Identification of unusual fatty acids of four alpine plant species from the Pamirs

Abstract

Fatty acid composition and structure in total lipids from the green above-ground parts of four alpine plants, Oxygraphis glacialis, Primula macrophylla, Rhodiola pamiroalaica, and Swertia marginata, were established by GC and GC–MS. A total of 55 fatty acids was detected, and 48 of them were identified. Ubiquitous palmitate, linoleate, and linolenate predominated in the lipids accounting for about 72–90% of the total fatty acids. At the same time, the latter contained numerous species, which were unusual for higher plants and included saturated odd-numbered n-acids (six C 15–C 25 species, 0.26–1.40%), saturated even-numbered very-long-chain n-acids (six C 20–C 30 species, 1.00–2.49%), iso-acids (nine C 15–C 26 species, 0.64–1.53%), anteiso-acids (four C 15–C 20 species, 0.08–1.57%), certain uncommon mono- and dienoic acids, as well as 16:3ω3, 18:3ω6, and 18:4ω3 acids that are absent from the most higher plants. Nine fatty acids were found here for the first time in higher plants and two may be new to science. The evidence on the unusual fatty acids is discussed with respect to their distribution in living organisms, pathways of biosynthesis, and chemotaxonomic role.