The photosensitizing activity of enoxacin, 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)- ... more The photosensitizing activity of enoxacin, 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)- 1,8-naphthyridine-3-carboxilic acid (ENX), toward membranes and DNA has been studied, taking into account human erythrocyte photohemolysis, unilamellar liposome alterations and plasmid pBR322 DNA photocleavage. Hydroxyl radicals and an aromatic carbene generated from ENX photodefluorination seem to be the active intermediates involved in the photosensitization process. The steady-state photolysis products do not participate in the process. The mechanism of photosensitization responsible for the membrane damage depends on the oxygen concentration and follows a different path with respect to that operative for DNA cleavage. Between oxygenated radicals, the hydroxyl seems the species mainly responsible for membrane damage, whereas DNA cleavage is mainly produced by the carbene intermediate. A molecular mechanism of the photosensitization induced by ENX is proposed.
We report the first example of a molecular switch of multifunctional dipolar ruthenium(III/II) pe... more We report the first example of a molecular switch of multifunctional dipolar ruthenium(III/II) pentaammine-N-methyl-(4,4'-bipyridinium) complexes, exclusively driven by light. This is achieved by using a two-phase (water/benzene) system in which RuIII/II complexes are soluble only in the water phase. The reversible redox switching is triggered by the selective irradiation of the water and the benzene compartments with 254 and 528 nm light, respectively.
In the present work, the preparation and characterization of hydrogels based on α,β-polyaspartylh... more In the present work, the preparation and characterization of hydrogels based on α,β-polyaspartylhydrazide (PAHy) chemically crosslinked with ethyleneglycol diglycidylether (EGDGE) containing Tolmetin sodium salt, are reported. In particular, these samples have been prepared both as water swellable microparticles and as gels at two different crosslinking degrees. The incorporation of Tolmetin sodium salt in PAHy–EGDGE microparticles has been performed after the
The photochemistry of 2-(3-benzoylphenyl) propionic acid (Ketoprofen) has been studied in the β-c... more The photochemistry of 2-(3-benzoylphenyl) propionic acid (Ketoprofen) has been studied in the β-cyclodextrin cavity by stationary and time-resolved (picosecond and nanosecond) spectroscopic techniques. Conformational calculations of the inclusion complex were ...
Phosphate buffer suspensions of unilamellar liposomes of phosphatidylcholine were irradiated with... more Phosphate buffer suspensions of unilamellar liposomes of phosphatidylcholine were irradiated with UVC (254 nm) and UVB (300 nm) light. The irradiation provoked lipid peroxidation and liposome lysis with release of entrapped glucose-6-phosphate. At the same intensity of absorbed light, the photochemical effect at 254 nm is higher than at 300 nm. The addition of copper(II) and manganese(II) reduced both the
The effects of a novel cationic amphiphilic cyclodextrin (SC6CDNH2) on the photoprocesses of the ... more The effects of a novel cationic amphiphilic cyclodextrin (SC6CDNH2) on the photoprocesses of the phototoxic non-steroidal anti-inflammatory drug diflunisal (DF) have been investigated in aqueous medium. Association between DF and SC6CDNH2 was indicated by steady-...
... Mariarita Barone, Angela Mascali and Salvatore Sortino*. Dipartimento di Scienze Chimiche, Un... more ... Mariarita Barone, Angela Mascali and Salvatore Sortino*. Dipartimento di Scienze Chimiche, Università di Catania, Viale Andrea Doria 8, I-95125, Catania, Italy. E-mail: ssortino@unict.it. ... 14, See, for example: AC Templeton, WP Wuelfing and RW Murray, Acc. Chem. ...
This work reports on the structural and spectroscopic properties of ethane-bridged Zn porphyrin d... more This work reports on the structural and spectroscopic properties of ethane-bridged Zn porphyrin dimers (1) in Langmuir-Schäfer (LS) thin films by combining scanning force microscopy (SFM) with film balance, UV-vis absorption, fluorescence, and nanosecond laser flash photolysis measurements. Results show that depending on the surface pressure the Langmuir films of pure 1 can be arranged in two different condensed phases, whereas SFM of the LS films shows characteristic fractal networks constituted by nanoscopic aggregates. The spectral findings agree with a picture in which 1 is apparently present in the anti conformation but aggregated in a sort of H-type structure whose optical features resemble those of the syn conformer. This type of structure is not responsive to light stimuli. By diluting 1 in arachidic acid the porphyrin aggregation is significantly minimized with 1 exhibiting almost exclusively the anti conformation. As a result the LS films become photoresponsive, showing fluorescence emission and triplet-triplet transient absorption.
The behavior of the symmetrical ethane-bridged bis(Zn porphyrin) (1) has been investigated at the... more The behavior of the symmetrical ethane-bridged bis(Zn porphyrin) (1) has been investigated at the airwater interface. The molecular organization of floating films of pure 1 and its mixture with amphiphilic substances, such as arachidic acid and n-octadecylamine, was ...
The photodegradation of the S(+)- and R(-)-ketoprofen (KP) enantiomers in the bovine serum albumi... more The photodegradation of the S(+)- and R(-)-ketoprofen (KP) enantiomers in the bovine serum albumin matrix was studied by steady-state photolysis with the use of lambda(irr) > 320 nm and transient absorption spectroscopy with lambda(exc) = 355 nm, at 1/1 and 2/1 KP/BSA molar ratios. R(-)-KP was found to be more labile than S(+). Triplet ketoprofen species were evidenced with lifetimes of 400 ns for S(+) and 600 ns for R(-)-KP. Further longer-lived transients with lifetimes of 2.6 and 6.0 mus for S(+) and R(-), respectively, were detected. On the basis of the binding constants of the drug enantiomers to the two main binding sites of the protein, obtained from circular dichroism experiments, the individual disappearance quantum yields of the 1:1 and 2:1 diastereomeric KP:BSA complexes could be estimated. The photoreactivity in the BSA matrix was rationalized on the basis of diastereoselective photodecarboxylation in the two main protein sites.
The photosensitizing activity of enoxacin, 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)- ... more The photosensitizing activity of enoxacin, 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)- 1,8-naphthyridine-3-carboxilic acid (ENX), toward membranes and DNA has been studied, taking into account human erythrocyte photohemolysis, unilamellar liposome alterations and plasmid pBR322 DNA photocleavage. Hydroxyl radicals and an aromatic carbene generated from ENX photodefluorination seem to be the active intermediates involved in the photosensitization process. The steady-state photolysis products do not participate in the process. The mechanism of photosensitization responsible for the membrane damage depends on the oxygen concentration and follows a different path with respect to that operative for DNA cleavage. Between oxygenated radicals, the hydroxyl seems the species mainly responsible for membrane damage, whereas DNA cleavage is mainly produced by the carbene intermediate. A molecular mechanism of the photosensitization induced by ENX is proposed.
We report the first example of a molecular switch of multifunctional dipolar ruthenium(III/II) pe... more We report the first example of a molecular switch of multifunctional dipolar ruthenium(III/II) pentaammine-N-methyl-(4,4'-bipyridinium) complexes, exclusively driven by light. This is achieved by using a two-phase (water/benzene) system in which RuIII/II complexes are soluble only in the water phase. The reversible redox switching is triggered by the selective irradiation of the water and the benzene compartments with 254 and 528 nm light, respectively.
In the present work, the preparation and characterization of hydrogels based on α,β-polyaspartylh... more In the present work, the preparation and characterization of hydrogels based on α,β-polyaspartylhydrazide (PAHy) chemically crosslinked with ethyleneglycol diglycidylether (EGDGE) containing Tolmetin sodium salt, are reported. In particular, these samples have been prepared both as water swellable microparticles and as gels at two different crosslinking degrees. The incorporation of Tolmetin sodium salt in PAHy–EGDGE microparticles has been performed after the
The photochemistry of 2-(3-benzoylphenyl) propionic acid (Ketoprofen) has been studied in the β-c... more The photochemistry of 2-(3-benzoylphenyl) propionic acid (Ketoprofen) has been studied in the β-cyclodextrin cavity by stationary and time-resolved (picosecond and nanosecond) spectroscopic techniques. Conformational calculations of the inclusion complex were ...
Phosphate buffer suspensions of unilamellar liposomes of phosphatidylcholine were irradiated with... more Phosphate buffer suspensions of unilamellar liposomes of phosphatidylcholine were irradiated with UVC (254 nm) and UVB (300 nm) light. The irradiation provoked lipid peroxidation and liposome lysis with release of entrapped glucose-6-phosphate. At the same intensity of absorbed light, the photochemical effect at 254 nm is higher than at 300 nm. The addition of copper(II) and manganese(II) reduced both the
The effects of a novel cationic amphiphilic cyclodextrin (SC6CDNH2) on the photoprocesses of the ... more The effects of a novel cationic amphiphilic cyclodextrin (SC6CDNH2) on the photoprocesses of the phototoxic non-steroidal anti-inflammatory drug diflunisal (DF) have been investigated in aqueous medium. Association between DF and SC6CDNH2 was indicated by steady-...
... Mariarita Barone, Angela Mascali and Salvatore Sortino*. Dipartimento di Scienze Chimiche, Un... more ... Mariarita Barone, Angela Mascali and Salvatore Sortino*. Dipartimento di Scienze Chimiche, Università di Catania, Viale Andrea Doria 8, I-95125, Catania, Italy. E-mail: ssortino@unict.it. ... 14, See, for example: AC Templeton, WP Wuelfing and RW Murray, Acc. Chem. ...
This work reports on the structural and spectroscopic properties of ethane-bridged Zn porphyrin d... more This work reports on the structural and spectroscopic properties of ethane-bridged Zn porphyrin dimers (1) in Langmuir-Schäfer (LS) thin films by combining scanning force microscopy (SFM) with film balance, UV-vis absorption, fluorescence, and nanosecond laser flash photolysis measurements. Results show that depending on the surface pressure the Langmuir films of pure 1 can be arranged in two different condensed phases, whereas SFM of the LS films shows characteristic fractal networks constituted by nanoscopic aggregates. The spectral findings agree with a picture in which 1 is apparently present in the anti conformation but aggregated in a sort of H-type structure whose optical features resemble those of the syn conformer. This type of structure is not responsive to light stimuli. By diluting 1 in arachidic acid the porphyrin aggregation is significantly minimized with 1 exhibiting almost exclusively the anti conformation. As a result the LS films become photoresponsive, showing fluorescence emission and triplet-triplet transient absorption.
The behavior of the symmetrical ethane-bridged bis(Zn porphyrin) (1) has been investigated at the... more The behavior of the symmetrical ethane-bridged bis(Zn porphyrin) (1) has been investigated at the airwater interface. The molecular organization of floating films of pure 1 and its mixture with amphiphilic substances, such as arachidic acid and n-octadecylamine, was ...
The photodegradation of the S(+)- and R(-)-ketoprofen (KP) enantiomers in the bovine serum albumi... more The photodegradation of the S(+)- and R(-)-ketoprofen (KP) enantiomers in the bovine serum albumin matrix was studied by steady-state photolysis with the use of lambda(irr) > 320 nm and transient absorption spectroscopy with lambda(exc) = 355 nm, at 1/1 and 2/1 KP/BSA molar ratios. R(-)-KP was found to be more labile than S(+). Triplet ketoprofen species were evidenced with lifetimes of 400 ns for S(+) and 600 ns for R(-)-KP. Further longer-lived transients with lifetimes of 2.6 and 6.0 mus for S(+) and R(-), respectively, were detected. On the basis of the binding constants of the drug enantiomers to the two main binding sites of the protein, obtained from circular dichroism experiments, the individual disappearance quantum yields of the 1:1 and 2:1 diastereomeric KP:BSA complexes could be estimated. The photoreactivity in the BSA matrix was rationalized on the basis of diastereoselective photodecarboxylation in the two main protein sites.
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