title: Regioselective enzymatic glycosylation of natural polyhydroxylated compounds: galactosylation and glucosylation of protopanaxatriol ginsenosides.
abstract: Ginsenoside Rg1 (1), the most representative Ginsenoside from Panax Ginseng C.A. Meyer belonging to the protopanaxatriol family, has been galactosylated by action of the beta-(1,4)-galactosyltransferase (GalT) from bovine colostrum, using UDP-galactose as an activated sugar donor. The enzyme showed the well-known specificity for the formation of a beta-linkage with the C-4 OH of the glucose acceptor, but it was not able to discriminate between the two glucose moieties of 1, giving a mixture of mono- and digalactosylated derivatives. Other natural Rg1-analogues such as F1, Rh1, Re, as well as the synthetic derivative 6'-O-acetyl-Rg1 have been also galactosylated, giving monolactosyl derivatives. GalT was also able to accept UDP-glucose as an activated sugar donor, giving rise to cellobiosyl derivatives of Rg1.
authors: Dipartimento di Chimica Organica e Industriale, Centro C.N.R. per lo Studio delle Sostanze Organiche Naturali, Università degli Studi di Milano, Via Venezian 21, 20133 Milano, Italy.
authors: B
authors: B
authors: Danieli
authors: L
authors: L
authors: Falcone
authors: D
authors: D
authors: Monti
authors: S
authors: S
authors: Riva
authors: S
authors: S
authors: Gebhardt
authors: M
authors: M
authors: Schubert-Zsilavecz
mesh_terms: D002240:Carbohydrate Sequence; D005690:Galactose / Q000737:chemistry; D036145:Ginsenosides; D006031:Glycosylation; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D005894:Panax / Q000737:chemistry*; D010946:Plants, Medicinal; D012502:Sapogenins / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry; D014315:Triterpenes
chemical_list: D036145:Ginsenosides; D012502:Sapogenins; D012503:Saponins; D014315:Triterpenes; C081552:protopanaxatriol; C035054:ginsenoside Rg1; D005690:Galactose