The seed oils from twenty-five Conifer species (from four families--Pinaceae, Cupressaceae, Taxodiaceae, and Taxaceae) have been analyzed, and their fatty acid compositions were established by capillary gas-liquid chromatography on two columns with different polarities. The oil content of the seeds varied from less than 1% up to 50%. Conifer seed oils were characterized by the presence of several A5-unsaturated polymethylene-interrupted polyunsaturated fatty acids (A5-acids) with either 18 (cis-5,cis-9 18:2, cis-5,cis-9,cis-12 18:3, and cis-5,cis-9,cis-12,cis-15 18:4 acids) or 20 carbon atoms (cis-5,cis-11 20:2, cis-5,cis-11,cis-14 20:3, and cis-5,cis-11 ,cis-14,cis-17 20:4 acids). Pinaceae seed oils contained 17-31% of A5-acids, mainly with 18 carbon atoms. The 20-carbon acids present were structurally derived from 20:1 n-9 and 20:2n-6 acids. Pinaceae seed oils were practically devoid of 18:3n-3 acid and did not contain either A5-18:4 or A5-20:4 acids. Several Pinaceae seeds had a A5-acid content higher than 50 mg/g of seed. The only Taxaceae seed oil studied (Taxus baccata) had a fatty acid composition related to those of Pinaceae seed oils. Cupressaceae seed oils differed from Pinaceae seed oils by the absence of A5-acids with 18 carbon atoms and high concentrations in 18:3n-3 acid and in A5-acids with 20 carbon atoms (A5-20:3 and A5-20:4 acids). A5-18:4 Acid was present in minute amounts. The highest level of A5-20:4 acid was found in Juniperus communis seed oil, but the best source of A5-acids among Cupressaceae was Thuja occidenta[is. Yaxodiaceae seed oils had more heterogeneous fatty acid compositions, but the distribution of A5-acids resembled that found in Cupressaceae seed oils. Except for Sciadopytis verticillata, other Taxodiaceae species are not interesting sources of A5-acids. The distribution profile of AS-acids among different Conifer families appeared to be linked to the occurrence of 18:3n-3 acid in the seed oils.JAOCS 73, 765-771 (1996).

The delta5-unsaturated polymethylene-interrupted fatty acid (delta5-UPIFA) contents and profiles of gymnosperm seeds are useful chemometric data for the taxonomy and phylogeny of that division, and these acids may also have some biomedical or nutritional applications. We recapitulate here all data available on pine (Pinus; the largest genus in the family Pinaceae) seed fatty acid (SFA) compositions, including 28 unpublished compositions. This overview encompasses 76 species, subspecies, and varieties, which is approximately one-half of all extant pines officially recognized at these taxon levels. Qualitatively, the SFA from all pine species analyzed so far are identical. The genus Pinus is coherently united--but this qualitative feature can be extended to the whole family Pinaceae--by the presence of delta5-UPIFA with C18 [taxoleic (5,9-18:2) and pinolenic (5,9,12-18:3) acids] and C20 chains [5,11-20:2, and sciadonic (5,11,14-20:3) acids]. Not a single pine species was found so far with any of these acids missing. Linoleic acid is almost always, except in a few cases, the prominent SFA, in the range 40-60% of total fatty acids. The second habitual SFA is oleic acid, from 12 to 30%. Exceptions, however, occur, particularly in the Cembroides subsection, where oleic acid reaches ca. 45%, a value higher than that of linoleic acid. Alpha-linolenic acid, on the other hand, is a minor constituent of pine SFA, almost always less than 1%, but that would reach 2.7% in one species (P. merkusii). The sum of saturated acids [16:0 (major) and 18:0 (minor) acids principally] is most often less than 10% of total SFA, and anteiso-17:0 acid is present in all species in amounts up to 0.3%. Regarding C18 delta5-UPIFA, taxoleic acid reaches a maximum of 4.5% of total SFA, whereas pinolenic acid varies from 0.1 to 25.3%. The very minor coniferonic (5,9,12,15-18:4) acid is less than 0.2% in all species. The C20 elongation product of pinolenic acid, bishomo-pinolenic (7,11,14-20:3) acid, is a frequent though minor SFA constituent (maximum, 0.7%). When considering C20 delta5-UPIFA, a difference is noted between the subgenera Strobus and Pinus. In the former subgenus, 5,11-20:2 and sciadonic acids are < or =0.3 and < or =1.9%, respectively, whereas in the latter subgenus, they are most often > or =0.3 and > or =2.0%, respectively. The highest values for 5,11-20:2 and sciadonic acids are 0.5% (many species) and 7.0% (P. pinaster). The 5,11,14,17-20:4 (juniperonic) acid is present occasionally in trace amounts. The highest level of total delta5-UPIFA is 30-31% (P. sylvestris), and the lowest level is 0.6% (P. monophylla). Uniting as well as discriminating features that may complement the knowledge about the taxonomy and phylogeny of pines are emphasized.

AbstractmThe fatty acid compositions of seed oils from 34 conifer species, mainly Pinaceae and secondarily Cupressaceae, have been determined by gas-liquid chromatography of the methyl esters. As noted in earlier studies, these oils were characterized by the presence of several D5-

The fatty acid compositions of the seed lipids from four Ephedra species, E. nevadensis, E. viridis, E. przewalskii, and E. gerardiana (four gymnosperm species belonging to the Cycadophytes), have been established with an emphasis on delta5-unsaturated polymethylene-interrupted fatty acids (delta5-UPIFA). Mass spectrometry of the picolinyl ester derivatives allowed characterization of 5,9- and 5,11-18:2; 5,9,12-18:3; 5,9,12,15-18:4; 5,11-20:2; 5,11,14-20:3; and 5,11,14,17-20:4 acids. Delta5-UPIFA with a delta11-ethylenic bond (mostly C20 acids) were in higher proportions than delta5-UPIFA with a delta9 double bond (exclusively C18 acids) in all species. The total delta5-UPIFA content was 17-31% of the total fatty acids, with 5,11,14-20:3 and 5,11,14,17-20:4 acids being the principal delta5-UPIFA isomers. The relatively high level of cis-vaccenic (11-18:1) acid found in Ephedra spp. seeds, the presence of its delta5-desaturation product, 5,11-18:2 acid (proposed trivial name: ephedrenic acid), and of its elongation product, 13-20:1 acid, were previously shown to occur in a single other species, Ginkgo biloba, among the approximately 170 gymnosperm species analyzed so far. Consequently, Ephedraceae and Coniferophytes (including Ginkgoatae), which have evolved separately since the Devonian period (approximately 300 million yr ago), have kept in common the ability to synthesize C18 and C20 delta5-UPIFA. We postulate the existence of two delta5-desaturases in gymnosperm seeds, one possibly specific for unsaturated acids with a delta9-ethylenic bond, and the other possibly specific for unsaturated acids with a delta11-ethylenic bond. Alternatively, the delta5-desaturases might be specific for the chain length with C18 unsaturated acids on the one hand and C20 unsaturated acids on the other hand. The resulting hypothetical pathways for the biosynthesis of delta5-UPIFA in gymnosperm seeds are only distinguished by the position of 11-18:1 acid. Moreover, 13C nuclear magnetic resonance spectroscopy of the seed oil from two Ephedra species has shown that delta5-UPIFA are essentially excluded from the internal position of triacylglycerols, a characteristic common to all of the Coniferophytes analyzed so far (more than 30 species), with the possibility of an exclusive esterification at the sn-3 position. This structural feature would also date back to the Devonian period, but might have been lost in those rare angiosperm species containing delta5-UPIFA.