Abstract:

In order to explore six herbs combined antibacterial activity in Sihuang Zhili granules against chicken E. coli in vitro. Minimum inhibitory concentration (MIC) of testing drug was detected against chicken E. coli by microtubule-plate method. The synergy index (SI) of fifteen Chinese drug pairs was detected by broth dilution checkerboard method in Sihuang Zhili granules and calculated the amount and ratio of herb couples when mutual compatibility of them showed synergism against chicken E. coli in vitro. The results showed that antibacterial effect of rhizoma coptidis was strongest in six herbs against chicken E. coli in vitro and MIC was 125 mg/mL. The combined antibacterial activity of four herb couples showed synergism. SI of scutellaria and cortex phellodendri was 0.27, ratio was 8:1, and MIC of its preparations was 31.3 mg/mL; SI of scutellaria and rhizoma coptidis was 0.63, ratio was 1:2, and MIC of its preparations was 62.5 mg/mL; SI of scutellaria and glycyrrhiza was 0.25, ratio was 1:4, and MIC of its preparations was 125 mg/mL; SI of scutellaria and radix et rhizoma rhei was 0.38, ratio was 1:2, and MIC of its preparations was 125 mg/mL. So this paper obtained ratio of four herbs couples according to detection of combined antibacterial effect in vitro, and to lay a foundation of further study on decomposed recipes of Sihuang Zhili granules.