Fluorescence quenching of fluoroquinolone antibiotics by 4-hydroxy-TEMPO in aqueous solution

Żamojć, Krzysztof; Wiczk, Wiesław; Zaborowski, Bartłomiej; Makowski, Mariusz; Pranczk, Joanna; Jacewicz, Dagmara; Chmurzyński, Lech

doi:10.1016/j.saa.2014.06.127

Cited by 18 publications

(8 citation statements)

References 25 publications

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“…In the chosen range of nitroxides' concentrations, there are no deviations from the observed linearity-the fluorescence quenching shows very clearly a linear dependence such as the one represented by the Stern-Volmer equation. Since it has been previously proven that 4-hydroxy-TEMPO impacts (shortens) on a fluorescence lifetime of selected fluoroquinolones [32], it indicates that dynamic, collisional fluorescence quenching occurred. Consequently, Table 1 presents the newly determined values of Stern-Volmer dynamic quenching constants (K D ) along with linear correlation coefficients (R 2 ) for Stern-Volmer plots and bimolecular quenching rate constants (k q ) obtained for the studied systems.…”

Section: Resultsmentioning

confidence: 99%

Fluorescence Quenching Studies on the Interactions between Chosen Fluoroquinolones and Selected Stable TEMPO and PROXYL Nitroxides

Żamojć

Bylińska

Wiczk

et al. 2021

IJMS

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The influence of the stable 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) nitroxide and its six C4-substituted derivatives, as well as two C3-substituted analogues of 2,2,5,5-tetramethylpyrrolidynyl-N-oxyl (PROXYL) nitroxide on the chosen fluoroquinolone antibiotics (marbofloxacin, ciprofloxacin, danofloxacin, norfloxacin, enrofloxacin, levofloxacin and ofloxacin), has been examined in aqueous solutions by UV absorption as well as steady-state and time-resolved fluorescence spectroscopies. The mechanism of fluorescence quenching has been specified and proved to be purely dynamic (collisional) for all the studied systems, which was additionally confirmed by temperature dependence experiments. Moreover, the selected quenching parameters—that is, Stern–Volmer quenching constants and bimolecular quenching rate constants—have been determined and explained. The possibility of electron transfer was ruled out, and the quenching was found to be diffusion-limited, being a result of the increase in non-radiative processes. Furthermore, as the chosen nitroxides affected the fluorescence of fluoroquinolone antibiotics in different ways, an influence of the structure and the type of substituents in the molecules of both fluoroquinolones and stable radicals on the quenching efficiency has been determined and discussed. Finally, the impact of the solvent’s polarity on the values of bimolecular quenching rate constants has been explained. The significance of the project comes from many applications of nitroxides in chemistry, biology and industry.

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Section: Resultsmentioning

confidence: 99%

Fluorescence Quenching Studies on the Interactions between Chosen Fluoroquinolones and Selected Stable TEMPO and PROXYL Nitroxides

Żamojć

Bylińska

Wiczk

et al. 2021

IJMS

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“…Although the studies on the fluorescence quenching (performed with steady state and transient methods) provide much information mainly about fluorescent dyes [21][22][23][24], such a technique has not been widely used for studies on TEMPO compounds as quenchers yet [25][26][27].…”

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confidence: 99%

Fluorescence quenching of 7-amino-4-methylcoumarin by different TEMPO derivatives

Żamojć

Wiczk

Zaborowski

et al. 2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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“…In this work we demonstrate a method for the detection and determination of 4-amino-TEMPO in aqueous solution using dihydroxycoumarins as fluorescent probes. We have previously examined the interactions between another stable nitroxide radical, namely 4-hydroxy-TEMPO, and various fluorescent species, i.e., polycyclic aromatic hydrocarbons [31] and coumarins [32,33], as well as fluoroquinolone antibiotics [34]. In most cases, we observed the strictly physical interactions between the reactants and the nitroxide, which acted as a fluorescence quencher.…”

Section: Introductionmentioning

confidence: 99%

Dihydroxy-Substituted Coumarins as Fluorescent Probes for Nanomolar-Level Detection of the 4-Amino-TEMPO Spin Label

Żamojć

Zdrowowicz

Hać

et al. 2019

IJMS

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This paper reports on dihydroxycoumarins as fluorescent probes suitable for the detection and determination of the nitroxide radical, namely 4-amino-TEMPO. Since 4-amino-TEMPO is used as a spin label for the detection of various radicals and damage caused by these species, its determination under physiological conditions might help us to understand the mechanism of the oxidative stress. Among different coumarins studied, only dihydroxy-substituted derivatives show high sensitivity, specificity, and selectivity for the nitroxide radical. In this assay, dihydroxy-substituted coumarins under the action of 4-amino-TEMPO show a very fast and significant increase in fluorescence intensity and lifetime. Among them 6,7-dihydroxycoumarin (esculetin) exhibits the strongest fluorescence enhancement (up to 40 times), with an estimated limit of detection equal to 16.7 nM—a significantly lower value when compared with UV-Vis or electron paramagnetic resonance (EPR) spectroscopy. The method is characterized by an easy procedure of sample preparation and very short time of analysis. The mechanism of the interaction between 6,7-dihydroxycoumarin and 4-amino-TEMPO has been examined with the use of a series of complementary techniques, such as steady-state and time-resolved fluorescence spectroscopy, UV-Vis spectroscopy, electron paramagnetic resonance spectroscopy, potentiometric titration, and high-performance liquid chromatography. It has been proven that the only route of the reaction in the system studied is a proton transfer from the molecule of esculetin to the amino group of the nitroxide. Biological studies performed on prostate cancer cells, breast cancer cells, and normal skin fibroblasts revealed significant anticancer properties of 6,7-dihydroxycoumarin, which caused a considerable decrease in the viability and number of cancer cells, and affected their morphology, contrary to normal fibroblasts. Furthermore, the experiment performed on prostate cancer cells showed that fluorescence emission of esculetin is closely related to intracellular pH—the higher pH, the higher observed fluorescence intensity (in accordance with a chemical experiment). On the other hand, the studies performed in different pH levels revealed that when pH of the solution increases, the observed fluorescence intensity enhancement under the action of 4-amino-TEMPO decreases (better sensing properties of esculetin towards the nitroxide in lower pH).

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Fluorescence quenching of fluoroquinolone antibiotics by 4-hydroxy-TEMPO in aqueous solution

Cited by 18 publications

References 25 publications

Fluorescence Quenching Studies on the Interactions between Chosen Fluoroquinolones and Selected Stable TEMPO and PROXYL Nitroxides

Fluorescence Quenching Studies on the Interactions between Chosen Fluoroquinolones and Selected Stable TEMPO and PROXYL Nitroxides

Fluorescence quenching of 7-amino-4-methylcoumarin by different TEMPO derivatives

Dihydroxy-Substituted Coumarins as Fluorescent Probes for Nanomolar-Level Detection of the 4-Amino-TEMPO Spin Label

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