An octadecatrienoic acid is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with formula , a

polyunsaturated fatty acid In biochemistry and nutrition, a polyunsaturated fat is a fat that contains a polyunsaturated fatty acid (abbreviated PUFA), which is a subclass of fatty acid characterized by a backbone with two or more carbon–carbon double bonds. Some polyunsa ...

whose molecule has an 18-

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

unbranched backbone with three double bonds. The name refers to many different

structural A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...

and

configurational isomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in ...

s, that differ in the position of the double bonds along the backbone and on whether they are in ''cis'' (''Z'') or ''trans'' (''E'') configuration. Some isomers have considerable biological, pharmaceutical, or industrial importance, such as: *

α-Linolenic acid α-Linolenic acid, also known as ''alpha''-linolenic acid (ALA) (from Greek ''alpha'' denoting "first" and ''linon'' meaning flax), is an ''n''−3, or omega-3, essential fatty acid. ALA is found in many seeds and oils, including flaxseed, ...

(9''Z'',12''Z'',15''Z''), found in many

cooking oil Cooking oil (also known as edible oil) is a plant or animal liquid fat used in frying, baking, and other types of cooking. Oil allows higher cooking temperatures than water, making cooking faster and more flavorful, while likewise distributing h ...

s * γ-Linolenic acid (6''Z'',9''Z'',12''Z''), found in the evening primrose (''Oenothera biennis'') *

Pinolenic acid Pinolenic acid (often misspelled as pinoleic acid) is a fatty acid contained in Siberian Pine nuts, Korean Pine nuts and the seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called ...

(5''Z'',9''Z'',12''Z''), found in the seeds of pines (''

Pinus A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as c ...

'' species) * Columbinic acid (5''E'',9''Z'',12''Z''), found in ''

Thalictrum ''Thalictrum'' () is a genus of 120-200 species of herbaceous perennial flowering plants in the buttercup family, Ranunculaceae, native mostly to temperate regions. Meadow-rue is a common name for plants in this genus. ''Thalictrum'' is a taxon ...

'' seed oils * α-Eleostearic acid (9''Z'',11''E'',13''E''), the main component of

tung oil Tung oil or China wood oil is a drying oil obtained by pressing the seed from the nut of the tung tree (''Vernicia fordii''). Tung oil hardens upon exposure to air (through polymerization), and the resulting coating is transparent and has a d ...

, produced from the nuts of

tung tree ''Vernicia fordii'' (usually known as the tung tree (, ''tóng'') and also as the tung-oil or tungoil tree (), the kalo nut tree, and the China wood-oil tree) is a species of flowering plant in the Euphorbiaceae, spurge family Euphorbiaceae. It i ...

(''Vernicia fordii'') *

β-Eleostearic acid β-Eleostearic acid, or (9''E'',11''E'',13''E'')-octadeca-9,11,13-trienoic acid, is an organic compound with formula or H3C(CH2)3(CH=CH)3(CH2)7COOH. It is an all-''trans'' isomer of octadecatrienoic acid. See also * α-Eleostearic acid, the ...

(9''E'',11''E'',13''E'') * Catalpic acid (9''E'',11''E'',13''Z''), found in the seeds of yellow catalpa (''Catalpa ovata'') and

southern catalpa ''Catalpa bignonioides'' is a short-lived species of ''Catalpa'' that is native to the southeastern United States in Alabama, Florida, Georgia, Louisiana, and Mississippi. Common names include southern catalpa, cigartree, and Indian bean tree It ...

(''Catalpa bignonioides'') * Punicic acid (9''Z'',11''E'',13''Z''), found in

pomegranate The pomegranate (''Punica granatum'') is a fruit-bearing deciduous shrub in the family Lythraceae, subfamily Punica, Punicoideae, that grows between tall. Rich in symbolic and mythological associations in many cultures, it is thought to have o ...

(''Punica granatum'') seed oil * α-Calendic acid (8''E'',10''E'',12''Z''), found in the

pot marigold ''Calendula officinalis'', Mary's gold, common marigold, the pot marigold, Scotch marigold, or ruddles, is a flowering plant in the daisy family, Asteraceae. It is probably native to southern Europe, but its long history of cultivation makes its ...

(''Calendula officinalis'') * β-Calendic acid (8''E'',10''E'',12''E''), found in the pot marigold (''Calendula officinalis'') in small or trace amounts, less than 2% of total lipids * Jacaric acid (8''Z'',10''E'',12''Z''), found in the blue jacaranda (''Jacaranda mimosifolia'')

References

{{chemistry index Fatty acids Alkenoic acids