| This study mainly investigated the anti-MRSA activities of Coptis chinensis Franch. and its alkaloids. Also, the compatibility between the alkaloids components in Coptis chinensis Franch and cefoxitin was investigated systematically. The key anti-MRSA components were screened by the spectrum-effect relationship; the key active components were chosen for the pairwise compatibility study to obtain the interaction between two components (synergistic, additive, or antagonistic effects), based on what the suitable proportion of the compatibility was assumed; the best proportion of the alkaloids of Coptis chinensis Franch. was investigated by the study of multi-component interactions, and the quadratic orthogonal rotation combination design was adopted for this study; the best proportion of the multi-component drug was validated by the in vitro anti-MRSA study compared with some other native proportion of the natural products, meanwhile, other microbial were adopted for the validation of the activities of optimal multi-component drug. The above mentioned study could provide scientific basis for the development of multi-component drug.The results showed that:1) The mecA gene of ATCC43300showed overexpression. Susceptibility test indicated that (3-lactamase test showed positive result, and the tolerance of inducible clindamycin turned out to be negative. In addition, the MICs of both methicillin and oxacillin on ATCC43300exceeded4μg/ml; the MICs of chlorineclindamycin and gentamicin on this bacteria exceeded8ug/ml and16μg/ml, respectively. It was inferred that the phenotype of PBP changed and the DNA of this type of strain probably contained mecA gene.2) The study of solvent separation combining activity screening showed that the anti-MRSA activity was correlated with the content of total alkaloids of Coptis extract, which indicated that the total alkaloids was the main active site.3) Berberine, coptisine, palmatine, jatrorrhizine and epiberberine were investigated to be the main components by spectrum-effect relationship study, and the results were validated by the study of the screening of the fraction prepared by high performance liquid chroma to graphy.4) Pairwise compatibility study showed that there were three compatibility relationships among the alkaloids components and cefoxitin:general antagonism, general synergism, antagonism or synergism when the concentration of the chemical changed. Based on the relationships, the suitable proportion among the components was given.5) The study of multi-component interactions indicated that the best multi-component drugs were:jatrorrhizine:coptisine:Berberine:epiberberine:palmatine=0.7020.863:1:0.491:0.526(alkaloids components), jatrorrhizine:coptisine Berberine:epiberberine:palmatine:cefoxitin=0.507:0.561:1:0.595:1.094:1.047.This study provided a new mode for the development of multi-component drug (either natural product or natural product-western medicine), and the development of anti-MRSA component drug was taken as an example. That is:determination of the critical pharmacodynamic components---investigation of the interactions among components (synergistic, additive, or antagonistic effects)----study of multi-component interactions to determine the optimal proportion----validation. The mode proposed in this study could be adopted by the drug development of other multi-component drugs. The method is simple, accurate, with good reproducibility, and it can provide reference for the development of the antibacterial component drugs.Following this mode, two multi-component drugs were provided, and it was proved that the multi-component drugs were highly efficient and showed advantages in resistant to other type of common flora. Although the multi-component drug of Coptis chinensis Franch is less efficient than some of the front-line antibiotics, it is of great value in treating intractable infection caused by drug resistant strains. The MRSA infection was successfully resolved using multi-component drug of Coptis chinensis Franch and cefoxitin, which meant that the anti-MRSA activity of cefoxitin was significantly enhanced by the combination of alkaloids components of Coptis chinensis Franch. |
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