Optimization of the extraction and purification of Corydalis yanhusuo W.T. Wang based on the Q-marker uniform design method

Corydalis yanhusuo W.T. Wang alkaloids are mainly divided into three categories: protoberberine, prototropine and aporphine alkaloids. Therefore, we have taken into account these three alkaloid contents when extracting and purifying crude drugs, which is essential for the quality control of C. yanhusuo and its derivative products. Herein, we investigated the feasibility of the Q-marker uniform design method in the optimization of the extraction and purification of C. yanhusuo. In this study, Q-marker-based comprehensive scoring (CS) and uniform design methods were used to optimize the extraction and purification of C. yanhusuo. The inspective factors included the solvent concentration, pH, liquid–solid ratio, extraction time and frequency. Then 8 Q-markers, the total alkaloid extraction and the extraction rate were considered as the evaluating indicators during the process. The results indicated that the optimal reflux extraction process of C. yanhusuo was as follows: a total amount of 20 times 70% ethanol (pH = 10 of diluted ammonia), heating and refluxing twice, and extracting each time for 60 min. The results of nine-resin screening exhibited that NKA-9 macroporous adsorption resin had the best separation and purification effect on 8 kinds of C. yanhusuo alkaloids with stronger enrichment. During the optimal enrichment process and elution conditions, the water-soluble impurities were washed off with 5 BV distilled water at a volume flow rate of 2 BV/h, and the elution solvent was 70% ethanol with an elution volume flow rate of 1.5 BV/h and an elution dosage of 12 BV. Additionally, the total alkaloids of the obtained product were over 50%, of which eight quality markers were (+)-corydaline 3.55%, tetrahydropalmatine 3.13%, coptisine 2.79%, palmatine hydrochloride 2.24%, dehydrocorydaline 13.11%, (R)-(+)-corypalmine 2.37%, protopine 2.71% and glaucine 14.03%. Our data demonstrated that the optimal extraction and purification process was stable and feasible, which was expected to provide an experimental basis and reference for the industrial production of C. yanhusuo.