Figure 14.

Examples of synthetic homo- and hetero-derivatives of psammaplin A. The blue dashed line box highlights derivatives that showed significant antibacterial effects against methicillin-resistant Staphylococcus aureus (MRSA) due to DNA gyrase inhibition and bacterial DNA synthesis arrest. The red dashed line box highlights derivatives that showed higher antibacterial activity than psammaplin A. The green dashed line box highlights a derivative that showed similar antibacterial activity to clinically used drugs vancomycin and ciprofloxacin. The yellow dashed line box highlights derivatives that possessed 50-fold higher activities than psammaplin A vs. Staphylococcus aureus and MRSA, in this case mainly by a nonspecific redox-based mechanism (reviewed in [122]).