ABSTRACT

Prosapogenin A (also known as Progenin III and polyphyllin V), a secondary steroidal saponin in Dioscorea zingiberensis tubers, has more superior pharmacological activities than its primary form Protogracillin. Conventional preparation methods, such as column chromatography, and acidic hydrolysis, are of very low efficiency and limited scale due to tedious procedures and large consumption of organic solvent. This study aims to establish a convenient method for efficiently obtaining Prosapogenin A by enzymatic hydrolysis of abundant Protogracillin in the raw material. In light of the highest hydrolysis performance, β-dextranase was selected from four commercial enzymes in this application. After optimization of the conditions by the response surface methodology using Box–Behnken design, the enzymatic hydrolysis was carried out in 0.20 M HAc-NaAc buffer (pH 4.81) containing β-dextranase/Protogracillin (5.0:1, w/w), and the system was constantly kept at 56.7°C water bath for 4 h. Consequently, Protogracillin has been almost completely hydrolyzed to be Prosapogenin A and the highest yield was 96.4 ± 1.4%. The newly proposed approach is efficient and promising for conveniently obtaining Prosapogenin A and aimed to provide a laboratory-scale experimental foundation for the preparation of Prosapogenin A in industrial applications.

摘要

Prosapogenin A（也称为 Progenin III 和 polyphyllin V），一种在薯蓣中的次级甾体皂苷块茎，比其主要形式 Protogracillin 具有更优越的药理活性。传统的制备方法，如柱层析、酸性水解等，由于程序繁琐，有机溶剂消耗大，效率低，规模有限。本研究旨在通过酶解原料中丰富的Protogracillin，建立一种高效获得Prosapogenin A的简便方法。鉴于最高的水解性能，β-葡聚糖酶在本申请中选自四种商业酶。使用 Box-Behnken 设计通过响应面法优化条件后，在含有 β-葡聚糖酶/Protogracillin (5.0:1, w/w ) 的 0.20 M HAc-NaAc 缓冲液 (pH 4.81) 中进行酶水解)，系统在 56.7°C 水浴中持续保持 4 h。因此，Protogracillin 几乎完全水解为 Prosapogenin A，最高产率为 96.4 ± 1.4%。新提出的方法对于方便地获得Prosapogenin A是有效且有前景的，旨在为Prosapogenin A的工业化制备提供实验室规模的实验基础。