CALICHEAMICINS, A NOVEL FAMILY OF ANTITUMOR ANTIBIOTICS

Novel antitumor antibiotics, calicheamicins β1Br, γ1Br, α2I, α3I, β1I, γ1I and δ1I were recovered from the fermentation broth of Micromonospora echinospora ssp. calichensis by solvent extraction, selective precipitation, normal phase, reversed phase and partition chromatography. The individual components were characterized by their UV, IR, 1H and 13C NMR spectral data.