Seeds of 40 oilseed species from 23 different plant families (Brassicaceae, Cucurbitaceae, Fabaceae, Sapindaceae, Malvaceae, Gnetaceae, Clusiaceae, Bruseraceae, Ranunculaceae, Convolvulaceae, Amaranthaceae, Tiliaceae, Basellaceae, Solanaceae, Umbelliferae, Labiatae, Compositae, Theaceae, Euphorbiaceae, Caesalpiniaceae, Sapotaceae, Anacardiaceae, and Connaraceae) grown in Vietnam were analyzed for oilseed oil content, FA, and vitamin E. The seed oil content varied between 0.2 g/100 g for Mangifera indica and 75.7 g/100 g for Calophyllum inophyllum, whereas only nine seeds contained more than 40% oil. The tocopherol content ranged from 26 (Sapindus mukorossi) to 9361 mg/kg (Litchi chinensis). In nine seed oils unusual FA such as conjugated, cyclopropenoic, or epoxy FA were found.The oleochemical industry is increasingly interested in custommade and novel oils with specific FA compositions for applications in the oil and pharmaceutical industries (1). Such oils can be used for the synthesis of high-quality products without expensive purification of raw materials. In addition, oilseed breeders are searching for species to produce beneficial new genotypes (1). A recent example is rapeseed oil with 40 to 60% lauric acid, which normally contains little or none of this FA (2).Plant seeds contain tocopherols and tocotrienols, which are used as natural antioxidants and vitamin E (3-5). In nature four different derivatives of tocopherols and tocotrienols (α-, β-, γ-, and δ) can be found, which differ in the methylation of the chroman ring. The antioxidant activity increases for tocopherols and tocotrienols in the order α to δ, whereas the biological activity is inversely proportional to the antioxidant activity (6,7). Plastochromanol-8 (P-8) is a related compound that is more effective against oxidation than α-tocopherol (8).A large part of the genetic resources of the world is located in the southern hemisphere. These can be considered as potential sources of raw material for the development of future medicines and food, as well as renewable resources with interesting FA and associated enzyme systems. Unfortunately, very little information about this genetic potential is available and many species are disappearing. Therefore, identifying commercially valuable lipid-bearing plants is a timely issue.Vietnam is very rich in plants, most of which have not been investigated with respect to their FA and tocopherol compositions. Some information about the FA composition of oilseeds is available in the Seed Oil Fatty Acid (SOFA) database (9), but to our knowledge this database contains only very limited data about seed oils from plants grown in Vietnam. Therefore, the aim of this work was to determine the FA and tocopherol compositions of native North Vietnamese seeds. Correlations between the content of PUFA and the tocopherol/tocotrienol composition were objects of special interest. MATERIALS AND METHODSPlant material. Seeds from 40 plant species grown in Vietnam were obtained from a typical Vietnamese market and used for the in...

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.

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Following our previous review on Pinus spp. seed fatty acid (FA) compositions, we recapitulate here the seed FA compositions of Larix (larch), Picea (spruce), and Pseudotsuga (Douglas fir) spp. Numerous seed FA compositions not described earlier are included. Approximately 40% of all Picea taxa and one-third of Larix taxa have been analyzed so far for their seed FA compositions. Qualitatively, the seed FA compositions in the three genera studied here are the same as in Pinus spp., including in particular the same delta5-olefinic acids. However, they display a considerably lower variability in Larix and Picea spp. than in Pinus spp. An assessment of geographical variations in the seed FA composition of P. abies was made, and intraspecific dissimilarities in this species were found to be of considerably smaller amplitude than interspecific dissimilarities among other Picea species. This observation supports the use of seed FA compositions as chemotaxonomic markers, as they practically do not depend on edaphic or climatic conditions. This also shows that Picea spp. are coherently united as a group by their seed FA compositions. This also holds for Larix spp. Despite a close resemblance between Picea and Larix spp. seed FA compositions, principal component analysis indicates that the minor differences in seed FA compositions between the two genera are sufficient to allow a clear-cut individualization of the two genera. In both cases, the main FA is linoleic acid (slightly less than one-half of total FA), followed by pinolenic (5,9,12-18:3) and oleic acids. A maximum of 34% of total delta5-olefinic acids is reached in L. sibirica seeds, which appears to be the highest value found in Pinaceae seed FA. This apparent limit is discussed in terms of regio- and stereospecific distribution of delta5-olefinic acids in seed triacylglycerols. Regarding the single species of Pseudotsuga analyzed so far (P. menziesii), its seed FA composition is quite distinct from that of the other two genera, and in particular, it contains 1.2% of 14-methylhexadecanoic (anteiso-17:0) acid. In the three genera studied here, as well as in most Pinus spp., the C18 delta5-olefinic acids (5,9-18:2 and 5,9,12-18:3 acids) are present in considerably higher amounts than the C20 delta5-olefinic acids (5,11-20:2 and 5,11,14-20:3 acids).

The fatty acid composition of the seed lipids of plants, in contrast to leaf lipids, may contain highly specific unusual fatty acids, which are often correlated to plant family. For example, petroselinic acid is typical for the Apiacea family, cyclopropene fatty acids are typical for the Malvaceae family, and cyclopentene‐ring containing fatty acids for the Flacourtiaceae family. Other fatty acids may be characteristic for certain sub‐families or only for certain species of plants within a family or genus. γ‐Linolenic acid, Δ5–18:3 and Δ5–20:3 fatty acids and others may occur in several plant families, but are still linked to certain related species only. They can be analyzed by high‐resolution capillary GLC. Particularly interesting is the situation in the family Ranunculaceae. GLC fingerprints of fatty acids are shown that may indicate a closer or less close relationship between species within this family.