The structures of roselipins 1A, IB, 2A and 2B were elucidated by spectroscopic studies including
1H-
1H COSY,
13C-
1H COSY,
13C-
1H HMQC and
13C-
1H 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-2
E, 6
E, 10
E-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.
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