Preparation Of Compound Quercetin Nanoemulsion And Its Compatibility Mechanism Research

Objective:Based on Mongolian Medicine Sendeng-4,the compound nanoemulsion was prepared with four quality control components of"quercetin,toosendanin,tannin and geniposide"as raw materials.The compatibility mechanism of compound nanoemulsion was investigated through safety inspection,in vivo and in vitro antibacterial and immune regulation experiments.Methods:1)The raw materials of nanoemulsion were screened by phase transformation method,and the formula was optimized by pseudo-ternary phase diagram.The morphology of nanoemulsion was observed by TEM（transmission electron microscope）,and the zeta potential,PDI（polydispersity index）and particle size distribution were measured by nanoparticle size analyzer.The stability of the nanoemulsion was investigated by centrifugation,illumination acceleration and room temperature storage.2)The drug loading of the nanoemulsion was determined by HPLC（high performance liquid chromatography）.3)Determined the MIC（minimum inhibitory concentration）and MBC（minimum bactericidal concentration）of the aqueous solution and nanoemulsion of quercetin,toosendanin,tannin and geniposide by the double dilution method.The combined antibacterial activity of toosendanin,tannin,geniposide and quercetin was studied by broth dilution checkerboard method.4)Through the acute toxicity experiment in mice,the safety of oral administration of quercetin,tannin,geniposide and blank nanoemulsion was investigated.In vivo antibacterial activities of quercetin suspension,quercetin nanoemulsion and blank nanoemulsion were compared to establish a mouse model of abdominal infection（systemic infection）.Kunming mice were given intragastric administration for 21 days,and the immunomodulatory effect of quercetin and its nanoemulsion were explored through the lymphatic transformation rate and the phagocytosis rate of peritoneal macrophages.Results:1)Compound quercetin nanoemulsion formula:m（quercetin）:m（tannin）:m（geniposide）:m（ethyl acetate）:m（Tween-80）:m（absolute ethanol）:m（distilled water）=0.14:0.068:0.15:4.5:20:10:65.14,nanoemulsion is clear and transparent,with good stability,average particle size is 19.6nm,zeta potential is-0.2mv,PDI is 0.052.2)Quercetin,tannin,and geniposide in the compound quercetin nanoemulsion have good linearity within the detection concentration range of 10.90～109.00μg·ml^-1,6.30～63.00μg·ml^-1,0.12～0.72mg·ml^-1,respectively.The average recovery rates were 99.62%、100.26%and 99.48%,and the maximum drug loads were 5.96mg·m L^-1,38.65 mg·m L^-1and 247.92 mg·m L^-1,respectively.3)Compared with geniposide,quercetin and tannin showed stronger antibacterial activity in vitro.When quercetin and tannin were combined with quercetin,the antibacterial effect was synergistic against E.coli（Escherichia coli）,S.aureus（Staphylococcus aureus）and P.aeruginosa（Pseudomonas aeruginosa）,respectively,while geniposide and quercetin showed antagonistic effect.4)According to the grade of acute toxicity test dose and the performance of animals after medication,it was determined that quercetin was safe,geniposide was slightly toxic,tannin was low toxic,and its toxicity needed to be further studied.With the increase of quercetin dose,the survival time of mice infected with E.coli was prolonged and the mortality rate was decreased.Quercetin can enhance the immune function of mice by enhancing the phagocytic function of peritoneal macrophages an improving the lymphocyte conversion rate.Conclusion:The compound quercetin nanoemulsion prepared in this study has high stability and meets the quality requirements of nanoemulsion.Preparation of nanoemulsion can obviously improve the solubility of quercetin and enhance its antimicrobial and immune pharmacological effects.The experimental study found that the antibacterial activity of geniposide was lower in vitro compared with other components,and the combined antibacterial activity of geniposide and quercetin showed antagonistic effect.Therefore,it is necessary to further explore other pharmacological effects and explain the compatibility mechanism of Mongolian Medicine Compound Sendeng-4,so as to provide a new research idea for the development of Mongolian Medicine.