Structure-guided synthesis of melittin analogs with reduced hemolysis and enhanced anti-inflammatory activity

Using melittin and its bioactive fragment as structural modifiers, we synthesized and characterized a series of analogs incorporating distinct modification patterns. Through nitric oxide production screening, analogs demonstrating anti-inflammatory potential were identified and subsequently evaluated for enzymatic stability, hemolytic activity, and cytotoxicity in vitro . Mechanistic investigations via enzyme-linked immunosorbent assay (ELISA) revealed their anti-inflammatory pathways, which was followed by in vivo validation of therapeutic efficacy. Notably, analogs E1 and S15-1 exhibited optimal pharmacological profiles with minimal hemolysis and potent anti-inflammatory performance. This study demonstrates that strategic structural modifications not only significantly reduce hemolytic activity and cytotoxicity but also preserve anti-inflammatory efficacy at concentrations exceeding melittin’s toxic threshold. Furthermore, the optimized analogs displayed enhanced α-helical content and protease resistance compared to melittin. These findings highlight the critical influence of modification sites and strategies on modulating the therapeutic index, biological stability, and safety profile of melittin-derived peptides.