Alkyl-and alkenylresorcinols inRapanea laetevirens seed lipids

The seed lipids ofRapanea laetevirens (Myrsinacea) were found to contain a series of 5-alkylresorcinols. Some of these alkylresorcinols have been reported previously in other plant families, but never before in the Myrsinaceae. The various homologs were shown by mass spectrometry to have alkyl side chains that included C11 and C13 saturated as well as C11, C13, and C15 monoenoic substituents. This is the first report of the natural occurrence of tridecenylresorcinol, the homolog with the C13 monoenoic side chain. The positions of the double bonds in the side chains were determined by mass spectrometry of their methoxy trimethylsilyloxy derivatives. Also found were embelin and rapanone, benzoquinone pigments which occur commonly in the Myrsinaceae. The fatty acid composition ofRapanea seed triglycerides was not unusual, consisting mainly of 16∶0 (27%), 18∶1 (22%), and 18∶2 (44%).