Biosynthesis of novel glucosides geldanamycin analogs by enzymatic synthesis.

Two new glucosides (1 and 2) of geldanamycin (GA) analogs were obtained from in vitro glycosylation by UDP-glycosyltransferase (YjiC). Based on spectroscopic (HR-ESI-MS, 1D, and 2D-NMR) analyses, the glucosides were elucidated as 4,5-dihydro-7-O-descarbamoyl-7-hydroxyl GA-7-O-beta-D-glucoside (1) and ACDL3172-18-O-beta-D-glucoside (2). Furthermore, the water solubility of compounds 1 and 2 was about 215.2 and 90.7 times higher respectively, than that of the substrates. Among compounds 1-4, only 3 showed weak antiproliferative activity against four human tumor cell lines: MDA-MB-231, SMMC7721, HepG2, and SW480 (IC50: 13.6, 15.1, 31.8, and 22.7 mu M, respectively).