Sciadonic acid, also known as eicosatrienoic acid, is a

polyunsaturated fatty acid Polyunsaturated fatty acids (PUFAs) are fatty acids that contain more than one double bond in their backbone. This class includes many important compounds, such as essential fatty acids and those that give drying oils their characteristic proper ...

. In regard to its structure, 5''Z'',11''Z'',14''Z''-eicosa-5,11,14-trienoic acid (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 Omega-6 fatty acids (also referred to as ω-6 fatty acids or ''n''-6 fatty acids) are a family of polyunsaturated fatty acids that have in common a final carbon-carbon double bond in the ''n''-6 position, that is, the sixth bond, counting from ...

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

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

. Sciadonic acid is a naturally occurring compound and has been found to play a role as a plant metabolite, commonly found in pine nut oil. Furthermore, there have been propositions of several health applications for sciadonic acid as an

anti-inflammatory agent Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as op ...

. Sharing close structural similarity to arachidonic acid, sciadonic acid acts as a replacement

phospholipid Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids ty ...

in the corresponding

biochemical pathways In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reac ...

Etymology

The root behind the

nomenclature Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. The principles of naming vary from the relatively informal conventions of everyday speech to the internationally agre ...

of sciadonic acid comes from its high abundance in the seed, leaves, and wood oils of the plant species ''

Sciadopitys verticillata ''Sciadopitys verticillata'', the or Japanese umbrella-pine, is a unique conifer endemic to Japan. It is the sole living member of the family Sciadopityaceae and genus '' Sciadopitys'', a living fossil with no close relatives. The oldest fossi ...

''.

Synthetic methods

There are a few methods reagarding the synthesis of sciadonic acid and other Δ5-fatty acids. One method is through

desaturase A fatty acid desaturase is an enzyme that removes two hydrogen atoms from a fatty acid, creating a carbon/carbon double bond. These desaturases are classified as: * Delta - indicating that the double bond is created at a fixed position from the ...

enzyme complexes in which the biosynthesis of sciadonic acid has been achieved in the organism '' Anemone leveillei'' via two Δ⁵-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 Δ⁹-elongase the biosynthesis of sciadonic acid is achieved in

transgenic plants Genetically modified plants have been engineered for scientific research, to create new colours in plants, deliver vaccines, and to create enhanced crops. Plant genomes can be engineered by physical methods or by use of '' Agrobacterium'' for the ...

. A second synthetic method is achieved through an

esterification In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glyceride ...

reaction catalyzed via Lipozyme RM IM and pine nut oil. Lipase-catalyzed esterification reactions leading to the development of Δ⁵-fatty acids can be achieved in solvent-free conditions using water-

jacketed vessel In chemical engineering, a jacketed vessel is a container that is designed for controlling temperature of its contents, by using a cooling or heating "jacket" around the vessel through which a cooling or heating fluid is circulated. A jacket is ...

Phylogenetic significance in gymnosperms

Sciadonic acid and several other Δ⁵-olefinic acids are found to be relatively abundant in

gymnosperm The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, '' Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμν ...

s. ''

Setaria verticillata ''Setaria verticillata'' is a species of grass known by the common names hooked bristlegrass, rough bristle-grass and bristly foxtail. It is native to Europe, but it is known on most continents as an introduced species and often a noxious weed. I ...

'' seeds and their fatty acid compositions allow for distinction between different Coniferophytes such as species from families such as

Cupressaceae Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdio ...

and

Taxodiaceae Taxodiaceae is a formerly recognized coniferous plant family comprising the following ten genera: *'' Athrotaxis'' *''Cryptomeria'' *'' Cunninghamia'' *†'' Cunninghamites'' *'' Glyptostrobus'' *''Metasequoia'' *'' Sciadopitys'' *'' Sequoia'' * ...

. Sciadonic acid is a distinctive fatty acid that shows presence in the oils of seeds, leaves, and woods of

conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ex ...

s. Indicating that plant families can be characterized by the fatty acid composition of their seed, leaves, and wood oils.

Health implications

Eicosanoid Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, around 20 carbon units in length. Eicosanoids are a su ...

s and metabolites found to be biologically active have correlated to tumor progression by several mechanisms such as interruption of

cell signaling In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellula ...

. In humans,

fatty acid desaturase A fatty acid desaturase is an enzyme that removes two hydrogen atoms from a fatty acid, creating a carbon/carbon double bond. These desaturases are classified as: * Delta - indicating that the double bond is created at a fixed position from the ...

s, FADS 1,2 and 3 are

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

coding genes found in chromosome 11q13, in which alterations can be attributed to several types of

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bl ...

s such as breast, ovarian and cervical cancer. In particular, the FADS2 enzyme, responsible for Δ⁶ 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

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 E₂. Reduction of pro-inflammatory mediator molecules also occurs in murine macrophages, regulating the activation of NF-κΒ and MAPK pathways.

References

{{Fatty acids Fatty acids Polyunsaturated compounds