Niu Xizhen

Preparation of polysaccharides in different molecular weights fromUlva pertusa Kjellm (Chorophyta)

As molecular weight controls the biological activities of polysaccharides, screening the optimal molecular weight of polysaccharides is important in drug research and application. In this study, hydrogen peroxide was employed as oxidant, and temperature, reaction time, and concentration of polysaccharides and hydrogen peroxide were examined for their effects on the preparation of polysaccharides in different molecular weights fromUlva pertusa. Our experiment suggested that the optimal degradation concentrations for polysaccharides and hydrogen peroxide were 2.5% (w/v) and 8.0% (v/v), respectively. The range of degradation measured by relative viscosity was mainly controlled by temperature and time. Results revealed that 35°C was the optimal temperature for obtaining low-degradation samples, and 50°C was the most favorable temperature to accelerate the reaction to yield highly-degraded samples. Four samples in different molecular weights A, B, C and D were finally prepared. The controllability was evaluated by the relative standard deviation (RSD) of relative viscosity, and the peak molecular weights and the polydispersity indexes (Mw/Mn) of molecular weights were measured by high performance gel permeation chromatography (HPGPC).

Immunosuppressive activities of fucoidan fromLaminaria japonica

Effects of fucoidan fromLaminaria japonica on 2,4-dinitrochlorobenzene induced delayed-type hypersensitivity (DTH) reaction and the serum levels of IgG, IgM, complement C3 and C4 were investigated in the present study. Results showed that oral administration of fucoidan at dose of 150 and 300 mg/(kg· d) for 9 days before the hapten challenge significantly inhibited 2,4-dinitrochlorobenzene induced delayed-type hypersensitivity reaction; and also inhibited the humoral immunity. Serum C3 and C4 levels were markedly reduced by fucoidan at dose of 150 and 300 mg/kg; and serum IgG and IgM levels were reduced by fucoidan at dose of 300mg/kg. The inhibitory effects of fucoidan on delayed-type hypersensitivity suggested that it may be potential medication for chronic inflammatory diseases in the future.