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Positively charged (zeta potential 22-31 mV) hydrogel microparticles based on low and high molecular weight chitosan were synthesized. The effect of the crosslinking agent on their physicochemical characteristics was studied. It was established, that among obtained hydrogel particles, the ones based on low molecular weight chitosan crosslinked with citrate anions, followed by additional treatment with glutaraldehyde, are the most promising as carriers of growth regulators or plant protection products.

Hydrogel negatively charged (–13.5 ± 5.0 mV) calcium pectinate nano- and submicroparticles (50–150 nm) were obtained. A technique for entrapment of a plant growth regulator (trans-cinnamic acid) in the particles up to 40 wt. % has been developed. It has been established that the complete release of trans-cinnamic acid in the Murashige–Skoog medium takes 2.5 hours. The obtained particles of calcium pectinate do not affect the growth processes of cells in suspension culture and can be used as neutral carriers for growth regulators.

The gut microbiota appears critical in the metabolic health and anti‐disease activity. In this review, we discuss three brown seaweed polysaccharides (alginate, laminarin, fucoidan) for their structural information, the digestive behaviour and the effects on gut microbiota. Bioactivities are associated with various physicochemical properties, like solubility, viscosity, hydration properties, molecular weight, monosaccharide composition, and so on. Brown seaweed polysaccharides can be completely utilised by microbes in the large bowel, and they can regulate the gut microbiota. The ultimate metabolite of these polysaccharides is mainly short‐chain fatty acids, which are able to regulate the ecology of the gut microbiota by increasing the growth of beneficial bacteria and inhibiting the growth of some harmful bacteria. In addition, this article also discusses the relationship between the structure and activity of modulating the gut microbiota. Results show that polysaccharides with low molecular weight are more conductive to modulate gut microbiota.

There are few studies on seaweed polysaccharides with UV/H

The study aimed to study the effects on structural characteristics and anti-inflammatory activities of algal sulfated polysaccharides isolated from Gracilaria lemaneiformis (GLP) after a combined treatment of UV irradiation (average irradiance of 6500 mJ/cm

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.

Conditions for the preparation of stable to sedimentation aqueous dispersions of interpolyelectrolyte complexes based on chitosan (Chit) and pectin (Pect) with particle diameter 0.5-0.9 μm for Pect/Chit and 1.0-2.0 μm for Chit/Pect have been determined. The absolute value of the zeta potential of these complexes is >10 mV for Pect/Chit and Chit/Pect when the molar ratio of the ionogenic groups of the polymers $$ {n}_{\mathrm{COOH}}/{n}_{{\mathrm{NH}}_2} $$ is 0.4-4.6 for Pect/Chit and 0.02-0.63 for Chit/Pect. Optical spectroscopy and electrophoretic light scattering have been used to determine the effect of molecular mass and the content of the free ionogenic groups in the polysaccharide macromolecules as well as the order of mixing the solution on the formation and properties of these interpolyelectrolyte complexes.

The study explored the changes of a sulfated polysaccharide (SP) from Gracilaria Lemaneiformis during simulated human digestive system. The results showed SP was scarcely degraded without significant difference. Moreover, the results of fermentation in vitro indicated 53.7% of SP were utilized by gut microbiota with the molecular weight decreasing by 59.41% at 48 h. Meanwhile, 50.07 ± 2.82 mM of short chain fatty acids were produced in culture medium. Besides, in contrast with the regulation of galacto-oligosaccharide sacrificing diversity and richness of community, SP could regulate the composition of microbiota in a mild way. What’s more, Proteobacteria and Firmicutes were the most sensitive phyla responding to changes of pH values in this study. And Sutterella, Phascolarctobacterium, Parabacteroides, Lachnospiraceae_UCG-004, Desulfovibrio and Bacteroides were dominant genera for degrading and utilizing SP. Furthermore, the metagenomic function characteristics of microbes might be changed by SP. Thus, SP could be a potential prebiotic.

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.

The study aimed to study the effects on structural characteristics and anti-inflammatory activities of algal sulfated polysaccharides isolated from Gracilaria lemaneiformis (GLP) after a combined treatment of UV irradiation (average irradiance of 6500 mJ/cm2) and H2O2 (50 mmol/L) for various time periods up to 60 min. After a 30-min treatment, the molecular weight and particle size of GLP was decreased by 15 and 2.6 fold, respectively with small but significant decrease in the contents of total sugars, uronic acids and proteins. There seemed to have no starch and the presence of longer side chains of branches in the GLP samples before and after UV/H2O2 treatment based on the I2-KI assay. Scanning electron microscope and atomic force microscope analysis confirmed that the UV/H2O2 treatment could modify the surface morphology of GLP. GLP treated for 5 min possessed the strongest in vitro anti-inflammatory activity by inhibiting the production of nitric oxide, tumor necrosis factor-α and interleukin-6 by 60.49%, 62.81% and 36.29%, respectively in IEC-6 cells when compared to the model. Therefore, UV/H2O2 treatment had the potential to enhance the anti-inflammatory activity of algal sulfated polysaccharides.

Silver nanoparticles have been synthesized by reducing AgNO3 in an alkaline medium under the action of a natural polysaccharide, pectin. The influences of the type of pectin used and the reagent mixing order during the synthesis on the sizes and plasmon resonance properties of nanoparticles have been studied by optical spectroscopy and transmission electron microscopy. The conditions that make it possible to obtain silver hydrosols having predetermined particle sizes of 8 ± 2 to 22 ± 6 nm and stable to aggregation for at least 3 months have been determined.

The development of environmentally friendly, non-toxic and cheap technology for synthesis of silver nanoparticles with desired properties is currently under intensive investigation because such materials show huge potential for numerous biomedical applications. In this paper, we propose the ‘green’ technique to obtain stable silver nanoparticles using reducing and stabilizing capacity of natural polysaccharide pectin. The relationship between physico-chemical characteristics of formed pectin-capped silver nanoparticles and type of used pectin, as well as synthesis conditions, has been determined. Pectin-Ag nanocomposites were produced via reduction of silver nitrate by pectin in alkaline medium at room temperature. The synthesized nanoparticles were characterized by ultraviolet-visible and Fourier-transform infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy and dynamic light scattering. It has been established that pectin-capped silver nanoparticles have a spherical shape with a mean diameter from 8 to 28 nm, a negative charge and an absorption maximum in the range from 401 to 412 nm, depending on the type of pectin constituent. Antibacterial activity of the free pectins and their nanocomposites with Ag0 was evaluated by diffusion and suspension methods against both gram-positive (Bacillus pumilus, Bacillus subtilis) and gram-negative (Escherichia coli) bacteria. The size and composition-dependent antibacterial activity of ‘green’ synthesized silver nanoparticles has been demonstrated. It has been shown that among the pectin varieties only amidated one displayed antibacterial action on Bacillus strains: the minimum inhibitory concentration (MIC) was 3.4–7.1 mg mL−1. It has been found that antibacterial activity of pectin-capped silver nanoparticles depended on the type of introduced pectin and its ratio. The synthesized nanoparticles exhibited significant antimicrobial activity toward gram-negative bacteria Escherichia coli (MIC 0.18-0.39 mM) as compared with gram-positive Bacillus bacteria (MIC 0.39–1.55 mM).