Enzymatic preparation of ginsenosides Rg2, Rh1, and F1.

During investigation of the hydrolysis of a protopanaxatriol-type saponin mixture by various glycoside hydrolases, crude preparations of beta-galactosidase from Aspergillus oryzae and lactase from Penicillium sp. were found to produce two minor saponins, ginsenoside Rg(2) [6-O-(alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl)-20(S)-protopanaxatriol] and ginsenoside Rh(1) (6-O-beta-D-glucopyranosyl-20(S)-protopanaxatriol), respectively, in high yields. Moreover, a naringinase preparation from Penicillium decumbens readily gave an intestinal bacterial metabolite, ginsenoside F(1) (20-O-beta-D-glucopyranosyl-20(S)-protopanaxatriol), as the main product, with a small amount of 20(S)-protopanaxatriol from a protopanaxatriol-type saponin mixture. Also, a hesperidinase from Penicillium sp. selectively hydrolyzed ginsenoside Re into ginsenoside Rg(1). This is the first report on the enzymatic preparation of minor saponins, ginsenosides Rg(2) and Rh(1), and of an intestinal bacterial metabolite, ginsenoside F(1), with high efficiency from a protopanaxatriol-type saponin mixture.