Optimization of sulfated modification conditions of tremella polysaccharide and effects of modifiers on cellular infectivity of NDV

Based on our previous research, sulfated modification conditions of Tremella polysaccharide (TPS), the chlorosulfonic acid to pyridine (CSA-Pry) ratio, reaction temperature and time, were optimized by L9 (34) orthogonal design taking the yield and degree of sulfation (DS) of modifiers as indexes. Two TPSs, TPStp and TPS70c, were modified under optimized conditions. The effects of two modifiers, sTPStp and sTPS70c, on cellular infectivity of NDV were determined by MTT method taking the non-modified TPStp, TPStc and TPS70c as controls. The results showed that the optimized modification conditions were reaction temperature of 80 °C, CSA-Pry ratio of 1:6 and reaction time of 1.5 h. Five polysaccharides at proper concentrations could significantly inhibit the infectivity of NDV to CEF. The virus inhibitory rates of sTPStp at 1.563 μg mL−1 group were the highest and significantly higher than those of other three non-modified polysaccharide groups in three sample-adding modes. This indicated that sulfated modification could significantly improve the antiviral activity of TPS. sTPStp possessed the best efficacy and would be as a component of antiviral polysaccharide drug.