Abstract
During investigation of the hydrolysis of a protopanaxatriol-type saponin mixture by various glycoside hydrolases, crude preparations of β-galactosidase from Aspergillus oryzae and lactase from Penicillium sp. were found to produce two minor saponins, ginsenoside Rg2 [6-O-(α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl)-20(S)-protopanaxatriol] and ginsenoside Rh1 (6-O-β-D-glucopyranosyl-20(S)-protopanaxatriol), respectively, in high yields. Moreover, a naringinase preparation from Penicillium decumbens readily gave an intestinal bacterial metabolite, ginsenoside F1 (20-O-β-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 Rg1. This is the first report on the enzymatic preparation of minor saponins, ginsenosides Rg2 and Rh1, and of an intestinal bacterial metabolite, ginsenoside F1, with high efficiency from a protopanaxatriol-type saponin mixture.
