Synthesis, antimicrobial activity and toxicity to nematodes of cyclam derivatives

- Synthesis and antimicrobial activity of cyclam derivatives are described.
- Cyclam [H2{H2(4-CF3PhCH2)2Cyclam}](CH3COO)2⋅(CH3COOH)2 has bactericidal and fungicidal activities.
- Cyclam derivatives represent a potential new class of antibiotics.

The antimicrobial activity and toxicity to nematodes of the cyclam salt [H2{H2(4-CF3PhCH2)2Cyclam}](CH3COO)2⋅(CH3COOH)2 were evaluated. Estimated minimum inhibitory concentrations (MICs) of 9, 261 and 15 µg/mL were obtained for Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, respectively. For selected Candida spp., the estimated MICs obtained ranged from 32 µg/mL to 63 µg/mL. Bactericidal activity was demonstrated but the compound was not reliably fungicidal. Concentrations of the cyclam salt up to 32 µg/mL did not significantly affect survival of the nematode Caenorhabditis elegans; however, concentrations equal or above this value significantly affected nematode survival in a dose-dependent manner.