ABSTRACT
A bicyclic depsipeptide, chromopeptide A (1), was isolated from a deep-sea-derived bacterium Chromobacterium sp. HS-13-94. Its structure was determined by extensive spectroscopic analysis and by comparison with a related known compound. The absolute configuration of chromopeptide A was established by X-ray diffraction analysis employing graphite monochromated Mo K α radiation (λ=0.71073 Å) with small Flack parameter 0.03. Chromopeptide A suppressed the proliferation of HL-60, K-562, and Ramos cells with average IC50 values of 7.7, 7.0, and 16.5 nmol/L, respectively.
ABSTRACT
Natural products produced by microorganisms have been an important source of new substances and lead compounds for the pharmaceutical industry. Chromobacterium violaceum is a Gram-negative β-proteobacterium, abundant in water and soil in tropical and subtropical regions and it produces violacein, a pigment that has shown great pharmaceutical potential. Crude extracts of five Brazilian isolates of Chromobacterium sp (0.25, 2.5, 25, and 250 µg/mL) were evaluated in an in vitro antitumor activity assay with nine human tumor cells. Secondary metabolic profiles were analyzed by liquid chromatography and electrospray ionization mass spectrometry resulting in the identification of violacein in all extracts, whereas FK228 was detected only in EtCE 308 and EtCE 592 extracts. AcCE and EtCE 310 extracts showed selectivity for NCI/ADR-RES cells in the in vitro assay and were evaluated in vivo in the solid Ehrlich tumor model, resulting in 50.3 and 54.6% growth inhibition, respectively. The crude extracts of Chromobacterium sp isolates showed potential and selective antitumor activities for certain human tumor cells, making them a potential source of lead compounds. Furthermore, the results suggest that other compounds, in addition to violacein, deoxyviolacein and FK228, may be involved in the antitumor effect observed.
Subject(s)
Animals , Humans , Male , Mice , Antineoplastic Agents/pharmacology , Chromobacterium/metabolism , Indoles/pharmacology , Neoplasms, Experimental/drug therapy , Antineoplastic Agents/isolation & purification , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Complex Mixtures , Indoles/isolation & purification , Indoles/therapeutic use , Spectrometry, Mass, Electrospray IonizationABSTRACT
Aims: This study evaluates potentials of Cupriavidus necator PHB4 transformant harboring the highly active polyhydroxyalkanoate synthase gene (phaC) of a locally isolated Chromobacterium sp. USM2 for its ability to incorporate 3-hydroxyheptanoate (3HHp) monomer. Methodology and results: A mixture of fructose and sodium heptanoate fed to the culture gave rise to poly(3- hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyheptanoate), [P(3HB-co-3HV-co-3HHp)] terpolymer synthesis, with traces of 3HHp monomers confirmed through gas chromatography (GC), proton (1H) and carbon (13C) NMR spectra. Conclusion, significance and impact of study: This study has revealed that the PHA synthase of Chromobacterium sp. USM2 has a broad range of substrate specificity. The synthase is able to polymerize 3-hydroxyalkanoate monomers having 4–7 carbon atoms.
ABSTRACT
Phytases are a group of enzymes that catalyze phytic acid hydrolysis with release of phosphorus (P). The ability of Chromobacterium sp. to produce phytase was detected in 115 out of 118 candidate bacteria isolated from different Brazilian biomas. This is the first report revealing the genus Chromobacterium as phytase producer.