Molecular structure, IgE binding capacity and gut microbiota of ovalbumin conjugated to fructose and galactose:A comparative study.

Ovalbumin (OVA) was modified by fructose (Fru) and galactose (Gal) to study the structure, IgG/IgE binding capacity and effects on human intestinal microbiota of the conjugated products. Compared with OVA-Fru, OVA-Gal has a lower IgG/IgE binding capacity. The reduction of OVA is not only associated with the glycation of R84, K92, K206, K263, K322 and R381 in the linear epitopes, but also with conformational epitope changes, manifested as secondary and tertiary structural changes caused by Gal glycation. In addition, OVA-Gal could alter the structure and abundance of gut microbiota at phylum, family, and genus levels and restore the abundance of bacteria associated with allergenicity, such as Barnesiella, Christensenellaceae_R-7_group, and Collinsela, thereby reducing allergic reactions. These results indicate that OVA-Gal glycation can reduce the IgE binding capacity of OVA and change the structure of human intestinal microbiota. Therefore, Gal glycation may be a potential method to reduce protein allergenicity.

A regular Chlorella mannogalactan and its sulfated derivative as a promising anticoagulant: Structural characterization and anticoagulant activity.

Chlorella is one of the most widely cultivated species of microalgae and has been consumed as a "green healthy food". In this study, a novel polysaccharide (CPP-1) was isolated from Chlorella pyrenoidosa, structurally analyzed, and sulfated as a promising anticoagulant. Structural analyses by chemical and instrumental methods such as monosaccharide composition, methylation-GC-MS and 1D/2D NMR spectroscopy analysis revealed that CPP-1 had a molecular weight of ~13.6 kDa, and mainly consisted of d-mannopyranose (d-Manp), 3-O-methylated d-Manp (3-O-Me-d-Manp), and d-galactopyranose (d-Galp). The molar ratio of d-Manp and d-Galp was 1.0:2.3. CPP-1 consisted of a (1→6)-linked ß-d-Galp backbone substituted at C-3 by the d-Manp and 3-O-Me-d-Manp residues in a molar ratio of 1:1, which was a regular mannogalactan. The sulfated Chlorella mannogalactan (SCM) with sulfated group content of 40.2 % equivalent to that of unfractionated heparin was prepared and analyzed. NMR analysis confirmed its structure, indicating that most free hydroxyl groups in the side chains and partial hydroxyl groups in the backbone were sulfated. Anticoagulant activity assays indicated that SCM exhibited strong anticoagulant activity by inhibiting intrinsic tenase (FXase) with IC50 of 13.65 ng/mL, which may be a safer anticoagulant as an alternative to heparin-like drugs.

Simulated digestion, dynamic changes during fecal fermentation and effects on gut microbiota of Avicennia marina (Forssk.) Vierh. fruit non-starch polysaccharides.

Grey mangrove (Avicennia marina (Forssk.) Vierh.) fruit is a traditional folk medicine and health food consumed in many countries. In this study, its polysaccharides (AMFPs) were obtained and analyzed by chemical and instrumental methods, with the results indicating that AMFPs consisted of galactose, galacturonic acid, arabinose, and rhamnose in a molar ratio of 4.99:3.15:5.38:1.15. The dynamic changes in AMFPs during the digestion and fecal fermentation processes were then investigated. The results confirmed that AMFPs were not depolymerized by gastric acid and various digestive enzymes. During fermentation, 56.05 % of the AMFPs were utilized by gut microbiota. Galacturonic acid, galactose, and arabinose from AMFPs, were mostly consumed by gut microbiota. AMFPs obviously decreased harmful bacteria and increased some beneficial microbiota, including Megasphaera, Mistuokella, Prevotella, and Megamonas. Furthermore, AMFPs obviously increased the levels of various short-chain fatty acids. These findings suggest that AMFPs have potential prebiotic applications for improving gut health.

Deaminative-cleaved S. monotuberculatus fucosylated glycosaminoglycan: Structural elucidation and anticoagulant activity.

Stichopus monotuberculatus is a tropical sea cucumber species and used as a folk medicine and tonic food. In this study, a fucosylated glycosaminoglycan (SmFG), the depolymerized SmFG (dSmFG) and its oligosaccharide fractions were prepared. The SmFG and its depolymerized products were comprised of a chondroitin-sulfate-E backbone, and various sulfated fucose side chains, including an unusual disaccharide side chain connected to the C-3 position of D-glucuronic acid (GlcA) or GlcA-ol. A peeling reaction occurred during the deaminative depolymerization process. The dSmFG and its fractions showed strong anticoagulant activity by selectively inhibiting intrinsic tenase complex, and had no anti-factor IIa, Xa and VIIa activity. The anticoagulant activity reduced with the decrease of molecular weight, and the unusual branch and novel reducing end may enhance the anticoagulant activity. These findings can provide significant information for development and utilization of depolymerized products from SmFG in food and pharmaceutical industries.

Structures of fructan and galactan from Polygonatum cyrtonema and their utilization by probiotic bacteria.

Polygonatum cyrtonema is a known tonic herb in Chinese Materia Medica, extensively consumed in China, but the structure and activity of its polysaccharide components remain to be clarified. Herein, two new polysaccharides (a fructan and a galactan) were purified from the dried and the processed P. cyrtonema rhizome, respectively. Structural analysis suggested that the fructan consisted of a (2 â†’ 6) linked ß-d-Fruf residues backbone with an internal α-d-Glcp residue and two (2 â†’ 1) linked ß-d-Fruf residues branches, and that the galactan was a (1 â†’ 4)-ß-d-galactan branched with a single ß-d-galactose at C-6 at about every nine residues in its main chain. The bioactive assay showed that the fructan and the galactan remarkably promoted growth of Bifidobacterium and Lactobacillus strains, indicating that they possess prebiotic activity. These findings may help expand the application of the polysaccharides from the tonic herb P. cyrtonema as functional ingredients in food products.

Kinetic study on the digestibility of lactose and lactulose using small intestinal glycosidases.

Lactose is mostly hydrolysed in the small intestine, whereas lactulose, recognised prebiotic carbohydrate, reaches the colon to be fermented by the intestinal microbiota. Digestibility of these substrates was investigated by an in vitro digestion model using a Rat Small Intestine Extract (RSIE). A kinetic study of lactose digestion showed levels of hydrolysis (82.8%) at 0.2 mg*mL-1 and the highest hydrolysis rate constant (kobt). Considering these conditions, lactulose showed high resistance to intestinal digestion by RSIE, resulting in low hydrolysis degrees (20.4%) after 5 h reaction. These results underline the suitability of these intestinal extracts under the studied conditions, as a reliable tool to evaluate carbohydrate digestion and support the evidences towards the higher resistance of galactosyl-fructose linkages during its intestinal degradation.

Physicochemical, bioactive and rheological properties of an exopolysaccharide produced by a probiotic Pediococcus pentosaceus M41.

This study aimed to investigate the physicochemical properties, health-promoting benefits and rheological properties of an EPS produced by a novel probiotic Pediococcus pentosaceus M41 isolated from a marine source. P. pentosaceus M41 was able to produce an EPS with average molecular weight of 682.07 kDa. EPS-M41 consisted of arabinose, mannose, glucose and galactose with a molar ratio of 1.2:1.8:15.1:1.0. EPS-M41 structure could be proposed as →3)α-D-Glc(1→2)ß-D-Man(1→2)α-D-Glc(1→6)α-D-Glc(1→4)α-D-Glc(1→4)α-D-Gal(1→ with arabinose linked at the terminals. At concentration of 10 mg.ml-1, the antioxidant capacity was 76.5% and 48.9% for DPPH and ABTS, respectively. EPS-M41 inhibited 86.8% and 90.8% of the α-amylase and α-glucosidase activities, respectively, at 100 µg.ml-1. A 77.5% and 46.4% of antitumor inhibition occurred by EPS-M41 against Caco-2 and MCF-7 cells, respectively. The apparent viscosity (ƞ) of all EPS-M41 solutions decreased with shear rate increases. Salt type and pH value had an impact on the rheological properties of EPS-M41.

A heteropolysaccharide purified from leaves of Ilex latifolia displaying immunomodulatory activity in vitro and in vivo.

A novel polysaccharide (ILP50-2) was extracted, isolated and purified from the leaves of Ilex latifolia Thunb. Its structure was characterized as a repeating unit consisting of α-L-Araf-(1→, →3)-α-L-Araf-(1→, →5)-α-L-Araf-(1→, →3,5)-α-L-Araf-(1→, →2)-α-L-Rhap-(1→, →2,4)-α-L-Rhap-(1→, ß-D-Galp-(1→, →4)-ß-D-Galp-(1→, →4)-ß-D-Glcp-(1→, →6)-α-D-Manp-(1→, and →3,6)-α-D-Galp-(1→. The absolute molecular weight of ILP50-2 was 1.49 × 105 g/mol, which adapted a compact coil conformation in 0.1 M NaCl solution with Rz of 25.4 nm. Furthermore, ILP50-2 exhibited immunoregulatory activity, mainly through enhancing the phagocytosis ability of macrophages and prompting the release of nitric oxide (NO) and cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß). Simultaneously, ILP50-2 was found to significantly increase the release of ROS and NO in zebrafish embryos, showing immunoregulatory effects in vivo.

Structural characterization of a low-molecular-weight polysaccharide from Angelica pubescens Maxim. f. biserrata Shan et Yuan root and evaluation of its antioxidant activity.

A novel heteropolysaccharide with about twenty sugar residues named DF80-2 was obtained from Angelica pubescens Maxim. f. biserrata Shan et Yuan root, one of the most widely used traditional Chinese medicines for thousands of years in China. The possible structure of DF80-2 was proposed considering the comprehensive results of physicochemical properties, methylation analysis, and 1D/2D NMR spectroscopy, which showed that its main chain was composed of (1→3)-, and (1→4)-linked-α-d-Glcp, (1→4)-linked-ß-d-Galp, (1→6)-linked-α-d-Manp, and (1→3)-linked-α-l-Araf, and the branch was present as the α-d-Glcp-(1→3)-ß-d-GalpA disaccharides stretched from O-6 position of (1→4)-linked-α-d-Glc moiety in the main chain. Congo red analysis, scanning electron microscopy and atomic force microscopy showed that DF80-2 possessed a triple helical conformation, and its branched monomers were interlaced with one another forming a regular network structure. DF80-2 exhibited antioxidant activity by effectively scavenging DPPH, and hydroxyl radicals, and chelating ferrous ions.

Hydration characteristics, structural effects and the taste quality of some polyhydroxy compounds in aqueous solutions of nicotinic acid (vitamin B3) at (288.15-318.15) K.

Physicochemical properties elucidating the hydration characteristics and structural effects of polyhydroxy compounds in mixed aqueous solutions offer significant information for the growth of pharmaceutical and food industries. Consequently, standard partial molar volumes and isentropic compressibilities at infinite dilution of saccharides, their derivatives and sugar alcohols in (0.01, 0.05, 0.09 and 0.13) mol kg-1 nicotinic acid(aq) (vitamin B3) solutions have been investigated by experimental density and ultrasonic velocity with respect to temperature. Their transfer values, compressibility hydration numbers, apparent massic volumes and isentropic compressibilities have also been determined. These parameters are important to study the taste behavior of polyhydroxy compounds and intermolecular interactions occurring in ternary mixtures. UV absorption spectra of the studied polyhydroxy compounds have been recorded in 1 × 10-4 mol kg-1 nicotinic acid(aq) solutions. The comparison of present results has been made with the studies reported earlier in l-ascorbic acid, thiamine HCl and pyridoxine HCl.

Ameliorative effect of supercritical fluid extract of Chrysanthemum indicum Linnén against D-galactose induced brain and liver injury in senescent mice via suppression of oxidative stress, inflammation and apoptosis.

ETHNOPHARMACOLOGICAL RELEVANCE: Chrysanthemum indicum Linne (C. indicum), a healthy food and folk medicine in China for thousands of years, has been reported to exert heat-clearing and detoxifying effects and extensively applied to treat various symptoms such as inflammation diseases, hepatitis and headache. AIM OF THIS STUDY: The purpose of the present study was to investigate the protective effect of the supercritical carbon dioxide fluid extract from flowers and buds of C. indicum (CISCFE) on D-galactose-induced brain and liver damage during aging process and to illuminate the underlying mechanisms. MATERIALS AND METHODS: Mice were orally administrated with CISCFE (100, 150 and 300 mg/kg) after injection with D-galactose. 24 h after the last administration, the blood samples, whole brain and liver tissues were collected for biochemical analysis, histological examination and western blot analysis. The body weight, spleen and thymus indexes, alanine transaminase (ALT), aspartate transaminase (AST), total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), malondialdehyde (MDA) in brain and liver, interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and necrosis factor-α (TNF-α) were detected. Besides, the expressions of Bax, Bcl-2 and cleaved caspase-3 were determined by western blot assay. RESULTS: The results indicated that CISCFE effectively increased the suppressed body weight, attenuated the decline of thymus and spleen indexes, and reduced the elevated levels of ALT and AST induced by D-gal. Furthermore, CISCFE might notably alleviate D-gal-induced abnormal alterations in structure and function of brain and liver dose-dependently via renewing normal antioxidant enzymes activities (SOD, CAT, GSH-Px), reducing MDA accumulation, decreasing inflammatory cytokines productions (IL-1ß, IL-6, TNF-α), as well as attenuating the increase of Bax/Bcl-2 ratio and cleaved caspase-3 activation in the liver and brain. CONCLUSIONS: Taken together, our present results suggested that CISCFE treatment could effectively mitigate the D-gal-induced hepatic and cerebral injury, and the underlying mechanism might be tightly related to the decreased oxidative stress, inflammation and apoptosis, indicating CISCFE might be an alternative and promising agent for the treatment of aging and age-associated brain and liver diseases.

Optimization of ultrasound-microwave assisted acid extraction of pectin from potato pulp by response surface methodology and its characterization.

The ultrasound-microwave assisted HCl extraction of pectin from potato pulp was optimized using the response surface methodology. Effects of extraction temperature, pH, and time on the yield were evaluated, and structural characteristics of pectin extracted under optimal conditions were determined. The yield was 22.86 ±â€¯1.29% under optimal conditions of temperature 93 °C, pH 2.0, and time 50 min. The obtained pectin was rich in branched rhamnogalacturonan I (61.54 mol%). Furthermore, the pectin was a low-methoxyl (degree of methylation, 32.58%) but highly acetylated (degree of acetylation, 17.84%) pectin and the molecular weight was 1.537 × 105 g/mol. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance indicated that pectin had a linear region of α-1, 4-linked galacturonic acids which could be methyl and acetyl-esterified, and rhamnose linked with galacturonic acid to form rhamnogalacturonan which was branched with side chains. Scanning electron microscopy showed most of pectin had a lamellae structure.

Structural characterization and in vitro hypoglycemic activity of a glucan from Euryale ferox Salisb. seeds.

In this research, a polysaccharide fraction (EFSP-1) was obtained from the seeds of Euryale ferox Salisb. by DEAE sepharose FF and Superdex™ 75 gel chromatography. The average molecular weight (Mw) of EFSP-1 was 8.75 kDa. Monosaccharides composition analysis indicated that EFSP-1 was a glucan. The structure of EFSP-1 was characterized by analysis of FT-IR, GC-MS and NMR, which indicated that the backbone of EFSP-1 was mainly composed of (1→4)-α-D-Glcp with branches substituted at O-6 and terminated with T-α-D-Glcp. Moreover, the hypoglycemic effect of EFSP-1 was investigated by establishing insulin resistance HepG2 and 3T3-L1 cells. The results showed that EFSP-1 could increase glucose consumption by up-regulating the expression of GLUT-4 via activating PI3K/Akt signal pathway in IR cells. Hence, EFSP-1 could be a potential functional food to ameliorate insulin resistance for diabetes therapy.

Extraction, structure, and emulsifying properties of pectin from potato pulp.

Effects of HCl, H2SO4, HNO3, citric acid, and acetic acid on the yield, structure, and emulsifying properties of potato pectins were investigated. Results showed that the highest yield (14.34%) was obtained using citric acid, followed by HNO3 (9.83%), HCl (9.72%), H2SO4 (8.38%), and acetic acid (4.08%). The degrees of methylation (37.45%) and acetylation (15.38%), protein content (6.97%), and molecular weight (3.207 × 105 g/mol) were the highest for pectin extracted using acetic acid, and (galactose + arabinose)/rhamnose was 33.34, indicating that it had a highly branched rhamnogalacturonan I domain. Fourier transform infrared spectroscopy showed a specific absorbance peak at 1064 cm-1, which corresponds to the acetyl groups in potato pectins. SEM showed that all potato pectins are morphologically different. The emulsifying activity (EA, 44.97%-47.71%) and emulsion stability (ES, 36.54%-46.00%) of the pectins were influenced by acid types, and were higher than those of commercial citrus and apple pectin.

Digestibility of fucosylated glycosaminoglycan from sea cucumber and its effects on digestive enzymes under simulated salivary and gastrointestinal conditions.

The digestibility of fucosylated glycosaminoglycan (FG) and its effects on digestive enzymes were investigated using an in vitro digestion model. Results showed that the molecular weight and the reducing sugar content of FG were not significantly changed, and no free monosaccharides released from FG were detected after the salivary, gastric and intestinal digestion, indicating that both the backbone and the sulfated fucose branches of FG are resistant to be cleaved in the saliva and gastrointestinal tract environments. Furthermore, FG can dose-dependently inhibit digestive enzymes such as α-amylase, pepsin and pancreatic lipase in different degrees under the simulated digestion conditions due to the sulfate and carboxyl groups. These physiological effects of FG may help control the postprandial glucose concentration and have the potential in the prevention or treatment of reflux disease and obesity. The findings may provide information on the digestibility and beneficial physiological effects of FG as a potential natural product to promote human health.

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-ß-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.

Purification, characterization, and bioactivities of a polysaccharide from mycelial fermentation of Bjerkandera fumosa.

In this work, a novel polysaccharide (named DBFM3) was isolated from mycelia of Bjerkandera fumosa by DEAE-32 and Sepharose CL-6B column chromatography. High-performance gel permeation chromatography showed that DBFM3 was homogeneous, with an average molecular weight of 1.8×105Da. Structural characteristics of the purified fraction were investigated by high-performance liquid chromatography (HPLC), FT-IR, and NMR. HPLC analysis indicated that DBFM3 was composed of mannose, galacturonic acid, and galactose at molar ratios of 1:18.16:0.702. Spectral analysis suggested that DBFM3 had (1→6), (1→3,6), (1→3) linkages and pyranose conformation. Antioxidant assay in vitro showed that DBFM3 exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activity, and has protective effect against DNA damage and damage to SH-SY5Y cells induced by H2O2. Immunological tests indicated that DBFM3 significantly increased lymphocyte proliferation in vitro. Furthermore, DBFM3 increased the proliferation of lymphocytes in the presence of concanavalin A or lipopolysaccharide as mitogen.

Effects of temperature, pH and sugar binding on the structures of lectins ebulin f and SELfd.

Ebulin f and SELfd are two lectins of Sambucus ebulus L. that show different stability and digestibility properties in gastric fluid due to their structural differences which may explain their different toxicological profiles. The main aim was to determine the effects of pH, temperature and sugar binding on the intrinsic structures of both proteins by fluorescence analyses. Quenching experiments were conducted, under different pH and temperature conditions, with acrylamide (uncharged) and iodide (charged), to study the possible changes of their intrinsic fluorescence. Results revealed that the native structure of SELfd is more folded than that of ebulin f. At pH 2.0, ebulin f displayed a more open structure than at neutral pH. It can be concluded that this is the main reason why ebulin f is accessible to pepsin action and more sensitive to degradation, in contrast to SELfd as we reported previously.

Production of xylooligosaccharides by autohydrolysis of hazelnut (Corylus avellana L.) shell.

Hazelnut shell (HS), husk and pruning residues were characterized and evaluated for xylooligosaccharides (XOS) production by autohydrolysis. HS contained the highest amount of xylan and yielded more XOS compared to other hazelnut residues. The temperature and holding time of HS autohydrolysis greatly influenced the composition of the liquor and the remaining solid. The highest XOS yield (62% of the feedstock xylan) was obtained at 190°C and 5min of holding time. At this temperature, 30min of holding time was required to maximize the percentage of XOS with low degree of polymerization. Xylose, acetic acid and furfural concentrations increased with treatment severity. The concentrations of the products in the autohydrolysis liquors followed specific trends with changing severity factor (log Ro) values. Solubilization of xylan in the treatments enhanced the cellulose and lignin contents in the remaining solids.

Polysaccharides with immunomodulating activity from roots of Gentiana crassicaulis.

Two polysaccharides, GCP-I-I and GCP-II-I, were obtained from 100°C water extracts of Gentiana crassicaulis roots by DEAE anion exchange chromatography and gel filtration. The results from methanolysis, methylation, FT-IR and NMR, indicated that these two fractions are typical pectic polysaccharides, with HG and RG-I regions and AG-I/AG-II side chains, and some of the galacturonic acid units of fraction GCP-I-I were methyl esterified. Fractions GCP-I-I and GCP-II-I, both exhibited potent complement fixation, and fraction GCP-I-I was more potent than positive control BPII. The higher complement fixation activity obtained in fraction GCP-I-I may be due to the higher Mw and/or higher amount of AG-II present in fraction GCP-I-I than fraction GCP-II-I. The polysaccharides from G. crassicaulis could be used as a potential natural immunomodulator.