Synthesis of novel pyrano-3,7-deoxyanthocyanin derivatives and study of their thermodynamic, photophysical and cytotoxicity properties

Gomes, Vânia; Pires, Ana Sofia; Fernandes, Iva; Mateus, Nuno; Freitas, Víctor de; Cruz, Luís

doi:10.1016/j.jphotochem.2021.113313

Cited by 8 publications

(6 citation statements)

References 55 publications

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“…However, when compared with a pyranoflavylium-type pigment studied in a previous work (Fig. 6, Ф F = 0.5% at pH ≈ 3) [26], it reveals a tenfold higher fluorescence quantum yield. The main difference is the flavylium core instead of xanthylium.…”

Section: Photophysical Propertiesmentioning

confidence: 54%

A pH-responsive fluorescent sensor based on a new pyranoxanthylium salt

Gomes

Mateus

Freitas

et al. 2021

Photochem Photobiol Sci

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Stimuli-responsive pigments are very interesting for several technological applications, such as food and cosmetic colorants, color-based sensors and fluorescence probes, among others. In this work, the synthesis of a new xanthylium-derived pigment was developed and the chemical and photophysical properties in hydroalcoholic solution at different pH values were investigated by UV-Vis and fluorescence spectroscopy. The UV-Vis titration of 3,6,8-trihydroxy-11-methylpyranoxanthylium has shown four different colored chemical species (AH + , A, A − and A 2− ) in hydroalcoholic solution in a pH range between 1 and 12 with the thermodynamic acidic constants of pK a1 = 4.80 ± 0.03, pK a2 = 6.51 ± 0.05 and pK a3 = 8.64 ± 0.01. Regarding fluorescence properties, this dye revealed an interesting pH-dependent emission behavior. In fact, the anionic quinoidal base A − predominant at pH range between 5 and 9 should be mainly responsible for the pronounced fluorescence intensity observed at λ ex 467 nm/λ em 510 nm pair (maximum at pH 7.5). This set of new insights make this dye useful as a potential "off-on-off" pH-responsive fluorescent probe for biological applications.

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Section: Photophysical Propertiesmentioning

confidence: 54%

A pH-responsive fluorescent sensor based on a new pyranoxanthylium salt

Gomes

Mateus

Freitas

et al. 2021

Photochem Photobiol Sci

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“…The synthesis and structural characterization of 4′,5-dihydroxyflavylium was performed according the procedures described in the literature . Then, 4′,5-dihydroxyflavylium dye was dissolved in an acetone/water (10:90 v/v) solution set at pH 2.9 and 37 °C and after 1 day, the reaction mixture was prepurified by liquid–liquid extraction, as already reported elsewhere .…”

Section: Methodsmentioning

confidence: 99%

“…The synthesis and structural characterization of 4′,5dihydroxyflavylium was performed according the procedures described in the literature. 22 Then, 4′,5-dihydroxyflavylium dye was dissolved in an acetone/water (10:90 v/v) solution set at pH 2.9 and 37 °C and after 1 day, the reaction mixture was prepurified by liquid− liquid extraction, as already reported elsewhere. 39 Afterward, 4′hydroxy-10-methylpyranoflavylium dye was purified by column chromatography loaded with C18 silica gel, eluted with acid hydroalcoholic solutions containing MeOH 20−30%, and further lyophilized.…”

Section: Methodsmentioning

confidence: 99%

Host–Guest Chemosensor Ensembles based on Water-Soluble Sulfonated Calix[n]arenes and a Pyranoflavylium Dye for the Optical Detection of Biogenic Amines

Pires,

Droguett Muñoz,

de Freitas

et al. 2024

J. Agric. Food Chem.

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Biogenic amines (BAs) are biologically active nitrogen-containing compounds formed during the food spoilage process and are often related as key markers of food quality, safety, and freshness. Because their presence in foods at high levels can cause significant health problems, researchers have been focused on developing novel strategies and methods for early detection and capture of these analytes. Herein, water-soluble sulfonated calix[n]arene macrocycles (SC4, SC6, and SC8) and a pH-sensitive dye (4′-hydroxy-10-methylpyranoflavylium) were investigated as host−guest systems for BA sensing. The hosts were able to bind the flavylium cation of the dye with association constants of 10 3 to 10 4 M −1 . The dye complexation also allowed tuning its pK a from 6.72 (free) toward high values: 7.68 (SC4), 7.79 (SC6), and 8.45 (SC8). These data were crucial to optimize the host−guest complexes as optical sensing systems for putrescine/tyramine (pH 7.2−7.6), yielding a colorimetric redshift from yellow to red. The BA sensing was also demonstrated by fluorescence quenching for the calix[n]arene/dye complexes and fluorescence recovery after the addition of BAs. 1 H NMR spectroscopy was used to demonstrate the interaction mode, confirming an encapsulation-driven mechanism. Overall, these host−guest systems demonstrated great potential for the detection of BAs, one of the main key markers of food spoilage.

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“…The synthesis and structural characterization of 4′,5-dihydroxyflavylium (3) was performed between 2,6-dihydroxybenzaldehyde (1) and 4hydroxyacetophenone (2) as already reported in the literature. 21 Pyranoflavylium-based dyes (4) and (5) were synthesized according to the following procedures: 4′,5-dihydroxyflavylium chloride salt (3) (1 equiv) was dissolved in H 2 O/EtOH 80:20 (v/v), 1 mg/mL) and oxaloacetic acid (10 equiv) or 4-aminocinnamic acid (5 equiv) were, respectively, added. The pH was adjusted to 2.6 for the reaction with oxaloacetic acid and 3.5 for the reaction of 4-aminocinnamic acid.…”

Section: Methodsmentioning

confidence: 99%

“…On the other hand, the chromatic properties with pH variation of natural and bio-inspired pyranoflavylium-based dyes have been studied over the last years . Oppositely to anthocyanins, their pH-dependent equilibrium forms are only due to acid-base reactions yielding species with a great color variation between them, namely, from red-orange acidic flavylium cation to blue and purple neutral and anionic quinoidal bases. − Over the last years, new pyranoflavylium-based molecules with specific and suitable functional groups have been carefully designed to tune their p K a values into the food spoilage pH window. − For these reasons, the use and application of these dyes as pH-indicators to develop smart labels and membranes to monitor food freshness in real-time and to detect food spoilage at early stages are much more promising. In our previous work, a suitable pyranoflavylium dye was designed and immobilized by conventional non-covalent interactions in cellulose acetate-based films produced by the classical solvent casting method .…”

Section: Introductionmentioning

confidence: 99%

Colorimetric pH-Responsive Biomaterials Based on Pyranoflavylium-Biopolymer Hybrid Conjugates

Pires

Gomes

Neves

et al. 2022

ACS Appl. Polym. Mater.

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The conjugation of functional molecules into marine-origin biopolymers has been extensively used toward the creation of new (bio)materials for applications in food and biomedical areas. Herein, two chitosan (CHT) and alginate (ALG) biobased conjugates functionalized with pH-dyes were successfully developed to be integrated as smart labels and tags in biocompatible packaging materials for food spoilage sensing. For that, two pyranoflavylium-based pH-indicator dyes, Pyflav (4) and Pyflav (5), were designed, synthesized, and then grafted onto CHT and ALG scaffolds via EDC/NHS carbodiimide coupling chemistry with substitution degrees of 14 and 1.2%, respectively. Afterward, the conjugates were fully characterized by Fourier transform infrared, 1H NMR, and dynamic light scattering techniques, and their acidity constants were determined by UV–vis spectroscopy, yielding a great color variation (from orange to purple, pK a 6.43 ± 0.04, for Pyflav-CHT (6) and from pink to purple, pK a 7.17 ± 0.02, for Pyflav-ALG (7) and compatible with the food spoilage pH range of many perishable foods (pH between 5.8 and 7.4).

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Synthesis of novel pyrano-3,7-deoxyanthocyanin derivatives and study of their thermodynamic, photophysical and cytotoxicity properties

Cited by 8 publications

References 55 publications

A pH-responsive fluorescent sensor based on a new pyranoxanthylium salt

A pH-responsive fluorescent sensor based on a new pyranoxanthylium salt

Host–Guest Chemosensor Ensembles based on Water-Soluble Sulfonated Calix[n]arenes and a Pyranoflavylium Dye for the Optical Detection of Biogenic Amines

Colorimetric pH-Responsive Biomaterials Based on Pyranoflavylium-Biopolymer Hybrid Conjugates

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