Biotransformation Of Ginsenosides From Stems And Leaves By A Strain Of Cellulosimicrobium Sp.

Ginseng(Panax ginseng C.A.Meyer,Araliacae)is used in Asian countries as a traditional medicine.The main pharmacologically active components in ginseng are ginsenosides.The rare ginsenosides often have better activities than the major ones.At present,More than 40 ginsenosides have been isolated.Their contents in ginseng are different.Some minor ginsenosides(e.g.Rd,Rg3,Rg2,CK,Rh2),whose amount in ginseng is much lower than the major ones,possess unique pharmacological activity.In this paper 20 kinds of microorganisms were screened from soil.A strain isolated from ginseng-cultivating soil was found to be able to transformginsenosides to give a series of bioactive metabolites.The strain was identified to be Cellulosimicrobium sp.strain 21 by 16S rDNA sequencing.Cellulosimicrobium sp.strain 21 transformed protopanaxadiol-type ginsenoside Rbl,Rb2 and Rc to the major product,ginsenoside Rg3,and other two products,ginsenoside compound Y and Mc.The transformation pathways of ginsenoside Rbl,Rb2 and Rc by Cellulosimicrobium sp.strain 21 were found to be:Rb1? Rd ? Rg3;Rb2 ?Rg3/compound Y;Rc ? Rg3/ginsenoside Mc.Ginsenoside Rg3 was a potential molecule with remarkable anti-tumor activity.Therefore,Cellulosimicrobium sp.strain 21 would be useful in ginsenoside Rg3 production.The biotransformation pathways of protopanaxatriol-type ginsenosides by Cellulosimicrobium sp.strain 21 were studied as follows:Re ? Rg2;Rhl ? protopanaxatriol.Therefore,the main products of protopanaxatriol-type ginsenosides by Cellulosimicrobium sp.strain 21 were ginsenoside Rg2 and PPT.Rd and Re in Ginsenosides from stems and leaves were higher than the other Ginsenosides.And Cellulosimicrobium sp.strain 21 in transformation of Rd with relatively high efficiency.The optimum conditions were determined:Optimum substrate concentration,1.5 mg/mL;pH,7.0-8.0;temperature,31-37?.The experimental results provided useful data for the production of ginsenoside Rg2 and Rg3 in industry and for the bacterial transformation of ginsenoside and provide theoretical basis for the research.