Study On Antibacterial Activity Of Selaginella Tamariscina (P.Beauv.) Spring In Vitro

Objective(s):1.To determine the antibacterial activity of the alcohol extracts from 36 Chinese herbal medicines such as Selaginella tamariscina(P.Beauv.)Spring and their extracted layer in vitro,and the Chinese medicinal materials with good antibacterial activity were screened out.2.To track and separate monomer compounds from the active extracts of Selaginella tamariscina(P.Beauv.)Spring,and indentify structure of active monomer compounds.3.To determine the antibacterial activity of monomer compounds in vitro.And evaluate the antibacterial effects of active compounds combined with clinical commonly antibacterial agents against in vitro.Methods:1.The monomer compounds were isolated and purified from active parts of Chinese medicines extract by using the Bioactivity-guided fractionation,antimicrobial susceptibility tests were combined with silica gel and Sephadex LH-20 chromato-graphic separate methods.The monomer active compounds' structures were identified by spectral analysis and physicochemical methods.2.Study on their antibacterial activity of the isolated compounds.First,the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)were determined by the standard broth microdilution method.Using disk agar diffusion method to screen antibacterial agents which showed combined effects.Then the checkerboard microdilution method and time-killing curve method were performed to examine anti-microbial activity of drug combination application.Results:1.Seven active compounds were isolated from the ethyl acetate layer of Selaginella tamariscina(P.Beauv.)Spring.Their structures by the managerial properties and spectral data were identified as ginkgetin(compound 1),hinokiflavone(compound 2),ametoflavone(compound 3),sciadopitysin(compound 4),apigenin(compound 5),ferulic acid(compound 6),and caffeic acid(compound 7).2.The antibacterial activity of the isolated compounds was measured in vitro.The results showed that they had antibacterial effects against various standard strains and their resistant strains.3.The combination of biflavonoids and commonly clinical antibacterial drugs by the checkerboard microdilution method showed that ginkgetin and imipenem combined with anti-MRSA,1 strain was synergistic,and 2 strains were additive;ginkgetin and ciprofloxacin combined with anti-PA,2 strains were synergistic,and 2 strains were additive.The combination of hinokiflavone and cefazolin against MRS A,1 strain was synergistic and 3 strains were additive;hinokiflavone and ciprofloxacin combined with anti-MRSA,7 strains were additive;hinokiflavone and ciprofloxacin combined with anti-PA,3 strains were additive.The combination of ameto:flavone and imipenem against MRSA,2 strains were synergistic and 1 strain was additive;ametoflavone and ciprofloxacin combined with anti-PA,1 strain was synergistic and 6 strains were additive;ametoflavone and fluconazole combined with anti-CA,2 strains were additive.sciadopitysin and cefazolin combined with anti-MRSA,1 strain was synergistic,3 strains were additive;sciadopitysin and ciprofloxacin combined with anti-PA,2 strains were synergistic and 4 strains were additive.4.For the strains with synergistic bacteriostatic action,further time-killing curves were examined.The results showed that ginkgetin and imipenem combined with anti-MRSA8,mode of action is synergistic;ginkgetin and ciprofloxacin combined with anti-PA5',mode of action is additive.The mode of action of hinokiflavone and cefazolin in combination with MRSA8 is synergistic.Ametoflavone and imipenem against MRSA8 is synergistic,and ametoflavone and ciprofloxacin against PA5' is additive.Sciadopitysin and cefazolin against MRSA747 is synergistic;sciadopitysin and ciprofloxacin against PA5' is synergistic.Conclusion(s):1.In this paper,we mad activity tracking against bacteria or fungi for the extracts from Selaginella tamariscina(P.Beauv.)Spring for the first time,the compounds were obtained from the ethyl acetate layer of its active part:ginkgetin,hinokiflavone,ametoflavone,sciadopitysin,apigenin,ferulic acid and caffeic acid.2.ginkgetin and imipenem combined with anti-MRSA were synergistic;it combined with ciprofloxacin against PA was additive.The combination of hinokiflavone and cefazolin against MRSA was synergistic.The synergistic effect of ametoflavone and imipenem against MRSA was synergistic,and combined with ciprofloxacin against PA was additive.sciadopitysin combined with cefazolin anti-MRSA was synergistic effect;and ciprofloxacin combined with anti-PA was synergistic.The combined antimicrobial effect of the above compounds and antimicrobial agents was first reported.