Studies On Prepauration Of Saponins And Diosgenin From Dioscorea Zingiberensis And Comprehensive Utilization Of Its Subsidiary Product

Steroidal saponins are the major bioactive constituents of Dioscorea zingiberensis. At present, medicines made from D. zingiberensis and with its total saponins as the major active constituents are suffering from many problems, such as ambiguity constituent, confusion quality control and so on. Diosgenin is the basic material for the synthesis of steroidal hormone medicines and one of its important sources is D. zingiberensis. However, the traditional method for the preparation of diosgenin was low utilization of raw materials and made seriously environmental pollution. So, in this work, some steroidal saponins from D. zingiberensis were isolated and characterized, and a rapid analysis method for steroidal saponins in crude extracts from D. zingiberensis was developed. In addition, an eco-friendly process was developed for the comprehensive utilization of D. zingiberensis.Five steroidal saponins were isolated by silica gel column chromatography, vacuum liquid chromatography and reverse phase CG161column chromatography from n-butanol extracted sample of D. zingiberensis. Their structures were identified as zingiberensis saponin (S-1), deltonin (S-2), dioscin (S-3), prosapogenin A of dioscin (S-4) and diosgenin diglucoside (S-5) by IR, ESI-MS,’H-NMR and13C-NMR, respectively. Moreover, compound S-4was isolated from D. zingiberensis for the first time.UPLC/Q-TOF MS as a powerful tool has been applied to the characterization of steroidal saponins in D. zingiberensis. A total of thirty-one steroidal saponins with five aglycone skeletons were detected in the crude extracts from D. zingiberensis. Five saponins were unambiguously identified by comparing the retention times and the MS and MS/MS data with the reference standards. Based on previous publications and our deduction, twelve saponins were identified or tentatively characterized in the crude extracts from D. zingiberensis. In addition, fourteen new steroidal saponins were identified or tentatively elucidated by Q-TOF MS from D. zingiberensis for the first time. However, for definite identification of these unknown saponins, further investigation is needed.The primary elements affecting the extraction and hydrolysis conditions of total saponins in D. zingiberensis were established by single factor test. The optimum extraction conditions were developed as follows:ethanol concentration70%(v/v), ethanol amount8times, backflow extraction3times, and2h for each time. The optimum hydrolysis conditions were also developed as follows:sulphuric acid concentration2mol-L"1, sulphuric acid amount30mL, and hydrolysis time4h.The optimal conditions for the preparation of starch from residue by single factor test were developed as follows:immersion time36h, triturating time2.5min, and triturating slurry liquid ratio1:8. In the enlargement experiment of starch preparation process, the yield of starch was40.62%and the recovery of starch was68.58%.