Design and straightforward synthesis of novel galloyl phytosterols with excellent antioxidant activity

Abstract

Novel galloyl phytosterols were rationally designed by incorporation of gallic acid into phytosterols through straightforward esterification. The esterification was successfully achieved by coupling of gallic acid and phytosterols through a mild chemical Steglich esterification reaction that is more straightforward than the enzymatic method. The identity of the newly synthesized galloyl phytosterols was confirmed by NMR, HPLC-MS and IR spectroscopies. Further evaluation of the novel galloyl phytosterols with radical scavenging, ferrous ion chelating, and Rancimat methods revealed its excellent antioxidant activities that are comparable to the most potent fat-soluble antioxidants. This novel antioxidant offers an intriguing solution for naturally derived antioxidants and will have great potential application as antioxidant in food industry. The methods developed in this study will be valuable for development of other phenolic phytosterols.

Keywords: Antioxidant activity; Gallic acid; Galloyl phytosterol; Phenolic phytosterol; Phytosterol; Steglich esterification.