In this thesis the chromatography on DEAE-Cellulose 52 was used to isolate the crude polysaccharide from purple sweet potato (PPSP) . To get the purest polysaccharide from the purple sweet potato for the purpose, the influence of different pH environments and whether the fractions eluted with the high and low ionic strength eluents in corresponding pH environment during the elution process had the hybrid phenomenon were studied. Finally, results suggested that the purest polysaccharide of purple sweet potato would be got in the neutral and low ionic strength solution of NaCl when the crude polysaccharide was isolated by the chromatography column on DEAE-Cellulose 52 according to this study, and in this thesis the low ionic strength solution of NaCl was 11.7g.L-1, the elution rate of polysaccharide eluted with it was about 3% and the purity was about 94%.

Extracting dihydromyricetin from Ampelopsis grossedentata by water extraction method. The orthogonal test and single factor experiment were used to optimize the best extraction condition. The ratio of liquid and material is 20:1, extraction time is 90min, extraction temperature is 90°C,holding time is 1d. The results of comparison between two purification methods show: Purify with acetone and recrystallization with water is better. The purity of dihydromyricetin is high to 98%, recovery rate was 59.2%.