Antimicrobial ambiguine isonitriles from the cyanobacterium Fischerella ambigua.
Five new antibacterial ambiguine K-O isonitriles (1-5) and eight previously described indole alkaloids were isolated from the cultured cyanobacterium Fischerella ambigua (UTEX 1903) by bioassay-guided fractionation. The planar structures of the new compounds were determined by spectroscopic analysis including MS and 1D and 2D NMR. X-ray crystallography was used to determine the absolute stereoconfiguration of ambiguine K isonitrile. The isolates were evaluated for their antibacterial activities against a set of bacterial targets, including Mycobacterium tuberculosis and Bacillus anthracis. Ambiguine K and M isonitriles showed the most potent activity against M. tuberculosis, with MIC values of 6.6 and 7.5 microM, respectively. Ambiguine A isonitrile showed the most potent activity against B. anthracis, with a MIC of 1.0 microM.
Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
Shunyan
S
Mo
Aleksej
A
Krunic
George
G
Chlipala
Jimmy
J
Orjala
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001408:Bacillus anthracis / Q000187:drug effects; D000458:Cyanobacteria / Q000737:chemistry*; D026121:Indole Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D009169:Mycobacterium tuberculosis / Q000187:drug effects; D019906:Nuclear Magnetic Resonance, Biomolecular
D000900:Anti-Bacterial Agents; D026121:Indole Alkaloids; C518548:ambiguine I isonitrile; C550793:ambiguine K isonitrile; C550792:ambiguine M isonitrile