In vitro cytotoxicity of nonpolar constituents from different parts of kava plant (Piper methysticum).

Kava (Piper methysticum), a perennial shrub native to the South Pacific islands, has been used to relieve anxiety. Recently, several cases of severe hepatotoxicity have been reported from the consumption of dietary supplements containing kava. It is unclear whether the kava constituents, kavalactones, are responsible for the associated hepatotoxicity.

Degradation of benz[a]anthracene by Mycobacterium vanbaalenii strain PYR-1.

Cultures of Mycobacterium vanbaalenii strain PYR-1 grown in mineral salts medium and nutrients in the presence of benz[a]anthracene metabolized 15% of the added benz[a]anthracene after 12 days of incubation. Neutral and acidic ethyl acetate extractable metabolites were isolated and characterized by high performance liquid chromatography (HPLC) and uv-visible absorption, gas chromatography/mass (GC/MS) and nuclear magnetic resonance (NMR) spectral analysis. Trimethylsilylation of the metabolites followed by GC/MS analysis facilitated identification of metabolites.

Fungal biotransformation of benzo[f]quinoline, benzo[h]quinoline, and phenanthridine.

Cultures of Umbelopsis ramanniana (=Mucor ramannianus) were grown in fluid Sabouraud medium for 3 days, dosed with 0.23 mM benzo[f]quinoline, benzo[h]quinoline, or phenanthridine (benzo[c]quinoline), and incubated for another 18 days. Cultures were extracted and metabolites (66-75% of the UV absorbance) were separated by high-performance liquid chromatography.

Effects of pH on the degradation of phenanthrene and pyrene by Mycobacterium vanbaalenii PYR-1.

The effects of pH on the growth of Mycobacterium vanbaalenii PYR-1 and its degradation of phenanthrene and pyrene were compared at pH 6.5 and pH 7.5.

Evidence for the existence of PAH-quinone reductase and catechol-O-methyltransferase in Mycobacterium vanbaalenii PYR-1.

Polycyclic aromatic hydrocarbon (PAH) quinone reductase (PQR) and catechol-O-methyltransferase (COMT), from the PAH-degrading Mycobacterium vanbaalenii PYR-1, were demonstrated to be constitutive enzymes located in the soluble fraction of cell extracts. PQR activities for the reduction of 9,10-phenanthrenequinone and 4,5-pyrene- quinone were 1.40+/-0.

Metabolism of aromatic hydrocarbons by the filamentous fungus Cyclothyrium sp.

The metabolism of biphenyl, naphthalene, anthracene, phenanthrene, pyrene and benzo[a]pyrene by Cyclothyrium sp. CBS 109850, a coelomycete isolated for the first time in Brazil from industrially polluted estuarine sediment, was studied. The metabolites were extracted and separated by high performance liquid chromatography (HPLC) and characterized by UV spectral analyses and mass, and proton nuclear magnetic resonance ((1)H NMR) spectrometry.

Degradation of benzo[a]pyrene by Mycobacterium vanbaalenii PYR-1.

Metabolism of the environmental pollutant benzo[a]pyrene in the bacterium Mycobacterium vanbaalenii PYR-1 was examined. This organism initially oxidized benzo[a]pyrene with dioxygenases and monooxygenases at C-4,5, C-9,10, and C-11,12. The metabolites were separated by reversed-phase high-performance liquid chromatography (HPLC) and characterized by UV-visible, mass, nuclear magnetic resonance, and circular dichroism spectral analyses.

Regio- and stereoselective metabolism of 7,12-dimethylbenz[a]anthracene by Mycobacterium vanbaalenii PYR-1.

The degradation of 7,12-dimethylbenz[a]anthracene (DMBA), a carcinogenic polycyclic aromatic hydrocarbon, by cultures of Mycobacterium vanbaalenii PYR-1 was studied. When M. vanbaalenii PYR-1 was grown in the presence of DMBA for 136 h, high-pressure liquid chromatography (HPLC) analysis showed the presence of four ethyl acetate-extractable compounds and unutilized substrate.

Synthesis and characterization of N-demethylated metabolites of malachite green and leucomalachite green.

Malachite green (MG), a triphenylmethane dye used to treat fungal and protozoan infections in fish, undergoes sequential oxidation to produce various N-demethylated derivatives (monodes-, dides(sym)-, dides(unsym)-, trides-, and tetrades-) both before and after reduction to leucomalachite green (LMG). The close structure resemblance of the metabolites with aromatic amine carcinogens implicates a potential genotoxicity from exposure to MG. The availability of the synthetic standards is important for metabolic and DNA adduct studies of MG.

Biotransformation of mirtazapine by Cunninghamella elegans.

The fungus Cunninghamella elegans was used as a microbial model of mammalian metabolism to biotransform the tetracyclic antidepressant drug mirtazapine, which is manufactured as a racemic mixture of R(-)- and S(+)-enantiomers. In 168 h, C. elegans transformed 91% of the drug into the following seven metabolites: 8-hydroxymirtazapine, N-desmethyl-8-hydroxymirtazapine, N-desmethylmirtazapine, 13-hydroxymirtazapine, mirtazapine N-oxide, 12-hydroxymirtazapine, and N-desmethyl-13-hydroxymirtazapine.

Transformation of cinoxacin by Beauveria bassiana.

The ability of the fungus Beauveria bassiana ATCC 7159 to transform the antibacterial agent cinoxacin was investigated. Cultures in sucrose-peptone broth were dosed with cinoxacin, grown for 20 days, and then extracted with ethyl acetate. Two metabolites were detected and purified by high-performance liquid chromatography.

Formation of conjugates from ciprofloxacin and norfloxacin in cultures of Trichoderma viride.

The formation of conjugates from two antibacterial fluoroquinolone drugs, ciprofloxacin and norfloxacin, was observed in cultures of Trichoderma viride that had been grown in sucrose-peptone broth and extracted 16 d after dosing with the drugs. Both conjugates were purified by high-performance liquid chromatography and found to be optically active. They were identified by mass and proton nuclear magnetic resonance spectra as 4-hydroxy-3-oxo-4-vinylcyclopent-1-enyl ciprofloxacin and 4-hydroxy-3-oxo-4-vinylcyclopent-1-enyl norfloxacin.