Effects Of Ultrasonic Depolymerization On The Rheological Property,Solution Conformation And Bioactivities Of Polysaccharides Isolated From The Seeds Of Plantago Asiatica L.

Objective: To study the effects of ultrasonic on the rheological property,solution conformation, antioxidative activity,i mmune regulatory activity and improving function of colon infla mmation of polysaccharides isolated from the seeds of Plantago asiatica L.Methods: Plantago asiatica L. polysaccharide(PLCP) was treated with ultrasonic with power of 300 w and frequency of 20 kHz for 0 s,15 s,30 s,1 min,2 min respectively. Then, rheometer with 50 mm stainless steel plate was used to detect the dynamic and static rheological property of these treated samples at temperature of 25 oC. GPC/SEC-MALS system was used to detect these indices: molecular weight Mw, radius of dispersion in Mw/Mn, root mean square radius Rg, fluid mechanics radius Rh, structural parameters ρ, intrinsic viscosity [η] and Mark-Houwink α constant, and solution conformation was deduced by these indices. DPPH values, FRAP value and ORAC value of polysaccharides were used to detect the effect of ultrasonic degradation on the antioxidant capacity of the polysaccharides. The in vitro i mmunoregulatory activities were detected by macrophage RAW264.7 proliferation assay, neutral red phagocytosis test, NO and TNF-αproduction test, along with T, B lymphocyte proliferation assay. Establish in vivo mouse model of colitis through oral feeding DSS, and then investigate the improving function of colon infla mmation of polysaccharides with or without ultrasonic degradation.Results: Ultrasonication decreased apparent viscosity and apparent viscosity’s dependence of shear rate, then eliminated the phenomenon of shear thinning. Ultrasonic treatment reduced elastic modulus G ’and viscous modulus G ". As viscous modulus dropped faster than elastic modulus, when we increasing duration of ultrasonic treatment, dominant component was changing from elastic modulus G ’ to viscous modulus G ", phase Angle tangent tan δ was increasing as well. Ultrasonic reduce Mw and change Mw/Mn of PLCP; With the increase of the ultrasonic time, hydrodynamics radius Rh, root mean square radius Rg, structural parameters ρ were reduced, Mark- Houwink α constant was increased, the solution conformation was changed from highly branching coil conformation to random coil structure. After ultrasonic depolymerization, DPPH radicals scavenging capacity and ferric ion reducing antioxidant capacity of PLCP was significantly improved, but oxygen radical absorbance capacity was not influenced significantly. In vitro i mmunoregulatory activities on macrophage RAW264.7 of PLCP were significantly improved. Ultrasound can significantly enhance the ability of the polysaccharides induce T, B lymphocyte proliferation. Ultrasonic degradation can significantly improve the polysaccharides’ capacity of these colitis symptoms: colon shortening symptoms, TNF-α, MIP-2 secretion increased, IL-4 secretion decreased, but on the immune organ index drop, colon MPO activity increased, IL-β secretion improve these symptoms is not significantly improved.Conclusion: Ultrasonic can change flow property, solution conformation, reduce Mw, change Mw/Mn,improve anti-oxidative activity and i mmune regulatory activity of PLCP. In some aspects, ultrasonic improve polysaccharide inhibiting colonic infla mmation in mice.