Microwave (MW) promoted high yield expedient synthesis of steryl ferulates – A class of novel biologically active compounds: A comparative study of their antioxidant activity with that of naturally occurring γ-oryzanol

Synthesis of Steryl Hydroxycinnamates to Enhance Antioxidant Activity of Rapeseed Oil and Emulsions

“…Steryl ferulates (FA esters of sterols) are bioactive compounds identified in an inner pericarp and aleurone layer of cereals grains such as: rice, wheat, rye, corn, and triticale. The mixture of steryl ferulates: 4,4′-dimethyl sterol esters 24-methylenecycloartanyl ferulate and cycloartenyl ferulate naturally present in rice is known as γ-oryzanol, while desmethylsterols (sitosterol, campesterol and their saturated forms, stanols) are dominated in other cereals [ 6 , 7 , 8 , 9 , 10 ]. Moreover, steryl caffeates (campesterol and cycloartenol caffeates) as well as steryl sinapate (24-methylenecholesteryl sinapate) were found in various rice varieties [ 11 , 12 , 13 ].…”

“…It is known that structural variations of phytosteryl esters affect their antioxidant activity (AA) [ 16 ]. Currently, different analytical methods: 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), cupric reducing antioxidant capacity (CUPRAC), oxygen radical absorbance capacity (ORAC), β-carotene bleaching, and reducing power assay have been used for analysis of antioxidant properties of phytosteryl esters [ 4 , 6 , 16 , 20 , 21 , 22 , 23 ]. However, degradation products and oxidative stability of edible oils enriched with phytosteryl esters were analyzed using chromatographic methods and Rancimat test, respectively [ 15 , 16 , 23 ].…”

“…In general, chemical, enzymatic or chemoenzymatic esterifications, and transesterification have been often proposed for the synthesis of phytosteryl esters of fatty acids, whereas the esterification of phytosterols with phenolic acids were reported only by some authors [ 4 , 6 , 7 , 8 , 16 , 20 , 21 , 22 , 23 ]. Recently, microwave and ultrasound irradiations have been successfully applied in esterification of phytosteryl esters [ 6 , 24 ].…”

“…In general, chemical, enzymatic or chemoenzymatic esterifications, and transesterification have been often proposed for the synthesis of phytosteryl esters of fatty acids, whereas the esterification of phytosterols with phenolic acids were reported only by some authors [ 4 , 6 , 7 , 8 , 16 , 20 , 21 , 22 , 23 ]. Recently, microwave and ultrasound irradiations have been successfully applied in esterification of phytosteryl esters [ 6 , 24 ]. Steryl ferulates were synthesized by different pathways, while an enzymatic and chemoenzymatic methods for esterification of phytosterols with CA, CouA, SA, and vanillic acid (VA) were mainly used [ 4 , 6 , 7 , 8 , 16 , 20 , 21 , 22 , 23 ].…”

“…Recently, microwave and ultrasound irradiations have been successfully applied in esterification of phytosteryl esters [ 6 , 24 ]. Steryl ferulates were synthesized by different pathways, while an enzymatic and chemoenzymatic methods for esterification of phytosterols with CA, CouA, SA, and vanillic acid (VA) were mainly used [ 4 , 6 , 7 , 8 , 16 , 20 , 21 , 22 , 23 ].…”