| The contents of saponins from Gynostemma from Gynostemma pentaphyllum of different times, different parts and different places were studied in order to utilize resources, obtain higher purify of saponins and find the optimum harvest days. Meanwhile the extraction process and isolation method of saponins from Gynostemma pentaphyllum were elucidated. The optimal parameters of extraction and isolation by resins and membrane were established, which provided a reference and corresponding process parameters for industrial production and also a scientific basis for the development and utilization.The contents of saponins in different samples were first determined by HPLC. The results showed that the leaves had the highest content of saponins and the roots had the lowest content at the same time, the content of saponins was the highest in August, while the lowest in May. Therefore, appropriate part and harvest time should be selected in accordance with content changes of saponins to protect Gynostemma Pentaphyllum resources.Extraction rate of saponins was taken as an index to compare there extraction method, including water extraction, pectinase extraction and cellulose extraction in the experiment. Three influencing factors on water extraction were extraction temperature, time and solid-liquid ratio, and four factors on enzymolysis extraction were extraction temperature, pH, time and the ratio of enzyme. The optimal parameters for water extraction were as follows: solid-liquid ratio 1:30, extraction temperature 83℃, time 110min; the optimal parameters for pectinase extraction were the ratio of pectinase enzyme 0.25%, extraction temperature 50℃, pH3.6, time 106min; the optimal parameters for cellulose extraction were the ratio of cellulose enzyme 0.13%, extraction temperature 58℃, pH5.9, time 112min. The highest rate could be obtained by water extraction and the rate by cellulose extraction was the lowest.Adsorption and desorption characteristics of six macroporous adsorption resins towards total saponins from Gynostemma pentaphyllum aqueous solution were studied. Resin XAD1600 was identified, and technology conditions of adsorption and desorption were optimized. The results showed the influencing order of three factors on adsorption rate of gypenosides was NaCl concentration, solution concentration and adsorption velocity. The optimal absorption conditions were adsorption velocity of 1.5BV/h, solution concentration of 4.0mg/mL, NaCl concentration of 4%. The optimal desorption conditions were as follows: water and 30% ethanol were taken as eluent to eliminate impurities respectively, and then 65% ethanol to elute gypenosides. The optimal conditions to desalinate were solution velocity of 6BV/h and the effective treatment amount of resin was 6BV; the optimal conditions to decolorize were solution velocity of 6BV/h and solution temperature 40℃.The amount ratio between resin 001×14.5 and D280 was 4:9.The UF characteristics of UF membrane were investigated, which had four kinds of retention molecular weight including 100K, 50K, 30K and 10K. The solution was filtered with 100K membrane and concentrated with 30k membrane. The optimal technical conditions of 100K membrane were pressure of 20Psi, temperature 45℃, solution concentration of 2.0mg/mL, and 30K membrane were pressure of 20Psi, temperature 35℃. Phosphoric acid, NaOH and NaClO solution were determined as the best cleaning agent of membrane after comparation.A series of studies were carried out and a suitable method on harvest, extraction and isolation of saponins from Gynostemma pentaphyllum was established. In view of rich Gynostemma pentaphyllum resources in china and especially in southwest region, its resources were used to present the investigation of chemical composition, extraction and isolation in order to make its products play a more important part in life.
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