Studies On Antimicrobial Activity And Material Basis Of The Ilicis Chinensis Folium

The bacterial resistance becomes a serious threat to human beings and the bacterial resistance develops faster than the discovery of new antimicrobial agents.Therefore,discovery of antibacterial components from Traditional Chinese Medicine opened up an important way for new antibiotics discovery.Ilicis Chinensis Folium(sijiqing),as dried leaves of IIlex chinensis Sims,has the effects of heat-clearing and detoxicating,etc.Some modern pharmacological studies have demonstrated its wide pharmacological functions,such as antibacterial and anti-inflammatory effects.However,there is no report about the material basis of antibacterial activity of Ilicis Chinensis Folium.This thesis mainly includes the following parts:The concentration of quercetin,protocatechuic and chlorogenic acid of IIlex Chinensis Sims leaves were measured by HPLC.The concentration in the leaves from Hebei is relatively high,whereas the leaves from Henan is relatively low.The minimum inhibitory concentration of quercetin,protocatechuic,chlorogeniand caffeic acid against MSSA,MRSA,KE+,KE-and P.Aeruginosa were detected using agar2-fold dilution method.The MIC value,> 128 μg/ml,showed insignificant antibacterial activity.Furthermore,antibacterial activity did not be further improved by mixing the 4compounds.The minimum inhibitory concentration of Sijiqing tablet and Ilicis Chinensis Folium water decoction against MSSA,MRSA,KE+,KE-and P.Aeruginosa were detected by agar2-fold dilution method.The MIC value,>2048μg/ml,showed insignificant antibacterial activity.Ilicis Chinensis Folium decoction without dilution was used to test against MSSA,MRSA,KE+,KE-and P.Aeruginosa for antibacterial effects.The strains were partly inhibited,which indicated that the high concentration of Ilicis Chinensis Folium water decoction showed limited antibacterial activity.Ilicis Chinensis Folium water decoction from different areas showed similar MIC values against the strains.Compared with the concentration of quercetin,protocatechuic and chlorogenic acid in Ilicis Chinensis Folium,it was found that their antibacterial activity against Escherichia coli was possibly correlated to the concentration of these components.Ilicis Chinensis Folium water decoction,Sijiqing tablet solution,protocatechuic acid and chlorogenic acid was respectively mixed with blank plasma of beagle.The MIC values of the mixtures were detected after incubated in the 37℃ water bathe for different periods.The MIC value was not significantly changed compared with those of groups without incubation.The combined treatment of Ilicis Chinensis Folium water decoction with cefotaxime,gentamicin and levofloxacin showed additive effects against Staphylococcus aureus and Escherichia coli,but no synergistic reaction.The Ilicis Chinensis Folium water decoction from different areas exhibited strong antiendotoxin effect and showed similar antiendotoxin efficacy.The minimum concentration against endotoxin of Ilicis Chinensis Folium water decoction,protocatechuic acid and chlorogenic acid were 0.00625g/ml,1mg/ml and 5mg/ml,respectively.Results of in vivo experiments in mice showed that the LD50 of Ilicis Chinensis Folium decoction on mice was 3.6g/kg,and the 95% confidence interval was(2.219-5.635)g/kg.Ilicis Chinensis Folium decoction had no significant effect on the mortality of mice after infection but it showed anti-inflammatory effects.In summary,this thesis would provide clues and strategies for the research and development of antibacterial Traditional Chinese Medicine.