title: Microbial conversion of rare ginsenoside Rf to 20(S)-protopanaxatriol by Aspergillus niger.
abstract: In this study, rare ginsenoside Rf was transformed into 20(S)-protopanaxatriol (PPT(S)) by glycosidase from Aspergillus niger. By investing the reaction conditions, the optimal conditions were obtained, as follows: pH 5.0, temperature 55 degrees C, and substrate concentration 1.25 mmol/l. Under optimal conditions, PPT(S) (1.13 micromol) prepared from 1.25 mumol Rf showed a higher yield (90.4%). The enzymatic reaction was analyzed by reversed-phase HPLC, suggesting the transformation pathway: Rf-->Rh1(S)-->PPT(S).
authors.affiliation: Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejon, Republic of Korea.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Gu
authors.forename: Dong-Liang
authors.initials: DL
authors.lastname: Zhang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.forename: Chang-Keun
authors.initials: CK
authors.lastname: Sung
mesh_terms: D001234:Aspergillus niger / Q000378:metabolism*; D001711:Biotransformation; D036145:Ginsenosides / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D012502:Sapogenins / Q000378:metabolism*; D013696:Temperature
chemical_list: D036145:Ginsenosides; D012502:Sapogenins; C081552:protopanaxatriol; C055328:ginsenoside Rf