Novel Synthesis of Steryl Esters from Phytosterols and Amino Acid

Abstract

The feasibility of esterification of phytosterol with the amino acid l-glutamic acid was established. The influence of various organic solvents was investigated, and n-butanol was selected as an ideal solvent for phytosteryl esters synthesis with l-glutamic acid. The reaction conditions were further optimized by orthogonal experiments, and a 92.3% degree of esterification was obtained when optimum conditions were used. FT-IR spectral, GC-MS, and NMR analyses were adopted to determine the steryl esters of l-glutamic acid. The FT-IR spectrum indicated the presence of ester bonds in the phytosteryl esters with l-glutamic acid, and on the basis of the detailed mass spectrography analysis, GC-MS and NMR offered an efficient and reliable way to confirm the steryl esters. This novel synthesis approach of phytosteryl esters with amino acid supplied a promising alternative to the substrate on esterification of phytosterols and thus can be readily applied to further studies of functional food ingredients of phytosteryl esters.

Romanian Viscum album L.—Untargeted Low-Molecular Metabolomic Approach to Engineered Viscum–AuNPs Carrier Assembly

“…In addition, the peaks at 1622, 1371, 1258, 1114, and 660 cm −1 were found in the synthesized AuNP solution (Figure 3a) and are shifted to higher wavenumbers (1641, 1382, 1267, 1153 and 671 cm −1 ), indicating binding of nanoparticles to the functional groups O-H, C=O, C-N, C-S, and C-O belonging to the various phytoconstituents (Figure 3a,b and Table 3) [79][80][81][82][83][84][85][86][87][88][89][90][91]. In particular, the hydroxyl group is considered to be involved in the binding of AuNPs [85][86][87][88][89][90][91][92][93][94][95][96][97][98]. 3) [79][80][81][82][83][84][85][86][87][88][89][90][91].…”

Plant Sterols: Chemical and Enzymatic Structural Modifications and Effects on Their Cholesterol-Lowering Activity

“…107 Hossen et al synthesized a new phosphatidyl derivative of plant sterols (phosphatidyl sitosterols) using phosphatidyl choline as a modifier via an enzymatic process catalyzed by phospholipase D. 108 Pang et al investigated the feasibility of esterification of plant sterols with L-glutamic acid, finding the esterification could reach 92% under optimum conditions. 109 Yuan et al synthesized ten β-sitosterol esters using Nphosphoryl amino acids as an acyl donor, and the yield reached 60−87% by employing dicyclohexylcarbodiimide (DCC)/ DMAP as a catalyst system under microwave irradiation. 110 He et al established an efficient two-step chemoenzymatic method to synthesize plant stanol hydrophilic derivatives (plant stanol sorbitol succinate) using D-sorbitol as a hydrophilic modifier.…”

Mild and Efficient Preparation of Phytosteryl Amino Acid Ester Hydrochlorides and Their Emulsifying Properties

“…Recently, some researchers have attempted to prepare emulsified water-soluble phytosterols, which could potentially increase their absorption, show improved effects on cholesterol and lipid profile, and indicate increased dose response in food systems. − However, oil-in-water phytosterol microemulsions, nanodispersions, and nanoliposomes are limitedly used in food products because of their poor stability, which affects the product quality. , Improving water solubility of bioactives can accelerate the speed of going into the tissues and enhance the absorbance rate in the body. For this reason, some other researchers pay attention to the synthesis of water-soluble phytosteryl derivatives, which are much more stable, such as phytostanyl sorbitol succinate and phytosteryl l -glutamic esters. , However, through repeated trials, it was unsuccessful to adopt the one-step method to synthesize steryl esters from phytosterols and amino acid using sodium bisulfate as a catalyst and n -butanol as a solvent . The reason was probably that amino acids were poorly soluble or even insoluble in most organic solvents, and a high temperature still could not promote the dissolution.…”

“…For this reason, some other researchers pay attention to the synthesis of water-soluble phytosteryl derivatives, which are much more stable, such as phytostanyl sorbitol succinate and phytosteryl L-glutamic esters. 29,30 However, through repeated trials, it was unsuccessful to adopt the one-step method to synthesize steryl esters from phytosterols and amino acid using sodium bisulfate as a catalyst and n-butanol as a solvent. 30 The reason was probably that amino acids were poorly soluble or even insoluble in most organic solvents, and a high temperature still could not promote the dissolution.…”

“…29,30 However, through repeated trials, it was unsuccessful to adopt the one-step method to synthesize steryl esters from phytosterols and amino acid using sodium bisulfate as a catalyst and n-butanol as a solvent. 30 The reason was probably that amino acids were poorly soluble or even insoluble in most organic solvents, and a high temperature still could not promote the dissolution. As a result, the above-mentioned one-step method was infeasible.…”