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The impact of benzoic acids, metabolites of flavonoids, on the iron-catalysed Fenton reaction
Klenovičová, Alexandra ; Mladěnka, Přemysl (advisor) ; Karlíčková, Jana (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Alexandra Klenovičová Supervisor: Prof. Přemysl Mladěnka, PharmDr., Ph.D. Consultant: Zuzana Lomozová, Ph.D. Title of diploma thesis: The impact of benzoic acids, metabolites of flavonoids, on the iron-catalysed Fenton reaction Oxidative stress is a condition in which there is an increased production of free radicals that exceeds endogenous antioxidant activity and leads to damage of biomolecules. A number of human diseases are associated with oxidative stress. However the use of antioxidants has failed in clinical trials, but it is possible that the fact that antioxidants may preferentially exhibit prooxidant activity under elevated antioxidant concentrations in various pathophysiological conditions. Various in vitro and epidemiological studies have confirmed the presence of antioxidant and prooxidant properties in flavonoids. However, on the basis of their pharmacokinetics, it is evident that after their oral intake, significant metabolism in the colon takes place, where small phenolic substances are formed in interaction with the intestinal microflora. There is a possibility that the antioxidant and harmful prooxidant properties that have been attributed to flavonoids are in fact a...
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The influence of benzoic acids (metabolites of flavonoids) on the copper-triggered Fenton reaction and hemolysis
Harčárová, Patrícia ; Lomozová, Zuzana (advisor) ; Karlíčková, Jana (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacognosis and Pharmaceutical Botany Student: Patrícia Harčárová Supervisor: Zuzana Lomozová, MSc., Ph.D. Title of diploma thesis: Effect of benzoic acids (flavonoid metabolites) on copper catalyzed Fenton reaction and hemolysis Keywords: flavonoids, benzoic acids, copper, Fenton reaction, hemolysis Copper is a biogenic trace element that is present in several enzymes and proteins in the human body. The ability of copper to change its oxidation state is essential for its biological functions and enables enzymatic redox reactions in the organism. Homeostasis of copper is strictly regulated in the human body as its disruption can lead to the toxic effects of copper. Flavonoids are secondary plant metabolites that are a common part of our diet and their consumption has positive effects on our bodies. However, under certain conditions, they can also have a pro-oxidative effect, which is related to their ability to reduce transition metal ions. Flavonoids are massively metabolized in the human body before reaching systemic circulation into small phenolic substances including benzoic acids. Seven benzoic acid derivatives were tested as part of this thesis. Their influence on the production of hydroxyl radicals arising during the...
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Novel Approaches in Electrochemical Determination of Xenobiotic Compounds and in Study of Their Interaction with DNA
Hájková, Andrea ; Vyskočil, Vlastimil (advisor) ; Trnková, Libuše (referee) ; Labuda, Ján (referee)
Presented Ph.D. Thesis is focused on the development of analytical methods applicable for determination of selected xenobiotic compounds and for monitoring DNA damage they can induce. The main attention has been paid to the development and testing of non-toxic electrode materials for preparation of miniaturized electrochemical devices and novel electrochemical DNA biosensors. 2-Aminofluoren-9-one (2-AFN) was selected as a model environmental pollutant, which belongs to the group of hazardous genotoxic substances. Its carcinogenic and mutagenic effects may represent a risk to living and working environment. 2-AFN has one oxo group, where the cathodic reduction occurs, and one amino group, where the anodic oxidation occurs. The voltammetric behavior of 2-AFN in the negative potential region was investigated at a mercury meniscus modified silver solid amalgam electrode (m-AgSAE) representing a non-toxic and more mechanically robust alternative to mercury electrodes. This working electrode was subsequently used for the development of a newly designed miniaturized electrode system (MES), which has many benefits as the possibility of simple field measurements, easy portability, and the measurement in sample volume 100 µL. Moreover, a glassy carbon electrode (GCE) was used for further investigation of...
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Use of Fenton Reaction for Drug Degradation in the Ecosystem
Tomešová, Lenka ; Smrček, Stanislav (advisor) ; Břichnáčová Habartová, Věra (referee)
The elimination of unwanted substances from the ecosystem can be accomplished by advanced oxidation processes (AOP). AOPs are used preferably in treatment of wastewater. One of the AOP's methods is Fenton's reaction. The degradation of drug residues by this reaction was the aim the project. The experiments were focused on finding possible degradation products, which could be much more hazardous than parent compounds. The study was primarily concerned with non-steroidal anti-inflammatory drugs (acetaminophen, diclofenac, ibuprofen, naproxen and salicylic acid) and antiepileptic carbamazepine. The complete decomposition of tested compounds was not observed by using HPLC and MS analysis. The products of decomposition were found in reaction mixture, in case of diclofenac dechloration of aromatic ring occurred. In cases of most compounds with exception of acetoaminophen and salicylic acid the reaction led to the formation of more polar products than parent compounds. The results imply that even more advanced oxidation processes do not cause complete destruction of organic compounds. Key words: Fentons reaction, drug residues, acetaminophen, diclofenac, ibuprofen, carbamazepine, naproxen, salicylic acid.
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Novel Approaches in Electrochemical Determination of Xenobiotic Compounds and in Study of Their Interaction with DNA
Hájková, Andrea
Presented Ph.D. Thesis is focused on the development of analytical methods applicable for determination of selected xenobiotic compounds and for monitoring DNA damage they can induce. The main attention has been paid to the development and testing of non-toxic electrode materials for preparation of miniaturized electrochemical devices and novel electrochemical DNA biosensors. 2-Aminofluoren-9-one (2-AFN) was selected as a model environmental pollutant, which belongs to the group of hazardous genotoxic substances. Its carcinogenic and mutagenic effects may represent a risk to living and working environment. 2-AFN has one oxo group, where the cathodic reduction occurs, and one amino group, where the anodic oxidation occurs. The voltammetric behavior of 2-AFN in the negative potential region was investigated at a mercury meniscus modified silver solid amalgam electrode (m-AgSAE) representing a non-toxic and more mechanically robust alternative to mercury electrodes. This working electrode was subsequently used for the development of a newly designed miniaturized electrode system (MES), which has many benefits as the possibility of simple field measurements, easy portability, and the measurement in sample volume 100 µL. Moreover, a glassy carbon electrode (GCE) was used for further investigation of...
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Novel Approaches in Electrochemical Determination of Xenobiotic Compounds and in Study of Their Interaction with DNA
Hájková, Andrea ; Vyskočil, Vlastimil (advisor) ; Trnková, Libuše (referee) ; Labuda, Ján (referee)
Presented Ph.D. Thesis is focused on the development of analytical methods applicable for determination of selected xenobiotic compounds and for monitoring DNA damage they can induce. The main attention has been paid to the development and testing of non-toxic electrode materials for preparation of miniaturized electrochemical devices and novel electrochemical DNA biosensors. 2-Aminofluoren-9-one (2-AFN) was selected as a model environmental pollutant, which belongs to the group of hazardous genotoxic substances. Its carcinogenic and mutagenic effects may represent a risk to living and working environment. 2-AFN has one oxo group, where the cathodic reduction occurs, and one amino group, where the anodic oxidation occurs. The voltammetric behavior of 2-AFN in the negative potential region was investigated at a mercury meniscus modified silver solid amalgam electrode (m-AgSAE) representing a non-toxic and more mechanically robust alternative to mercury electrodes. This working electrode was subsequently used for the development of a newly designed miniaturized electrode system (MES), which has many benefits as the possibility of simple field measurements, easy portability, and the measurement in sample volume 100 µL. Moreover, a glassy carbon electrode (GCE) was used for further investigation of...
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Use of Fenton Reaction for Drug Degradation in the Ecosystem
Tomešová, Lenka ; Smrček, Stanislav (advisor) ; Břichnáčová Habartová, Věra (referee)
The elimination of unwanted substances from the ecosystem can be accomplished by advanced oxidation processes (AOP). AOPs are used preferably in treatment of wastewater. One of the AOP's methods is Fenton's reaction. The degradation of drug residues by this reaction was the aim the project. The experiments were focused on finding possible degradation products, which could be much more hazardous than parent compounds. The study was primarily concerned with non-steroidal anti-inflammatory drugs (acetaminophen, diclofenac, ibuprofen, naproxen and salicylic acid) and antiepileptic carbamazepine. The complete decomposition of tested compounds was not observed by using HPLC and MS analysis. The products of decomposition were found in reaction mixture, in case of diclofenac dechloration of aromatic ring occurred. In cases of most compounds with exception of acetoaminophen and salicylic acid the reaction led to the formation of more polar products than parent compounds. The results imply that even more advanced oxidation processes do not cause complete destruction of organic compounds. Key words: Fentons reaction, drug residues, acetaminophen, diclofenac, ibuprofen, carbamazepine, naproxen, salicylic acid.
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Novel Approaches in Electrochemical Determination of Xenobiotic Compounds and in Study of Their Interaction with DNA
Hájková, Andrea
Presented Ph.D. Thesis is focused on the development of analytical methods applicable for determination of selected xenobiotic compounds and for monitoring DNA damage they can induce. The main attention has been paid to the development and testing of non-toxic electrode materials for preparation of miniaturized electrochemical devices and novel electrochemical DNA biosensors. 2-Aminofluoren-9-one (2-AFN) was selected as a model environmental pollutant, which belongs to the group of hazardous genotoxic substances. Its carcinogenic and mutagenic effects may represent a risk to living and working environment. 2-AFN has one oxo group, where the cathodic reduction occurs, and one amino group, where the anodic oxidation occurs. The voltammetric behavior of 2-AFN in the negative potential region was investigated at a mercury meniscus modified silver solid amalgam electrode (m-AgSAE) representing a non-toxic and more mechanically robust alternative to mercury electrodes. This working electrode was subsequently used for the development of a newly designed miniaturized electrode system (MES), which has many benefits as the possibility of simple field measurements, easy portability, and the measurement in sample volume 100 µL. Moreover, a glassy carbon electrode (GCE) was used for further investigation of...
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