycans present in milk glycoproteins (e.g. lactoferrin and immunoglobulin G) can provide infants with nutritional and protective effects similar to breast milk. In this study, we enriched N‐glycoproteins from WPC 70 using ultrafiltration and anion exchange chromatography on DEAE Sepharose Fast Flow column, with N‐glycan content and N‐glycoprotein purity as evaluation indicators. The results showed that changing feed flow rate and molecular weight cut‐off was more effective to improve ultrafiltration separation than changing feed concentration. When using a 100 kDa ultrafiltration membrane with a feed flow rate of 10 rpm and a feed concentration of 10 mg/mL, N‐glycan content could be increased by 200%. However, anion exchange chromatography was more efficient for purification, increasing N‐glycan content by 700%. This study provided a reliable method for N‐glycan enrichment and a scientific basis for further research and potential application of N‐glycans in infant formula and whey products.

Separation and purification of bovine nasal cartilage-derived chondroitin sulfate and evaluation of its binding to bovine serum albumin

This study employs an optimized and environmentally friendly method to extract and purify chondroitin sulfate (CS) from bovine nasal cartilage using enzymatic hydrolysis, ethanol precipitation, and DEAE Sepharose Fast Flow column chromatography. The extracted CS, representing 44.67 % ± 0.0016 of the cartilage, has a molecular weight of 7.62 kDa. Characterization through UV, FT-IR, NMR spectroscopy, and 2-aminoacridone derivatization HPLC revealed a high content of sulfated disaccharides, particularly ΔDi4S (73.59 %) and ΔDi6S (20.61 %). Interaction studies with bovine serum albumin (BSA) using fluorescence spectroscopy and molecular docking confirmed a high-affinity, static quenching interaction with a single binding site, primarily mediated by van der Waals forces and hydrogen bonding. The interaction did not significantly alter the polarity or hydrophobicity of BSA aromatic amino acids. These findings provide a strong foundation for exploring the application of CS in tissue engineering and drug delivery systems, leveraging its unique interaction with BSA for targeted delivery and enhanced efficacy.

Enzyme-Assisted Ultrasonic Extraction and Antioxidant Activities of Polysaccharides from Schizochytrium limacinum Meal.

Enzyme-assisted ultrasonic extraction (EAUE) was utilized and optimized for extracting polysaccharides from Schizochytrium limacinum meal (SLMPs) via the response surface methodology. The optimal EAUE conditions were determined as follows: enzyme concentration at 5.18%, ultrasonic temperature at 53 °C, ultrasonic duration of 40 min, ultrasonic power at 60 W, and a liquid-to-material ratio of 34 mL/g, achieving a polysaccharide extraction yield of 11.86 ± 0.61%. The purified polysaccharide component, SLMP1-1, isolated using DEAE Sepharose Fast Flow and Sephadex G-100 columns, exhibited potent antioxidant activity. SLMP1-1, with a molecular weight of 25.5 kDa, comprises glucose, mannose, arabinose, and galactose in a molar ratio of 16.39:14.75:1:693.03. 1H NMR analysis revealed the α configuration of SLMP1-1. Antioxidant assessments, including DPPH, ABTS, and ferric ion reduction assays, were detected with inhibitory values at 21.82-82.98%, 38.21-98.46%, and 3.30-20.30% at 0.2-1.0 mg/mL. This confirmed the effective antioxidant capacity of SLMP1-1, which is notably enhanced post oral and gastric digestion. The findings suggest that polysaccharides extracted from Schizochytrium limacinum meal hold significant promise as natural antioxidants.

Structural characterization of a glycoprotein from white jade snails (Achatina Fulica) and its wound healing activity

Snail mucus is rich in proteins and polysaccharides, which has been proved to promote wound healing in mice in our previous research. The aim of this study was to investigate the effective component in snail mucus that can exert the wound healing potential and its structural characterization. Here, the glycoprotein from the snail mucus (SM1S) was obtained by DEAE-Sepharose Fast Flow and Sephacryl S-300 columns. The structural characteristics of SM1S were investigated via chromatographic techniques, periodic acid oxidation, FT-IR spectroscopy and NMR spectroscopy. Results showed that SM1S was a glycoprotein with a molecular weight of 3.8 kDa (83.23 %), consists of mannose, glucuronic acid, glucose, galactose, xylose, arabinose, fucose at a ratio of 13.180:4.875:1043.173:7.552:1:3.501:2.058. In addition, the periodic acid oxidation and NMR analysis showed that SM1S contained 1,6-glycosidic bonds, and might also contain 1 → 4 and 1 → 2 glycosidic or 1 → 3 glycosidic bonds. Furthermore, the migration experiment of human skin fibroblasts in vitro suggested that SM1S had a good effect to accelerate the scratch healing of cells. This study suggested that SM1S may be a prospective candidate as a natural wound dressing for the development of snail mucus products.

Ultrasonic extraction of Moringa oleifera seeds polysaccharides: Optimization, purification, and anti-inflammatory activities

Natural polysaccharides exhibit numerous beneficial properties, such as antioxidant, antitumor, hypoglycemic, and hypolipidemic activities. Moringa oleifera seeds are of high dietary and therapeutic value which drew a lot of attention. However, the regulation effect on anti-inflammatory activity of polysaccharides remains to be studied. Herein, novel bioactive polysaccharides (MOSP-1) were extracted from Moringa oleifera seeds, and the anti-inflammatory properties of MOSP-1 were uncovered. Ultrasound-assisted extraction (UAE) was used to prepare the polysaccharides with optimized conditions (70 °C, 43 min, and liquid-solid-ratio 15 mL/g). Then, DEAE-Sepharose Fast Flow columns were applied to isolate and purify MOSP-1. Rhamnose, arabinose, galactose, and glucose were identified as the monosaccharide constituents of MOSP-1, with a molecular weight of 5.697 kDa. Their proportion in molarity was 1:0.183:0.108:0.860 and 8 types of glycosidic linkages were discovered. Bioactive assays showed that MOSP-1 possessed scavenging activities against DPPH and ABTS radicals, confirming its potential antioxidation efficacy. In vitro experiments revealed that MOSP-1 could reduce the expression of inflammation-related cytokines, inhibit the activation of ERK, JNK, and p38 (the MAPK signaling pathway), and enhance phagocytic functions. This study indicates that polysaccharides (MOSP-1) from Moringa oleifera seeds with anti-inflammatory properties may be used for functional food and pharmaceutical product development.

Study on Immunoregulatory Effects of Fucoidan from Sargassum graminifolium In Vivo and Immunoactivation Activity of Its Fecal Fermentation Products Using Co-Culture Model.

Fucoidan, brown seaweed-derived dietary fibers (DFs), can be considered a promising candidate for modulating immune responses. Due to its structural complexity and diversity, it is unclear whether Sargassum graminifolium fucoidans (SGFs) also show marvelous immunoregulatory effects. In the present study, two fractions, SGF-1 and SGF-2, were purified from SGFs by DEAE-Sepharose Fast Flow and Sephacryl S-400 HR column chromatography. We investigated the in vivo immune regulatory activity of SGF-2 and explored the immune activation of SGF-2 fecal fermentation products with in vitro fecal fermentation combined with a Caco-2/RAW264.7 co-culture system. In vivo results exhibited that SGF-2 could elevate the thymus/spleen indices, CD8+ splenic T lymphocyte subpopulations, and CD4+ Foxp3+ splenic Tregs. The 16S high-throughput sequencing results showed that SGF-2 administration significantly increased the relative abundance of Lactobacillus, Alloprevotella, Ruminococcus, and Akkermansia. In addition, it was found that SGF-2 fermented by feces could significantly improve the phagocytosis, NO, and cytokine (TNF-α, IL-6, and IL-10) production of macrophages in the co-culture system. These results indicated that SGFs have the potential to modulate immunity and promote health by affecting the gut microbiota.

Structural characterization of chia seed polysaccharides and evaluation of its immunomodulatory and antioxidant activities

This study aims to extract an active heteropolysaccharide Chia seed polysaccharide (CSP-A) and further purified by DEAE Sepharose Fast Flow and Sepharose CL-6B chromatographic column, characterize its structure, and evaluate its antioxidant and immunomodulatory activities. Structural analysis revealed that CSP-A was composed of d-mannose, d-glucuronic acid and d-xylose in a molar ratio of 1:3:4 with molecular weight of 1.688 × 105 Da, owning 4 sugar residues of β-d-Manp-(1→, →4)-α-d-GlcpA-(1→, →2,4)-β-d-Xylp-(1→, and → 4)-β-d-Manp-(1 →. Congo red assay and microscopic characteristics showed that CSP-A in its solution may possess a helical conformation. In vitro experiments showed that CSP-A had moderate DPPH· and OH· scavenging activities. CSP-A also enhanced the phagocytosis ability of RAW 264.7 cells and prompted the release of NO, TNF-α, IL-6 and IL-1β from RAW 264.7 cells, which indicated CSP-A had immune regulation effect. This experiment provides scientific basis for further utilization and development of chia seeds, a kind of functional food.

Characterisation and skin protection activities of polysaccharides from Schnabelia terniflora

The bioactivities of crude polysaccharides from leaves (L-Ps) and flowers (F-Ps) of Schnabelia terniflora (Maxim.) P. D. Cantino were studied, and the characteristics of purified fractions were analysed by HPLC, HP-GPC and NMR. L-Ps exhibited strong DPPH radical scavenging activity (IC50 value of 251.53 ± 4.62 μg/mL) and tyrosinase inhibition (IC50 value of 163.52 ± 2.59 μg/mL). However, the maximum moisture absorption (74.67 ± 1.53%) and retention (68.00 ± 3.61%) abilities were observed in F-Ps. Two main fractions separated by DEAE-Sepharose fast flow column from L-Ps were eluted with 0.1 and 0.3 M NaCl, while one main fraction from F-Ps was eluted with 0.1 M NaCl. Purified fractions were obviously different in monosaccharide composition, molecular weight and 1H NMR and 13C NMR spectra. Therefore, the current manuscript can provide an important evidence for the potential development of L-Ps and F-Ps as promising ingredients in cosmetics industry.

Structural Characterization and Immunomodulatory Activity of Polysaccharides from Polygonatum sibiricum Prepared with Deep Eutectic Solvents

Deep eutectic solvents (DES), as a new, efficient, and green solvents, have attracted more attention in recent years. This study was performed to extract Polygonatum sibiricum polysaccharides using DES (DPSP). Subsequently, DPSP was subjected to DEAE-Sepharose Fast Flow and Sephadex G-100 column for further purification (DPSP-3). Structural characterization and immunomodulatory activity in RAW264.7 cells were performed. Results showed that the yield of DPSP was (15.62 ± 0.71)%, and its yield was 1.53 times that of the polysaccharides extracted using the pharmacopoeia method (PSP). DPSP-3 had a smaller molecular weight (3.2 × 106 Da) and a higher ratio of galactose (65.75%) and mannose (19.76%) as compared to PSP. The scanning electron microscope (SEM) showed that DPSP-3 had curly shape, lamellar surface, and a few spherical edges, which were significantly different from PSP and DPSP. Both PSP and DPSP-3 could significantly improve phagotrophic capacity and increase the release of ROS, NO, IL-6, and TNF-α in RAW 264.7 cells, and DPSP-3 had better immunomodulatory activity. In summary, compared to the pharmacopoeia method, polysaccharides prepared using the DES extraction method showed higher yield and improved immunomodulatory activity.

Structural properties and immune-enhancing activities of galactan isolated from red seaweed Grateloupia filicina.

A water-soluble polysaccharide (GFP) was isolated from Grateloupia filicina and fractionated using a DEAE Sepharose Fast Flow column to evaluate immunostimulatory activity. Carbohydrates (62.0%-68.4%) and sulfates (29.3%-34.3%) were the major components of GFP and its fractions (GFP-1 and GFP-2), with relatively lower levels of proteins (4.5%-15.4%) and uronic acid (1.4%-3.9%). The average molecular weight (Mw ) for GFP and its fractions was calculated between 98.2%-243.7 kDa. The polysaccharides were composed of galactose (62.1%-87.2%), glucose (4.5%-33.2%), xylose (3.1%-5.3%), mannose (1.4%-2.2%), rhamnose (1.2%-2.0%), and arabinose (0.9%-1.7%) units connected through →3)-Galp-(1→, →4)-Galp-(1→, →2)-Galp-(1→, →6)-Galp-(1→, →3,4)-Galp -(1→, →3,6)-Galp-(1→, →4,6)-Galp-(1→, →3,4,6)-Galp-(1→, →2,3)-Galp-(1→, →2,4)-Galp-(1→, →4)-Glcp-(1→, →6)-Glcp-(1→ and →4,6)-Glcp-(1→residues. The isolated polysaccharides effectively induced RAW264.7 murine macrophages by releasing nitric oxide (NO) and various cytokines via nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Further, the expression of toll-like receptor-2 (TLR-2) and TLR-4 in RAW264.7 cells indicated their activation through TLR-2 and TLR-4 binding receptors. Among the polysaccharides, GFP-1 highly stimulated the activation of RAW264.7 cells, which was mainly constituted of (→1) terminal-D-galactopyranosyl, (1→3)-linked-ᴅ-galactopyranosyl, (1→4)-linked-ᴅ-galactopyranosyl and (1→3,4) -linked-ᴅ-galactopyranosyl residues. These findings demonstrate that GFP-1 from G. filicina are effective at stimulating the immune system and this warrants further investigation to determine potential biomedical applications.

Characterization of the antioxidant activities of the exopolysaccharides produced by Streptococcus thermophilus CGMCC 7.179

Streptococcus thermophilus is a traditional starter for yogurt making. Here, an eps gene cluster encoded for exopolysaccharides (EPS) was identified in the genome of S. thermophilus CGMCC 7.179. After purifying by DEAE-Sepharose Fast-Flow column chromatography, three main components ST-ESP1, ST-EPS2 and ST-EPS3, consisted of mannose, glucuronic acid, galacturonic acid, glucose and N-acetylglucosamine, were obtained. ST-EPS2 showed stronger antioxidant activity than the others in vitro. Moreover, ST-EPS2 could significantly upregulate the transcription levels of NF-E2-related factor-2 (Nrf2) and promote the expression of antioxidant-related proteins involved in Nrf2, suggesting ST-EPS2 protected the intestinal epithelial NCM 460 cells by attenuating the intracellular reactive oxygen species (ROS) level rising against oxidative stress. The potential binding mode of the mannose, galacturonic acid and N-acetylglucosamine with Keap1 simulated through molecular docking confirmed the action of ST-EPS2 with the protein Nrf2. Those results demonstrated that the ST-EPS2 provided opportunities for a natural antioxidant agent exploration in the food industry.

Extraction, characterization, and biological activities of exopolysaccharides from plant root soil fungus Fusarium merismoides A6.

The exploration of polysaccharides from microorganisms is of great importance. In this study, a new type of exopolysaccharide excreted by Fusarium merismoides A6 (FM-EPS) was isolated, and the extraction conditions were optimized using a response surface methodology (RSM). The extraction temperature at 0°C, a precipitation time of 7.83h, and an ethanol precipitation concentration of 77.64% were predicted and proved to be the best extraction conditions with the maximum extraction yield of 0.74g/mL. Then, two fractions of F. merismoides A6 exopolysaccharides (FM-EPS1 and FM-EPS2) were obtained through DEAE Sepharose fast flow column chromatography. As indicated by monosaccharide composition analysis, both fractions mainly consisted of mannose, glucose, galactose, and ribose, with an average molecular weight of 5.14 × 104 and 6.50 × 104g/mol, respectively. FT-IR and NMR spectroscopy indicated the FM-EPSs had both α- and β-glycosidic bonds. Moreover, the determination of antioxidant and antiproliferative activities in vitro proved that FM-EPSs had good antioxidant activities and antiproliferation activities. FM-EPS1 showed stronger antioxidant activities than FM-EPS2. FM-EPS2 showed antiproliferation activities on HeLa and HepG2 cells, while FM-EPS1 had no obvious antiproliferative activity. Therefore, FM-EPSs could be explored as potential antioxidant and anticancer agent applied in food, feed, nutraceutical, pharmaceutical, cosmetics, and chemical industries.

Isolation, Characterization, Antioxidant, and Wound Healing Activities of Extracellular Polysaccharide from Endophytic Fungus Talaromyces purpureogenus.

In this study, two extracellular polysaccharides (TEPS1 and TEPS2) were isolatedfrom the endophytic fungus (Talaromyces purpureogenus) and purified by DEAE-Sepharose Fast Flow column using NaCl as gradient eluent. The HPLC analysis displayed that TEPS1 was composed of mannose (38.70%), ribose (25.02%), glucose (19.34%), and galactose (16.94%) while the TEPS2 composed by mannose (100%). The NMR results indicated that TEPS1 exhibited α-glycosidic configurations. The both polysaccharides, TEPS1 and TEPS2 were exhibited a good antioxidant activity interms of DPPH, ABTS, and •OH scavenging. However, TEPS1 showed a higher antioxidant activity than TEPS2. The IC50 of TEPS1 were 32.16, 192.57, and 54.67μg·mL-1, for DPPH, ABTS, and •OH radicalscavenging, respectively. Furthermore, TEPS1 showed the high cellular antioxidant and wound healing activity in the human embryonic kidney (HEK293) cell line. Overall, these two polysaccharides were promising inantioxidant activity.

Immunomodulatory activity of glycoproteins isolated from chickpea (Cicer arietinum L.).

Chickpea (Cicer arietinum L.) is a well-known legume widely used as traditional medicine. This study aimed to characterize the structure and evaluate the immunomodulatory activity of one glycoprotein [crude chickpea glycoprotein-1 (CAG-1)] isolated from chickpea. CAG-1 was extracted with hot alkaline water and purified with DEAE-Sepharose Fast Flow and Superdex-200 column chromatography. CAG-1, with a molecular weight of 8,106 Da, contained 57.12% polysaccharide and 35.41% protein. The polysaccharide part was mainly composed of glucose (Glc). The protein part was connected mainly by aspartic (Asp) and glutamic (Glu). The results of nuclear magnetic resonance (NMR) analysis indicated the presence of α-d-Glcp-(1 → 4)-α-d-Glcp-(1 → 4)-α-d-Glcp-(1 → . In addition, the sugar chains of the glycoprotein were not hydrolyzed under alkaline conditions, suggesting that the glycoprotein was N-glycosidic; thus, the sugar chain was linked to the protein chain by Asp. An immunological study showed that CAG-1 stimulated the production of nitric oxide (NO), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and monocyte chemotactic protein 1 (MCP-1) in RAW 264.7 macrophages in a dose-dependent manner.

Structural characteristics, anticoagulant and antithrombotic mechanism of a novel polysaccharide from Rosa Chinensis Flos

This is the first report on a polysaccharide (RCJ2-Ib) isolated from Rosa Chinensis Flos. RCJ2-Ib was obtained through the extraction with water, precipitation with ethanol, separation with DEAE-52 column and purification with DEAE-Sepharose Fast Flow column and Sephadex G100 column. GC, FT-IR and NMR analyses revealed that RCJ2-Ib (3.3 kDa) was a 1,4-linked polymannuronic acid containing substantial β-D-anomers units. The anticoagulant effect of RCJ2-Ib evaluated by using rabbit ear venous blood and an acute blood stasis rat model showed that RCJ2-Ib had obvious anticoagulant activity in regulating endogenous and exogenous coagulation pathways and reducing serum thromboxane B2 and endothelin-1. In addition, RCJ2-Ib could also increase the number of Lactobacillus and Escherichia coli. As a result, RCJ2-Ib has the potential to inhibit thrombosis and maintain the intestinal environment.

Structural characterization of a pectic polysaccharide from laoshan green tea and its inhibitory effects on the production of NO, TNF-α and IL-6

A novel pectic polysaccharide, named GTPS3-1, was isolated and purified from Laoshan green tea polysaccharide (GTPS) through DEAE Sepharose Fast Flow and Sephacryl S-300 columns, its structure was characterized and its anti-inflammatory activity was explored. GTPS3-1, with a molecular weight of 26.05 kDa, was mainly composed of galacturonic acid, galactose, rhamnose and arabinose in a molar ratio of 4.72:2.5:1.68:1 on the basis of monosaccharide composition. Structural analysis results revealed that GTPS3-1 was a highly branched pectin consisting of →3)-Galp-(1→, →2)-Rhap-(1→, →3,5)-Araf-(1→, →3)-Rhap-(1→, GalpA-(1→, →3,4)-Galp-(1→, →4)-GalpA-(1→, →5)-Araf-(1→, →2,4)-Rhap-(1→, Rhap-(1→ and Araf-(1→ according to FT-IR, methylation and NMR analyses. In addition, GTPS3-1 inhibited the production of NO, TNF-α and IL-6 in a dose-dependent manner, which resulted in the amelioration of inflammatory injury in LPS-induced RAW 264.7 cells. These results would provide a theoretical basis for practical application of the novel polysaccharide as an anti-inflammatory adjuvant.

The antifungal activity of a serine protease and the enzyme production of characteristics of Bacillus licheniformis TG116

The growth of Phytophthora capsica, Rhizoctonia solani, Fusarium graminearum, Fusarium oxysporum and Botrytis cinerea were all inhibited by the fermentation supernatant of Bacillus licheniformis TG116, a biocontrol strain isolated from Typhonium giganteum Engl. previously with broad-spectrum resistance to plant pathogens. The fermentation supernatant of the TG116 has a great stability on temperature and UV, and shows the biological activity of protease and cellulase. The antifungal protease produced by B. licheniformis TG116 was purified to homogeneity by ammonium sulfate precipitation, DEAE Sepharose Fast Flow column chromatography and Sephadex G-50 column chromatography. The inhibition of protease by the three surfactants increased with increasing concentration inhibition. Among these surfactants, EDTA showed the strongest inhibition, with only 25% protein activity at a concentration of 1.1mmol·L-1. Gene amplification verified the presence of a gene fragment of serine protease in the strain TG116. The antimicrobial substance isolated from the fermentation broth of TG116 is a serine protease component.

The structural characteristic of bamboo shoot shell polysaccharides extracted using ultrasound‐assisted phosphotungstic acid hydrolysis and its protection against cell oxidative injury

SummaryIn this study, crude polysaccharide (BSSP) was extracted from bamboo (Phyllostachys edulis) shoot shell using the ultrasonic‐assisted phosphotungstic acid hydrolysis method. Then, BSSP was further fractionated by DEAE Sepharose fast flow column and serial NaCl solution elutions to obtain two fractions, BSSP‐A and BSSP‐B. The results showed that the maximum yield of BSSP was 195.2 mg g−1 (19.52%) under optimised conditions. Structural analysis indicated that both BSSP‐A and BSSP‐B were heteropolysaccharides with α‐pyranoside bond structure and mainly consisted of xylose by scanning electronic microscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, thermal characterisation and nuclear magnetic resonance spectroscopy. BSSP‐B showed a better protective effect than BSSP‐A against H2O2‐induced oxidative injury in WRL‐68 cells by protecting the cell membrane structure, maintaining mitochondrial membrane potential and increasing intracellular antioxidant enzymes activities. Immunoblotting indicated that polysaccharides might up‐regulate the expression of antioxidant enzymes through the Keap1/Nrf2 signalling pathway and thus alleviate H2O2‐induced cell injury. The findings of this study suggested that polysaccharides from bamboo shoot shell may act as potent antioxidants in functional food industries.