Sciadonic acid, also known as eicosatrienoic acid
[Sciadonic acid. ChemSpider. (n.d.). Retrieved November 10, 2022, from http://www.chemspider.com/Chemical-Structure.392828.html ] In regard to its structure, sciadonic acid has 3 double bonds in the 5, 11, and 14 positions all of which are in the cis configuration. It is further classified as Δ5-fatty, and an omega-6 acid due to the methylene interrupted double bond at carbon-5 and a final double bond 6 carbons away from the methylene tail of the
/ref> Furthermore, there have been propositions of several health applications for sciadonic acid as an anti-inflammatory agent. Sharing close structural similarity to arachidonic acid, sciadonic acid acts as a replacement phospholipid in the corresponding biochemical pathways.
Etymology and natural occurrence
The root behind the
nomenclature of sciadonic acid comes from its high abundance in the seed, leaves, and wood oils of the plant species
Sciadopitys verticillata.
Oftentimes, the acid is found in conifers together with other fatty acids (Juniperonic acid, Pinolenic acid, Taxoleic acid, coniferonic acid) that have a double bond in the position 5, separated by more than one methylene group from the next double bond.
Synthetic methods
There are a few methods reagarding the synthesis of sciadonic acid and other Δ5-fatty acids. One method is through
desaturase enzyme complexes in which the
biosynthesis of sciadonic acid has been achieved in the organism
Anemone leveillei via two Δ
5-desaturases, AL10 and AL21.
Both desaturases have shown success in the synthesis of sciadonic acid, however, the mechanisms show different substrate specificity. AL21 has broad substrate specificity and acts on both saturated (16:0 and 18:0) and unsaturated (20:2, ω-6) fatty acids.
In contrast AL10 has a much greater substrate specificity binding only to a C20 unsaturated fatty acid (20:2, n-6) When AL10 is co-expressed with a Δ
9-elongase the biosynthesis of sciadonic acid is achieved in transgenic plants. A second synthetic method is achieved through an
esterification reaction catalyzed via Lipozyme RM IM and pine nut oil. Lipase-catalyzed esterification reactions leading to the development of Δ
5-fatty acids can be achieved in solvent-free conditions using water-
jacketed vessel.
Phylogenetic significance in gymnosperms
Sciadonic acid and several other Δ
5-olefinic acids are found to be relatively abundant in
.
Setaria verticillata seeds and their fatty acid compositions allow for distinction between different Coniferophytes such as species from families such as
Cupressaceae and
Taxodiaceae.
[Wolff, R.L., L.G. Deluc, A.M. Marpeau, and B. Comps, Chemotaxonomic Differentiation of Conifer Families and Genera Based on the Seed Oil Fatty Acid Compositions: Multivariate Analyses, Trees 12:57–65 (1997)][Wolff, R.L., Clarification on the Taxonomic Position of Sciadopitys verticillata Among Coniferophytes Based on the Seed Oil Fatty Acid Compositions, J. Am. Oil Chem. Soc. 75:757–758 (1998)] Sciadonic acid is a distinctive fatty acid that shows presence in the oils of seeds, leaves, and woods of
. Indicating that plant families can be characterized by the fatty acid composition of their seed, leaves, and wood oils.
Health implications
and metabolites found to be biologically active have correlated to tumor progression by several mechanisms such as interruption of
cell signaling. In humans, fatty acid desaturases, FADS 1,2 and 3 are
enzyme coding genes found in the 11q13 region of chromosome 11, in which alterations can be attributed to several types of
such as breast, ovarian and cervical cancer. In particular, the FADS2 enzyme, responsible for Δ
6 desaturation is no longer functional.
In healthy tissues sciadonic acid is usually not within detectable concentrations. However, detectable concentrations have been found in human breast cancer tissues
and in pooled human blood plasma.
Due to structural similarity, Sciadonic acid has shown potential as a substitute for
arachidonic acid in cellular
phospholipid pools in signaling pathways.
In keratinocytes, sciadonic acids release from the cellular membrane phospholipid pool reduces levels of pro-inflammatory arachidonic acid and the corresponding pro-inflammatory down-stream mediator prostaglandin E
2.
Reduction of pro-inflammatory mediator molecules also occurs in murine macrophages, regulating the activation of NF-κΒ and MAPK pathways.
