Synthesis Process Of Phytosterol Derivatives

Phytosterol is similar to cholesterol in structure and has physiological effects such as hypolipidemic,anticancer and anti-inflammatory.However,its insolubility in water and insolubility in oil limits its application in food and medicine.To improve its solubility,this study chemically modifies phytosterols and establishes a common assay method for phytosterols and their derivatives.For the modification study of oil-soluble phytosterol esters,firstly,by comparing the catalytic efficiency of the ionic liquid BSO₃HMim HSO₄,lipase Novozym 435 and dodecylbenzenesulfonic acid（DBSA）on phytosterol esters of oleic acid,it was found that DBSA has a high conversion rate for the reaction at a relatively mild reaction temperature（60℃）,so DBSA was chosen as the catalyst for the esterification reaction of oleic acid and phytosterol Therefore,DBSA was selected as the catalyst for the esterification reaction of oleic acid and phytosterol,and the reaction temperature was 60℃,the acid-alcohol ratio was 3:1,and the proportion of DBSA was 7.5%,and the reaction equilibrium was reached at 12h,at which the conversion was 89.88%.The reaction was carried out with fatty acids of different carbon numbers under the optimized conditions.The physicochemical properties of the resulting phytosterol esters of oleic acid after the reaction system was extracted,decolorized by activated carbon and molecular distillation were in accordance with the standards,and the products were structurally characterized.For the synthesis of water-soluble phytosterol esters,the route was designed to generate the intermediate productβ-sitosterol hemisuccinate,and then react with hydrophilic substances such as PEG 1000,sorbitol and hyaluronic acid.During the synthesis ofβ-sitosterol hemisuccinate,the effect of nine commercial ionic liquids and homemade ionic liquids on the reaction ofβ-sitosterol hemisuccinate was compared,and it was confirmed that the homemade ionic liquid Ch Cl·Sn Cl₂had catalytic activity on the reaction,but there was still a big difference in the conversion rate than that of commercial ionic liquids.Among the commercial ionic liquids,the highest conversion rate was catalyzed by BSO₃HMim HSO₄,and the sterol conversion rate was up to97%at the reaction temperature of 110℃,the acid-alcohol ratio of the substrate was 1.5:1,the added ionic liquid was 10%of the sterol mass,and the substrate concentration was 100 mmol/L for 6 h.Theβ-sitosterol hemisuccinate was extracted with ice-dilute hydrochloric acid and water,and the excess anhydride in the reaction system could be removed without column chromatography and other methods.Three routes for the reaction ofβ-sitosterol hemisuccinate with hydrophilic substances:First,β-sitosterol hemisuccinate and PEG 1000 are catalyzed by immobilized lipase to produce water-soluble phytosterol esters.The reaction temperature was 50°C,the PEG molar ratio was twice that of phytosterol esters,and the maximum conversion was up to 35%at 30%lipase addition.Secondly,DES（Ch Cl:sorbitol=1:1）was tried as the reaction medium,and the esterification reaction ofβ-sitosterol hemisuccinate with sorbitol was carried out under the catalysis of ionic liquid.Thirdly,the crude product of the reaction between theβ-sitosterol hemisuccinate and hyaluronic acid was tested by GPC,and the heavy average molecular weight Mw of the measured sample changed from 7468 to 8065,which initially indicated that the reaction grafting ofβ-sitosterol hemisuccinate and hyaluronic acid was successful and laid the foundation for the subsequent synthesis of water-soluble sterol esters.Based on the CAD,a universal detection method for phytosterols and their derivatives was established:a C18 column（5μm,4.6 mm×150 mm）was used,methanol:formic acid=1000:1 as the mobile phase,the flow rate was set to 0.6 m L/min,the column temperature was set to 30℃,the atomization temperature was set to 30℃,the power rate was 3.6,the sampling frequency was 5 Hz,the filtration constant was 4 s,and the nitrogen flow rate was 0.6 m L/min,and the nitrogen flow rate was 0.6 m L/min.Based on this condition,the separation of phytosterols andβ-sitosterol hemisuccinate could be achieved with a flat baseline.Under the optimized conditions,the methodological validation was performed for the determination of stigmasterol,cholesteryl stearate,cholesteryl hemisuccinate.