Elsamicins, new antitumor antibiotics related to chartreusin. I. Production, isolation, characterization and antitumor activity.

New antitumor antibiotics, elsamicins A and B, were isolated from the culture broth of an unidentified actinomycete strain J907-21 (ATCC 39417). They are structurally related to chartreusin, containing the common aglycone, chartarin, but contain different sugar moieties. Elsamicin A, the major component, has an amino sugar in the molecule which makes the antibiotic much more water-soluble than chartreusin. Elsamicin A exhibits strong inhibitory activity against various murine tumors including leukemia P388, leukemia L1210, and melanoma B16 but elsamicin B which lacks the amino sugar showed only marginal activity. The potency of elsamicin A was 10-30 times more potent than that of chartreusin in terms of minimum effective dose.