ABSTRACT
In this study,in order to detect the antimicrobial activity of artemisinin and its derivatives artesunate and dihydroartemisinin,two methods including broth dilution and plate punching method were used to detect the antibacterial activity against gram-negative bacteria(Escherichia coli)and gram-positive bacteria(Staphylococcus aureus)of artemisinin,dihydroartemisinin and artesunate at various concentrations within 5 mmol·L~(-1)and at four time points(8,16,24,32 h).Two antibacterial positive drugs,streptomycin against E.coli and penicillin against S.aureus,were used as positive controls.Plate punching method showed that,unlike the results of 5 mmol·L~(-1)dihydroartemisinin or artesunate,no inhibition zone was detected at the same concentration of artemisinin after 24 h-treatment against E.coli.Broth dilution method showed that,the antibacterial activity of dihydroartemisinin against E.coli.was stronger than those of both artesunate and artemisinin;IC_(50)at24 h-treatment was 155.9μmol·L~(-1)for dihydroartemisinin,370.0μmol·L~(-1)for artesunate and none for artemisinin.Interestingly,dihydroartemisinin and artesunate showed the strongest antibacterial activity between 16-24 h,while artemisinin showed relatively stronger antibacterial activity between 8-16 h.Dihydroartermisinin showed no antibacterial activity against S.aureus.Above all,the antibacterial activity of artemisinins against E.coli is dihydroartemisinin>artesunate>artemisinin.Artemisinin and its derivatives have showed different antibacterial kinetics,and no antibacterial activity against S.aureus.has been detected with dihydroartemisinin.
Subject(s)
Anti-Bacterial Agents , Pharmacology , Artemisinins , Pharmacology , Artesunate , Pharmacology , Escherichia coli , Microbial Sensitivity Tests , Staphylococcus aureusABSTRACT
Objective To investigate the bacteriostatic effect of 4 kinds of traditional Chinese herbal medicine on extensively drug‐resistant A .baumannii(XDRAB) bacteriostatic effect ,find a new way for the clinical treatment of the XDRAB infection .Meth‐ods The minimal inhibitory concentrations(MICs) of scutellaria ,forsythia ,rhizoma coptidis ,honeysuckle were determined by using broth two‐fold dilution method .Results The mean values of MICs of scutellaria ,forsythia ,rhizoma coptidis ,honeysuckle were 30 .99 ,187 .50 ,27 .61 and 75 .00 mg/mL ,respectively .Among the 4 kinds of traditional Chinese herbal medicines ,rhizoma coptidis got the strongest antimicrobial effect strongest inhibitory effect .There was no significant difference in the inhibitory effect of the strains collected from local or nonlocal(P>0 .05) .Conclusion The 4 kinds of Chinese herbal medicine had in vitro antibacterial ac‐tivity to XDRAB in different degree.
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Objective To analyze the inhibition effect of antimicrobial peptide human βdefensin 3 (hBD3 )against methicillin resistant Staphylococcus aureus (MRSA)N31 5.Methods Antimicrobial peptide hBD3 was synthesized.The direct inhibition on N31 5 was detected by the MIC (minimal inhibitory concentration,MIC)test,antibacterial activity test and the analysis on some important functional genes.The peptide was combined with penicillin,tetracycline,cephradine, rifampin,vancomycin,cefuroxime and chloramphenicol to evaluate the effects on antibiotic MIC values.Results The MIC of hBD3 against N31 5 was 8 μg/mL and the bactericidal activity was observed while the hBD3 concentration reached 2 μg/mL.The peptide hBD3 could improve the expression of agr and reduce the expression of icaA.With 5 μg/mL peptide hBD3,the MIC values against N31 5 of penicillin,cephradine,vancomycin,cefuroxime and chloramphenicol were dropped down.Conclusion There is considerable bactericidal activity of antimicrobial peptide hBD3 against MRSA N31 5. Antibiotic peptide hBD3 could be used to prevent the spread of antibiotic resistant bacteria in the future.
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OBJECTIVE To investigate the in vitro antibacterial effect of Asi-antidiarrheal capsule a Chinese herbal compound on hyperthyroid diarrhea.METHODS It was determined by drug dilution method in test tube to determine Asi-antidiarrhea capsule.The compound positive control drug was diphenoxylate co.We made in vitro antibacterial test with 8 kinds of bacteria respectively.RESULTS Asi-antidiarrhea capsule had powerfully bacteriostatic action on Shigella dysenteriae,Staphylococcus aureus and Streptococcus pneumoniae(MIC31.25 mg/L).But diphenoxylate co contrally was less effective on S.aureus,Str.pneumoniae,Str.pyogenes and Sh.dysenteriae(MIC 0.25 mg/L).CONCLUSIONS Asi-antidiarrhea capsule can be used to hyperthyroid diarrhea.Meanwhile,it has powerfully antibacterial effect.It provides evidence of pharmacodynamics for healing infectious diarrhea in the future.
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Objective To prepare the preparation of ginkgolic acids gel and to study its antibacterial activity in vitro.Methods The gel was prepared with ginkgolic acids as main component and with Carbopol 940 as base material.The content of ginkgolic acids in the gel was determined by high performance liquid chromatography and the minimum inhibitory concentration (MIC) of the gel against staphylocococus aureus and propionibacteria was measured in vitro by means of liquid-doubling dilution.Results The ginkgolic acids gel has inhibitory effects on staphylocococus aureus and propionibacteria to various extents.And the MIC was 31.756 mg?mL-1 for staphylocococus aureus and 0.992 mg?mL-1 for propionibacteria.Conclusion The preparation of the gel is feasiblye and the the properties of the gel were stable.The ginkgolic acids gel possesses good antibacterial effects on staphylocococus aureus and propionibacteria.
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The studies on the extract processes of Radix Aucklandiae and Rhizoma Coptidis, and the preparation method for Xianglian Drop Pills have been carried out. The preparation method included the adsorption of volatile oil of Radix Aucklandiae with the extract mixture of Radix Aucklandiae and Rhizoma Coptidis. Water in adequate amount was added into the above mixture, The mixture was grinded into homogeneous pasty, then added with melted PEG 4000. After being mixed well on water bath the mixed melt was poured into the home-made drop pill apparatus(at 90℃) preheated, dropped into dimethyl silicone at rate of 24 drops/min through the drop head with internal apeture for 45mm and external apeture for 6. 1mm、and cooled well. The drop pills were obtai ned by removal of dimethylsilicone. Every examination of prepared drop pills coincided with the requests in general notice of drop pills in Pharmacopoeia of the Republic of China(1990). The in vitro antibacterial test showed that Xianglian Drop Pills had the same antibiotic effect as Xianglian Pills did.