Enzymatic synthesis of two ginsenoside Re-β-xylosides

Two new beta -xylosyl derivatives of ginsenoside Re, 20(S)-protopanaxatriol 6-O-alpha -L-rhamnopyranosyl-(1 -->2)-[beta -D-xylopyranosyl-(1 -->4)]-beta -D-glu20-O-beta -D-glucopyranosyl and 20(S)-protopanaxatriol 6-O-alpha -L-rhamnopyranosyl-(1 -->2)-[beta -D-xylopyranosyl-(1 -->6)]-beta -D-glucopyranosyl-20-O-beta -D-pyranoside, were respectively synthesized from beta -nitrophenyl beta -D-xylopyranoside and phenyl beta -D-xylopyranoside as donors and ginsenoside Re as the acceptor in 25% acetone and acetonitrile by a cellulase preparation from Trichoderma viride and a beta -galactosidase preparation from Aspergillus oryzae. The latter enzyme preparation also catalyzed the hydrolysis of ginsenoside Re to the minor saponin, ginsenoside Rg(2).