A pH-sensitive hydrogel based on carboxymethylated konjac glucomannan crosslinked by sodium trimetaphosphate: Synthesis, characterization, swelling behavior and controlled drug release.

The pH-sensitive hydrogel consisting of carboxymethylated konjac glucomannan (CMKGM) and sodium trimetaphosphate (STMP) was prepared for a potential intestinal targeted delivery system. Both the CMKGM and the CMKGM hydrogel were characterized by FT-IR spectra, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The Congo red and atomic force microscope (AFM) results showed a coil-to-helix transition of CMKGM in alkaline conditions with the degree of substitution (DS) increased from 0.20 to 0.49. Rheological measurements indicated that the DS and the STMP content collectively influence the mechanical stiffness and swelling properties of the obtained hydrogels. In addition, the swelling behavior of the hydrogels revealed that they were sensitive to pH value changes and were following a Korsmeyer-Peppas gastrointestinal release behavior, indicating that the release was controlled by non-Fickian diffusion. Furthermore, all the results suggested that the prepared pH-sensitive hydrogel may serve as a potential biomaterial for the intestine-targeted delivery system.

Effects of Extraction Methods on Physicochemical and Structural Properties of Common Vetch Starch.

Three extraction methods: water extraction, lactic acid bacteria fermentation, and back-slopping fermentation were applied to extract a new type of legume starch, common vetch starch. Our results showed that the lactic acid bacteria fermented starch had the highest amylose content (35.69%), followed by the back-slopping fermented starch (32.34%), and the water-extracted starch (30.25%). Furthermore, erosion surface, lower molecular weight, smaller particle size, larger specific surface area, and a higher proportion of B1 chain were observed in the fermented starch, especially in the back-slopping fermented starch. All the extracted starches showed a type C structure, but a type CB structure was observed in the back-slopping fermented starch. In addition, the relative crystallinity of the lactic acid bacteria fermented starch (34.16%) and the back-slopping fermented starch (39.43%) was significantly higher than that of the water-extracted starch (30.22%). Moreover, the swelling power, solubility, pasting, and thermal properties of the fermented starches were also improved. In conclusion, the fermentation extraction method, especially back-slopping fermentation, could improve the quality of the extracted common vetch starch when compared with the traditional water extraction method.

An antioxidative galactomannan extracted from Chinese Sesbania cannabina enhances immune activation of macrophage cells.

In the present study, the antioxidant activities and immunostimulatory ability of a polysaccharide extracted from Chinese Sesbania cannabina, which was identified to be a galactomannan in our previous study, were investigated. The extracted polysaccharide exhibited strong DPPH, ABTS and hydroxyl radical scavenging activities and ferrous ion chelating activity in a concentration-dependent manner. The immune-enhancing effect of our polysaccharide on RAW 264.7 macrophage cells was investigated by determining the cell viability, phagocytic activity, NO and intracellular ROS production and mRNA expression of cytokines. The results indicated that the polysaccharide could increase the production of NO and intracellular ROS, as well as effectively trigger transcriptional activation of TLR-2/4, NF-κB, IL-10/1ß/6, IFN-γ, Ik-Bα, iNOS, COX-2 and TNF-α. These findings provide useful information for potential application of the polysaccharide extracted from Chinese Sesbania cannabina in the food industry.

Isolation, physical, structural characterization and in vitro prebiotic activity of a galactomannan extracted from endosperm splits of Chinese Sesbania cannabina seeds.

The purpose of this study was to identify and determine the physical and structural characterization of the water-soluble galactomannan extracted from endosperm splits of Chinese S. cannabina seeds. The Sesbania galactomannan (SP) was extracted and purified using a novel method with a high yield (40.3 ± 7.2%). The molecular structure of SP was determined by monosaccharide composition, FTIR and NMR spectroscopy. The structural data showed that SP was galactomannan which composed by a ß-(1/4)-linked mannose backbone with galactopyranosyl residues attached through α-(1/6) linkages. The constant mannose/galactose (M/G) ratio and average molecular weight (Mw) of SP was 1.6:1 and 2.16 × 105 g/mol, respectively. The physical results revealed that SP had many branches on the backbone and existed as a random coil state in aqueous solution. SP was a good biopolymer which had smooth and clearer surface with homogeneous composition, and had some degree of crystallinity and prebiotic activity. As a consequence, SP could be a potential prebiotic and was expected to be suitable for applications in food, pharmaceutical, biomedical or cosmetic industries as a promising new biomaterial.