Search for new seed oils. XV. Oils of boraginaceae.

In a search for a preferred source of gamma-linolenic (all-cis-6,9,12-octadecatrienoic) acid, seed oils of 33 species of Boraginaceae were examined. The desired triene was found primarily in the subfamily Boraginoideae in amounts ranging from 0.2 to 18%. Oils of this subfamily also contain 0.2 to 15% of the tetraene, all-cis-6,9,12,15-octadecatetraenoic acid. Total unsaturation and the relative proportions of the common acids varied widely in oils of the family. Monoene predominated in the subfamily Cordioideae, diene in Heliotropioideae, and a diverse composition among the Boraginoideae; seven had iodine values of 200 or above.Cordia verbenacea seed oil was unique among those examined in having 43% of C(20) acids and 23% of components more volatile in gas chromatography than the usual triglycerides.