Abstract
Four novel antitumor antibiotics (PD 114, 759, PD 115, 028, PD 119, 707, and PD 119, 193) are produced as a complex by a new species of Actinomadura. The proposed name for the culture is Actinomadura verrucosospora subsp. veractimyces ATCC 39363. The antibiotics are extremely bioactive, with MIC values of <0.006ng/ml against several bacteria and ID50 values of 0.003-0.107ng/ml against L1210 leukemia cells in vitro. Antitumor activities vs. P388 leukemia in vivo were observed at doses of 0.313, 0.40, and 0.5μg/kg (daily×5) for PD 119, 707, PD 115, 028, and PD 114, 759, respectively.
