Cytotoxic metabolites of Streptimonospora salina.

Streptimonospora salina gen. nov., sp. nov. was found to produce three phenoxazinone antibiotics, 2-amino-3 H-phenoxazin-3-one (1), 2-methylamino-3 H-phenoxazin-3-one (2), 2-acetylamino-3 H-phenoxazin-3-one (3), and one phenazine antibiotic, phenazine-1-carboxylic acid (4). The chemical structures of the compounds were determined using 1D and 2D NMR spectrometry and electrospray mass spectrometry (ESMS). Compounds 1-4 exhibited modest cytotoxicity against a human renal carcinoma cell line ACHN with IC₅₀ values of 35.4, 12.4, 65.4, and 82.9 μM, respectively. Compound 2 was discovered for the first time from a biological origin. [ABSTRACT FROM AUTHOR]