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  • Author or Editor: Péter Móricz x
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The isolation and characterization of antibacterial chamomile components were performed by the use of direct bioautography and solid phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS). Four ingredients, active against Vibrio fischeri, were identified as the polyacetylene geometric isomers cisand trans-spiroethers, the coumarin related herniarin, and the sesquiterpene alcohol (−)-alpha-bisabolol.

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The aim of the present study was the chemical characterization of some medically relevant essential oils (tea tree, clove, cinnamon bark, thyme, and eucalyptus) and the investigation of antibacterial effect of the components of these oils by use of a direct bioautographic method. Thin-layer chromatography (TLC) was combined with biological detection in this process. The chemical composition of the oils was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Eucalyptol (84.2%) was the main component of the essential oil of eucalyptus, eugenol (83.7%) of clove oil, and trans-cinnamic aldehyde (73.2%), thymol (49.9%), and terpinen-4-ol (45.8%) of cinnamon bark, thyme and tea tree oils, respectively. Antibacterial activity of the separated components of these oils as well as of their pure main components (eucalyptol, eugenol, trans-cinnamic aldehyde and thymol) was observed against the Gram-negative luminescence gene-tagged plant pathogenic bacterium Pseudomonas syringae pv. maculicola (Psmlux) and the Gram-negative, naturally luminescent marine bacterium Vibrio fischeri. On the whole, the antibacterial activity of the essential oils could be related to their main components, but the minor constituents may be involved in this process. trans-Cinnamic aldehyde and eugenol were the most active compounds in TLC-bioautography. The sensitivity of TLC-bioautographic method can be improved by using luminescent test bacteria. This method is more cost-effective and provides more reliable results in comparison with conventional microbiological methods, e.g., disc-diffusion technique.

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The BioArena system, which integrates the up-to-date methodology and biological results of bioautography with OPLC as an efficient planar separation technique (compact spots, etc.), is especially suitable for investigating biochemical interactions in an adsorbent bed after chromatographic separation. The first results from BioArena show that formaldehyde (HCHO), which can originate from pathogen cells in some situations, can play a special role in the antibiotic activity of trans -resveratrol. When l -arginine and glutathione were used as endogenous HCHO-capturing molecules in the culture medium the antimicrobial activity of trans -resveratrol on the adsorbent layer decreased substantially. It has been observed that trans -resveratrol generates a time-dependent, and therefore concentration-dependent, duplicate inhibiting effect on the pathogen, and that the BioArena system was suitable for illustration of this new phenomenon. It is probable that this effect occurs as a result of HCHO, with special emphasis on the possibility of interaction between the HCHO and H 2 O 2 of endogenous origin on the adsorbent layer incubated with pathogen cells. It seems that the BioArena system will be an important, indispensable complement to the basic separation technique OPLC.

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JPC - Journal of Planar Chromatography - Modern TLC
Authors: Ernő Tyihák, Ágnes Móricz, Péter Ott, György Kátay and Zsuzsa Király-Véghely

New results with BioArena as a complex separation and detection (evaluation) system support earlier observations that formaldehyde (HCHO) and its reaction products play a special and crucial role in the effects of antibiotic in general. It has been established that antibiotic-like compounds (e.g. trans -resveratrol, Cu(II) ions) have a duplicate inhibiting effect on pathogen cells as a result of the action of HCHO. HCHO as a key molecule of the formaldehydome participates in series of interactions which can be screened by means of different spectroscopic and chromatographic techniques; accumulation of HCHO and its reaction products in TLC spots is limited, however, so indirect detection is advantageous. In BioArena the planar stationary phase bed after TLC/HPTLC and, mainly, OPLC separation can be used for manifestation of deprivation of HCHO from antibiotic spots, for observation of the duplicate effect of substances with a direct effect, and for demonstration of cell proliferation promotion and retardation.

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The BioArena system, which integrates the modern technique and biological results of bioautography with layer liquid chromatography is especially suitable for investigating biochemical interactions. Formaldehyde (HCHO) and its reaction products play a crucial role in the antibiotic activity of trans -resveratrol and other molecules — when HCHO-capturing molecules are used in culture media the antimicrobial activity of antibiotic-like compounds decreases substantially. HCHO and hydrogen peroxide are present as normal endogenous compounds in cells, so there is a possibility of interaction in which singlet oxygen ( 1 O 2 ) and excited HCHO can be formed. The 1 O 2 can oxidize water molecules and so H 2 O 3 can be formed, from which, by disproportion, among other reactions, ozone (O 3 ) also can be formed in the chromatographic spots. Elimination of HCHO and/or O 3 from the spots results in a decrease in the antiproliferative effect.

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JPC - Journal of Planar Chromatography - Modern TLC
Authors: Emil Mincsovics, Péter Ott, Ágnes Alberti, Andrea Böszörményi, Éva Héthelyi, Éva Szőke, Ágnes Kéry, Éva Lemberkovics and Ágnes Móricz

Bioassay-guided isolation of antibacterial components of chamomile flower methanol extract was performed by overpressured layer chromatography (OPLC) with on-line detection, fractionation combined with sample clean-up in-situ in the adsorbent bed after off-line sample application. The antibacterial effect of the eluted fractions and of those compounds remaining on the adsorbent layer after separation was tested with direct bioautography (DB) against the bioluminescent Pseudomonas savastanoi pv. maculicola and Vibrio fischeri. The fractions with high biological activity were analyzed by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and liquid chromatography and tandem mass spectrometry (LC-MS/MS). Two active uneluted compounds were characterized by off-line OPLC-MS using a thin-layer chromatography (TLC)-MS interface. Mainly, essential oil components, coumarins, flavonoids, phenolic acids, and fatty acids were identified in the active fractions.

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