title: Preparation of minor ginsenosides C-Mc, C-Y, F2, and C-K from American ginseng PPD-ginsenoside using special ginsenosidase type-I from Aspergillus niger g.848.
abstract: BACKGROUND
  Minor ginsenosides, those having low content in ginseng, have higher pharmacological activities. To obtain minor ginsenosides, the biotransformation of American ginseng protopanaxadiol (PPD)-ginsenoside was studied using special ginsenosidase type-I from Aspergillus niger g.848.
  
  
  METHODS
  DEAE (diethylaminoethyl)-cellulose and polyacrylamide gel electrophoresis were used in enzyme purification, thin-layer chromatography and high performance liquid chromatography (HPLC) were used in enzyme hydrolysis and kinetics; crude enzyme was used in minor ginsenoside preparation from PPD-ginsenoside; the products were separated with silica-gel-column, and recognized by HPLC and NMR (Nuclear Magnetic Resonance).
  
  
  RESULTS
  The enzyme molecular weight was 75 kDa; the enzyme firstly hydrolyzed the C-20 position 20-O-β-D-Glc of ginsenoside Rb1, then the C-3 position 3-O-β-D-Glc with the pathway Rb1→Rd→F2→C-K. However, the enzyme firstly hydrolyzed C-3 position 3-O-β-D-Glc of ginsenoside Rb2 and Rc, finally hydrolyzed 20-O-L-Ara with the pathway Rb2→C-O→C-Y→C-K, and Rc→C-Mc1→C-Mc→C-K. According to enzyme kinetics, K m and V max of Michaelis-Menten equation, the enzyme reaction velocities on ginsenosides were Rb1 > Rb2 > Rc > Rd. However, the pure enzyme yield was only 3.1%, so crude enzyme was used for minor ginsenoside preparation. When the crude enzyme was reacted in 3% American ginseng PPD-ginsenoside (containing Rb1, Rb2, Rc, and Rd) at 45°C and pH 5.0 for 18 h, the main products were minor ginsenosides C-Mc, C-Y, F2, and C-K; average molar yields were 43.7% for C-Mc from Rc, 42.4% for C-Y from Rb2, and 69.5% for F2 and C-K from Rb1 and Rd.
  
  
  CONCLUSIONS
  Four monomer minor ginsenosides were successfully produced (at low-cost) from the PPD-ginsenosides using crude enzyme.
authors.affiliation: College of Biotechnology, Dalian Polytechnic University, Dalian, People's Republic of China ; Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Science, Jilin University, Changchun, People's Republic of China.
authors.forename: Chun-Ying
authors.initials: CY
authors.lastname: Liu
authors.affiliation: College of Biotechnology, Dalian Polytechnic University, Dalian, People's Republic of China.
authors.forename: Rui-Xin
authors.initials: RX
authors.lastname: Zhou
authors.affiliation: Institute for Brain Disorders, Dalian Medical University, Dalian, People's Republic of China.
authors.forename: Chang-Kai
authors.initials: CK
authors.lastname: Sun
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Science, Jilin University, Changchun, People's Republic of China.
authors.forename: Ying-Hua
authors.initials: YH
authors.lastname: Jin
authors.affiliation: College of Biotechnology, Dalian Polytechnic University, Dalian, People's Republic of China.
authors.forename: Hong-Shan
authors.initials: HS
authors.lastname: Yu
authors.affiliation: College of Biotechnology, Dalian Polytechnic University, Dalian, People's Republic of China.
authors.forename: Tian-Yang
authors.initials: TY
authors.lastname: Zhang
authors.affiliation: College of Biotechnology, Dalian Polytechnic University, Dalian, People's Republic of China.
authors.forename: Long-Quan
authors.initials: LQ
authors.lastname: Xu
authors.affiliation: College of Biotechnology, Dalian Polytechnic University, Dalian, People's Republic of China.
authors.forename: Feng-Xie
authors.initials: FX
authors.lastname: Jin
keywords: Aspergillus niger g.848; Panax quinquefolius; ginsenosidase type-I; minor ginsenosides; protopanaxadiol-type ginsenosides