Scaffold Simplification Yields Potent Antibacterial Agents That Target Bacterial Topoisomerases

Area of Science:

• Medicinal Chemistry
• Drug Discovery
• Microbiology

Background:

• Antibiotic resistance necessitates the development of novel antibacterial agents.
• Lead compound LK1819 showed promise but required optimization.
• Scaffold simplification is a strategy to enhance compound potency and properties.

Purpose of the Study:

• To optimize antibacterial compounds through systematic scaffold simplification.
• To design and synthesize novel amide derivatives with modified core structures.
• To evaluate the in vitro antibacterial activity and mechanism of action of simplified analogs.

Main Methods:

• Systematic scaffold simplification of LK1819.
• Synthesis of novel amide derivatives with biphenyl systems.
• In vitro antibacterial activity testing against ESKAPE pathogens.
• Mechanistic studies including reporter systems and enzymatic assays.
• Toxicity and cytotoxicity assessments against human cell lines.

Main Results:

• Simplified analogs exhibited potent, broad-spectrum antibacterial activity.
• Minimum inhibitory concentrations (MICs) were 10-100 times lower than ciprofloxacin.
• Compounds inhibit bacterial DNA replication by targeting topoisomerase I and DNA gyrase.
• Compounds demonstrated moderate toxicity with a sufficient selectivity window.

Conclusions:

• Scaffold simplification successfully yielded highly potent antibacterial agents.
• The simplified compounds possess a defined mechanism of action targeting DNA replication.
• These agents represent a promising foundation for developing new antibiotics and potential anticancer drugs.