Trieicosapentaenoin (also known as 1,2,3-trieicosapentaenoyl glycerol or glyceryl trieicosapentaenoate) is a highly polyunsaturated triacylglycerol (TAG) composed of three eicosapentaenoic acid (EPA, C20:5 n-3, all-cis-5,8,11,14,17) chains esterified to a glycerol backbone. Found in fish oils and algal lipids, this ultra-long-chain omega-3 TAG represents the culmination of the PUFA series from trilinolenin and is valued for its cardiovascular protective potential, despite its pronounced oxidative instability.

Chemical Structure

Trieicosapentaenoin has the molecular formula C63H92O6 and a molecular weight of 945.4 g/mol. Each eicosapentaenoyl chain contains five cis double bonds, resulting in a highly unsaturated conformation with a total of 15 double bonds. This extreme degree of unsaturation confers a very high lipophilicity (logP ~18.8) and makes the molecule particularly susceptible to lipid peroxidation due to multiple bis-allylic positions.

Physical Properties

Trieicosapentaenoin is typically described as a yellow, low-viscosity liquid with a predicted melting point below -20°C and an approximate density of 0.93 g/cm³. Because of its high oxidative sensitivity, it requires storage at -80°C under inert conditions. It is soluble in organic solvents such as chloroform and ethanol but remains immiscible in water. Its InChI encoding reflects the all-Z configuration, supporting its use as a reference standard in LC-MS and ion mobility spectrometry applications.

Biological Functions

Upon hydrolysis by lipases, trieicosapentaenoin releases EPA, a key anti-inflammatory precursor involved in the biosynthesis of resolvins and protectins. Through these pathways, EPA contributes to endothelial health, reduces platelet aggregation, and lowers triglyceride levels via activation of PPARα signaling. Compared with alpha-linolenic acid (ALA) conversion from trilinolenin, EPA derived from this TAG form is significantly more bioavailable and biologically active.