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Steryl ferulates synthesised from commercial sterols as well as commercial oryzanol were used to better understand how structural features affect antioxidant activity in vitro by the ABTS(+) radical decolorization assay, by oxidative stability index (OSI) of soybean oil, and by analysis of antioxidant activity during frying. Steryl ferulates inhibited the ABTS(+) radical by 6.5-56.6%, depending on their concentration, but were less effective, especially at lower concentrations, than ferulic acid. Ferulic acid and steryl ferulates had either no effect, or lowered the OSI of soybean oil by up to 25%, depending on the concentration. In their evaluation as frying oil antioxidants, steryl ferulates with a saturated sterol group had the best antioxidant activity, followed by sterols with one double bond in the C5 position. The results indicate that a dimethyl group at C4 as well as a C9,C19 cyclopropane group, as found in oryzanol, negatively affects antioxidant activity in frying oils., (Published by Elsevier Ltd.)

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., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Phytosterols and their derivatives have attracted much attention because of their health benefits to humans and are widely used in food, pharmaceuticals, and cosmetics in the past decades. While most of the research has focused on free phytosterols and phytosteryl esters of fatty acids, few researches reported on phytosteryl phenolates, the esters of phytosterols with phenolic acids. Two novel group phytosteryl phenolates, namely phytosteryl sinapates and vanillates, were successfully chemoenzymatically synthesised in this work and their structures confirmed. Fourier transform infrared (FTIR) and high performance chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS) using atmospheric pressure chemical ionisation (APCI) under both positive and negative ion modes were employed for this purpose. High antioxidant capacity of phytosteryl sinapates was observed using both oxygen radical absorbance capacity (ORAC) assay and cooked ground meat model system. Although phytosteryl vanillates showed lower antioxidant capacity than phytosteryl sinapates, they were stronger antioxidants than vanillic acid and vinyl vanillate in both assays employed. Conjugation of phytosterols with sinapic or vanillic acid rendered higher antioxidant capacity. Further studies on health benefits of phytosteryl sinapates and vanillates are necessary., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Phytosterols and phytostanols are known to lower low-density lipoprotein-cholesterol (LDL-C) levels in humans by up to 15%, and at least two products, Benecol and Take Control, are now on the market as naturally derived fatty acid esters of phytostanols (stanol esters) and phytosterols (sterol esters), respectively. A synthetic process was developed to synthesize gram quantities of trans-feruloyl-beta-sitostanol from ferulic acid and beta-sitostanol, with high purity and yields of approximately 60%. The process involves (a) condensation of trans-4-O-acetylferulic acid with the appropriate phytostanol or phytostanol mixture in the presence of N,N-dicyclohexylcarbodiimide and 4-(dimethylamino)pyridine, (b) separation of the trans-4-O-acetylferuloyl products by preparative liquid chromatography, (c) selective deacetylation of the feruloyl acetate, and (d) chromatographic purification of the feruloylated phytostanols. The process was successfully applied to synthesize stanol trans-feruloyl esters from "Vegetable Stanols", a mixture of approximately 70:30 beta-sitostanol and beta-campestanol, in comparable purity and yield.