Structure-property influence on the amphiphilicity of phenolipids

Phenolipids are amphiphilic antioxidants having both hydrophilic phenolic moiety and hydrophobic molecules. Alkyl esters of phenolic acids are the main known phenolipids. These compounds can be considered as potential replacements for synthetic antioxidants such as butylated hydroxyanisole or butylated hydroxytoluene commonly used in the fat industry. Therefore, it is desirable to better understand of physicochemical properties of phenolic acid esters.

The aim of this work was the estimation of lipophilicity of some phenolipids, p-hydroxycinnamic acid derivatives, especially sinapic acid alkyl esters. The lipophilicity was expressed as partition coefficient (Log P) and measured by shaking-flask methods. Additionally, the obtained results were compared with calculated data in the ALOGPS 2.1.

The examination of the data allows concluding that the lipophilicity increases with the elongation of alkyl chain length of phenolipids. Significant increases in hydrophobic properties of the synthesized phenolic acid esters were observed in comparison with the parent compounds. Additionally, the effect of substitution in the aromatic ring of the phenolic acid was associated with Log P.

The lipophilic properties of phenolipids are crucial to applying them in the food, cosmetic, and pharmaceutical industries.