Incorporation and photodegradation of flavin and indole derivatives in anionic, cationic and neutral micellar dispersions

Bueno, C Villanueva; Silva, E; Edwards, A.

doi:10.1016/s1011-1344(99)00122-0

Cited by 10 publications

(6 citation statements)

References 21 publications

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“…The association constants Kf for ¡ and K i for tryptophan are determined to be 3.4-103 and 0.77.103 M -l, respectively, by fluorescence quenching experiments [18]. With these values, we could reproduce the experimental results in Fig.…”

Section: Resultsmentioning

confidence: 57%

Magnetic field effect on electron transfer reactions of flavin derivatives associated with micelles

2003

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The magnetic field effects (MFEs) on the electron transfer reactions from indole derivatives to flavin derivatives in micellar solutions are studied. The MFEs on the free radical yields observed by transient absorption (TA) reflect effectively the association of the donor and acceptor molecules with the micelles. In the system of riboflavin and indole, the MFE increases rapidly with increasing concentration of sodium dodecyl sulfate (SDS) higher than the critical micellar concentration. In contrast, in the system of flavin mononucleotide and Ÿ the increase of MFE is very slow even at higher concentrations of SDS. This result shows that riboflavin is well associated with the SDS micelle and the diffusion process of the radical pair is rest¡ by the micellar cages. The MFE in the system of riboflavin and indole is twice as large as that of fiboflavin and tryptophan. This result shows the difference of the dynamics of radicals in mieelles. The escape rate of the cation radical generated from tryptophan is much faster than that generated from Ÿ The dependence of the MFEs on the type of surfaetant is studied. The effect of the Coulomb force between the ionic reactant motecules and the charged head group of the surfactant and the effeet of the molecular size are discussed by comparison of the MFE intensities.

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Section: Resultsmentioning

confidence: 57%

Magnetic field effect on electron transfer reactions of flavin derivatives associated with micelles

2003

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“…When TPRF was use as photosensitizer, we observed that the photodegradation in SUV was greater than that in homogeneous medium for all the indole derivatives. Nevertheless, TPRF was the most photostable flavin derivative when compared with LF and RF in the same microenvironment (13,17). TPRF was localized in the lipid interphase; moreover, the photoprocess is very efficient because the microenvironment increases the triplet lifetime of the flavin (28).…”

Section: Photodegradation Studiesmentioning

confidence: 96%

“…The synthesis of 2'3'4'5' riboflavin tetrapropionate was performed as previously described (16,17). The compound was recrystalized from 95% methanol and characterized by IR and 1 H NMR spectroscopy (16).…”

Section: Synthesismentioning

confidence: 99%

Effect of the Incorporation Into Unilaminar Vesicle on the Photodegradation of Indoles Sensitized by Flavins

Bueno

Alarcon

Edwards

2013

J. Chil. Chem. Soc.

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In this work we study the incorporation into dipalmitoylphosphatidylcholine (DPPC) small unilamellar vesicle (SUV), of three indols: Trp, indol-3 acetamide and N-acetyl tryptophan ethyl ester (NATE), and of three flavins: riboflavin (RF), lumiflavin (LF), and 2'3'4'5' riboflavin tetrapropionate (TPRF). The incorporation into the vesicle was determined by selective fluorescence quenching for the indols, and by equilibrium dialysis for the flavins. The more hydrophobic compound, the greater incorporation into the vesicle; therefore, TPRF and indol-3-acetamide and NATE are the flavins and indols, with the higher incorporation. Consequently, the higher efficiency for the indol photodegradation and the photoproducts generation was obtained when the hydrophobic compounds were irradiated with monochromatic light in the presence of the vesicle.

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“…The incorporation and photodegradation of indole derivatives in anionic, cationic and neutral micellar dispersions in the presence of RF were studied by Bueno et al 7 The photocatalytic degradation of IAA and IBA in aqueous environments was also reported. 8 In several of these studies the importance of type I mechanism in the photooxidation process was noticed.…”

Section: Introductionmentioning

confidence: 99%

Triplet state quenching of phenosafranine dye by indolic compounds studied by transient absorption spectroscopy

Broglia

Previtali

Bertolotti

2015

Photochem Photobiol Sci

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The interaction of the triplet state of the synthetic dye phenosafranine (3,7-diamino-5-phenylphenazinium chloride) with indolic compounds of biological relevance was investigated in water by means of laser flash photolysis. The rate constants for the triplet quenching were determined. The quenching process may be explained by an electron transfer from the indole to the dye in its triplet state. The rate constants present a typical dependence of an electron transfer process with the one-electron oxidation potential of the indole. Indole-3-acetic acid and its homologous indole propionic and indole butyric acids are the most effective quenchers with rate constants reaching the diffusion limit. Rate constants for indole itself, tryptophan and indole-3 carboxylic acid are one order of magnitude lower. The electron transfer nature of the quenching reaction is further confirmed by the detection of the semi-reduced form of the dye by its transient absorption. The absorption coefficients of the transient species were estimated, and the quantum yield of the charge separation process was determined. The efficiency of formation of radical species is between 60 and 90% of the triplets intercepted.

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Incorporation and photodegradation of flavin and indole derivatives in anionic, cationic and neutral micellar dispersions

Cited by 10 publications

References 21 publications

Magnetic field effect on electron transfer reactions of flavin derivatives associated with micelles

Magnetic field effect on electron transfer reactions of flavin derivatives associated with micelles

Effect of the Incorporation Into Unilaminar Vesicle on the Photodegradation of Indoles Sensitized by Flavins

Triplet state quenching of phenosafranine dye by indolic compounds studied by transient absorption spectroscopy

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