Leucomycins

Macrolide antibiotics are classified by the size of the macrocyclic lactone ring of aglycone as 14-, 15- or 16-membered ring macrolides. Macrolides are characterized by similar chemical structures, mechanisms of action and resistance, but vary in the different pharmacokinetic parameters, and spectrum of activity. Leucomycin (other name: kitasamycin) is a mixture of 16-membered macrolide substances having antibacterial activity isolated from the broth filtrate of Streptomyces kitasatoensis. It has activity against Gram-positive bacteria, some Gram-negative bacteria, spirochetes, and rickettsiae. It inhibits bacterial protein synthesis both in vivo and in vitro. Recently, renewed interest in synthesis of 16-membered macrolide derivatives has been evoked by their interesting properties.