Studies On Hydroxy Process By Microbe Of Digitoxin

Digitalis glycosides are mostly kind of druggery for congestive heart failure(CHF). Digitalis glycosides also can cure arrhythmia and angina and have the power of resisting tumour. However,digitalis glycosides have some disadvantages about slow drainage,being prone to cumulation,and cure quantity is close to poisoning quantity(cure quantity is 60%about poisoning quantity ).Therefore,we do some microbial transformation with digitoxin which is one kind of digitalis glycosides,and we hope that some new digitalis glycosides could be gotten which are quick result,high effect and low poison.Curvularia lunataKA-91,Absidia coerulea307(AC307) and Penicillium raistrickii (ATCC10490) are choosed for this experiment.Thin layer chromatography(TLC) is used to analysis the result of the transformation.After analyse,two products are get when digitoxin is biotransformed by Curvularia lunata KA-91,named productⅠand productⅡ, and the biotransformation yields are 27.3%and 4.6%.One product is get when digitoxin is biotransformed by Absidia coerulea AC307,named productⅢ,and the biotransformation yield is 5.8%.Penicillium raistrickii ATCC1049 can not biotransform digitoxin.Preparative liquid chromatography(PLC) and columned chromatography are used for purifying product.Then high pour protuctⅠis gotton,and the pour rate is hyper than 95%. By MS,H-NMR,C-NMR,HSQC,HMBC and some other ways,the structure about protuctⅠis knowen as 3β-[(2-dihydroxy-O-6-Dideoxy-β-D-ribo-hexopyranosyl-(1→4)-O-2,6-dideoxy-β-D- ribo- hexopyranosyl-(1→4)-O-2,6-dideoxy-β-D- ribo-hexopyranosyl) oxy]-14-dihydroxy- 5β- card-20(22)-enolide,which is a new compound obtained for the first time.The technics about the transformation by Curvularia lunata KA-91 are confirmed firstly.The optimum conditions contain:the quantity of spore inoculation is 10~5/ml,original pH is 6.0,the strain incubated in 250 ml shake flasks with 60 ml medium,at 28℃,180r/min for 24h,100mL digitoxin dissolved in methanol and chloroform is added(The last concentration of digitoxin is 0.017%).Two products obtained after 56h transformed by Curvularia lunata KA-91,is productⅠand productⅡ.Then the biotransformation yield of productⅠis attained to 40.0%and of productⅡis attained to 11.2%.One new approach and new technics are founded about synthesis of cardiac glycoside by Microbial bioconvertion.