Synthesis and antibacterial activity evaluation of octapeptin derivatives
Octapeptin has strong antibacterial activity against Gram-negative bacteria such as Escherichia coli,Klebsiella pneumoniae and Acinetobacter baumannii,while it also has activity against some Gram-positive bacteria.This study used natural octapeptin A3 and B3 as lead compounds for structural modification.Twenty-one peptide derivatives(including A3 and B3)containing eight amino acid residues were prepared by solid-phase synthesis,and evaluated for antibacterial activity and renal cytotoxicity.Among them,three compounds 6,7 and 17 exhibited broad-spectrum antibacterial activity and significantly enhanced the activity for Gram-positive bacteria while maintaining the activity of Gram-negative bacteria.Several compounds improved the activity for Pseudomonas aeruginosa.Compound 7 was active against all test strains and had relatively low renal cytotoxicity.The results provide a basis for the further development of novel polypeptide antibiotics.