| Neohesperidin is a flavonoid containing methoxyl group,which has a wide range of biological activities.However,due to poor water solubility,unstable chemical properties and easy degradation,the bioavailability and biological activity are reduced,which seriously limits its application as a nutrient and medicine.Embedding hydrophobic active substances in food macromolecule transport system is a way to improve the solubility and bioavailability of hydrophobic active substances.At present,nanotechnology is rarely applied to the preparation of neohesperidin-food macromolecule carriers.Therefore,the construction of novel nanoparticle food system can promote the stabilization of natural and green food nanoparticle system,and provide new ideas and new means for the nutritional enhancement of hydrophobic nutrients or active factors such as neohesperidin.In this paper,the interaction between neohesperidin and cyclodextrin,lipids and proteins to form nanoparticles was systematically studied.On the basis of traditional experiments,combined with the method of computer simulation,the interaction mechanism between them was further clarified.The main contents are as follows:1.The inclusion effect of cyclodextrin cavity hydrophobicity on the insoluble small molecule nehesperidin(NH)was explored.The binding ability ofβ-cyclodextrin(β-CD)、Hydroxypropyl-β-cyclodextrin(HP-β-CD)、2,6-dimethyl-β-cyclodextrin(DM-β-CD)、Sulfobutyl-β-cyclodextrin(SBE-β-CD)、γ-cyclodextrin(γ-CD)、Hydroxypropyl-γ-cyclodextrin(HP-γ-CD)to neohesperidin(NH)was analyzed by phase solubility test using NH as a model.The results showed that HP-β-CD had the best solubilizing effect.Then,the inclusion complex of NH-HP-β-CD was prepared by freeze-drying method in aqueous solution.The physicochemical properties and binding mechanism of NH-HP-β-CD inclusion complex were analyzed.The results showed that the phase of NH-HP-β-CD complex was significantly changed,NH was completely dispersed into HP-β-CD in an amorphous state,and they were bonded by hydrogen bond or van der Waals force.By inclusion of HP-β-CD,the solubility of NH in 37℃water was increased from 161.81μg/m L to 1096.17μg/m L,and the solubility of NH were significantly improved.2.The effect of meglumine(MEG)on the complexation efficiency of hydroxypropyl-β-cyclodextrin(HP-β-CD)was found that it could greatly improve the water solubility of NH(5.81 mg/m L).NH、MEG、HP-β-CD ternary inclusion complex was prepared by physical mixed solvent co-evaporation method.The inclusion complex was characterized by Differential scanning calorimetry(DSC)、Fourier transform infrared spectroscopy(FT-IR)and powder X-ray diffraction(PXRD).The mechanism of inclusion interaction between the subject and the object was established by Nuclear magnetic resonance hydrogen spectrum(~1H-NMR)and molecular docking simulation.On the basis of preliminary screening study,MEG was found to be the most effective cosolvent to solve the problem.DSC and PXRD results showed that the crystallinity of NH changed obviously,indicating the formation of a new solid form.The presence of MEG significantly increased the apparent stability constant(Kc)and the complexation efficiency(CE)of HP-β-CD,and the solubility and dissolution of NH as well.Molecular simulation studies also confirmed that the addition of MEG can form more stable complexes.3.The neohesperidin liposome(NH-CP、NH-CP-CD)was successfully prepared by ultrasonic method and ethanol precipitation method by combining phospholipid compound technology with HP-β-CD inclusion technology.The average particle size of the prepared liposome was lower and the distribution was uniform,and the morphology was spherical.By FTIR and PXRD analysis,the diffraction peak of NH crystal disappeared completely,indicating that NH was successfully dispersed in liposomes in molecular form.There was intermolecular force at the polar end of NH molecule and phospholipid.NH-PC and NH-PC-CD complex could significantly improve the solubility of NH.The solubility of NH-PC and NH-PC-CD in water was increased to 321.77μg/m L and 318.75μg/m L,which was 2.01 and 1.99 times of the corresponding free drugs.The encapsulation rates of NH in NH-PC and NH-PC-CD complexes were 96.52±2.15%and 95.62±1.17%,respectively.The in vitro release studies showed that60.81%and 80.78%of NH were released from NH-PC and NH-PC-CD,respectively,and non-Fick diffusion was the main release mechanism of the both.The in vitro simulated gastrointestinal digestion studies showed that NH-PC and NH-PC-CD could significantly improve the absorption of NH and the bioaccessibility of NH liposomes was NH-PC-CD>NH-PC,so the stability of NH liposome was related to the composition of the carrier.This study has certain guiding significance for the design of lipid food delivery system for embedding functional food.4.In order to prove that ovalbumin(OVA)can be used as a carrier of NH,OVA-NH nanoparticles were formed from OVA and NH by p H-shifting method,and their binding mechanism was investigated by multispectral thermodynamics and molecular docking simulation.The results showed that the concentration of NH affects the encapsulation efficiency,load and particle size of OVA-NH nanoparticles.In addition,NH had obvious fluorescence quenching effect on OVA.The secondary structure of OVA and NH complexes changed significantly after the formation of OVA and NH complexes.The results of isothermal titration showed that hydrophobic interaction and hydrogen bonding had important effects on the formation of OVA and NH complexes.The molecular docking results showed that van der Waals forces and hydrogen bonds contributed to the free binding energy of the complex.There were multiple possible surface binding sites between OVA and NH.The results provide a new idea for exploring the interaction mechanism between OVA and NH.OVA,as a carrier of NH,has a broad application prospect in functional food.5.OVA-NH prepared by free radical induced grafting had higher grafting rate.The grafting degree andζpotential were measured,and the mass ratio of NH to OVA was determined to be0.5:1,which was the best ratio.By introducing Arabic gum(GA),the polyelectrolyte complex(PEC)of OVA-NH and GA was prepared by electrostatic interaction.When the mass ratio of GA-CS to GA was 4:1 and the p H value was 3.0,the particle size of the nanoparticles was 112.2nm,and the nanoparticles were the most stable.The potential changes of OVA-NH and OVA-NH/GA in simulated gastrointestinal environment were investigated.It was found that the presence of GA improved the colloid stability of the complex.The bioaccessibility of NH in OVA-NH and OVA-NH-GA samples were 63.98%and 72.78%,respectively,which were significantly higher than NH(20.85%).The bioavailability of NH was improved by the addition of GA. |
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