Antibacterial effects in vitro of several common chinese medicinal herbs upon Esherichia coli

The in vitro antibacterial activities of a total of 8 ethanolic extracts from Chinese medicinal herbs were investigated by filter paper, double dilution and other methods against Esherichia coli. Diameter of inhibition zone (DIZ), minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined in the test. The results were as follows: These Chinese herbal medicines showed different degrees of inhibitory effects on tested bacteria. Extract of Scutellaria baicalensis exhibited the highest activity, Schisandra chinensis came second. The DIZ value of Scutellaria baicalensis was 14.6 mm, while Schisandra chinensis was 13.4 mm. The MIC value of Scutellaria baicalensis was low to 0.78125 mg/ml, the MBC value was 1.5625 mg/ml. The MIC value of Schisandra chinensis was 1.5625 mg/ml, the MBC value was 3.125 mg/ml. We found a certain parallel relationship between the size of inhibition circle and minimum inhibitory concentration, generally speaking, the herb which had a larger inhibition circle diameter showed a smaller MIC value, the herb with a smaller diameter showed a bigger MIC value. Copyright © 2013 American Scientific Publishers. Website © 2013 Publishing Technology.