Preparation And Anti-allergic Activity Of Quercetin Liposomes

Quercetin is a kind of flavonoid widely found in plants,which exists in the form of glycosides in food.Quercetin is an important dietary source of flavonoids.The study shows that quercetin has many important biological activities such as antioxidant,anti-inflammatory,anti-allergy and anticancer activities,which has great applications in pharmacological research.However,quercetin is easy to be oxidized to produce quercetin o-quinone,and the stability is poor.Therefore the bioavailability of quercetin is low,limiting its clinical environment.And the application is somewhat limited.The liposome is a class of nanovesicles with low toxicity and high biocompatibility,which is a kind of very promising delivery system.Liposomes can effectively improve the stability and absorption rate of drugs in vivo,so as to improve the efficacy of drugs.In this paper,quercetin liposomes were prepared,and the stability and anti-allergy effects of free quercetin and quercetin liposomes were compared.The main findings are as follows:1.Quercetin liposomes were prepared by the thin-film dispersion method.The concentration of quercetin,p H of solvent,the ratio of phosphatidylcholine and cholesterol were selected as three univariate factors.The optimal process formulation was determined by the single-factor and response surface optimization method.After verification,the results predicted by the response surface model were consistent with the actual results.The optimal formulation was quercetin concentration of 0.14 mg/m L,the phosphatidylcholine-cholesterol ratio of 7.8:1mg/mg,PBS p H of 6.8.The final encapsulation rate of liposomes was 65.82±1.35%.The particle size was 192.1±3.24nm and the polydispersity index（PDI）was 0.137,respectively.2.By comparing the effects of temperature,light,and metal ions on quercetin and quercetin liposomes,it was found that the preservation rate of free quercetin and quercetin liposomes increased with temperature.The dark environment is better suitable for storage.The order of influence of metal ions on both was Fe³⁺>K⁺>Ca²⁺.Moreover,the stability of quercetin liposomes was higher in all the above conditions,indicating that the embedding of lipids played a protective effect on quercetin.In addition,the release rate of quercetin liposome was lower than that of quercetin in simulated gastric and intestinal fluid experiments,indicating that quercetin has a certain sustained-release effect.The hyaluronidase inhibition test showed that quercetin had better enzymatic activity than free quercetin,whose effect was close to that of positive control（dipotassium glycyrrhizinate）.3.In the cell degranulation assay,the levels of cell degranulation markers and inflammatory factors were measured after the induction of compound 48/80.The results showed that quercetin and liposomes could reduce the release rate of hexosamine and histamine,inhibit calcium influx,and reduce the levels of inflammatory factors IL-4,IL-8,and MCP-1.The quercetin group had better acellular degranulation than the free quercetin.There were significant differences between both the liposome and quercetin groups in the determination ofβ-hexosaminidase,histamine,and inflammatory factors.