Barakacin: A Thiazolyl-indole Alkaloid Isolated from a Ruminal Pseudomonas sp.

Abstract

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.

Antibacterial Activity of Endophytic Actinomycetes Isolated from the Medicinal Plant Vochysia divergens (Pantanal, Brazil)

“…Fractionation, isolation and purification of the obtained extract using various chromatographic techniques resulted in compounds 1–9 in pure forms (Figure S9 ). Thorough analyses of the HPLC/UV, ESIMS and NMR spectroscopy data (Figure S10 –S43), and by comparison with literature data (Laatsch, 2012 ), the compounds were identified as 1-acetyl-β-carboline ( 1 ) (Shaaban et al, 2007 ; Savi et al, 2015b ), indole-3-carbaldehyde ( 2 ) (Zendah et al, 2012 ; Savi et al, 2015b ), tryptophol ( 3 ) (Rayle and Purves, 1967 ), 3-(hydroxyacetyl)-indole ( 4 ) (Zendah et al, 2012 ), brevianamide F ( 5 ) (Shaaban, 2009 ), cyclo-(L-Pro-L-Phe) ( 6 ) (Barrow and Sun, 1994 ), cyclo-(L-Pro-L-Tyr) ( 7 ) (Barrow and Sun, 1994 ), cyclo-(L-Pro-L-Leu) ( 8 ) (Yan et al, 2004 ), and cyclo-(L-Val-L-Phe) ( 9 ) (Pickenhagen et al, 1975 ) (Figure 9 ). In order to determine the compounds responsible for the biological activity observed for the crude extract of strain LGMB491, we evaluated the antibacterial activity of compounds 1–9 against S. aureus and methicillin-resistant S. aureus .…”

Screening of metabolites from endophytic fungi of some Nigerian medicinal plants for antimicrobial activities

“…associated with Viscum coloratum (96), from endophytic actinomycetes (85,97), from Pseudomonas sp. (98), and from a Red Sea sponge Hyrtios erectus (86). Indole-3-carbaldehyde showed moderate cytotoxic (86) and antibacterial activities (85).…”

Isolation, Purification and Structure Elucidation of New Secondary Metabolites from Terrestrial, Marine, and Ruminal Microorganisms

“…It is the first natural thiazolyl-indole alkaloid. [135] (↔) 1 H-1 H COSY and (→) HMBC correlations of barakacin (92) From the above spectral information, the molecular formula, and subsequently the double bond equivalence as well as the precise connectivities of fragments A-C, the structural formula of barakacin was finally established as 2-{4-[bis-(1H-indol-3-yl)methyl]-thiazol-2-yl}-phenol (92). The structure was confirmed on the basis of the MS and NMR interpretation and by comparison with related spectra, as well as literature data.…”

“…After concentration, the aqueous residue was extracted with ethyl acetate. The extracts from the mycelium and the water phase were similar on TLC and were combined, yielding 3.54 g of a greenish- (135)…”

“…2-n-Heptyl-1-hydroxy-1H-quinolin-4-one (135) was isolated before by Hays et al as antibiotic from Pseudomonas aeruginosa. [263] Lightbown and Jackson revealed that 2-n-heptyl-1-hydroxy-1H-quinolin-4-one (135) was an antagonist of dihydrostreptomycin and an inhibitor of electron transport through the cytochrome b~c 1 segment of the respiratory chain. [264,265] Kitamura et al proved that 2-n-heptyl-1-hydroxy-1Hquinolin-4-one (135) at high concentrations inhibited 12-lipoxygenase and cyclooxygenase.…”