The new chromophenazines A-F [9-methyl-5-(3'-methylbut-2'-enyl)-5H-benzo[a]phenazin-7-one (1a), 9-methyl-5-(3'-methylbut-2'-enyl)-7-oxo-5,7-dihydrobenzo[a]phenazine-1-carboxylic acid (1b), 5-(3'-methylbut-2'-enyl)-7-oxo-5,7-dihydrophenazine-1-carboxamide (2), 3-benzoyl-5-(3'-methylbut-2'-enyl)-5,10-dihydrophenazine-1-carboxylic acid (5a), 3,7-dibenzoyl-5-(3'-methylbut-2'-enyl)-5,10-dihydrophenazine-1-carboxylic acid (5b), and 3,7-dibenzoyl-5-(3'-methylbut-2'-enyl)-5,10-dihydrophenazine-1-carboxamide (5c)], together with phenazine-1-carboxylic acid, 1-phenazinecarboxamide, 1-phenazinol, tryptophol, and anthranilic acid, were isolated from Streptomyces sp. Ank 315. The structures of the new compounds were established on the basis of spectroscopic data, 1D NOE, 2D NMR, and ESIMS measurements and comparison with literature values.

A new thiazolyl-indole alkaloid, barakacin (1), has been isolated from the ruminal bacterium Pseudomonas aeruginosa strain ZIO. On the basis of detailed spectroscopic analyses and comparison with the data of related compounds, its structure has been determined as 2-{4-[bis-(1H-indol-3-yl)-methyl]-thiazol-2-yl}-phenol. In addition, the known compounds phenazine-1-carboxylic acid, 3-(hydroxyacetyl)-indole, indole-3-carbaldehyde, and glycolipid A were isolated. The discovery of compounds with a new skeleton emphasizes the importance for exploring new ecological niches like the rumen of bovines for the detection of new natural products. This paper describes the fermentation, isolation, structure elucidation and biological activities of compound 1.

Microorganisms are a rich source of structurally unique and pharmaceutically important bioactive substances leading to an impressive arsenal of antibacterial agents such as the cephalosporins (eg. cephalosporin C, 30), tetracyclines (31), rifamycins, Compounds isolated from Streptomyces platensis may be useful in the treatment of thrombocytopenia.