Microdilution inhibition test of Chinese herbs to assess their effect against clinical strains of Ureaplasma urealyticum in vitro

Abstract

Objective To explore the antibacterial effect of Chinese crude drugs against clinical strains of Ureaplasma urealyticum(UU), including eight pure herbs and three compound herbs, and determine their minimal inhibitory concentrations(MICs). Methods Isolates were collected from clinical patients with UU infection, and cultured in UU broth. In order to test the different effects on clinical strains of UU, the assays were performed by microdilution inhibition tests, and MICs of the herbs against the clinical strains of UU were calculated. Results The MICs of eight pure herbs against clinical strains of UU were as follows: Galla Chinensis:0.313∼1.25 g/L; Fructus Forsythiae: 1.25∼5.00 g/L; Cortex Phellodendri:1.25∼5.00 g/L; Radix Paeoniae Rubra:1.25∼2.50 g/L; Semen Plantaginis:2.50∼10.00 g/L; Herba Lysimachiae: 5.00∼20.00 g/L; Rhizoma Coptidis: 5.00∼20.00g/L, Herba Houttuyniae: 10.00∼20.00 g/L. The MICs of compound herbs were: Liuheji: 0.625∼2.50 g/L; Bazhengsan: 5.00∼20.00 g/L; Wulinsan:2.50∼20.0 g/L. Conclusion Galla Chinensis, Fructus Forsythiae, Cortex Phellodendrim, Radix Paeoniae Rubra, and Semen Plantaginis, exerted the stronger antibacterial effect against clinical strains of UU, whereas Herba Lysimachiae, Rhizoma Coptidis and Herba Houttuyniae, had relatively weaker activity against UU. Compound herbs, Bazhengsan and Wulinsan, and particularly Liuheji, also had antibacterial effects against UU. Further studies of the effects and mechanisms of action of Chinese crude drugs against UU infections are worthwhile.