Bioactive Secondary Metabolites from a New Terrestrial Streptomyces sp. TN262

During our search for Streptomyces spp. as new producers of bioactive secondary metabolites, the ethyl acetate extract of the new terrestrial Streptomyces isolate TN262 delivered eight antimicrobially active compounds. They were identified as 1-acetyl-β-carboline (1), tryptophol (2), cineromycin B (3), 2,3-dihydrocineromycin B (4), cyclo-(tyrosylprolyl) (5), 3-(hydroxyacetyl)-indole (6), brevianamide F (7), and cis-cyclo-(l-prolyl-l-leucyl) (8). Three further metabolites were detected in the unpolar fractions using GC–MS and tentatively assigned as benzophenone (9), N-butyl-benzenesulfonamide (10), and hexanedioic acid-bis-(2-ethylhexyl) ester (11). This last compound is known as plasticizer derivatives, but it has never been described from natural sources. In this article, we describe the identification of the new Streptomyces sp. isolate TN262 using its cultural characteristics, the nucleotide sequence of the corresponding 16S rRNA gene and the phylogenetic analysis, followed by optimization, large-scale fermentation, isolation of the bioactive constituents, and determination of their structures. The biological activity of compounds (2), (3), (4), and those of the unpolar fractions was addressed as well

Venturicidin C, a new 20-membered macrolide produced by Streptomyces sp. TS-2-2

Venturicidin C (1), a new 20-membered macrolide along with the known venturicidins A (2) and B (3) were isolated from the crude extract of the Appalachian bacterial strain Streptomyces sp. TS-2-2. Additionally, nine other known compounds namely nocardamine, dehydroxynocardamine, desmethylenlnocardamine, ferrioxamine E (FOE), adenosine, riboflavin, cyclo(d)-trans-4-OH-Pro-(d)-Phe, cyclo(d)-Pro-(d)-Phe, and N-(2-phenylethyl)-acetamide were also isolated and identified. The structure of the new macrolide 1 was elucidated by the cumulative analyses of NMR and HR-MS spectrometry data. Complete NMR assignments for the known venturicidins A (2) and B (3) are also provided, for the first time, in this report. Venturicidins A-C did not inhibit the proliferation of A549 lung cancer cell lines but all displayed potent antifungal activity