Structure elucidation of roselipins, inhibitors of diacylglycerol acyltransferase produced by Gliocladium roseum KF-1040

The structures of roselipins 1A, 1B, 2A and 2B were elucidated by spectroscopic studies including H-1-H-1 COSY,C-13-H-1 COSY,C-13-H-1 HMQC and C-13-H-1 HMBC NMR experiments, and degradation experiments. They have the common skeleton of 2,4,6,8,10,12,14,16,18-nonamethyl-5,9, 13-trihydroxy-2E,6E, 10E-icosenoic acid modified with a D-mannose and a D-arabinitol. Roselipin A and B groups were stereoisomers at the arabinitol moiety, which esterified the fatty acid from the different terminal hydroxy residue. Roselipin 2 group was 6"-O-acetyl roselipin 1 group.