Optimization ultrasonic extraction process of total saponins from Clematis tangutica (Maxim.) Korsh by response surface methodology

Single-factor tests and response surface method (RSM) were used to optimize the extraction process of total saponins in Clematis tangutica (Maxim.) Korsh.In order to obtain the maximum yield of the extraction of total saponins, three main factors including alcohol concentration, ultrasonic extraction time and ratio of raw material to alcohol were determined with the Box-Behnken design and established a quadric regression equation to predict the yield of total saponins.Results showed that the optimum extraction conditions were as follows:alcohol concentration 80%, ultrasonic extraction time 50min, and ratio of raw material to alcohol 1:30.Under the conditions, the optimum extraction yield of total saponins was 15.78mg/g, which was well matched with the predictive extraction yield 16.19mg/g.