Original Polysaccharide Research Articles

Efficient degradation and enhanced anticomplementary activity of Belamcanda chinensis (L.) DC. polysaccharides via trifluoroacetic acid treatment with different degrees

The degradation of Belamcanda chinensis (L.) DC. polysaccharides was carried out by five concentrations of trifluoroacetic acid (TFA) (1–5 mol/L), and their physicochemical properties, degradation kinetics and anticomplementary activity were investigated. The findings revealed a notable reduction in the molecular weight of BCP, from an initial value of 2.622 × 105 g/mol to a final value of 6.255 × 104 g/mol, and the water solubility index increased from 90.66 ± 0.42 % to 97.78 ± 0.43 %. The degraded polysaccharides of B. chinensis exhibited a comparable monosaccharide composition comprising Man, GalA, Glc, Gal, and Ara. As the concentration of TFA increased, the degradation rate constant increased from 1.468 × 10−3 to 5.943 × 10−3, and the process followed the first-order degradation kinetic model (R2 > 0.97) and the random fracture model (R2 > 0.96). Furthermore, the five degraded polysaccharides still exhibit good thermal stability. In vitro experiments showed that DBCP-3 exhibited more potent anticomplementary activity than the original polysaccharides and positive drugs, which was strongly correlated with its Mw (r = 0.6–0.8), inhibiting complement activation by blocking C2 and C4. These results indicated that TFA degradation has a positive effect on polysaccharides, of which DBCP-3 is expected to treat diseases involving hyperactivation of the complement system.

Changes in physicochemical and gut microbiota fermentation property induced by acetylation of polysaccharides from Cyperus esculentus

In this study, the impact of acetylation on physicochemical, digestive behavior and fermentation characteristics of Cyperus esculentus polysaccharides (CEP) was investigated. Results indicated that the acetylation led the molecules to be more likely aggregated, followed by a higher crystallinity, a lower apparent viscosity and a higher ratio of G" to G' (tan δ). Importantly, the acetylated polysaccharides (ACEP) had a lower digestibility, but its molecular weight was lower than that of original polysaccharides (CEP) following a simulated saliva-gastrointestinal digestion. Gut microbiota fermentation indicated that both polysaccharides generated outstanding short-chain fatty acids (SCFAs), in which the acetylated polysaccharides had a faster fermentation kinetics than the original one, followed by a quicker reduction of pH and a more accumulation of SCFAs, particularly butyrate. Fermentation of both polysaccharides promoted Akkermansia, followed by a reduced richness of Klebsiella. Importantly, the current study revealed that the fermentation of acetylated polysaccharides enriched Parabacteroides, while fermentation of original ones promoted Bifidobacterium, for indicating their individual fermentation characteristics and gut environmental benefits.

STUDY OF THE MECHANISM OF SORPTION OF Cu2+, Co2+, AND Mn2+ IONS ON A MODIFIED NATURAL POLYMER – PECTIN

Sorption materials based on apple pectin modified with biologically active organic acids (salicylic, anthranilic, 5-aminosalicylic, nicotinic) capable of effectively extracting Cu2+, Co2+ and Mn2+ ions from aqueous solutions of their salts have been obtained. The regularities of the sorption kinetics of Cu2+, Co2+ and Mn2+ ions by modified pectin samples were studied. An increase in the efficiency of extraction of d-metal ions by modified pectin sorbents compared to the original polysaccharide was revealed. Sorption isotherms of Cu2+, Co2+, Mn2+ ions by modified pectins have been obtained and analyzed for compliance with known theoretical models. Integral kinetic curves have been obtained, and the values of the experimental sorption capacity of biosorbents have been calculated. It was found that the process of sorption of Cu2+, Co2+ and Mn2+ ions on the studied biosorbents proceeds in the diffusion mode. The predominance of the external diffusion nature of the limiting stage of the process of extracting transition metal ions with modified pectins was established. The rate constants of sorption processes are calculated. The values of the apparent activation energy of the sorption process are determined. The thermodynamic parameters of the extraction of Cu2+, Co2+ and Mn2+ ions by pectin sorbents have been calculated. It has been established that the sorption of Cu2+, Co2+, and Mn2+ ions by modified polysaccharide materials is an exothermic process, which can be considered as physical adsorption of metal ions due to solvation and complex formation with the participation of sorbent sorption centers and solvent (water) molecules. The obtained new highly active biosorbents can be recommended as enterosorbents for detoxification of the human body.
 Keywords: sorption, d-metal ions, pectin, modification, kinetic curves, thermodynamic parameters.

Commercial Utilization of Microbial Polysaccharides: A Brief Global Perspective

Microbial polysaccharides are the water soluble renewable biopolymers which comprise a variety of polysaccharides produced by bacteria, fungi and yeast. These microbial polysaccharides have unusual molecular structure and peculiar conformations rendering them with unique and potentially interesting properties. In recent years, demand of natural polymers for various industrial applications has led to an increased attention towards production of microbial polysaccharides. Since the microbial origin polysaccharides have properties identical to the currently used gums they have been widely used as an alternative in various food, pharmaceutical, and cosmeceutical industries as emulsifiers, binders, gelling agents and suspending agents. There has been an increase in the adoption of microbially sourced polysaccharides and this surge in demand has resulted in the manufacturers to now focus on enhancing their production capacity. The current review deals with the worldwide commercial utilization of the microbial polysaccharides and their present status in the polysaccharide market.

Fermentation-mediated variations in structure and biological activity of polysaccharides from Tetrastigma hemsleyanum Diels et Gilg

Variations in the structure and activities of polysaccharides from Tetrastigma hemsleyanum Diels et Gilg fermented by Sanghuangporus sanghuang fungi were investigated. Compare with the unfermented polysaccharide (THDP2), the major monosaccharide composition and molecular weight of polysaccharide after fermentation (F-THDP2) altered dramatically, which caused galactose-induced conversion from glucose and one-third of molecular weight. F-THDP2 had a molecular weight of 1.23 × 104 Da. Moreover, the glycosidic linkage of F-THDP2 varied significantly, a 1, 2-linked α-d-Galp and 1, 2-linked α-d-Manp backbone was established in F-THDP2, which differed from that of 1, 4-linked α-d-Glcp and 1, 4-linked β-d-Galp in THDP2. In addition, F-THDP2 showed a more flexible chain conformation than that of THDP2 in aqueous solution. Strikingly, F-THDP2 exhibited superior inhibitory effects on HeLa cells via Fas/FasL-mediated Caspase-3 signaling pathways than that of the original polysaccharide. These variations in both structure and biological activities indicated that fermentation-mediated modification by Sanghuangporus sanghuang might a promising novel method for the effective conversion of starch and other polysaccharides from Tetrastigma hemsleyanum Diels et Gilg into highly bioactive biomacromolecules, which could be developed as a potential technology for use in the food industry.

Preparation, characteristics, and antioxidant activities of carboxymethylated polysaccharides from Paeonia x suffruticosa petals

Two carboxymethylated polysaccharides (CPSP30, CPSP60) were obtained from the petals of Paeonia x suffruticosa Andrews (PSP30, PSP60, respectively) with different molecular weight. Chemical characterization, morphological properties and antioxidant activities of PSP and CPSP were determined. PSP were mainly composed of galactose, glucose, fructose and galacturonic with different molar percentages. CPSP were mainly composed of arabinose, galactose, glucose with different molar percentages. The signals of carboxymethyl groups were found in Fourier transform infrared spectroscopy (FT-IR) and 13C nuclear magnetic resonance (NMR) spectra. Scanning electron microscopy (SEM) indicated that the original polysaccharides had a smooth surface, while the modified polysaccharides had an irregular lamellar structure. Thermal analysis indicated that the modified polysaccharides (CPSP30, CPSP60) presented higher thermal stability than the original polysaccharides. All polysaccharides presented typical structures of non-crystalline compounds. Carboxymethylation did not destroy the triple-helical structures of the polysaccharides. With its lower molecular weight, CPSP30 had higher scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), OH, and Fe2+ chelating ability than PSP30. The scavenging DPPH and OH abilities of both derivatives were higher than that of original polysaccharides. This study demonstrates that carboxymethylation improved the solubilities and antioxidant abilities of the original polysaccharides, thus enhancing their potential for application in food and pharmaceutical industry.

Carrageenans and Their Oligosaccharides from Red Seaweeds Ahnfeltiopsis flabelliformis and Mastocarpus pacificus (Phyllophoraceae) and Their Antiproliferative Activity.

Comparative structural analysis of gelling polysaccharides from A. flabelliformis and M. pacificus belonging to Phyllophoraceae and the effect of their structural features and molecular weight on human colon cancer cell lines (HT-29, DLD-1, HCT-116) was carried out. According to chemical analysis, IR and NMR spectroscopies, M. pacificus produces kappa/iota-carrageenan with a predominance of kappa units and minor amounts of mu and/or nu units, while the polysaccharide from A. flabelliformis is iota/kappa-carrageenan (predominance of iota units) and contains negligible amounts of beta- and nu-carrageenans. Iota/kappa- (Afg-OS) and kappa/iota-oligosaccharides (Mp-OS) were obtained from the original polysaccharides through mild acid hydrolysis. The content of more sulfated iota units in Afg-OS (iota/kappa 7:1) was higher than in Mp-OS (1.0:1.8). The poly- and oligosaccharides up to 1 mg/mL did not show a cytotoxic effect on all tested cell lines. Polysaccharides showed an antiproliferative effect only at 1 mg/mL. Oligosaccharides had a more pronounced effect on HT-29 and HCT-116 cells than the original polymers, while HCT-116 cells were slightly more sensitive to their action. Kappa/iota-oligosaccharides exhibit a greater antiproliferative effect and more strongly decrease the number of colonies forming in HCT-116 cells. At the same time, iota/kappa-oligosaccharides inhibit cell migration more strongly. Kappa/iota-oligosaccharides induce apoptosis in the SubG0 and G2/M phases, while iota/kappa-oligosaccharides in the SubG0 phase.

Physicochemical Properties and Antiherpetic Activity of κ-Carrageenan Complex with Chitosan.

Nanoparticles formation is one of the ways to modulate the physicochemical properties and enhance the activity of original polysaccharides. For this purpose, based on the polysaccharide of red algae, κ-carrageenan (κ-CRG), it polyelectrolyte complex (PEC), with chitosan, were obtained. The complex formation was confirmed by ultracentrifugation in a Percoll gradient, with dynamic light scattering. According to electron microscopy and DLS, PEC is dense spherical particles with sizes in the range of 150-250 nm. A decrease in the polydispersity of the initial CRG was detected after the PEC formation. Simultaneous exposure of Vero cells with the studied compounds and herpes simplex virus type 1 (HSV-1) showed that the PEC exhibited significant antiviral activity, effectively inhibiting the early stages of virus-cell interaction. A two-fold increase in the antiherpetic activity (selective index) of PEC compared to κ-CRG was shown, which may be due to a change in the physicochemical characteristics of κ-CRG in PEC.

Effect of fermentation modification on the physicochemical characteristics and anti-aging related activities of Polygonatum kingianum polysaccharides

In order to fully investigate the anti-aging value of the plants polysaccharides, the fermentation method was applied to modify the Polygonatum kingianum polysaccharides (PKPS), and the ultra-filtration was used to further segment the hydrolyzed polysaccharides. It was found that the fermentation induced an increase in the in vitro anti-aging-related activities of PKPS including antioxidant, hypoglycemic and hypolipidemic activity, and cellular aging-delaying ability. In particular, the low Mw fraction PS2-4 (10-50 kDa) separated from the fermented polysaccharide exhibited superior anti-aging activity on experimental animals. PS2-4 extended the Caenorhabditis elegans lifespan by 20.70 %, with an increased effect of 10.09 % compared to the original polysaccharide; it was also more effective than the original one in improving movement ability and reducing lipofuscin accumulation of worms. This fraction was screened as the optimal anti-aging active polysaccharide. After fermentation, the main molecular weight distribution of PKPS changed from 50–650 kDa to 2–100 kDa, and the chemical composition and monosaccharide composition also changed; the initial rough and porous microtopography turned into smooth state. These alterations in physicochemical characteristics suggest that fermentation exerted an influence on the structure of PKPS, which contributed to the enhanced anti-aging activity, indicating that fermentation was promising in the structural modification of polysaccharides.

Review: Oral Beads as a Platform for Sustained Drug Delivery

Multiparticulate drug delivery systems extend the frontier of pharmaceutical progress future by offering marvellous prospects for designing unique controlled and delayed-release oral preparations. Beads are composed of many distinct units. The preparation of microbeads drug delivery system is one of the alternatives which include neither utilization of harsh chemical nor raised temperature. This presented review gives a special emphasis on beads technology, ionic gelation and modified methodologies for preparation of beads. In general, the ionic gelation method mainly relies on the cross-linking between polyelectrolytes counterions and eventually, hydrogels will be formed. Natural origin polysaccharides biopolymers utilization has been widely augmented especially in controlled \ sustained formulation; accordingly, an eco-friendly pharmaceutical product can be provided. Furthermore, the review shed light on merits, limitations, promising polymers involved in the preparation, recent advances of multiple-unit drug delivery system approach based on Ionotropic gelation method, pharmaceutical application, and several basic evaluation characteristics.

Periodate oxidation of plant polysaccharides provides polysaccharide-specific oligosaccharides

Although polysaccharides are frequently used in foods, detailed characterization and/or identification of their structures using a single method remains a challenge. We investigated the suitability of periodate oxidation as an approach to depolymerize polysaccharides, allowing characterization and/or identification of the original polysaccharides based on ESI-MS analyses of the released oligosaccharides. Various periodate oxidation conditions were tested on (arabino)xylan, galactomannan, xyloglucan and homogalacturonan. Each polysaccharide required a different oxidation condition to release a substantial level of oligosaccharides. These oligosaccharides had highly complex structures due to the presence of e.g., dialdehyde sugars, hemialdals, and remnants of (oxidized) sugars, as verified by ESI-MS/MS. Despite these oligosaccharides were highly complex and lost some polysaccharide structural features, each periodate-oxidized sample comprised polysaccharide structure-dependent MS oxidized oligosaccharide profiles. Our findings are a good starting point to find a more generic chemical polysaccharide depolymerization approach based on periodate oxidation to identify polysaccharides by oligosaccharides fingerprinting using MS.

Characterization of a polysaccharide hydrogel with high elasticity produced by a mutant strain Sphingomonas sanxanigenens NX03

Microbial polysaccharides as renewable bioproducts have attracted lots of attention in various industries. Hesan (Highly elastic Sanxan), an exopolysaccharide produced by a plasma mutagenic strain Sphingomonas sanxanigenens NX03, was characterized. It possessed the same monosaccharide composition as the original polysaccharide Sanxan produced from wild-type strain NX02, but significantly reduced acetyl and glyceryl contents. Textural analysis showed the springiness and cohesiveness of Hesan gel was much higher than Sanxan gel, and rheological behaviors indicated it possessed a lower loss factor, and its conformational transition temperatures at different concentrations were obviously lower than Sanxan gel and high-acyl gellan gel, which suggested that Hesan gel was highly elastic and temperature-sensitive. Additionally, Hesan gel could be efficiently produced through micro-aerobic static culture in shallow (10.46 ± 0.30 g/L) and deep liquids (3.21 ± 0.32 g/L), which was significantly different from the fermentation of other water-soluble polysaccharides. In short, this study characterizes a new mutant strain and its polysaccharide products.

Preparation and Characterization of Auricularia cornea Ehrenb Polysaccharide-Zn Complex and Its Hypoglycemic Activity through Regulating Insulin Resistance in HepG2 Cells

With Auricularia cornea Ehrenb polysaccharide (ACEP) as raw material, the purpose of the study was to prepare Auricularia cornea Ehrenb polysaccharide-zinc (ACEP-Zn) complex. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and other means are used to analyze the physical-chemical properties and structure of ACEP and ACEP-Zn, to investigate the inhibition of α-glycosidase and α-amylase enzymes, and to explore its effects on the glucose metabolism of insulin-resistant HepG2 cells. Nuclear magnetic resonance (NMR) results show that a group of COO-, -CH3, and -OH in the sugar chain binds to Zn2+. Compared with the original polysaccharides, the surface morphology of ACEP-Zn changed obviously, and the molecular weight (Mn) of ACEP-Zn decreased, but the molecular agglomeration of ACEP-Zn increased. Moreover, the inhibitory effect of ACEP-Zn on α-glucosidase and α-amylase was stronger than that of the original polysaccharide. The results indicated that the structure of Auricularia cornea Ehrenb polysaccharide was changed obviously after the zinc complex, and its hypoglycemic activity was enhanced in vitro. In the cell experiment, the glucose consumption of IR-HepG2 cells was significantly increased at a concentration of 50–200 μg/mL ( P < 0.05 ). The activity of SOD and NOS significantly increased ( P < 0.01 ), and the activity of intracellular PK increased ( P < 0.05 ). Therefore, it was speculated that the hypoglycemic effect of Auricularia cornea Ehrenb polysaccharide combined with zinc was related to the alleviation of liver cell damage caused by oxidative stress and the improvement of glucose metabolism of IR-HepG2 cells. The study provides a theoretical basis for the application of the polysaccharide-zinc complex in the hypoglycemic functional food field.

Influence of UV/H2O2 treatment on polysaccharides from Sargassum fusiforme: Physicochemical properties and RAW 264.7 cells responses

There are few studies on seaweed polysaccharides with UV/H2O2 treatment, so the aim of this study was to evaluate the effects of UV/H2O2 treatment on physicochemical properties and RAW 264.7 cells responses of polysaccharides from Sargassum fusiforme (PSF). Results showed that the contents of reducing sugar and sulfate in PSF with UV/H2O2 treatment for 2 h increased by 202.86% and 31.77%, respectively, and the contents of total sugar, protein and uronic acid decreased by 14.29%, 57.11% and 43.18% compared with those of original polysaccharides. In addition, UV/H2O2 treatment did not change the monosaccharide types of original polysaccharides, but it could change its monosaccharide composition and surface morphology. Besides, polysaccharides after UV/H2O2 treatment for 0.5–2 h had lower toxicity than original polysaccharides in RAW 264.7 cells. Typically, PSF with UV/H2O2 treatment for 2 h (PSF-T2) could effectively inhibit pro-inflammatory molecules production (including NO, IL-1β, IL-6 and TNF-α), and down-regulate related genes expression (including Tlr4, Irak, Il-1β, Il-6, Il-12 and Tnf-α). Therefore, UV/H2O2 treatment is a potential way to prepare polysaccharide with better anti-inflammatory activity.

Are Structurally Modified Galactomannan Derivatives Biologically Active?

Galactomannans are versatile macromolecules with broad industrial potential. The influence of changes in the chemical structures and respective bioactivities of these polysaccharides have been extensively studied. The derivatives obtained by sulfation, complexation, and phosphorylation are the most studied biological properties in galactomannans. The derivatives obtained have shown several pharmacological activities such as antiviral, antimicrobial, anticoagulant, fibrinolytic, chemopreventive, anticancer, antioxidant, chondroprotective, analgesic, immunomodulatory, and antileishmanial. Considering the relevance of these studies, we aim to provide an overview of studies that apply galactomannan modification or derivatization strategies to improve their properties for applications in the biomedical area. We identified the success of most modified galactomannans for pharmacological purposes. However, some studies found loss of bioactivity of the original polysaccharide after chemical changes to its original structures.

Inhibition of Calcium Oxalate Formation and Antioxidant Activity of Carboxymethylated Poria cocos Polysaccharides.

Three carboxymethylated Poria cocos polysaccharides (PCP-C1, PCP-C2, and PCP-C3) with -COOH contents of 6.13%, 10.24%, and 16.22%, respectively, were obtained by carboxymethylation of the original polysaccharide (PCP-C0), which has a molecular weight of 4 kDa and a carboxyl (-COOH) content of 2.54%. The structure of the PCP-Cs was characterized by FT-IR, 1H NMR, and 13C NMR spectra. The four PCP-Cs exhibited antioxidant activity, and their ability to scavenge radicals (hydroxyl and DPPH) and chelate ferrous ions was positively correlated with the degree of carboxymethylation. As the content of -COOH groups in the PCP-Cs increases, their ability to regulate the growth of calcium oxalate (CaOx) crystals was enhanced, thus inhibiting the growth of calcium oxalate monohydrate (COM) crystals and inducing the formation of more calcium oxalate dihydrate (COD) crystals. The formed CaOx crystal was more round and blunt, the absolute value of the Zeta potential on the crystal surface increased, and the aggregation between crystals was inhibited. Thermogravimetric analysis curves showed that the proportions of PCP-C0, PCP-C1, PCP-C2, and PCP-C3 incorporated into the crystal were 20.52%, 15.60%, 10.65%, and 9.78%, respectively, in the presence of 0.4 g/L PCP-Cs. PCP-C protection resisted oxidative damages of human kidney proximal tubular epithelial cells (HK-2) caused by oxalate, resulting in increased cell viability and superoxide dismutase activity and decreased reactive oxygen species levels, malondialdehyde content, and 8-hydroxy-deoxyguanosine expression. Hence, PCP-Cs, especially PCP-C3, can inhibit the formation of CaOx crystals and may have the potential to be an alternative antistone drug.

Purification and characterization of novel exopolysaccharides produced from Lactobacillus paraplantarum KM1 isolated from human milk and its cytotoxicity

BackgroundMicrobial origin polysaccharides have gained popularity due to lesser toxicity, better degradability and selectivity as compared to their synthetic counterparts and can be used as emulsifier, stabilizer, thickener, texturizer, flocculating and gelling agent. Here main emphasis on exopolysaccharide production from potential lactic acid bacteria that has GRAS status. ResultsThis work was aimed at isolating, purifying and characterizing an extracellular polysaccharide (EPS) produced by a foodgrade lactic acid bacteria Lactobacillus paraplantarum KM1. L. paraplantarum KM1 was isolated from human milk and identified by conventional and molecular techniques. The 16S rRNA sequence of the isolate was registered in National Centre for Biotechnology Information (NCBI) under accession number KX671558. L. paraplantarum KM1 was found to produce EPSs in lactose containing MRS medium, and the maximum yield (47.4 mg/ml) was achieved after 32-h incubation. As evident from TLC and HPLC analyses, the polysaccharide was found to be a heteropolymer-containing glucose, galactose and mannose as main sugars. Different oligosaccharides namely hexoses were obtained after partial hydrolysis of the polymer using MALDI-ToF-MS. The total molecular weight of all polysaccharides present was 348.7 kDa with 100 °C thermal stability as well as water soluble in nature. Cell cytotoxicity revealed that the purified EPS was safe for consumption; thus, it can be used in various food industries as emulsifying and texture agent. ConclusionsThe present study highlighted that exopolysaccharides could be harnessed to improve food products in terms of texture, emulsifying agents, pharmaceutical industry (antioxidants, antitumour, anti-inflammatory and antiviral agents) and as safety purposes.

Electrochemical Biosensors with Cross-Linked Hydrogels

Leland C. Clark Jr. and Champ Lyons introduced in 1962 the principle of the first electrochemical biosensor with immobilized glucose oxidase (GOx) [1]. This device was specifically designed and used for fast glucose analysis in blood samples from diabetics. Since then, the biosensor field has experienced important growth. In last few decades, this field has been widely explored in many different environments, such as clinical, biotechnological, food and pharmaceutical. This type of device is object of attention because it allows analysis with high specificity, sensitivity, selectivity and low response time.A key parameter for the proper functioning of electrochemical biosensors is the enzyme immobilization onto the electrochemical interface [2]. Immobilization must be performed in a way that the selected enzyme maintains either structure and spatial orientation. In addition, substrate and product have to be able to diffuse to/from the active site, where the biological reaction takes place. One of the simplest and cost effective immobilization method is the polymer entrapment using natural origin polysaccharides. In that frame, chitosan is currently receiving a great deal of interest because of its intrinsic properties: biocompatible, biodegradable, high abundance, low cost of production and it easily forms hydrogels. However, the poor stability of the hydrogel is of major concern [3] when used as an immobilization strategy in the construction of electrochemical biosensors, since it affects the biosensor lifespan.In the present work, amperometric glucose biosensors based on glucose oxidase (GOx) immobilization onto highly ordered titanium dioxide nanotube arrays (TiO2NTAs) was used to determine the long term stability of the constructed probes. TiO2NTAs were grown by electrochemical anodization of a titanium metal disc in ethylene glycol containing ammonium fluoride (0.3%w/w) and water (2%w/w). The electrochemical synthesis was performed at 30 V for 17 hours. This anodization time yields the maximum sensitivity of the sensor. Higher times result in the nanotube walls collapse. Finally, a thermal annealing was performed at 500 ⁰C for 3 h in air to crystallize TiO2 nanotubes from amorphous to anatase phase.In the sensor architecture chitosan was used as a base material for enzyme immobilization in the hydrogel matrix: Ti/TiO2NTAs/GOx–Chitosan. In order to increase the stability of the immobilization matrix, different crosslinking agents were evaluated onto the chitosan matrix: glutaraldehyde, hypochlorous acid and poly(ethylene glycol) diacrylate. Non-modified chitosan provided a biosensor lifespan around 30 days. In contrast, the used of modified chitosan either increases the long-term stability even the sensitivity of the biosensor.

A study on the Fe3O4@Fructus mori L. polysaccharide particles with enhanced antioxidant activity and bioavailability.

Molecular conformation is closely related to the functional properties of macromolecules. In order to prove that the bioactivity of mulberry fruit polysaccharides (MFPs) is greatly affected by the conformation, and to improve adsorption properties, we have designed Fe3O4@MFPNPs core-shell nanoparticles. The spherical Fe3O4@MFPNPs have been successfully synthesized with particle size distribution in the ranges of 3-10 nm and 68-164 nm, which are smaller than their previously prepared original polysaccharides and MFP-Fe(iii). The Fe3O4@MFPNPs showed better antioxidant activity in comparison to MFP and MFP-Fe(iii). The difference in the antioxidant activity between Fe3O4@MFPNPs and MFP-Fe(iii), both of which were modified based on elemental iron, may be attributed to their different conformations: MFP-Fe(iii) were rod-shaped, while Fe3O4@MFPNPs were spherical. Furthermore, Fe3O4@MFPNPs also exhibited greater absorption in the small intestine, which can promote its application in human health.

The effect of ultrasound irradiation on the physicochemical properties and α-glucosidase inhibitory effect of blackberry fruit polysaccharide

In this study, the influence of ultrasound irradiation on the characterization and α-glucosidase inhibitory effect of polysaccharide from blackberry fruit (BBP, molecular weight of 591.39 kDa) was investigated. After degraded, BBP-8, BBP-16 and BBP-24 three fractions were obtained with molecular weight of 363.93, 249.51 and 177.42 KDa, respectively. Moreover, compared with the particle size of BBP (1070.5 nm), that of BBP-8, BBP-16 and BBP-24 were decreased to 679.9, 548.8 and 395.4 nm, respectively. However, the monosaccharide composition test, FT-IR, and tertiary structure analysis all indicated that the ultrasound did not destroy the primary structure of the original polysaccharide. In addition, the degraded polysaccharide (BBP-24) exhibited the stronger α-glucosidase inhibitory activity than that of BBP. By fluorescence spectrum and circular dichroism spectrum analysis, we found that the polysaccharide could induce the structure change like rigidity structure (α-helixe) and loop structure (random coil) of α-glucosidase to inhibit its activity by binding to the α-glucosidase. The polysaccharide with different molecular weight showed different binding capacity which was related to its inhibitory effect on the α-glucosidase. In general, the results suggested that appropriate degradation was benefit for the enhancement of the inhibitory effect on α-glucosidase of blackberry polysaccharide, and ultrasound irradiation was a green and efficient method to produce bioactivity-added polysaccharide for use in the functional food.