Transformation And Study On The Nano-preparation Of Baicalin

Scutellaria baicalensis georgi is a traditional Chinese medicine with bactericidal function.Its main ingredients are baicalin and baicalein.Studies have shown that baicalein is the active ingredient that exerts its effects.This paper focuses on improving the efficacy of Scutellaria baicalensis georgi and establishing the rapid determination method of baicalin and baicalein.Firstly,the optimization of the enzymatic hydrolysis conditions for the conversion of baicalin into baicalein was carried out.Second,baicalein can quench the room-temperature phosphorescence(RTP)of PEI-Mn/Zn S QDs through baicalein can produce electron transfer effect by electrostatic interaction with PEI-Mn/Zn S QDs,and baicalin can quench the room temperature fluorescence of Cd Te QDs,so,rapid method for the determination of baicalin and baicalein were established.And on that basis,further studies showed that QDs could improve the antibacterial activity of baicalin.Finally,the preparation of baicalin nanoparticles was used to improve the efficacy of the drug in the body.The obtained experimental results have a good reference value for the further development and application of Scutellaria baicalensis georgi.The details are as follows:(1)The conversion of baicalin to baicalein and its conversion rate were studied by using neutral methanol extract from Scutellaria baicalensis.Useing enzymatic decomposition(cellulase and pectinase)and UV Spectrophotometry,taking baicalin conversion rate as an index,the best technology of baicalin conversion was obtained by controlling single factor test and response surface.The order of influence of different factors is as follows: temperature< time < concentration of cellulase < p H,among which p H has the most significant effect on the result.The optimal extraction process was obtained by combining the response surface optimum process with the actual operation:p H = 5,the concentration of cellulase was 32 U/g,the time was 6.5 h,and the temperature was 50?.This method is simple and rapid,and has a good guiding effect on the production of crude drugs.(2)It is known that baicalin as an electron acceptor and PEI-Mn/Zn S QDs as an electron donor,baicalein can quench the room-temperature phosphorescence(RTP)of PEI-Mn/Zn S QDs through baicalein can produce electron transfer effect by electrostatic interaction with PEI-Mn/Zn S QDs.Based on that,a relatively simple and fast phosphorescence method for the detection of baicalein(BAI)was established.PEI-Mn/Zn S QDs were prepared by water-phase coprecipitation method.The experimental results showed that the degree of phosphorescence quenching of QDs had a linear relationship(r = 0.997)with concentration of BAI in the range of 0.07-0.60 mg/L when p H value of 8.0 and reaction time of 10 min.The detection limit is 0.039 mg/L,the relative standard deviation is 4.1%,and spiked recoveries from practical sample are in the range of 96.0%-100.7%.The established method could effectively avoid the interference of common ions and amino acids,etc.and could be used for the rapid determination of BAI in scutellaria baicalensis georgi and serum,which is expected to be applied to the determination and analysis of BAI in medicine industry.It also provides a technical basis for the detection of other drugs based on quantum dot electron transfer mechanism.(3)Both QDs and phenolic compounds have certain antibacterial properties,so it is necessary to improve their antibacterial activity.Cd Te QDs were mixed with baicalin and theophylline,and their fluorescence intensity was determined.In the mixture of baicalin and QDs,baicalin quenched the fluorescence of QDs,and the quenching degree was related to the concentration of baicalin.The linear equation was P0/P = 0.0279 C + 0.9126(mg/L),the linear correlation coefficient R = 0.993,and the detection limit was 0.038 mg/L.No fluorescence quenching was observed in theophylline-QDs.By comparing the damage degree of Escherichia coli by mixed culture and microscope,we concluded that baicalin-QDs mixture could enhance its antibacterial activity,but theophylline-QDs mixture had no significant effect on its antibacterial activity.Therefore,Cd Te QDs can be mixed with baicalin to produce antimicrobial agents with stronger antibacterial activity.(4)Baicalin chitosan nanoparticles were prepared by coagulation method and their properties were analyzed.A single-factor experiment was designed to investigate the influence of stirring speed,time,chitosan,chitosan solution p H and baicalin mass ratio on the preparation of nanoparticles.Taking the encapsulation rate as the evaluation index,the optimization scheme was obtained by response surface analysis.The optimal solution for the preparation of baicalin nanoparticles was 700 r/min rotating speed,20 min stirring time,p H = 4 of chitosan solution,mass ratio of chitosan to baicalin 4:1.This method is simple and practical to prepare baicalin nanoparticles.The baicalin nanoparticles obtained have regular shape and full morphology,and have certain application value in pharmaceutical field.