Triplet Excited States and Singlet Oxygen Production by Analogs of Red Wine Pyranoanthocyanins

Silva, Gustavo Thalmer M.; Thomas, Suma S.; Silva, Cassio Pacheco; Schlothauer, Jan C.; Baptista, Maurı́cio S.; Freitas, Adilson A.; Bohne, Cornelia; Quina, Frank H.

doi:10.1111/php.12973

Cited by 16 publications

(18 citation statements)

References 32 publications

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“…Interestingly, although the formation of triplet states at room temperature has not been clearly demonstrated for other flavylium cations, the pyranoflavylium salts of Scheme 41 were observed to readily form triplet states in acidic acetonitrile solutions at room temperature. 286 The triplets where shown to have microsecond lifetimes and are quenched by oxygen forming singlet oxygen detected by its emission in the nearinfrared spectral region.…”

Section: Fluorescence: Excited State Proton Transfermentioning

confidence: 99%

Natural and Synthetic Flavylium-Based Dyes: The Chemistry Behind the Color

et al. 2021

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Flavylium compounds are a well-known family of pigments because they are prevalent in the plant kingdom, contributing to colors over a wide range from shades of yellow-red to blue in fruits, flowers, leaves, and other plant parts. Flavylium compounds include a large variety of natural compound classes, namely, anthocyanins, 3deoxyanthocyanidins, auronidins, and their respective aglycones as well as anthocyaninderived pigments (e.g., pyranoanthocyanins, anthocyanin-flavan-3-ol dimers). During the past few decades, there has been increasing interest among chemists in synthesizing different flavylium compounds that mimic natural structures but with different substitution patterns that present a variety of spectroscopic characteristics in view of their applications in different industrial fields. This Review provides an overview of the chemistry of flavylium-based compounds, in particular, the synthetic and enzymatic approaches and mechanisms reported in the literature for obtaining different classes of pigments, their physical-chemical properties in relation to their pH-dependent equilibria network, and their chemical and enzymatic degradation. The development of flavylium-based systems is also described throughout this Review for emergent applications to explore some of the physical-chemical properties of the multistate of species generated by these compounds.

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Section: Fluorescence: Excited State Proton Transfermentioning

confidence: 99%

Natural and Synthetic Flavylium-Based Dyes: The Chemistry Behind the Color

et al. 2021

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“…Besides strong absorption in the red visible spectrum (600–800 nm) and a high extinction coefficient (50.000–100.000 M −1 ·cm −1 ), to prevent the need of using great amounts of PS, the photosensitizing agent suitable for PDT must be available in a pure form, and it should be easy to obtain and have a high singlet oxygen quantum yield [ 181 ].…”

Section: Photodynamic Therapymentioning

confidence: 99%

“…The production of an oxygen singlet by triplet excited state of anthocyanins derivatives (pyranoanthocyanins) was recently reported [ 181 ], and the fluorescence properties of purple-fleshed sweet potato recently established [ 17 ].…”

Section: Photodynamic Therapymentioning

confidence: 99%

Exploring the Applications of the Photoprotective Properties of Anthocyanins in Biological Systems

Oliveira

Correia

Pereira

et al. 2020

IJMS

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Due to their physical and chemical characteristics, anthocyanins are amongst the most versatile groups of natural compounds. Such unique signature makes these compounds a focus in several different areas of research. Anthocyanins have well been reported as bioactive compounds in a myriad of health disorders such as cardiovascular diseases, cancer, and obesity, among others, due to their anti-inflammatory, antioxidant, anti-diabetic, anti-bacterial, and anti-proliferative capacities. Such a vast number of action mechanisms may be also due to the number of structurally different anthocyanins plus their related derivatives. In this review, we highlight the recent advances on the potential use of anthocyanins in biological systems with particular focus on their photoprotective properties. Topics such as skin aging and eye degenerative diseases, highly influenced by light, and the action of anthocyanins against such damages will be discussed. Photodynamic Therapy and the potential role of anthocyanins as novel photosensitizers will be also a central theme of this review.

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“…In fact, due to the reported ability to form quinones and quench singlet oxygen, these pigments may be used in the PDT type I mechanism 11 . Besides anthocyanins, also anthocyanin derived pigments, analogues of pyranoanthocyanins have been proposed as PS 12 .…”

Section: Introductionmentioning

confidence: 99%

Photoactivated cell-killing amino-based flavylium compounds

Oliveira

Araújo

Pereira

et al. 2021

Sci Rep

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Photodynamic therapy (PDT) is a well-established therapeutic for the treatment of different diseases. The growing interest of this technique required the development of new photosensitizers with better photo-features. This work reports the study of the potential of five nature-inspired amino-based flavylium compounds with different structural features as photosensitizers towards topical PDT. In terms of dark cytotoxicity the five pigments were tested towards confluent skin cells in both fibroblasts and keratinocytes. In the range of concentrations tested (6.3–100 μM), keratinocytes were more prone to growth inhibition and the IC50 values for 5OH4′NMe2, 7NEt2st4′NMe2 and 7NEt24′NH2 were determined to be 47.3 ± 0.3 μM; 91.0 ± 0.8 μM and 29.8 ± 0.8 μM, respectively. 7NEt24′NMe2, 7NEt2st4′NMe2 and 7NEt24′NH2 showed significant fluorescence quantum yields (from 3.40 to 20.20%) and production of singlet oxygen (1O2). These latter chromophores presented IC50 values of growth inhibition of keratinocytes between 0.9 and 1.5 µM, after 10 min of photoactivation with white light. This cellular damage in keratinocyte cells upon white light activation was accompanied with the production of reactive oxygen species (ROS). It was also found that the compounds can induce damage by either type I (ROS production) or type II (singlet oxygen) PDT mechanism, although a higher cell survival was observed in the presence of 1O2 quenchers. Overall, a structure–activity relationship could be established, ranking the most important functional groups for the photoactivation efficiency as follows: C7-diethylamino > C4′-dimethylamino > C2-styryl.

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Triplet Excited States and Singlet Oxygen Production by Analogs of Red Wine Pyranoanthocyanins

Cited by 16 publications

References 32 publications

Natural and Synthetic Flavylium-Based Dyes: The Chemistry Behind the Color

Natural and Synthetic Flavylium-Based Dyes: The Chemistry Behind the Color

Exploring the Applications of the Photoprotective Properties of Anthocyanins in Biological Systems

Photoactivated cell-killing amino-based flavylium compounds

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