Preliminary screening via dose–response analysis of the antibacterial activities of six Chinese medicinal plant extracts

This first-attempt study quantitatively provided dose–response assessment of in vitro antibacterial activity of typical Chinese medicinal plant extracts. The diameter of inhibition zone determined by disc diffusion method was adopted to quantify antibacterial activity of various plant extracts upon Escherichia coli. Our findings indicated that antibacterial activities of crude plant extracts obtained by maceration (mac.) and decoction (dec.) were significantly different. Moreover, extracts of Phyla nodiflora (mac.), Coptis chinensis Franch (mac.) and C. chinensis Franch (decoction) were found to be more feasible to be antibacterial agents for possible therapeutic uses. In addition, P. nodiflora (mac.) was very likely most cost-effective among all extracts.