Preparation And Biological Activity Of Zein-Pectin Core/Shell Nanoparticles Loaded With Resveratrol

Natural polyphenols Resveratrol is widely found in a variety of plants and has a range of healthy and beneficial effects,such as antioxidant,cardiovascular protection,prevention of neurodegenerative diseases,and anticancer effects.However,because of low water-soluble,poor stability,rapid metabolism in the body and other defects,the biological effects of resveratrol are greatly limited.The use of nano-delivery system to encapsulate resveratrol helps to overcome these shortcomings and improve bioavailability.Nano-delivery system based on zein is a hotspot in recent years.Zein,which isoelectric point is about pH 6.2,is the main storage protein of maize,containing more than 50% non-polar amino acids(leucine,alanine and proline).The fact that zein is soluble in high concentrations of ethanol aqueous solution but insoluble in water making it suitablely encapsulate hydrophobic drugs and nutrients.Nevertheless zein is prone to aggregation in the near-neutral pH due to hydrophobic interaction.In this paper,zein-pectin core/shell nanoparticles loaded with resveratrol was prepared by antisolvent method and electrostatic deposition method,using zein as core and natural anionic polysaccharide pectin as wall material.Conditions for the preparation of resveratrol nanoparticles were determined by morphological structure,particle size and?-potential,loading characteristics.The effects of pH,temperature,ionic strength and long-term storage on the stability of resveratrol nanoparticles were investigated.The biological activities of resveratrol after encapsulation were explored by antioxidant activity and cytotoxicity experiments.At the same time the in vitro digestion and the antioxidant properties after digestion of the transport system were studied.The results were as follows:1.Pectin concentration can affect the stability of resveratrol nanoparticles.When the pectin concentration was 0.055%,stable nanoparticles could be formed.The size of the nanoparticles was about 220 nm and the ?-potential was around-28 mV.Electron microscopy showed that the nanoparticles were spherical and uniform in size.When the content of resveratrol in the nanoparticles was 7.49%,the highest particle yield and loading efficiency of the nanoparticles were obtained,97.59% and 86.38%,respectively.2.The stability of the composite nanoparticles mainly depended on strong electrostatic repulsion and steric repulsion.At pH 2-7,especially near the isoelectric point of zein(pH 6.5),the nanoparticles could keep steady without large particles precipitate.At pH 4,the nanoparticles could resistant to 80? for 1 h,and no large particles were seen at high sucrose concentrations(10% w/v),but the solution precipitated when the salt concentration reached to 70 mM.No significant change in particle size for resveratrol nanoparticles stored at 4? for 28 days.After freeze-drying,the samples could be easily dissolved in distilled water to form clear liquid,which indicated a good redispersibility.3.The results of in vitro antioxidant experiments showed that the scavenging ability of resveratrol free radicals was enhanced.Compared to un-encapsulated resveratrol,a better iron ion reduction force was also found when the concentration of resveratrol reached 200 ?g/m L.MTT assay displayed that the inhibitory effect of resveratrol nanoparticles on human hepatocellular carcinoma Bel-7402 cells was time-dependent and dose-dependent.The IC50 values of resveratrol nanoparticles were lower than that of free resveratrol whether treating 24 hours or 48 hours.After encapsulated,tumor cell proliferation could be inhibited at 10 ?M of resveratrol.4.The simulated gastrointestinal digestion experiment showed that the release rate of resveratrol was higher than that of resveratrol mixtures or free resveratrol at different time points.After digestion,the bioaccessibility of resveratrol nanoparticles was 77.07%,while the bioavailability of resveratrol mixture was 55.70% and pure resveratrol was 59.82%.The DPPH free radical scavenging experiment revealed that the resveratrol nanoparticles had strongest scavenging capacity(SC50=35.10 ?M)after simulated digestion.Although the SC50 of ABTS radical scavenging rate was nonsignificant different compared to that of resveratrol mixtures(35.04 ?M,38.58 ?M,respectively),it was still lower than that of free resveratrol(59.71 ?M).Therefore,the zein-pectin core/shell nanoparticles loaded with resveratrol prepared in this study have a good application prospect.