Aromatase inhibitory fatty acid derivatives from the pollen of Brassica campestris L. var. oleifera DC.

Two new fatty acid derivatives, 9Z,12Z,15Z-octadecatrienoic acid sorbitol ester (1) and (10,11,12)-trihydroxy-(7Z,14Z)-heptadecadienoic acid (2), were isolated from the pollen of Brassica campestris L. var. oleifera DC., along with the four known fatty acid derivatives, 9Z,12Z,15Z-octadecatrienamide, N-(2-hydroxyethyl) (3), hexadecanoic acid sorbitol ester (4), 15,16-dihydroxy-9Z,12Z-octadecadienoic acid (5), and 9Z,12Z,15Z-octadecatrienoic acid 2,3-dihydroxypropyl ester (6). Their structures were elucidated by extensive spectroscopic analysis, including 1D- and 2D-NMR as well as HR-ESI-MS experiments. All compounds were tested using a noncellular aromatase assay, and the results showed that some compounds possessed strong inhibitory activity.