M Consuelo Cuquerella

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Photoreaction of 1-ethyl-6-fluoro-7-(1-piperazinyl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (norfloxacin, NFX) and other 6-fluoroquinolones in aqueous solution gives rise to the corresponding 6-hydroxy derivatives. Although two mechanisms have been proposed for this photonucleophilic aromatic substitution, direct evidence for any of them is still(More)
The photophysical properties of 1-ethyl-6-fluoro-7-(1-piperazinyl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (norfloxacin, NFX) and some of its derivatives have been studied to evaluate the role of the free carboxylic acid and the nonprotonated piperazinyl group in the behavior of the 1,4-dihydro-4-oxoquinoline ring. Steady state and time-resolved(More)
A series of fluoroquinolones (FQs), including enoxacin (ENX), pefloxacin (PFX), norfloxacin (NFX), its N(4')-acetyl derivative (ANFX), ofloxacin (OFX), and rufloxacin (RFX) have been investigated to determine their potential as DNA photosensitizers via thymine cyclobutane dimer (T<>T) formation in DNA. At fluoroquinolone concentrations and light doses(More)
Although the carcinogenic potential of ultraviolet radiation is well-known, UV light may interact with DNA by direct absorption or through photosensitization by endogenous or exogenous chromophores. These chromophores can extend the "active" fraction of the solar spectrum to the UVA region and beyond, which means that photosensitizers increase the(More)
The aim of the present work is to determine the influence of C5 substitution on the photophysical properties of 2-thiopyrimidines (2-TPyr). For this purpose, 2-thiouracil, 5-t-butyl-2-thiouracil and 2-thiothymine (TU, BTU and TT, respectively) have been selected as target thionucleobases for the experimental studies and, in parallel, for DFT theoretical(More)
Two cholic acid (ChA) analogues, containing a 4-nitrobenzo-2-oxa-1,3-diazole (NBD) moiety at C-3, were incorporated into ChA aggregates and submitted to fluorescence quenching by the two enantiomers of several tryptophan derivatives. In all cases, a significant stereodifferentiation was observed; the most remarkable effect was found when comparing the(More)
The role played by type I (radical) and type II (singlet oxygen) mechanisms in the Rufloxacin (RFX)-photoinduced production of 8-hydroxy-2'-deoxyguanosine in DNA has been evaluated. This fluoroquinolone drug has been shown to be able to photoinduce increased levels of some DNA base oxidation products, such as 8-OH-dGuo, that are indicative of mutagenic and(More)
Photodegradation of ofloxacin (OFX) under aerobic conditions gives rise to N-demethylation, mainly involving coupling of radical cation OFX(*)(+ )()with superoxide radical anion. Although H(2)O(2) is produced as a byproduct, oxidative damage to DNA to give 8-OH-dGuo is associated with a type II mechanism. When the photosensitizing potentials of OFX and(More)
Although the phototoxic and photoallergic properties of fluoroquinolone antibiotics (FQ) are remarkable, the mechanisms involved in these processes are not completely understood. For this reason, it is considered worthwhile to study in detail the photochemical interactions of lomefloxacin (LFX) and its N-acetyl derivative ALFX, two 6,8-dihalogenated(More)