Bartosz Kędzierski

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1. Pyrrolizidine alkaloids (PAs) are metabolized primarily to putative dehydroalkaloid (PA pyrrole) metabolites and to PA N-oxide by rat liver microsomal monooxygenases. 2. The dehydroalkaloids are highly reactive and either bind covalentely to tissue nucleophiles or are hydrolysed to the more stable pyrrole,(More)
Rats display a marked sex difference in the oxidation of the pyrrolizidine alkaloid senecionine, especially with respect to N-oxidation. This sex difference was largely eliminated following treatment with dexamethasone. These observations suggested the potential involvement of the male-specific cytochrome P-450 UT-A and the P-450 PCN-E in the metabolism of(More)
The pyrrolizidine alkaloid, senecionine, is N-oxidized by purified pig liver flavin-containing monooxygenase but not by purified rabbit lung flavin-containing monooxygenase. The activity of the pig liver enzyme toward senecionine was linear with time and amount of enzyme. The oxygenation was not due to some indirect mechanism, such as O2- release from the(More)
The commonly accepted belief regarding the configuration of the major pyrrole metabolite of pyrrolizidine alkaloids has been revised. This paper provides evidence that a racemic mixture of (+/-) 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine is the product of the microsomal transformation of esters of heliotridine and retronecine instead of pure(+) or(More)
An improved method utilizing reverse-phase liquid chromatography on a styrene-divinylbenzene column (PRP-1) and ultraviolet detection was developed for the simultaneous determination of the pyrrolizidine alkaloids (PAs) senecionine, seneciphylline, and retrorsine and their major metabolites produced during in vitro transformation of PAs by microsomal enzyme(More)
The (+)- and (-)-enantiomers of benzo[a]pyrene 7,8-oxide are hydrated stereospecifically at C-8 to (-)- and (+)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene, respectively, by rat hepatic epoxide hydrolase. The (-)-enantiomer of benzo[a]pyrene 7,8-oxide is metabolized by microsomal epoxide hydrolase at a rate 3- to 4-fold greater than the (+)-enantiomer. At(More)
The authors describe a patient with an extensive inflammation of the neck soft tissues as a complication of the peritonsillar abscess. Follow-up computed tomography revealed gasi-form follicles in the inflammed neck soft tissues, suggesting gas gangrene. We report disseminate ways of the inflammation process on the financial tonsil, reasons of the gangrene(More)
In this study, the optimisation of horse chestnut seed extraction was performed to determine the best extraction solvent in the recovery of pharmacologically active escin from raw material. All extracts were obtained by accelerated solvent extraction and were analysed for their antioxidant potential (DPPH test), phenolic content (Folin-Ciocalteu (FC) assay)(More)