MICROBIAL TRANSFORMATION OF CUCURBITACIN-E 2-O-BETA-D-GLUCOPYRANOSIDE

Cucurbitacin E 2-O-beta-D-glucopyranoside [1] was transformed by Curvu laria lunata NRRL 2178 into cucurbitacin E [2] and three new metabolit es. The novel metabolites were identified by one- and two-dimensional H-1- and C-13-nmr spectroscopic techniques and high-resolution mass sp ectrometry as (24R)-hydroxy-23,24-dihydrocucurbitacin E and (24S)-hydr oxy-23,24-dihydrocucurbitacin E [4 and 5], and the 3-acetyloxy-3-methy lbutyl ester of (23-27)-penra-norcucurbitacin I 22-oic acid [6].