Synthesis And Comparative Study Of Sonodynamic Activity Of Methylene Blue Analogues

Sonodynamic therapy(SDT)has received much attention of scholars in the worldwide because of its unique advantages in the field of anti-tumor and anti-bacterial and potential clinical applications.Screening and designing effective sonosensitizers with low toxicity is the main content of pushing the application of PDT in the field of anti-tumor and anti-bacteria.Based on the related literatures and preliminary work of the research group,a series of methylene blue(MB)analogues were designed and synthesized.According to the comparative study on the sonodynamic activity of MB analogues,the influence of different substituent group on the sonodynamic activity of MB were preliminarily discussed.Firstly,a series of MB analogues were synthesised,they were 3,7-bis(di-n-propylamino)-phenothiazine-5-ium iodide(PRB),3,7-bis(di-n-pentylamino)-phe-nothiazine-5-ium iodide(PEB),3,7-di-p-amino phenothiazine-5-ium iodide(PA-B),3,7-di-cyclohexylamino-phenothiazine-5-ium iodide(CYB)respectively.The structures of these compounds were characterized by MS and ~1H-NMR.Secondly,we investigated the intracellular accumulation ability and proliferation inhibition on K562 cell of MB and its analogues with and without ultrasound.The results showed that with the extension of 3,7 amino carbon chain,compounds intracellular accumulation ability of MB analogues increased.Concluded that the cell proliferation inhibition of MB and its analogues may be related to the extension of carbon chain.Further study found that the extension of 3,7 amino carbon chain can help enhance its sonodynamic damage of cell,but its sonodynamic activity enhancement degree was not positively correlation with the extension of carbon chain.Compounds that introduced in toluene and cyclohexyl showed sonodynamic antitumor effect but the sonodynamic activity were not better than MB.Thirdly,we studied the sonodynamic antibacterial activity and its influence factors of MB and its analogues on Escherichia coli(E.coli).The results showed that the sonodynamic antibacteria activity of MB analogues were better than MB,and the extension carbon chain structure and the introduction of electronic groups can enhance the sonodynamic antibacteria activity.With the increase of ultrasonic time,the concentration of the compounds,the sonodynamic antibacteria effect were enhanced.Additionally,changes in the adding order of MB and its analogues further confirmed the sonodynamic activity of MB and its analogues.Finally,oxidation and extraction photometry was ued to investigate the mechanism of the sonodynamic activity of MB and its analogues.Also,we studied the influence factors of reactive oxygen species(ROS)yield and its kinds,for instance,MB and its analogues concentrations and ultrasonic time.The results showed that with the adding of MB and its analogues,the production of ROS gradually enhanced,MB and its analogues were mainly composed of singlet oxygen and hydroxyl free radical.Above all,the extension of 3,7 amino carbon chain in MB can help enhance its sonodynamic damage of cell,and the extension carbon chain structure and the introduction of electronic groups in MB can enhance its sonodynamic antibacteria activity.It is hoped that this research on the structure-activity ralationships of phenothiazinium compounds can provide theory support for the screening of phenothiazinium sonosensitizer.