Inhibition of α-glucosidase activity and intestinal glucose transport to assess the in vivo anti-hyperglycemic potential of dodecyl-acylated phlorizin and polydatin derivatives.

A diet containing natural active compounds that can inhibit the hydrolytic activity of α-glucosidase on carbohydrates and intestinal glucose absorption is an effective means of controlling postprandial hyperglycemia. Phlorizin and polydatin as phenolic glycosides have a high affinity for the catalytic site of α-glucosidase, but exhibited unsatisfactory competitive inhibitory capacity, with an IC50 of 0.97 and >2 mM, respectively. However, dodecyl-acylated derivatives of phlorizin and polydatin exerted α-glucosidase inhibitory capacity, with an IC50 of 55.10 and 70.95 µM, respectively, which were greatly enhanced and much stronger than that of acarbose with an IC50 of 2.46 mM. The SPR assay suggested the high affinity of dodecyl phlorizin and dodecyl polydatin to α-glucosidase with equilibrium dissociation constant (KD) values of 12.0 and 7.9 µM, respectively. Both dodecyl phlorizin and dodecyl polydatin reduced the catalytic ability of α-glucosidase by reversible noncompetitive and uncompetitive mixed inhibition, which bind noncovalently to the allosteric site 2 through hydrogen bonds and hydrophobic interactions, thereby inducing the secondary structure unfolding and intrinsic fluorescence quenching of α-glucosidase. Confocal microscopy detection visually showed significant inhibitory effects on FITC-labeled glucose uptake in intestinal Caco-2 cells by phlorizin, polydatin, dodecyl phlorizin and dodecyl polydatin. In addition, based on the differentiated Caco-2 cell monolayer model, dodecyl phlorizin and dodecyl polydatin suppressed intestinal glucose transport more effectively than phlorizin and polydatin, suggesting that they were promising in vivo hypoglycemic active compounds.

UV/H2O2-Degraded Polysaccharides from Sargassum fusiforme: Purification, Structural Properties, and Anti-Inflammatory Activity.

The main purpose of this study was to analyze the structural properties and anti-inflammatory activity of the purified fractions derived from UV/H2O2-degraded polysaccharides from Sargassum fusiforme. Results indicated that twofractions with different monosaccharide compositions and morphological characteristics, PT-0.25 (yield 39.5%) and PT-0.5 (yield 23.9%), were obtained. The average molecular weights of PT-0.25 and PT-0.5 were 14.52 kDa and 22.89 kDa, respectively. In addition, PT-0.5 exhibited better anti-inflammatory activity with a clear dose dependence. The mechanism was associated with the inhibition of LPS-activated Toll-like receptor 4-mediated inflammatory pathways in RAW264.7 cells. The results showed that PT-0.5 was a complex polysaccharide mainly composed of 4-Fucp, t-Manp, 6-Galp, t-Fucp, and 3,4-GlcAp. These results would provide theoretical support for studying the structural properties and biological activities of UV/H2O2-degraded polysaccharides.

Alginate coated biogenic silver nanoparticles for the treatment of Pseudomonas infections in rainbow trout.

Pseudomonas species are among the main pathogens causing rainbow trout infections. The present study provides a simple, green, sustainable, and rapid technique to synthesize of biogenic alginate-capped silver nanoparticles (Alg-Ag NPs) suitable for the treatment of Pseudomonas infections. It has been shown that the mechanism (aggregative or autocatalytic) of Alg-Ag NPs formation depended on Alg concentration and the heating approach used. The rate constants and activation energy were calculated. Alg-Ag NPs were characterized by UV-Vis, FTIR, XRD, TEM, AFM, XPS, and DLS. The optimal conditions for the fabrication of spherically-shaped (17-19 nm) and negatively-charged (zeta-potential <-50 mV) Alg-Ag NPs, which are stable during 9 months, included hot-plate assisted synthesis at 100 °C in diluted (1 mg/mL) Alg solutions. In vitro studies showed that Alg-Ag NPs exhibited prominent antimicrobial activity against collection Pseudomonas strains (inhibition zones ranged from 9.0 ± 1.0 to 19.0 ± 1.0 mm), with no significant loss of antibacterial efficacy after 9 months of storage. AFM analysis confirmed that the antibacterial effect of Alg-Ag NPs dealt with the direct nanomechanical disrupting of bacterial cells. The ability of Alg-Ag NPs to inhibit the growth of virulent P.aeruginosa, P.fluorescens and P. putida strains isolated from infected rainbow trout was evaluated. All tested strains were susceptible to Alg(10)-Ag NPs, while Alg(1)-Ag NPs demonstrated a limited strain-specific antibacterial effect. The obtained data displayed the prospects for the application of biogenic Alg-Ag NPs to create novel delivery systems for combating Pseudomonas infections in rainbow trout.

Honeycomb-Structured Porous Films from Poly(3-hydroxybutyrate) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate): Physicochemical Characterization and Mesenchymal Stem Cells Behavior.

Surface morphology affects cell attachment and proliferation. In this research, different films made of biodegradable polymers, poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB-co-HV), containing different molecular weights, with microstructured surfaces were investigated. Two methods were used to obtain patterned films-water-assisted self-assembly ("breath figure") and spin-coating techniques. The water-assisted technique made it possible to obtain porous films with a self-assembled pore structure, which is dependent on the monomer composition of a polymer along with its molecular weight and the technique parameters (distance from the nozzle, volume, and polymer concentration in working solution). Their pore morphologies were evaluated and their hydrophobicity was examined. Mesenchymal stem cells (MSCs) isolated from bone marrow were cultivated on a porous film surface. MSCs' attachment differed markedly depending on surface morphology. On strip-formed stamp films, MSCs elongated along the structure, however, they interacted with a larger area of film surface. The honeycomb films and column type films did not set the direction of extrusion, but cell flattening depended on structure topography. Thus, stem cells can "feel" the various surface morphologies of self-assembled honeycomb films and change their behavior depending on it.

Structural characterization and anti-photoaging activity of a polysaccharide from Sargassum fusiforme.

In this study, a purified algal polysaccharide (P1) was isolated from Sargassum fusiforme and its structural characteristics and anti-photoaging activity were studied. Results showed that P1 had a molecular weight of 289 kDa and was mainly composed of mannuronic acid, guluronic acid and fucose with molar ratio of 7.67:2.35:1.00. The backbone of P1 was →4)-ß-ManA-(1→4)-α-GulA-(1→4)-ß-ManA-(1→4)-ß-ManA-(1→4)-α-GulA-(1→4)-ß-ManA-(1→3,4)-ß-ManA-(1→ with a terminal group of α-Fucp-(1→ linked to O-3 position of →3,4)-ß-ManA-(1→. In addition, P1 could inhibit the expressions of MMPs (MMP-1, MMP-3 and MMP-9) in the UVB-irradiated HaCaT cells, indicating that P1 could reduce collagen loss caused by UVB irradiation. It also reduced the contents of ROS and inflammatory factors (TNF-α, IL-6 and IL-1ß), indicating that P1 could reduce the oxidative stress and inflammation response. Thus, Sargassum fusiforme polysaccharide P1 could be used as a potential functional food to relieve skin photoaging.

Effects of UV/H2O2 degradation and step gradient ethanol precipitation on Sargassum fusiforme polysaccharides: Physicochemical characterization and protective effects against intestinal epithelial injury.

In this study, the degraded purified fraction from Sargassum fusiforme polysaccharides (SFP), named DSFP, was produced by the treatment of ultraviolet/hydrogen peroxide (UV/H2O2) degradation and step gradient ethanol precipitation. Results showed that the treatment significantly reduced the molecular weight of polysaccharides, from 282.83 kDa to 18.54 kDa, and influenced their surface morphology and roughness. SFP and DSFP were typical sulfated polysaccharides, mainly composed of fucose, galacturonic acid, glucuronic acid, galactose, and mannose. Both SFP and DSFP increased cell migration during intestinal epithelial wound healing and stimulated the cell cycle progression by promoting the transition from G0/G1 to S phase in the rat intestine epithelium cells (IEC-6). But DSFP had a stronger positive effect on wound healing and cell migration than SFP. It reinforced the intestinal barrier function and attenuated lipopolysaccharides-induced intestinal inflammation. DSFP significantly downregulated the expression of Toll-like receptor 4, tumor necrosis factor-α, interleukin-6, interleukin-1ß, and inducible nitric oxide synthase by 53.14%, 92.41%, 66.01%, 68.24%, and 78.09%, respectively, and upregulated that of interleukin-10 by 2.48 folds when compared to the model. Therefore, the treatment (UV/H2O2 degradation and step gradient ethanol precipitation) could effectively improve the protective effects against intestinal epithelial injury.

Physicochemical aspects of design of ultrathin films based on chitosan, pectin, and their silver nanocomposites with antiadhesive and bactericidal potential.

Implant-related infection is one of the serious problems in regenerative medicine. Promising approach to overcome the problems caused by bacterial growth on the medical implants is their modification by bioactive coatings. A versatile technique for designing multilayer films with tailored characteristics at the nanometer scale is layer-by-layer assembly. In this study, multilayer films based on biopolymers (pectin and chitosan) and their nanocomposites with silver nanoparticles have been prepared and evaluated. The buildup of multilayers was monitored using the quartz crystal microbalance with dissipation technique. The morphology of the obtained films was investigated by atomic force microscopy. We have demonstrated that pectin-Ag-containing films were characterized by the linear growth and smooth defect-free surface. When pectin-Ag was substituted for the pectin in the multilayer systems, the properties of the formed coatings were significantly changed: the film rigidity and surface roughness increased, as well as the film growth acquired the parabolic character. All prepared multilayer films have shown antibacterial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The significant decrease in the number of the adhered E. coli on the multilayer surface has been determined; moreover, many of the cells were misshapen with cytoplasm leaking. The prepared multilayer films showed a mild activity against S. aureus predominantly due to the antiadhesive effect. Our results indicate that antibacterial activity of biopolymer multilayers is determined by the film composition and physicochemical characteristics and can be associated with their antiadhesive and bactericidal behaviors.

Polysaccharides from Sargassum fusiforme after UV/H2O2 degradation effectively ameliorate dextran sulfate sodium-induced colitis.

In this study, degraded polysaccharides from Sargassum fusiforme (PSF-T2) were prepared by UV/H2O2 treatment for 2 h, and its effects on ameliorating dextran sulfate sodium-induced colitis were evaluated using a mouse model. Results showed that PSF-T2 relieved colitis symptoms, characterized by increasing the colon length and body weight, decreasing disease activity index and relieving colon damage. In addition, PSF-T2 decreased the secretion and expression of IL-1ß, IL-6 and TNF-α, and increased the expression of MUC-2, ZO-1 and occludin. Besides, PSF-T2 promoted the production of short-chain fatty acids and modulated gut microbiota composition (increasing the abundance of Lactobacillaceae, Lachnospiraceae, Oscillospiraceae and Desulfovibrionaceae, and decreasing Bacteroidaceae and Erysipelotrichaceae). These results suggested that polysaccharides from Sargassum fusiforme after UV/H2O2 degradation could ameliorate colitis by decreasing inflammation, protecting the intestinal barrier and modulating gut microbiota. It can provide a theoretical basis for the preparation of bioactive polysaccharides by free radical degradation.

Fabrication and Characterization of Poly (vinyl alcohol) and Chitosan Oligosaccharide-Based Blend Films.

In the present study, we report the development of poly (vinyl alcohol) (PVA) and chitosan oligosaccharide (COS)-based novel blend films. The concentration of COS was varied between 2.5-10.0 wt% within the films. The inclusion of COS added a brown hue to the films. FTIR spectroscopy revealed that the extent of intermolecular hydrogen bonding was most prominent in the film that contained 5.0 wt% of COS. The diffractograms showed that COS altered the degree of crystallinity of the films in a composition-dependent manner. As evident from the thermal analysis, COS content profoundly impacted the evaporation of water molecules from the composite films. Stress relaxation studies demonstrated that the blend films exhibited more mechanical stability as compared to the control film. The impedance profiles indicated the capacitive-dominant behavior of the prepared films. Ciprofloxacin HCl-loaded films showed excellent antimicrobial activity against Escherichia coli and Bacillus cereus. The prepared films were observed to be biocompatible. Hence, the prepared PVA/COS-based blend films may be explored for drug delivery applications.

Regulation effects of indigestible dietary polysaccharides on intestinal microflora: An overview.

The human intestinal contains rich and diverse microbiota that utilizes a variety of polysaccharides. The intestinal microflora extends the metabolic functions of the body, obtaining energy from indigestible dietary polysaccharides. It is not only a highly competitive environment but also a comprehensive collaboration for these polysaccharides, as the microbiota work to maximize the energy harvested from them through the intestine. Indigestible dietary polysaccharides help to manage colon health and host health by affecting the gut microbial population. These polysaccharides also influence the metabolic activity of the intestinal microbiota by stimulating the formation of SCFAs. Most of these metabolic activities affect host physiology because the epithelium absorbs secondary metabolites and end products or transports them to the liver, where they could exert other beneficial effects. This article reviews the carbohydrates existing in the human intestine, the regulating actions of indigestible polysaccharides on intestinal microflora, and the molecular basis of the degradation process of these polysaccharides. PRACTICAL APPLICATIONS: Large deals of researches have shown that indigestible polysaccharides possess an outstanding regulation effect on the intestinal microflora, which indicates that indigestible polysaccharides have the potential to be used as prebiotics in the functional food and pharmaceutical industries. However, it is not clear how gut microbiota metabolizes these dietary polysaccharides, and how the resulting gut metabolites may further affect the intestinal microflora population and metabolism. This paper reviews the indigestible dietary polysaccharides existing in the human intestine, the regulation of polysaccharides on gut microbiota, and the molecular basis of the degradation process of these polysaccharides. This review helps to better understand the relationship between indigestible dietary polysaccharides and intestinal microflora, which will provide powerful evidence for the potential use of these polysaccharides as functional foods.

Polyvinyl alcohol and pectin blended films: Preparation, characterization, and mesenchymal stem cells attachment.

The design of novel wound dressings for chronic wound treatment is still of great importance. One of the promising approaches is application of mesenchymal stem cells (MSCs), immobilized on a flexible polymer film, for healing. In this study, blended films based on polyvinyl alcohol (PVA) and pectin with different component ratio have been prepared by solution casting method and evaluated. Physicochemical properties of the formed PVA/pectin films, including their morphology, wettability, swelling, stability, mechanical characteristics, have been studied. We demonstrated that the surface of PVA/pectin films could be modified by ultraviolet or dielectric barrier discharge plasma exposure. After both ultraviolet and plasma treatment, the hydrophilicity of PVA/pectin films increased. It has been shown that additional crosslinking of PVA/pectin films with glutaraldehyde resulted in reinforcement of their structure. MSCs were cultured on neat and modified PVA/pectin samples to evaluate the effects of film characteristics and composition on cell behavior. It has been determined that MSCs effectively adhered to glutaraldehyde-crosslinked PVA/pectin films and formed on them the monolayer culture of fibroblast-like cells. The additional modification of PVA/pectin films with collagen resulted in enhancement of MSCs adhesion. Our results show that the obtained PVA/pectin films with adhered MSCs can be suggested for potential application as a part of novel complex wound dressings.

Degradation of polysaccharides from Sargassum fusiforme using UV/H2O2 and its effects on structural characteristics.

The depolymerization effect of UV/H2O2 on the polysaccharides from Sargassum fusiforme (PSF), a brown algae, were studied. The structural changes of PSF before and after UV/H2O2 treatment were analyzed, and molecular weight changes during in vitro digestion were determined. Results indicated that the molecular weight of PSF was reduced from ∼289 to ∼12.6 kDa within 2 h with UV/150 mmol/L H2O2, and the depolymerization effect of UV/H2O2 was significantly higher than that of UV or H2O2 alone. In addition, the UV/H2O2 treatment had a high recovery rate of total sugar (93.54 %) and clearance rate of protein (76.34 %). The monosaccharide composition showed that UV/H2O2 treatment could increase the mole percentage of mannose (37.44 %) and decrease the mole percentage of fucose (14.88 %). The helix-coil transition, X-ray diffraction (XRD) and atomic force microscopy (AFM) imaging showed that the UV/H2O2 treatment depolymerized PSF. Rheological studies indicated that PSF with UV/H2O2 treatment had lower viscosity. In vitro digestion showed that PSF was minimally digested with the in vitro gastrointestinal tract simulation, but PSF with UV/H2O2 treatment could be digested in the low acid environment in the simulated gastric juice, but was minimally digested with the simulated intestinal juice. This studied suggested that the preparation and application of functional PSF with low molecular weight might be beneficial.

Fabrication and characterization of pectin-based three-dimensional porous scaffolds suitable for treatment of peritoneal adhesions.

Formation of peritoneal adhesions is common complication after abdominal and pelvic surgery. They bear a significant health problem with an influence to quality of life and health care expenses. Promising approach for their prevention is using of biodegradable barrier films for physical separation of peritoneal surfaces. In the present study, highly porous pectin-based three-dimensional (3D) scaffolds were obtained by freeze-drying technique. Physico-chemical properties of the formed materials, including their morphology, porosity, density, and stability, have been studied. The evaluation of their biocompatibility, biodegradation, and potential antiadhesion effect was studied by in vivo experiment. To reinforce the scaffolds structure and improve their stability in physiological solutions, pectin chains were cross-linked with divalent cations. We determined optimal cross-linking conditions, which allow obtaining scaffolds with desired biodegradation rate. These cross-linked scaffolds fully dissolved within 8 days in the peritoneal cavity with low presence of complications and some antiadhesive effect. It has also been determined that mesenchymal stem cells from adipose tissue could effectively adhere to the scaffolds with preservation of their viability. Our results show that obtained materials can be suggested as mechanical scaffold for delivery of the stem cells culture to peritoneal surfaces as a part of complex antiadhesive barrier system.

Layer-by-layer buildup of polysaccharide-containing films: Physico-chemical properties and mesenchymal stem cells adhesion.

Layer-by-Layer assembled polyelectrolyte films offer the opportunity to control cell attachment and behavior on solid surfaces. In the present study, multilayer films based on negatively charged biopolymers (pectin, dextran sulfate, carboxymethylcellulose) and positively charged polysaccharide chitosan or synthetic polyelectrolyte polyethyleneimine has been prepared and evaluated. Physico-chemical properties of the formed multilayer films, including their growth, morphology, wettability, stability, and mechanical properties, have been studied. We demonstrated that chitosan-containing films are characterized by the linear growth, the defect-free surface, and predominantly viscoelastic properties. When chitosan is substituted for the polyethyleneimine in the multilayer system, the properties of the formed films are significantly altered: the rigidity and surface roughness increases, the film growth acquires the exponential character. The multilayer films were subsequently used for culturing mesenchymal stem cells. It has been determined that stem cells effectively adhered to chitosan-containing films and formed on them the monolayer culture of fibroblast-like cells with high viability. Our results show that cell attachment is a complex process which is not only governed by the surface functionality because one of the key parameter effects on cell adhesion is the stiffness of polyelectrolyte multilayer films. We therefore propose our Layer-by-Layer films for applications in tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2093-2104, 2018.