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Starch nanoparticles (SNPs) was produced from type-A, B and C native starches (corn, potato and Trichosanthes kirilowii pulp starches respectively), via the nanoprecipitation method. The SNPs showed different amylose contents, water contact angles, surface morphologies and urea clearance performances. In this work, to examine the parameters of SNPs that may change the urea adsorption capacity, urea adsorption performance in adsorption environments with different pH values, urea concentrations, and adsorption times was examined. Thereafter, the characteristics of SNPs were tested by water contact angle measurements (WCA), transmission electron microscopy, specific surface area measurements, gel permeation chromatography, and zeta potential analysis. The results showed that the Trichosanthes kirilowii pulp (C) SNPs show better adsorption than the corn (A) and potato (B) SNPs. The hydrophobicity of SNPs promotes the urea adsorption of the SNPs. Using grey relational analysis, it was found that WCA and Mn are the critical parameter affecting the adsorption performance, with WCA and Mn within the ranges of 31–33° and 1900–2100 kDa, respectively, were found to be the conditions for optimal urea adsorption. [ABSTRACT FROM AUTHOR]

Background Abelmoschus manihot (Linn.) Medicus is a traditional herbal medicine whose flowers, stems and leaves exhibit widely pharmacological activities. However, only the flowers have long been used as medicine while the stems and leaves were mainly discarded and burned, which undoubtedly caused enormous waste of these resources and serious environment pollution. Many researches have indicated that bioactivities of polysaccharides were significantly improved after sulfation. The aim of this study was to investigate the characterization and immunomodulatory activity of polysaccharides from stems and leaves of A. manihot and a sulfated derivative. Results A mixed neutral polysaccharide (SLAMP-a) and two acidic polysaccharides (SLAMP-c and SLAMP-d) were obtained from stems and leaves of A. manihot by DEAE-cellulose chromatography. SLAMP-a was a water-insoluble mixture while its sulfated derivative (S-SLAMP-a3), prepared with aminosulfonic acid, was a homogeneous polysaccharide with excellent solubility. The average molecular weights of S-SLAMP-a3, SLAMP-c and SLAMP-d were 1044.2 kDa, 477.8 kDa and 264.2 kDa respectively. SLAMP-a and its sulfate mainly contained glucose, and SLAMP-c and SLAMP-d were both composed of mannose, rhamnose, glucuronic acid, glucose, galactose, and arabinose. In vitro study indicated that S-SLAMP-a3, SLAMP-c and SLAMP-d exhibited significant immunomodulatory activity, while SLAMP-a showed little effects. Conclusion SLAMP-c and SLAMP-d from A. manihot stems and leaves could be explored as immunomodulatory agents, which would provide a way to utilize these enormously discarded resources and avoid massive waste. Additionally, the neutral polysaccharide, SLAMP-a, could also be developed after sulfation, suggesting that these disused resources would be further used effectively. [ABSTRACT FROM AUTHOR]