New phenophospholipids equipped with multi-functionalities: Regiospecific synthesis and characterization.

ABSTRACT

HYPOTHESIS: In multi-phase systems, many complex reactions take place at the interface where a molecule equipped with manifold functionalities is demanded. By taking advantage of the surface-active property of phosphatidylcholine (PC) scaffold and antioxidant properties of phenolic acids, new multifunctional molecules are generated, which are expected to confer physical and oxidative stability to sensitive bioactive ingredients in delivery systems. EXPERIMENTS This work reports a successful synthesis of two new arrays of phenophospholipids sn-1-acyl(C12-C18)-sn-2-caffeoyl and sn-1-caffeoyl-sn-2-acyl phosphatidylcholines via mild scalable regiospecific pathways; as structurally verified by MS, 1H/13C NMR analyses, and characterized by critical micelle concentrations (CMC), FTIR, and DSC analysis. Synthesized phenophospholipids are subjected to stabilizing o/w emulsion, and antioxidation tests as demonstrated by TBARS (Thiobarbituric Acid Reactive Substances) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays. FINDINGS: This study has demonstrated that; (1) phenophospholipids with a broad spectrum of CMC are created, affording superior emulsion stability than soybean PC; (2) all phenophospholipids present improved oxidation inhibition and sn-2-caffeoyl phenophospholipids display superior performance to sn-1-caffeoyl phenophospholipids, soybean PC or admixture of caffeic acid and soybean PC; (3) incorporation of caffeoyl in PC scaffold does not sacrifice radical scavenging ability of caffeic acid, whilst the ion chelating capacity of sn-1-myristoyl(C14)-sn-2-caffeoyl PC enhance by 4.5 times compared to soy PC. Fluorescence Microscopy imaging verified the location of phenophospholipids in the interface as desired. Among synthetic phenophospholipids, sn-1-myristoyl(C14)-sn-2-caffeoyl PC commits the cut-off effect in most desired functionalities, which might be of great potential for multi-purpose applications.