Abstract
Corn silk polysaccharide (CSP) was isolated by heated 80 degrees C ethanol 70%. The extracted light (83.70 L*) with a yellowish (13.09 b*) reddish (1.98 a*) CSP had an ash content of 2.53 +/- 0.03%. It is mainly composed of seven monosaccharides (xylose 23.64, glucose 16.65, ribose 17.35, galactose 13.64, rhamnose 11.93, arabinose 11.87 and mannose 4.85 mol%) and showed four peaks in C-13 NMR correlated to the anomeric carbon of arabinose and/or xylose residues. The thermal characteristics exhibited the breakdown of CSP glycosidic bonds at 321.16 degrees C. The rheological properties showed that the raising of share rate (gamma) caused a reduction in apparent viscosity for all tested concentrations, whilst the elastic G ' and viscous G '' storage moduli of CSP were enhanced by increasing the oscillation frequency. The immunomodulatory effects of CSP on RAW264.7 cells showed a significant (P < 0.05) increase in NO secretion up to a concentration of 80 mu g mL(-1) from CSP. Additionally, the phagocytosis index and acid phosphatase activity were enhanced (P < 0.05) in a dose-dependent manner by increasing CSP concentrations.