NOCARDICYCLIN-A AND NOCARDICYCLIN-B - NEW ANTHRACYCLINE ANTIBIOTICS PRODUCED BY NOCARDIA-PSEUDOBRASILIENSIS

Nocardicyclins A (1) and B (2), new anthracycline antibiotics have bee n isolated from the mycelial cake of Nocardia pseudobrasiliensis IFM 0 624 (JCM 9894). The molecular formulae of 1 and 2 have been determined as C30H35NO11 and C32H37NO12, respectively, and the structures were c haracterized by 1- and 8-methoxyl groups, a 10-carbonyl group and a no vel carbon-methylated aminosugar constituent. Nocardicyclin A (1) exer ts cytotoxic activity against L1210 and P388 leukemia. Nocardicyclins A (1) and B (2) are active against Gram-positive bacteria including My cobacterium spp. and Nocardia spp., but inactive against Gram-negative bacteria.