Fatty acids of the seeds from pine species of the Ponderosa-Banksiana and Halepensis sections. The peculiar taxonomic position of Pinus pinaster

Abstract

The fatty acid compositions of pine seed oils were determined from 11 species of the Banksiana subsection and three species of the Ponderosa subsection. All were collected in North America (United States, Mexico, and Cuba). These analyses also included the seed oils from the unique European species of the Ponderosa-Banksiana section (Banksiana subsection), Pinus pinaster, and from three pine species of the Halepensis section, which are related to the Banksiana subsection. Emphasis was placed on their Δ5-olefinic acid content and profile. Principal-component analysis of fatty acid compositions showed that all North American species constituted a fairly homogeneous group. However, P. jeffreyi was slightly eccentric, and P. pinaster, a west-Mediterranean species, was completely isolated from the North American group. Other species from the Banksiana and Ponderosa subsections could not be distinguished on the basis of their seed oil fatty acid compositions. With respect to Δ5-olefinic acids, the North American species (except for P. jeffreyi) had 5,9-18:2, 5,9,12-18:3, 5,11-20:2, and 5,11,14-20:3 acid concentrations in the ranges 1.9 to 3.2, 17.7 to 22.9, 0.2 to 0.4, and 2.0 to 3.5%, respectively (sum, 22.7–28.5%). Levels of corresponding acids in P. pinaster were 0.9, 7.9, 0.9, and 7.0%, respectively (sum, 16.7%). Other differences were observed for linoleic acid (42.6 to 48.6% vs. 52.2%) and α-linolenic acid (0.3 to 0.6% vs. 1.4%). Pinus pinaster was close to species of the Halepensis section (5,9-18:2, 0.5 to 1.0%; 5,9,12-18:3, 3.1 to 4.4%; 5,11-20:2, 0.4 to 0.5%; 5,11,14-20:3, 3.6 to 5.4%; sum, 8.6–11.1%), which were clearly separated from the Ponderosa-Banksiana section. Among all pines analyzed, P. pinaster presented the highest level of sciadonic (5,11,14-20:3) acid, a component that has three ethylenic bonds in common with arachidonic and eicosapentaenoic acids.