ginsenoside-rg3 and panaxadiol

The rare ginsenoside Rg3 is attracting more attention because of its good physiological activity and urgent need. There are many pathways to obtain ginsenoside Rg3, including chemical and biological methods. Among these, the conversion of the protopanaxadiol-type ginsenosides by microbial hydrolysis is a trend due to its high efficiency and mild conditions. For effectively extracting from the other panaxadiol saponins, the conversion process for ginsenoside Rg3 was investigated using β-glycosidase-producing endophytic fungus in Panax ginseng in this study. The metabolic pathways are as follows: ginsenoside Rb1 → Gyp-XVII and ginsenoside Rb1 → ginsenoside Rd → ginsenoside Rg3. Phylogenetic analysis of 16S rDNA gene sequence, showed that GE 32 strain belonged to Flavobacterium species. These results suggest that the process of rare ginsenoside Rg3 production by endophytic bacteria GE 32 is efficient for the industrial production and application. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on cultivable β-glycosidase-producing endophytic bacteria from Panax ginseng. Flavobacterium sp. GE32 could convert major ginsenoside Rb1 into Gyp-XVII and minor ginsenoside Rg3. Strain GE 32 has potential to be applied on the preparation for minor ginsenoside Rg3 in pharmaceutical industry.

Topics: Biotransformation; DNA, Ribosomal; Flavobacterium; Ginsenosides; Glycoside Hydrolases; Hydrolysis; Panax; Phylogeny; Sapogenins; Saponins

Cobalt nitrate, nickel sulphate, hydrogen peroxide, sodium nitroprusside, and culture filtrates of Pseudomonas monteili, Bacillus circularans, Trichoderma atroviridae, and Trichoderma harzianum were tested to elicit ginsenoside production in a cell suspension line of Panax quinquefolius. Abiotic elicitors preferentially increased panaxadiols whereas biotic elicitors upregulated the panaxatriol synthesis. Cobalt nitrate (50 μM) increased total ginsenosides content by twofold (54.3 mg/L) within 5 days. It also induced the Rc synthesis that was absent in the control cultures. Elicitation with P. monteili (2.5 % v/v, 5 days) also supported 2.4-fold enhancement in saponin yield. Elicitation by T. atroviridae or hydrogen peroxide induced the synthesis of Rg3 and Rh2 that are absent in ginseng roots. The highest ginsenosides productivity (3.2-fold of control) was noticed in cells exposed to 1.25 % v/v dose of T. atroviridae for 5 days. Treating cells with T. harzianum for 15 days afforded maximum synthesis and leaching (8.1 mg/L) of ginsenoside Rh1.

Topics: Bacillus; Cobalt; Culture Media; Ginsenosides; Hydrogen Peroxide; Nickel; Nitroprusside; Panax; Plant Cells; Pseudomonas; Trichoderma

Bioassay-guided fractionation, combined with screening based on EGF-responsive neural stem cells (NSCs) differentiation assay, has been used to search for active molecules from Panax notoginseng. Ginsenosides Rg3 (1), Rk1 (2), and Rg5 (3) were identified as potential neurogenic molecules. The degrees of their neurogenic effects were found to be 3 > 2 > 1. The neurogenic effect of 3 represents a biphasic dose- and time-dependent regulation. Transient exposure of NSCs to 8 microM 3 for 24 h followed by 1 microM and 72 h incubation was the optimal procedure for the induction of neurons in NSCs, and compound 3 resulted in an approximately 3-fold increase in neurogenesis at the expense of astrogliogenesis. The neurogenic effect of 3 was completely eliminated by the Ca2+ channel antagonist nifedipine. These findings imply that 3 may be utilized as a pharmacological agent in studying the molecular regulation of neurogenesis of brain stem cells and, subsequently, for treatment of neurodegenerative diseases.

Topics: Brain Stem; Calcium Channel Blockers; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Epidermal Growth Factor; Ginsenosides; Glycosides; Molecular Structure; Neurodegenerative Diseases; Neurons; Nifedipine; Panax notoginseng; Plants, Medicinal; Stem Cells; Time Factors; Triterpenes