Researches On The Ultrasonic-assisted Extraction And Preparation And Antioxidant Activity Of Soybean Isoflavone Aglycones

Soybean isoflavone is a kind of secondary metabolites in the process of soybeangrowth, which belongs to the polyphenolic compounds. Form of isoflavones in soybean isthe glycosides and free aglycones, and the glycosides accounted for97%-98%of the total,while the free aglycone accounted for only2%-3%. Isoflavones have many biologicalactivities, the isoflavone aglycone is the main active component, but the content of the freeaglycone is very low. The extraction of soybean isoflavone aglycone and refining hasbecome a research hotspot in resent years. This paper put focus on the extraction ofsoybean isoflavone from soybean meal and its purification and detection of antioxidantactivity of soybean isoflavone aglycone. In this paper, there were mainly three contents:1. The study on isoflavone aglycones hydrolysis method and Optimization of processconditions.Three kinds of method were established for extracting soybean isoflavone aglycones bysingle factor and orthogonal design method in this paper:1.1Two-phase system of ultrasonic assisted hydrolysis, the optimum process conditions asfollow: ultrasonic time75min, temperature60℃, and the aglycone extraction rate is0.091%.1.2Two-phase system of ultrasonic assisted enzymatic hydrolysis, the optimum processconditions as follow: ultrasonic time60min, temperature45℃, amount of enzyme10U, pH5,and aglycone extraction rate is0.2138%.1.3Two-phase system ultrasound-assisted acid hydrolysis, the optimum process conditionsas follow: ultrasonic time75min, temperature55℃, concentration of hydrochloric acid1.5mol/L, and aglycone extraction rate is0.1815%.Comparing three methods, method of two-phase system of ultrasonic assistedenzymatic hydrolysis is best and of which extraction rate is the highest. The results showedthat its extraction conditions are more moderate and efficient.2. The study on isoflavone aglycone in purified preparation and determination.2.1The macroporous resin chromatography was used to purify the aglycone crude firstly.The oil, protein, inorganic salt and other sticky impurities were removed by washingwith the mobile phase system, which is higher polar ethanol-water mix system, in theways of gradient eluted program. Then silica gel column chromatography was used tofurther purify aglycone. The mobile phase was identified by TLC.2.2Aglucone purification of the final results detected by HPLC is68.53%, of which24.58%of daidzein, glycitein1.32%, genistein42.63%.3. The study on antioxidant activity of isoflavone aglycone.3.1The optimum concentration of H₂O₂induced PC12cells injury which used to establishinjuried model was detected from two aspects of cell morphology and cell survival rate.The experimental results showed that the optimum concentration of H₂O₂is150μmol/L, and the cellular damage effect is remarkable, and the injuried model is stability.3.2The injured model of PC12cells by H₂O₂was established to detect the aglyconeantioxidant activity. The experimental results showed that the aglycone performed agood activity. And the cell model is stable and reliable.