SQ109 analogues as potential antimicrobial candidates

The antimicrobial activity of five novel SQ109 derivatives including SQ109 against bacteria, yeast and filamentous fungi is reported herein. Using broth microdilution techniques, compounds 2 and 3 were found to be active against most tested fungi and bacteria, with minimum inhibitory concentrations (MICs) ranging from 0.98 to 31 μg ml−1, except for Klebsiella pneumonia where the MIC was 250 μg ml−1. SQ109 and derivative 4 did not show any significant activity against most of the organisms used. However, their reduced derivatives 1 and 5 showed promising activity with MICs between 0.49 and 62.5 μg ml−1 against most of the microorganisms used.