Gamma-indomycinone, a new pluramycin metabolite from a deep-sea derived actinomycete.

A new member of the pluramycin class of antibiotics, gamma-indomycinone [1], has been isolated along with the known compounds rubiflavinone C-1 [2] and beta-indomycinone [3] from the culture broth of a Streptomyces sp. obtained from a deep-sea sediment core. Each compound is composed of an anthraquinone-gamma-pyrone nucleus, but bears a different side-chain. Compounds 2 and 3 were identified by comparison of their spectral data with published data, while gamma-indomycinone [1] was characterized using 1H-nmr and mass spectrometry.