A new epimer of ocotillol from stems and leaves of American ginseng.

A new minor C-3 epimer of ocotillol, named 3α-ocotillol (1), was isolated along with ocotillol (2) from the stems and leaves of American ginseng for the first time. The structure of the new sapogenin was elucidated as (20S, 24R)-dammar-20,24-epoxy-3α,6α,12β,25-tetraol by the combination analysis of NMR and mass spectrometry. The complete signal assignments of the two compounds were carried out by means of 2D NMR spectral analysis.