Study of thermodynamic properties and intermolecular forces in the formation of aqueous aggregation of Arachidonic acid

Arachidonic acid is a 20-carbon fatty acid with four non-conjugated cis-double bonds.This fatty acid participates in cell signaling as a secondary messenger [1,2]. The thermodynamic properties and intermolecular forces of its molecular aggregation were estimated by the GROMACS software [3] with gromos96 43a1 force field at 300K. Arachidonic acid solvation in water occurs during two processes: 1) hydration of every molecule individually and then 2) formation of molecular aggregation. Changes in both enthalpy and entropy are negative (Fig. 1), indicating that the formation of molecular aggregates has a dominant contribution. The formation of hydrogen bonding between the polar heads of the molecules as well as between the polar heads of the molecules and water molecules plays an important role in the formation of the micelle. The number of hydrogen bonds is seven for each molecule. In addition, polar interactions between polar heads of molecules and also van der Waals interactions between hydrophilic tails play important roles in the formation of its micelle.