A COMPARISON OF THE BACTERICIDAL AND PHOTOBACTERICIDAL ACTIVITIES OF AMINOACRIDINES AND BIS(AMINOACRIDINES)

An attempt was made to increase the activity of some antibacterial acr idines in two ways: (a) via the use of bis-aminacrines (analogues of 1 ,6-bis-[9-acridinamins]hexane), in order to increase the potential for DNA intercalation and (b) via photoactivation, as several acridines a re known to produce the cytotoxin singlet oxygen on irradiation. The b actericidal activity of the simple aminoacridines was much higher than that of the corresponding bis-acridine compounds. In addition, on low -power illumination of the compounds in liquid culture, many of the mo nomeric compounds exhibited marked increases in activity against both Gram-negative and Gram-positive bacteria, whereas the bis-acridines sh owed little or no increase.