Preparation And Antioxidant Performance Of Micro-nanocarriers Loaded With Polyphenols

Free radicals can cause skin aging and organ diseases,which seriously threaten the health of the human body.Antioxidants are effective free radical scavengers,but they have the disadvantages of low solubility,easy degradation of light,and easy discoloration,which limit their use on the skin,so it is very important to improve their stability and bioavailability.In addition,the mechanism of action of antioxidants is more complicated,and there may be better results after mixing two or more kinds.Nanoemulsions have excellent structural characteristics and can be better moisturized and penetrated on the skin surface.The carrier technology mainly encapsulates the functional ingredients in the inner core structure to improve the solubility and stability,but the specific location of the functional ingredients and the impact on the properties of the emulsion are still not very clear;in addition,the stability of the emulsion is also a problem to be solved.The addition of liquid lipidsin nanostructured lipids will prevent the carrier matrix from forming a perfect lattice,resulting in more defects,and more functional ingredients can be incorporated.Compared with nanoemulsions,nanostructured lipid carriers can stabilize the functional components more firmly and have a higher loading capacity.Both carrier technologies have the advantages of low toxicity,drug protection,and slow release.Based on the above research background,this paper mainly uses nanoemulsion and nanostructured lipid carrier to encapsulate resveratrol and phenethyl resorcinol,in order to improve the chemical stability,antioxidant properties of active polyphenols and stability of the carrier,the following three aspects have been carried out:1.The phase transition component method was used to prepare a blank nanoemulsion and a polyphenol loaded nanoemulsion.The effects of emulsification temperature,surfactant compounding ratio,oil-to-surfactant ratio and other factors on the particle size and stability of the blank emulsion were discussed;the change in the characteristic peak of the fluorescence spectrum confirmed that resveratrol was encapsulated in the lipophilic environment of the emulsion.The physical stability of the polyphenol loaded nanoemulsion was investigated from the three aspects of storage time and temperature,centrifugation and high and low temperature cycle experiments.DSC results confirm that oil phase crystallization is the main reason for emulsion freeze-thaw instability.The chemical stability and oxidation resistance of resveratrol and phenethyl resorcinol were analyzed by UV-Vis and EPR,and it was confirmed that the active polyphenols encapsulated in nanoemulsion have better photostability and anti-oxidation.Resveratrol has a stronger ability to scavenge free radicals than phenethyl resorcinol,and the combined effect of the two is better.2.The effect of the addition of resveratrol and phenethyl resorcinol on the stability of the emulsion was studied,mainly from three aspects of mass ratio,temperature and ionic strength,and the antioxidant effects of the two active polyphenols were further explored.Resveratrol and phenethyl resorcinol will work together with the surfactant to stabilize the emulsion.The increase in temperature increases the stability and oxidation resistance,while the increase in ionic strength significantly reduces the emulsion stability and oxidation resistance.Combine the above content,it is speculated that the active polyphenols mainly exist in the hydrophobic core of the emulsion,and may also be distributed in a small amount at the oil-water interface and in the aqueous micelles.3.The solvent diffusion method was used to prepare resveratrol nanostructured lipid carrier with biodegradable PEG-40 hydrogenated castor oil as a surfactant.The effects of solid-liquid lipid ratio,surfactant content,and resveratrol addition on the average particle size and polydispersity index of lipid carrier were investigated,and the regular spherical morphology of lipid carrier was determined by TEM.Characterization methods such as FTIR,DSC and XRD confirmed that resveratrol was encapsulated in the lipid carrier and confirmed the amorphous lattice structure inside the lipid carrier.The lyophilized powder obtained after lyophilization of the lipid carrier has a good ability of reconstitution.