Rose-bengal-photosensitized formation of hydrogen peroxide and hydroxyl radicals

Różanowska, Malgorzata Barbara; Ciszewska, Joanna; Korytowski, Witold; Sarna, Tadeusz

doi:10.1016/1011-1344(95)90259-7

Cited by 24 publications

(13 citation statements)

References 23 publications

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“…Similar trapping EPR studies were carried out using DMPO, a spin trap capable of reacting with a variety of free radicals , but neither of the studied four dyes showed significant photoproduction of ROS other than 1 O 2 (data not shown). There are reports on RB undergoing type‐I photosensitized reactions resulting in oxygen free radical formation , but our experiments did not support these. Some of the studied dyes are known to undergo protonation under acidic conditions (p K a = 6.7 and 7.4 for NR, p K a = 3.9 and 4.7 for RB and p K a = 5.08 for MVI, ), and therefore pH dependence of TEMPO detectable 1 O 2 photoproduction was also studied.…”

Section: Resultscontrasting

confidence: 96%

Assessing the Applicability of Singlet Oxygen Photosensitizers in Leaf Studies

Kovács

Ayaydin

Kálai

et al. 2013

Photochem & Photobiology

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Singlet oxygen ((1) O2 ) is of special interest in plant stress physiology. Studies focused on internal, chlorophyll-mediated production are often complemented with the use of artificial (1) O2 photosensitizers. Here, we report a comparative study on the effects of Rose Bengal (RB), Methylene Violet (MVI), Neutral Red (NR) and Indigo Carmine (IC). These were infiltrated into tobacco leaves at concentrations generating the same fluxes of (1) O2 in solution. Following green light-induced (1) O2 production from these dyes, leaf photosynthesis was characterized by Photosystem (PS) II and PSI electron transport and oxidative damage was monitored as degradation of D1, a PSII core protein. Cellular localizations were identified on the basis of the dyes' fluorescence using confocal laser scanning microscopy. We found that RB and NR were both localized in chloroplasts but the latter had very little effect, probably due to its pH-dependent photosensitizing. Both RB and intracellular, nonplastid MVI decreased PSII electron transport, but the effect of RB was stronger than that of MVI and only RB was capable of damaging the D1 protein. Intercellularly localized IC had no significant effect. Our results also suggest caution when using RB as photosensitizer because it affects PSII electron transport.

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Section: Resultscontrasting

confidence: 96%

Assessing the Applicability of Singlet Oxygen Photosensitizers in Leaf Studies

Kovács

Ayaydin

Kálai

et al. 2013

Photochem & Photobiology

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“…Based on our results a possible mechanism for the interaction of photoexcited QDs with oxygen and the electron donor, NADH, (or NADPH) is now considered by analogy with known mechanisms for conventional organic photosensitisers through the following reactions (Equations –):

Q D^{*} + N A D H \to Q D^{e -} + N A D^{•} + H^{+}

Q D^{e -} + O_{2} \to Q D + O_{2}^{- •}

2 O_{2}^{- •} + 2 H^{+} \to H_{2} O_{2} + O_{2}

N A D^{•} + O_{2} \to N A D^{+} + O_{2}^{- •}

…”

Section: Discussionmentioning

confidence: 89%

Quantification of Reactive Oxygen Species Generation by Photoexcitation of PEGylated Quantum Dots

Yaghini

Pirker

Kay

et al. 2014

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Photocatalytic generation of reactive oxygen species (ROS) from quantum dots (QDs) has been widely reported yet quantitative studies of ROS formation and their quantum yields are lacking. This study investigates the generation of ROS by water soluble PEGylated CdSe/ZnS QDs with red emission. PEGylation of QDs is commonly used to confer water solubility and minimise uptake by organs of the reticuloendothelial system; therefore studies of ROS formation are of biomedical relevance. Using non-photolytic visible wavelength excitation, the superoxide anion radical is shown to be the primary ROS species generated with a quantum efficiency of 0.35%. The yield can be significantly enhanced in the presence of the electron donor, nicotinamide adenine dinucleotide (NADH), as demonstrated by oxygen consumption measurements and electron paramagnetic resonance spectroscopy with in situ illumination. Direct production of singlet oxygen is not detectable from the QDs alone. A comparison is made with ROS generation by the same QDs complexed with a sulfonated phthalocyanine which can generate singlet oxygen via Förster resonance energy transfer between the QDs and the phthalocyanine.

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“…EPR spectra of solid HA were measured in a 2-mm quartz tube. EPR measurements of aqueous samples in 0.01 M Na 2 CO 3 at pH=10.8 of 2 mg/ml HA were carried out at room temperature using quartz flat cell and in situ irradiation of the samples (Rozanowska et al, 1995).…”

Section: Methodsmentioning

confidence: 99%