微生物酶催化制备人参皂苷20(S)-Rg2,20(S)-Rh1和20(S)-PPT

摘要 人参次级皂苷具有较强的抗癌、抗癌转移等药理活性，但由于在人参中含量少或不存在，因此以人参中含量较高的主要人参皂苷制备药效更高的人参次级皂苷不仅有必要，而且很有意义．本文以微生物Microbacterium esteraromaticum GS514的培养液中分离的粗酶为催化剂水解人参皂苷Re和Rg1，并通过1H NMR和13C NMR谱进行了水解产物的结构表征．实验结果表明，反应体系中无机盐NaCl的存在与否直接影响人参皂苷Re，Rg1与粗酶液的反应结果.人参皂苷与粗酶液直接反应，人参皂苷Re不发生反应，人参皂苷Rg1通过C6所连β-D-吡喃葡萄糖的选择性水解转化成人参皂苷F1.如果该反应是在无机盐NaCl存在下进行，人参皂苷Re通过对C20 所连β-D-吡喃葡萄糖的选择性水解定向转化为20(S)-人参皂苷Rg2；人参皂苷Rg1定向转化成20(S)-人参皂苷Rh1以及20(S)-原人参三醇（PPT）.这说明NaCl的加入激活了C20β-D-吡喃葡萄糖苷酶的活性，这对定向合成不同次级人参皂苷具有重要意义.

Enzyme-catalyzed Preparation of 20(S)-Ginsenoside Rg2,20(S)-Ginsenoside Rh1 and 20(S)-PPT

The prosapogenins of ginsenosides have significant phamacological activities such as antitumor and antimetastatic effects.Owing to low or non-existent content of the prosapogenins in normal ginseng,it is necessary and meaningful to prepare more active prosapogenin by degradation of major ginsenosides.In this paper,ginsenosides Re and Rg1 were hydrolyzed by crude enzyme of strain Microbacterium esteraromaticum GS514 and the resultant's structures were determined by 1H NMR and 13C NMR analyses.The experimenta...