Two new aminophenoxazinone compounds with antitumor activity, elloxazinone A and B, were isolated from the culture filtrate of Streptomyces griseus Acta 2871. Their chemical structures were determined by mass spectrometry, NMR spectroscopy and X-ray analysis. Elloxazinones A and B showed a moderate inhibition of the proliferation of human cells from gastric adenocarcinoma in vitro but a strong inhibition of hepatocellular carcinoma cells whereas elloxazinone B strongly inhibited the proliferation of human breast carcinoma cells.

Acta 2871 -[isolation and structure determination of the title compounds (Ia) and (Ib), resp., which exhibit antitumor activity]. -(GRAF, E.; SCHNEIDER, K.; NICHOLSON, G.; STROEBELE, M.; JONES, A. L.; GOODFELLOW, M.; BEIL, W.; SUESSMUTH, R. D.; FIEDLER*, H.-P.; J. Antibiot. 60 (2007) 4, 277-284; Mikrobiol. Inst., Eberhard-Karls-Univ., D-72076 Tuebingen, Germany; Eng.) -A. Forchert 43-200

Bendigoles AϳC are the first secondary metabolites to be isolated from a member of the actinomycete genus Gordonia. They were detected in a culture filtrate extract of Gordonia australis Acta 2299 by HPLC-diode array analysis and characterized as new steroids by mass spectrometry and NMR experiments. Bendigole C show binding affinity to the human progesterone and AϳC to androgen receptor but are inactive at mineralocorticoid and estrogen receptors. In in vitro transactivation studies bendigoles A and C showed moderate and weak androgenic activities.

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