Study On The Preparation Of Ursolic Acid /β- Cyclodextrin Inclusion Complex By Ultrahigh Pressure

Ursolic acid(UA) belong to triterpenic acid, which have many kinds of biological activities, such as anti-cancer, anti-liver injury, anti-bacterial, anti-inflammatory, anti-virus, hypoglycemic, etc. It has received an universal attention in medicine, health food and cosmetics, etc. Whereas, Ursolic acid also has some shortages in practical applications: the low solubility lead to the low bioavailability. Ursolic acid, through includingβ-cyclodextrin(β-CD)'s, which can significantly improve the physicochemical and biological properties of Ursolic acid .The formation of inclusion complex was mainly based on the weak interaction force between host and guest, as ultra-high pressure may affect the interactions between host and guest .Therefore,the ultra–high pressure makes this possible. Therefore, in this paper,take ursolic acid as the guest, Inclusion complex of ursolic acid withβ-cyclodextrin was prepared by the ultra-high pressure method. Study the inclusion effect and formation mechanism through comparing with the ursolic acid/β-cyclodextrin(UA/β-CD) under atmospheric preparation such as grinding method, ultrasonic method, mixing method and so on.First ,prepare ursolic acid/β-cyclodextrin respectively in ultra-high pressure and atmospheric pressure,characterized by IR, XRD, DSC, SEM. Analyze formation mechenism of the ursolic acid/β-cyclodextrin from thermodynamics angle furtherly,and use Materials Studio on molecular simulation of ursolic acid/β-cyclodextrin. The results are as follows:(1)IR analysis show that several characteristic peak of ursolic acid in inclusion complex spectrum changed obviously;XRD analysis show that two sharp diffraction peak's strength(2θ=5.48?,14.48?)of ursolic acid in inclusion complex spectrum decreased obviously or disappeared.DSC show the position of most inclusioin complex endothermic peak move in the direction of high temperature .Fluorescence spectrum analysis shows that ursolic acid fluorescence intensity were significantly enhanced as theβ- cyclodextrin to join .All show that guest molecule are included by host molecular, the SME obviously show the formation of the new object.(2)The inclusion complex ofβ-cyclodextrin and ursolic acid in ultra-high pressure and atmospheric pressure conditions is in the ration of 1:1,the formation of inclusion complex increase the ursolic acid in water solubility,that is, formed Solubilization effect .The K constants increase with the increasing of temperature. Through calculation, all enthalpy changeΔH0 and entropy changesΔS0 determined were positive, all Ginns free energeΔG0 were negative,it suggests that the inclusion interaction was endothermic reaction and spontaneously occurred by balance of hydrophobic force and Van der Waals' force opposed.(3)The most stable conformation of the inclusion complex is the hydroxyl end upwords and carboxyl end downwards for ursolic acid,which passes through in to the cavity ofβ-cyclodextrin and form hydrogen bond between ursolic acid andβ-cyclodextrin.Simulation system in water environment, total energy and potential energy by 500Mpa pressure condition is lower than it by atmospheric pressure condition which shows that pressurized makes system more stable, but system density is bigger than it by atmospheric pressure condition which shows that pressure compressed the system and reduced system volume.