The Effects Of Some Chinese Herbs And Inorganic Salts On Mycobacterium Tuberculosis Biofilms

Tuberculosis?TB?caused by Mycobacterium tuberculosis?Mtb?is a worldwide disease with high infection and high mortality.In recent years,the emergence of drug-resistant tuberculosis,especially human immunodeficiency virus-tuberculosis?HIV-TB?,multidrug-resistant tuberculosis?MDR-TB?and extensively drug-resistant tuberculosis?XDR-TB?,has brought great challenges to tuberculosis control globally.A large number of studies suggest that Mycobacterium tuberculosis can exist as a biofilm,and the formation of biofilm may be the cause of the increase of drug resistance and one of the important mechanisms of M.tuberculosis.Biofilms?BF?are surface bound communities of microbial cells found in oligotrophic environments and are strongly implicated in bacterial virulence,which can secrete polysaccharide matrix,fibrin and lipid proteins enclosed themselves.In this paper,12 inorganic salt were selected for the screening of M.tuberculosis H37Rv and the intervention of biofilm growth activity respectively.The results showed that NaNO₂ had better activity against M.tuberculosis H37Rv and inhibition M.tuberculosis H37Rv biofilm growth,the MIC and MBC values are 4mmol/L.When 3mmol/L NaNO₂ combined with 3.2?g/ml rifampicin,it had good synergistic antibacterial and inhibited biofilm growth activity.NaNO₂ can intervene the synthesis of M.tuberculosis H37Rv ATP,resulting in a decrease in ATP content and weak fluorescence,This may be the mechanism which inhibits the biofilm growth of M.tuberculosis.Traditional Chinese medicine?TCM?is one of the important sources of new drug discovery and has a great storage capacity in china.In this paper,we have used the unique and diverse medicinal plant resources in Guizhou to establish a library of plant samples.30traditional Chinese medicines were selected for the screening of M.tuberculosis H37Rv and the intervention of biofilm growth activity respectively.The results showed that Sophora flavescens methanol extract?0.4 mg/ml?can significantly inhibit the growth of M.tuberculosis H37Rv biofilm,When the drug concentration is increased to 0.8 mg/ml,M.tuberculosis H37Rv can be killed.The 80%ethanol extract of Cornus officinale Sieb.et Zucc?3.2mg/ml?had better activity against M.tuberculosis H37Rv.Further results showed that on the Lowenstein-Jenden medium,the small polarity part of ethanol extract from Cornus officinale Sieb.et Zucc is the effective active site against M.tuberculosis H37Rv,the large polarity part can not significantly promote the growth of M.tuberculosis H37Rv.However,on the 7H9-ADC Middlebrook medium,can significantly promote the growth of M.tuberculosis H37Rv biofilms,and show a dose-effect relationship.The results showed that different Chinese herbal medicine had different effect on the formation of M.tuberculosis H37Rv biofilm.Further study by bioassay guided isolation will lay the foundation for the discovery of the molecular skeleton with the interventional effect on formation of M.tuberculosis H37Rv biofilm.In this paper,a methodological optimization of M.tuberculosis H37Rv biofilm was evaluated by Crystal Violet staining?CV?.The results showed that there was a significant dose-effect relationship under the conditions of M.tuberculosis strain suspension?10⁸ CFU/ml?100?l,incubation time?7 days?,crystal violet staining?1%?and staining time?15min?.