Respinomycins A1, A2 B, C and D, a novel group of anthracycline antibiotics. I. Taxonomy, fermentation, isolation and biological activities.

Respinomycins are a novel group of anthracycline antibiotics produced by Streptomyces xanthocidicus. Respinomycins A1, A2, B, C and D were isolated by EtOAc extraction, silica gel column chromatography, centrifugal partition chromatography and preparative silica gel thin layer chromatography. Respinomycins A1 and A2 induced the terminal differentiation of human leukemia K-562 cells.