Study on the physicochemical properties and antibacterial mechanism of precipitation in baicalin and berberine hydrochloride
Objective The substances produced by traditional Chinese medicine through the self-precipitation phenomenon have special properties and development potential.This paper takes the precipitation produced by baicalin and berberine hydrochloride as the research object,explores its physical and chemical properties,and studies its antibacterial effect and mechanism.Methods The physical and chemical properties of the preipitation were determined by differential scanning calorimetry,infrared spectroscopy scanning,and ultraviolet spectroscopy scanning.The antibacterial activity of baicalin,berberine hydrochloride and precipitation against Escherichia coli and Staphylococcus aureus was studied by Oxford cup method.The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of baicalin,berberine hydrochloride and precipitation against Escherichia coli and Staphylococcus aureus were further studied by double dilution method,and the antibacterial mechanisms of baicalin,berberine hydrochloride and precipitation against Escherichia coli and Staphylococcus aureus were studied by measuring the growth curve of the bacterial body,the relative content of extracellular nucleic acid,the content of extracellular soluble protein and electrical conductivity.Then,the changes in antibacterial mechanisms of baicalin and berberine hydrochloride were analyzed and compared before and after the reaction.Results The results of differential scanning calorimetry showed that there was a heat change before and after the reaction of berberine hydrochloride with baicalin.The precipitation was a new substance different from berberine hydrochloride and baicalin,and its functional groups and UV absorption changed.Berberine hydrochloride,baicalin,and precipitation have different antibacterial activities and mechanisms.In general,berberine hydrochloride has the best antibacterial activity,followed by self precipitation,and baicalin is relatively weak.The MIC of berberine hydrochloride against Escherichia coli was 0.9375 mg/mL,and the MBC was 7.5 mg/mL;The MIC against Staphylococcus aureus was 0.9375 mg/mL,and the MBC was 7.5 mg/mL.The MIC of baicalin against Escherichia coli was 1.875 mg/mL,and the MBC was 7.5 mg/mL;The MIC against Staphylococcus aureus was 3.75 mg/mL,and the MBC was 15 mg/mL.The MIC and MBC of precipitation against Escherichia coli were 3.75 mg/mL and 3.75 mg/mL,respectively;The MIC against Staphylococcus aureus was 3.75 mg/mL,and the MBC was 3.75 mg/mL.The three substances had significant inhibitory effects on the growth of Escherichia coli and Staphylococcus aureus,but their mechanisms of action varied.Conclusion The three substances that showed good antibacterial activity against Escherichia coli and Staphylococcus aureus,from strong to weak,were berberine hydrochloride,baicalin,and precipitation.All of them changed their permeability by damaging the bacterial cell membrane,affecting bacterial growth,and thereby inhibiting bacterial growth.Although the three substances could cause a large amount of exudation from the bacterial body,there were differences in the release of intracellular substances.The research results provided a reference for further understanding the precipitation of traditional Chinese medicine.
NETL
NSTL
万方数据
