Lipophilization of phenolic acids with phytosterols by a chemoenzymatic method to improve their antioxidant activities

Abstract

In this study, a two‐step method for chemoenzymatic lipophilization of phenolic acids with phytosterols was studied. Optimal conditions for esterification involved the use of a binary solvent containing hexane and 2‐butanone (3 mL, 8:2, v/v), a relatively equal molar ratio of vinyl ester to phytosterols (0.1 mmol), and 100 U/mL of lipase from Candida rugosa at 55°C. Various phenolic acids were used, but only ten of them were successes. Their antioxidant activities were evaluated by total oxidation (TOTOX) value and thiobarbituric acid reactive substances (TBARS) value. Phytosteryl 4‐hydroxybenzoate, phytosteryl vanillate, and phytosteryl ferulate showed potential for use as food antioxidants. Practical applications: There is increasing interest in the development of antioxidants from natural sources because of the concerns about the safety of synthetic antioxidants. Lipophilization of phenolic acids was carried out to improve the hydrophobicity and change the antioxidant capacity of phenols. This study focuses on phytosterol, which is a food‐grade mixture of steroid compounds, having development and application potential as a cost effective food additive. According to our results, phytosteryl phenolates, which are defined as esters between phytosterols and phenolic acids, have the potential for use as alternative food antioxidants in the food industry. The lipophilization of phenolic acids with phytosterols was carried out via a two‐step chemoenzymatic route as the figure showed. The intermediate vinyl esters were first chemically produced and subsequently esterified with phytosterols catalyzed by lipase from Candida rugosa.

Enzymatic synthesis of steryl hydroxycinnamates and their antioxidant activity

“…But applying the C. antarctica lipase A in similar conditions as published earlier , lead to a yield of 21.3% of steryl phloretate (Table ). It has been stated before that the double bond in the side chain improves the yield, for transesterification of vinyl phenolates with sterols by C. rugosa lipase . In another study it has been shown that in a solvent‐free system p ‐coumaric acid was esterified more efficiently to 1‐octanol by C. rugosa lipase, compared to ferulic acid .…”

Effect of novel synthesised policosanyl phenolates on lipid oxidation

“…(Xi'an, China (Wang et al 2015a). All reagents used in this study were analytical grade and were purchased from Sigma-Aldrich Korea (Korea).…”

“…Various phenolic esters have been synthesised using fatty alcohols or acids (Whitaker et al 2001;Sørensen et al 2012). Recently, various phytosteryl phenolates have also been synthesised and have shown excellent antioxidant capacities in lipids (Tan & Shahidi 2011, 2013Fu et al 2014;Wang et al 2015a).…”

Stability of Sun Creams Formulated with Thermal Spring Waters from Ourense, Northwest Spain

“…The primary oxidation of lipids was analyzed through the index of peroxides (PV) [30] and secondary oxidation (PA) by p-anisidine value according to the AOAC procedure [31]. Total oxidation of the creams was calculated by the TOTOX index, calculated as PA + 2 PV [32] and defined the overall oxidation state.…”