Polysaccharide-Mediated Synthesis of Melanins from Serotonin and Other 5-Hydroxy Indoles

Vercruysse, Koen; Clark, Astiney M.; Alatas, Noor; Brooks, Dylan; Hamza, Nafisa; Whalen, Margaret M.

doi:10.4155/fsoa-2017-0118

Cited by 6 publications

(9 citation statements)

References 37 publications

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“…Such retention times are in line with those reported for MN-like pigments generated from other phenolic or catecholic compounds. [14][15][16]23 For each of the purified pigment materials a stock solution at 1mg/mL was prepared in distilled water. Figure 1 presents a photograph of these stock solutions.…”

Section: Resultsmentioning

confidence: 99%

“…However, such enzymes may not be a necessity to generate the appearance of the typical dark colors associated with the presence of MN-like pigments. Non-enzymatic biomolecules like polysaccharides (PS) [22][23] can promote the oxidation of catecholic or indolic precursors into darkly-colored materials and the association of MN-like pigments with extracellular PS materials has been reported and discussed before. 1,[33][34] Similarly, the amyloid-like protein Pmel17/Silver/gp100 is capable of generating MN-like pigments in vitro or in vivo.…”

Section: Discussionmentioning

confidence: 99%

“…[49][50] Our observation that the various L-DOPA-based MN materials are capable of inducing IL-1 or IL-6 release from immune cells (see Figure 4) is in accordance with our previous observations and other reports. [19][20][21]23 Despite their differences in mode of synthesis, PS-mediated, base-mediated or Fe 2+ /H 2 O 2 -mediated oxidation, all L-DOPA-based materials we have evaluated thus far appeared to enhance the ILrelease from immune cells. Thus, this biological effect may not be majorly impacted by the physicchemical differences that exist between these different materials.…”

Section: Discussionmentioning

confidence: 99%

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Light- or Dark-Colored, L-DOPA-Based Melanins

Vercruysse¹,

Whalen²

2018

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This report is a continuation of previous research on the H 2 O 2 -mediated synthesis of melanin-like pigments. We synthesized and characterized L-DOPA-based pigments using air-or H 2 O 2 -mediated oxidation. We compared their physic-chemical properties and evaluated their capacity to affect the interleukin release from immune cells. The use of higher concentrations of H 2 O 2 resulted in melanin-like materials with a distinct chemical signature in their FT-IR spectra and a lighter color. All pigments enhanced the interleukin release from immune cells. The possibility that lighter-colored melanins can be generated is discussed in the context of the importance of melanin-based pigmentation in human physiology.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Light- or Dark-Colored, L-DOPA-Based Melanins

Vercruysse¹,

Whalen²

2018

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“…[9][10][11][12][13]26 In SEC, molecules are separated on the basis of differences in their hydrodynamic volume (often related to the molecular mass of the molecule): the lower the retention time, the higher the hydrodynamic volume of the analyte. In our SEC analyses, the lower limit of exclusion, as determined by the injection of water, was about 15 minutes.…”

Section: Small Scale Experiments: Partmentioning

confidence: 99%

“…Some of these compounds have been the subject of previous studies on the formation of MN-like pigments performed in our laboratories. [9][10][11][12][13] Fig. 1: Chemical structures of compounds used in this study: catechol (1), pyrogallol (2), dopamine (3), norepinephrine (4), epinephrine (5), tyrosine (6), serotonin (7) and homogentisic acid (8).…”

Section: Introductionmentioning

confidence: 99%

Dark- or Light-Colored Melanins: Generating Pigments Using Fe2+ and H2O2

Vercruysse

Russell²,

Knight³

et al. 2017

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We have studied the formation of melanin-like pigments from catechol or pyrogallol and a wide range of other phenolic compounds using Fe 2+ and H 2 O 2 . Combining UV_Vis spectroscopic measurements and size-exclusion chromatography analyses we evaluated the impact of the intensity of the oxidation reaction by varying the concentration of H 2 O 2 present in the reaction mixtures. All compounds tested, except tyrosine, reacted readily leading to mixtures that were black, brown or yellow-orange in color. For many compounds tested, the use of increasing concentrations of H 2 O 2 resulted in either precipitation of the pigment or the formation of a soluble, lighter-colored pigment. With catechol or pyrogallol as model compounds, and using different concentrations of H 2 O 2 , several materials were synthesized, purified and dried. The physic-chemical properties of these materials were compared to the properties of melanin-like pigments synthesized from the same precursors using air-oxidation in an alkaline environment. For both precursors, a distinct chemical change, as judged from FT-IR spectroscopy, was introduced in the melanin structures when using H 2 O 2 as the oxidizing agent and the relative intensity of this distinct signal strengthened with increasing concentration of H 2 O 2 used in the reaction. In general, our results suggest that depending on the precursor molecule and the intensity of the oxidizing reaction conditions involved, light-or dark-colored melanin-like pigments can be generated. This may be an important factor when evaluating the visible outlook of histological or archeological specimens: the presence of a lighter color or the absence of a dark color may not necessarily mean the absence of melanin-like biomolecules.

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Melanins as Sustainable Resources for Advanced Biotechnological Applications

et al. 2020

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Melanins are a class of biopolymers that are widespread in nature and have diverse origins, chemical compositions, and functions. Their chemical, electrical, optical, and paramagnetic properties offer opportunities for applications in materials science, particularly for medical and technical uses. This review focuses on the application of analytical techniques to study melanins in multidisciplinary contexts with a view to their use as sustainable resources for advanced biotechnological applications, and how these may facilitate the achievement of the United Nations Sustainable Development Goals.

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Polysaccharide-Mediated Synthesis of Melanins from Serotonin and Other 5-Hydroxy Indoles

Cited by 6 publications

References 37 publications

Light- or Dark-Colored, L-DOPA-Based Melanins

Light- or Dark-Colored, L-DOPA-Based Melanins

Dark- or Light-Colored Melanins: Generating Pigments Using Fe2+ and H2O2

Melanins as Sustainable Resources for Advanced Biotechnological Applications

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