9,11,13octadecatrienoic acid

9(E),11(E),13(E)-Octadecatrienoic acid (β-ESA) is a conjugated polyunsaturated fatty acid that is found in plant seed oils and in mixtures of conjugated linolenic acids synthesized by the alkaline isomerization of linolenic acid. It reduces growth of Caco-2 colon cancer cells in a dose-dependent and time-dependent manner. In vitro, β-ESA induces DNA fragmentation and upregulation of pro-apoptotic Bax mRNA. β-ESA decreases protein expression of the apoptosis suppression factor Bcl-2 and induces apoptosis in T24 bladder cancer cells via production of reactive oxygen species. It also inhibits bacterial fatty acid dioxygenase with a Ki value of 49 nM in vitro.

alpha-Eleostearic acid (cis-eleostearic acid) is a conjugated fatty acid present in Anemone seeds and can be used as a chemical taxonomic marker for Anemone.

9(Z),11(E),13(E)-Octadecatrienoic Acid ethyl ester (α-ESA) is a conjugated polyunsaturated fatty acid commonly found in plant seed oil. This fatty acid accounts for about 60% of the total fatty acid composition of bitter gourd seed oil and about 70% in tung oil. α-ESA is metabolized and converted to conjugated linoleic acid (9Z,11E-CLA) in rats. It has shown potential as a tumor growth suppressor. In colon cancer Caco-2 cells, α-ESA induced apoptosis through up-regulation of GADD45, p53, and PPARγ. In DLD-1 cells supplemented with α-ESA, apoptosis was induced via lipid peroxidation with an EC50 of 20 μM. It also inhibits DNA polymerases and topoisomerases with IC50s ranging from ~5-20 μM for different isoforms of the enzymes. α-ESA ethyl ester is a neutral, more lipid soluble form of the free acid.