13-Hydroxy-9Z,11E,15E-octadecatrienoic acid from the leaves of Cucurbita moschata.

A new unsaturated hydroxy fatty acid was isolated from the leaves of Cucurbita moschata through repeated silica gel column chromatography and chemical methods. The structure of the new fatty acid was determined as 13-hydroxy-9,11,15-octadecatrienoic acid on the basis of several spectral data including 2D-NMR. The stererostructures of double bonds were determined to be 9Z, 11E and 15E by coupling patterns of related proton signals in the 1H-NMR and NOESY experiments.