Galactosylation of steroidal saponins by β-galactosidase from Lactobacillus bulgaricus L3

The galactosylation of furostanosides and spirostanosides were investigated by using beta-galactosidase from Lactobacillus bulgaricus L3 as a catalyst and lactose as a sugar donor. Four novel galactosylated furostanoside products (compounds 1-4) from compound F, compound G, compound I, and compound H were obtained and their structures were identified by HR-ESI-MS, 1D and 2D NMR spectra. The result showed that galactosyl moiety was found to be added to the 6-OH of the 26-O-glucosyl in these four furostanoside substrates.