The Methods Of Screening New Antifungal Drugs And The Antimicrobial Activity Of Components From Bupleurum

Objective: Establishing the methods of screening new antifungal drugs by the rules of The National Center for Drug Screening (NCDS). One specie from Chinese medicine named Bupleurum show inhibitory microbes effect without and with antibiotics. The isolation of monomers (saikosaponins) from Bupleurum and their chemical structure was investigated, then the antimicrobial activity of monomers was studied.Methods: Preliminary screening of 39 samples, the components of Bupleurum were tested by Agar diffusion, microdilution method and checkerboard microdilution method. To determine the antimicrobial activity of components, 10 clinical isolates of Erythromycin-resistant staphylococcus aureus (ERSA), 10 clinical isolates of Methicillin-resistant staphylococcus aureus (MRSA), 10 clinical isolates of Fluconazole-resistant Candida albicans (FRCA), 10 clinical isolates of Candida albicans(Ca), Ca (ATCC10231) strains, Staphylococcus aureus (ATCC26003) strains and MRSA(ATCC29213) strains were tested.Results: Preliminary screening of 39 samples from NCDS was done. The MIC of Bp3 (saikosaponins) to ERSA, MRSA, FRCA and Ca was 16-64μg/ml, 16-64μg/m, 64-128μg/ml and 32-128μg/ml respectively. The FIC of Bp3 with Erythromycin (Em) on ERSA, Cephazolin(C1) and Vancomycin(Vm) on MRSA were 0.313-0.75, 0.375-0.75 and 0.5-1.0 respectively, and they had synergic or additive effect. The FIC of Bp3 with Fluconazole (FCZ) on FCZA and Amphotericin B on Ca were 0.313-0.625 and 0.375-1.0 respectively, and they had synergic or additive effect.Conclusion: The method of screening new antifunal drugs was effective and preliminary screening of 39 samples was done. The chemical structure of Bp3 is Pentaeyclic triterpennoids. Bp3 not only had antimicrobial effect on Sa and Ca but also had synergic or additive effect with Em, C1, Vm, FCZ and AmB.Keyword: antifungal, minimum inhibitory concentrations, saikosaponins of Bupleurum, synergic effect, additive effect, Fractional inhibitory concentration, Candida...