IDENTIFICATION OF ALPHA-PARINARIC ACID IN THE SEED OIL OF SEBASTIANA-BRASILIENSIS SPRENGEL (EUPHORBIACEAE)

Besides some usual fatty acids, the seed oil of Sabastiana brasiliensi s (Euphorbiaceae) contains up to 39% (estimated by ultraviolet spectro scopy) of alpha-parinaric acid (cis, trans, trans,cis-9,11,13,15-octad ecatetraenoic acid). The fatty acids were analyzed by gas chromatograp hy and gas chromatography/mass spectrometry as their methyl esters. Th e structure of alpha-parinaric acid was proven by a combination of che mical and spectroscopic methods, conducted with the crude oil, the met hyl ester mixture, and the isolated fatty acid methyl ester. Complete assignment of the H-1 and C-13 nuclear magnetic resonance (NMR) shifts of alpha-parinaric acid was carried out by two-dimensional NMR experi ments.