Optimization of cellulase hydrolysis extraction of total flavonoids from Radix Rehmanniae Preparata by response surface methodology

In order to optimize the extraction method of total flavonoids from Radix Rehmannia glutinosa by cellulose-assisted extraction, based on single factor experiments, enzyme concentration, hydrolysis temperature, hydrolysis time were selected as influencing factors and the yield of total flavonoids as response during extraction. The experiment method was designed according to Box-Behnken central composite experiment and each variable and their interactions effects on the yield of total flavonoids were studied. The quadratic multinomial model on the yield of total flavonoids and each factor was established by using the Design-Expert software. The optimum reactive condition of extracting process was determined by means of response surface method when the p H kept in 4.5. The results showed that the optimum conditions for total flavonids were enzyme concentration 80 U/m L, hydrolysis temperature 38 ℃ and hydrolysis time 48 min, respectively. Under this condition, the extraction yield of total flavonids was 2.89% and the relative error was 1.05% which compared to the predictive value being of 2.86%. Meanwhile the results indicated that the feasible model fitted well with the experimental data. From this study, it could be concluded that the extraction system was reliable and practical, the certain reference and theoretical guidance for further research can be provided.