Tribehenin, also known as glyceryl tribehenate, is a saturated very-long-chain triacylglycerol (TAG) composed of three behenic acid (docosanoic acid, C22:0) chains esterified to a glycerol backbone. Derived from rapeseed and peanut oils, this lipid extends the saturated TAG series beyond triarachidin, and is valued for its ultra-high melting point and its structuring role in cosmetics and pharmaceutical formulations.

Chemical Structure

Tribehenin has the molecular formula C69H134O6 and a molecular weight of 1059.8 g/mol. Its symmetric sn-glycerol core, bearing three straight-chain behenoyl groups at the sn-1, sn-2, and sn-3 positions, confers extreme hydrophobicity (XLogP3 31.7) and a high number of rotatable bonds (68). These features promote rigid β-crystalline packing and slow lipase hydrolysis, characteristic of long-chain C22 TAGs.

Physical Properties

Tribehenin is a white to off-white powder or crystalline solid with a melting point of 83°C and a density of 0.899 g/cm³. Its predicted boiling point is approximately 912°C, with a flash point of 322°C. The compound is sparingly soluble in chloroform or DMF (around 10 mg/mL with sonication) but remains insoluble in water. Its high molecular complexity (1070) and topological polar surface area (TPSA 78.9 Ų) contribute to its ability to form gels without unwanted crystallization.

Biological Functions

Tribehenin is slowly hydrolyzed into behenic acid, a fatty acid known to enrich sphingolipids and support myelin sheath composition. Due to its long-chain structure, tribehenin provides prolonged energy storage in specialized fats and is metabolized more gradually than shorter-chain TAGs, offering sustained metabolic support.