Phenolic Esters Synthesis And Antibacterial Activity

Natural phenolic acid compounds mainly made of phenyl propenoid acid (C6-C3) or benzoic acid (C6-C1) derivatives.They have a wide range of physiological activity, such as anti-oxidation, removal of free radicals, anti-ultraviolet radiation, antibacterial and antiviral effect and been used in medicine, pesticides, cosmetics and food additives and other area. The strong hydrophilic property of phenolic compounds restricted their applications in some extent. In this dissertation, the phenolic compounds were modified by the esterification with long chain fatty alcohols to increase lipophilicity. The purpose of the study was to increase the lipophilicities and enlarge the applications of these compounds.The phenolic acid compounds with hydroxyl and carboxyl groups were not easy to esterify with high yields. In order to increase the yield of esterification, the acids, alkali, DDC, thionyl chloride, as well as enzyme were screened. The optimized conditions are as follows: the molar ratio of phenolic acid and fatty alcohol was 1:2, the molar ratio of catalyst p-toluenesulfonic acid and phenolic acid was 2:1, the dioxane was used as the solvent and refluxing 10h at 120℃. A series of gallic acid alkyl esters and ferulic acid alkyl esters were synthesized using these conditions.The antibacterial activities of the synthetic compounds were evaluated on escherichia coli, staphylococcus aureus, pseudomonas aeruginosa. The most synthetic compounds have shown the strong inhibitory effect on staphylococcus aureus. The strongest one is iso-army gallic ester.