1980 Volume 33 Issue 2 Pages 205-212
New antitumor antibiotics, macbecins I and II, were isolated from the culture broth of Nocardia sp. No. C-14919. Macbecins I and II belong to the ansamycin group and have a benzoquinone and hydroquinone nucleus, respectively. Both showed antitumor activity against murine leukemia P 388 in vivo.