Submitted to: Japan Oil Chemists' Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: October 27, 2000
Publication Date: N/A
Technical Abstract: Here we report a lipase-catalyzed route to ferulyl-substituted structured lipids. These lipids have been engineered to function as an all natural sunscreen, possessing the proper ultraviolet (UV) absorbance (290-375 nm) of a ferulyl moiety and the water-insolubility of a lipid. The synthesis of this sunscreen is industrially attractive since the transesterification is conducted neat, without the use of solvents, at moderate temperatures, and removal of the enzyme/support after the reaction by simple filtration. Several commercial lipases were screened to determine which possessed the greatest propensity to catalyze the esterification of ferulic acid and the alcoholysis of ethyl ferulate (ethyl 4-hydroxy-3-methoxy cinnamate) with alcohols. The stirred batch reactions were performed under inert atmospheres in t-butanol and toluene at temperatures between 25 deg and 80 deg C. Enzyme activity was determined to be dependent on the water content of the reaction with near anhydrous conditions affording the greatest enzyme activity. The transesterification of ethyl ferulate was accomplished without solvents under similar reaction conditions using mono and triacylglycerols or vegetable oil. The synthesis with vegetable oil afforded a 78% yield of the UV-absorbing lipids resulting in 24% (wt) active ingredient in the reaction mixture. The sun protection factor (SPF) of the reaction mixture diluted to 15% UV-absorbing lipids was 10.2 while the mixture proved to be photo-stable over hours of UV exposure, retaining a SPF of 8.0. Efforts to conduct similar experiments using supercritical carbon dioxide as the reaction media have also been attempted.