Study On Transformation Of Ginsenosides And Panax Notoginseng Suspension Culture

The ginseng saponins (ginsenoside) are the main active ingredients of Panax notoginseng, which contain wide pharmacological effects. The natural ginsenosides of Panax notoginseng carry out their important pharmacological activities only when the ginsenosides are transformed into minor saponins. As many factors affect the transformation in vivo, the transformation efficiency is very low. People pay more attention to get minor ginsenosides through various attempts. Among these attempts, microbial transformation has predominance due to its stereoselectivity, mild reaction conditions, and environmental compatibility.In this study, the Panax notoginseng were fermented by the fungus islolated from the root of Panax notoginseng, which had positive activity of transforming ginsenosides. The changes of saponins were determined by reversed-phase high-performance liquid chromatography (HPLC). Morphologic identification and ITS sequence analysis of the fungus were carried out. The results showed the strain belonged to the genus Trichoderma compared and analyzed its morphology and characteristics of colony and sporulation structure. The ITS length of the strain was550bp, and only one deletion mutation occasionally was taken place at the134site of ITS. It was indicated that the strain was high similar to other strains of Trichoderma longibrachiatum Rifai (ATCC186481, ATCC208859, DAOM167674, DAOM231259). So the strain was identifided as T. longibrachiatum. HPLC results showed that the main change of fermented product was converting major ginsenoside Rbl to the more active minor ginsenoside Rd. The TLC analysis of ginsenoside Rbl convertion by the strain showed a strong ability of T. longibrachiatum to transform ginsenoside Rb1to Rd. Enzymatic production of Rd occurred by hydrolyses of the terminal glucopyranosyl moieties at the C-20carbon of ginsenoside Rbl showing the biotransformation pathway:Rb1â†'Rd.In view of the different pharmacological effects of raw and steamed Panax notoginseng, this study carried out the effects of different steaming times on Panax notoginseng for ginsenoside composition. Steaming mainly decreased the contents of ginsenosides Rgl and Rbl, but increased the content of20(S)-Rg3, Rh1and C-K. Chemical structures of these ginsenoside may be showing the transformation pathways of steaming:Rb1â†'C-K or20(S)-Rg3; Rg1â†'Rh1.To study the dynamics of ginsenoside biosynthesis in suspension culture of Panax notoginseng, the calli of Panax notoginseng were suspended in liquid medium for40d, and the changes of ginsenosides were determined by HPLC method. Results:cell growth was slow in suspension culture, but the contents of six ginsenosides were varied with different culture time. The contents of four ginsenosides Rgl, Re, Rh1and Rb1showed the increases from about3.63to9.72mg/g,2.34to7.02mg/g,0.42to2.37mg/g and0.24to1.86mg/g, respectively, during25and30days of the culture. Rh2and F1had no obvious change. Such results indicated that the protopanaxatriol saponions (Rgl, Re and Rh1) increased significantly during the growth phase.