Lipidology, Volume 1, Issue 2 (December 2024) – 1 article

Wollemi pine, Wollemia nobilis W. G. Jones, K. D. Hill & J. M. Allan (Araucariaceae) was discovered in a remote canyon 150 km north-west of Sydney, Australia. As fewer than 100 adult trees of this plant survive in the wild, efforts to conserve this species have included seed storage. Fresh and stored seeds were analysed for yield and composition of the seed oil. The seed kernels, from both fresh and stored seed, were rich in oil with contents of 42% and 48%, respectively. The fatty acid profile of Wollemi pine seed oil was determined by GC-MS analyses of fatty acid methyl ester derivatives. Oleic acid makes up 32% of the fatty acid profile, while the major polyunsaturated fatty acid is linoleic acid (25%). Most of the detectable omega-3 fatty acid content of the oil is α-linolenic acid (3%). The seed oil has a high content of C20 to C24 fatty acids (25%) consisting of long-chain saturated fatty acids (19%). The polyunsaturated C20 omega-6 fatty acid content consists of eicosadienoic acid, dihomo-γ-linolenic acid, and arachidonic acid (total 4%). ¹H NMR analyses of the intact oil showed that the lipids were largely in the form of triglycerides with a degree of unsaturation of 1.5 double bond equivalents per fatty acid residue. In artificially aged or stored seeds, minor additional ¹H NMR spectral signals were attributed to an omega-3 epoxylipid, tentatively identified as cis-15,16-epoxy-9Z,12Z-octadecadienoic acid or ester derivative. Other minor signals were characteristic of a hydroxy or a hydroperoxy E,Z diene containing fatty acid. These products are typically formed by metabolic lipid oxidation of fatty acids. The content of the omega-3 epoxylipid, determined by the ¹H NMR method, varied with storage conditions and duration from less than 0.1% to a maximum of 3.3%. Full article