Anti-Nocardia activity and mechanism of oxyresveratrol
Objective To explore the anti-Nocardia activity of oxyresveratrol(OXY),clarify its antibacterial effect,and initially explore the mechanism of its inhibition of Nocardia,so as to provide a more theoretical basis for screening new anti-nocardia drugs.Methods The OXY antibacterial activity against 12 strains of Nocardia was screened by the disk diffusion method.The minimal inhibitory concentration(MIC)and minimal bactericidal concentration(MBC)of OXY against Nocardia were determined to clarify its anti-Nocardia activity.The effect of OXY on the growth of Nocardia was evaluated by the determination of A620.The effects of OXY on the morphology and structure of Nocardia were investigated by the optical microscope,the scanning electron microscope and the transmission electron microscope.Finally,the contents of alkaline phosphatase(AKP)and K+in the supernatant of the culture medium were detected to explore the effect of OXY on the integrity of Nocardia cell walls and membranes.Results By using disk diffusion method,it was found that both 25 and 50 mg/mL OXY could inhibit the growth of 12 strains of Nocardia,and 12.5 mg/mL OXY could inhibit the growth of Nocardia to some extent.The MIC and MBC values of OXY against 12 strains of Nocardia were 0.2 and 0.4 mg/mL,respectively.The results of A620 showed that both 0.5×MIC OXY and 1×MIC OXY could significantly inhibit the growth of Nocardia.OXY significantly changed the morphology of N.cyriacigeorgica;the bacteria shrank,became round,the cell wall became rough,and the cells broke down.OXY could also destroy the integrity of the Nocardia cell wall and membrane,and the content of AKP and K+in the supernatant increased with the increase of the OXY concentration.Conclusion OXY had good antibacterial activity against Nocardia,and its MIC and MBC values were 0.2 and 0.4 mg/mL,respectively.OXY might exert an antibacterial effect by destroying the integrity of the Nocardia cell wall and membrane.
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