A novel melanin-like pigment derived from black tea leaves with immuno-stimulating activity

Sava, Vasyl; Галкин, Б. Н.; Hong, Meng-Yen; Yang, Ping-Cheng; Huang, G. S.

doi:10.1016/s0963-9969(00)00173-3

Cited by 98 publications

(72 citation statements)

References 13 publications

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“…TFTIR studies carried out by Sava et al (2001) reported that absorption is reduced at 3450 cm −1 and 1650 cm −1 , after acid hydrolysis treatment undertaken during purification step due to formation of reactions between phenolic and carboxylic groups to form lactones. Also treatment with chloroform and ethyl acetate could have reduced absorption at 2900–2850 cm −1 in spectra.…”

Section: Discussionmentioning

confidence: 99%

Purification and characterisation of a sulphur rich melanin from edible mushroom Termitomyces albuminosus Heim

2018

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Production, purification and characterisation of a black pigment from Termitomyces albuminosus as melanin is reported, for the first time, from shaken submerged culture condition using scanning electron microscopy (SEM), elemental analysis, ultraviolet–visible (UV-VIS), and Fourier transformed infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR) and 13C (CP/MAS) NMR spectra. SEM results on T. albuminosus revealed nanogranular nature of melanin nanoparticles within size range of 400–100 nm with fractal dimension D = 1.195–1.73. Elemental analysis of melanin indicated 54.6% C, 3.5% H, 2.4% N, 26.9% O, and 12% S. UV-VIS and FTIR spectra confirmed to the characteristic of melanin and were identical to the reference commercial sepia melanin. Further validation of the identity of pigment as melanin was achieved by EPR analysis. Termitomyces albuminosus melanin is postulated to be DOPA-type melanin confirmed by 13C (CP/MAS) NMR spectral analysis showing chemical shift at 200–170 ppm carbonyl, 160–110 ppm aromatic region, and with high 40–30 ppm open chain aliphatic region. Chemical modification through oxidation and cysteinylation (Pheomelanin) is implied as indicated by relatively high sulphur content (12%).

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Section: Discussionmentioning

confidence: 99%

Purification and characterisation of a sulphur rich melanin from edible mushroom Termitomyces albuminosus Heim

2018

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“…The molecular mass of the MAKS was measured following Sava 33 . MAKS was dissolved in ammonia at 0.2%, with ultrasonic assistance, then ammonia in the sample was removed using a rotary evaporator 21,32 .…”

Section: Evaluation Of Molecular Massmentioning

confidence: 99%

Characterization of melanin extracted from apricot (Armeniaca sibirica) and its effect on hydrazine-induced rat hepatic injury

Li¹,

Li²,

Zhao³

2016

ScienceAsia

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ABSTRACT:Melanin is a complex, highly coloured natural antioxidant with potent biological activities and diverse applications. A potential source of melanin is the Siberian apricot (Armeniaca sibirica) whose kernel skin is currently a waste by-product. To explore its potential, melanin from apricot kernel skin was extracted. The molecular mass was determined by gel chromatography and its structure was examined by elemental analysis, UV-Vis, infrared, and solid-state nuclear magnetic resonance ( 13 C-NMR) spectroscopy. In addition, its protective effect against hydrazineinduced hepatic injury in rats was evaluated. The results showed that melanin has < 5% sulphur (S) content, indicating that it consists mostly of eumelanin. Its UV-Vis, infrared and 13 C-NMR spectra were very similar to those of synthetic melanin, although it had relatively high carboxylate, aliphatic, and phenol-skeleton content. Two distinct fractions (2.4 ± 0.12 and 0. ± 560.1 kDa) were detected. Injections of hydrazine at 65 mg/kg body-weight (b.wt.) doses resulted in significant (p < 0.01) increases in lipid peroxidation (malondialdehyde contents) in liver homogenates and serum alanine aminotransferase and aspartate aminotransferase activities (64%, 69%, and 98% increase relative to the controls, respectively). It also induced significant (p < 0.05 or 0.01) decreases in liver homogenate catalase, glutathione peroxidase, and superoxide dismutase activities and reduced glutathione content (48%, 28%, 7%, and 98% reduction, respectively). Administering melanin prior to hydrazine, at 10 mg/kg b.wt., strongly inhibited these changes and ameliorated histopathological hepatic injury. The results indicated that melanin alleviated hydrazine-induced liver injury by relieving oxidative stress, which may provide a novel protective strategy for protection against liver diseases.

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“…The structures of melanins have rarely been studied due to the difficulties in the isolation of melanins from natural sources and the poor solubility of the pigments. Melanins are insoluble in water and common organic solvents (such as hexane, chloroform, ethyl acetate, ethanol, methanol or acetone) (Sava et al, 2001a;Hsieh and Lien, 2012;Wang et al, 2006) and can be dissolved only in alkaline solutions. The range of available structural investigation methods is therefore limited.…”

Section: Introductionmentioning

confidence: 99%

“…Despite their frequent occurence, plant melanins have been poorly investigated, generally in studies limited to their isolation and characterization of their physical and chemical properties (e.g. solubility, stability and oxidized bleaching) (Claussen and Pepper, 1968;Sava et al, 2001a). Little structural information is available, namely the pigment is devoid of nitrogen and the C/H ratio of 1.11 indicating an aromatic nature.…”

Section: Introductionmentioning

confidence: 99%

Structural characterization of allomelanin from black oat

et al. 2016

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The brown to black coloration found in plants is due to the melanins, which have been relatively poorly investigated among the plant pigments. The aim of this work was to study the dark pigment extracted from the black oat hull with respect to composition and structure. Ultraviolet-visible (UV-Vis) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and Fourier transform infrared (FT-IR) spectroscopy were applied for the characterization of the pigment. UV-Vis spectroscopy revealed that the extracted material displayed the absorption profile typical of melanins. MALDI-TOF MS measurements demonstrated that oat melanin is a homopolymer built up from p-coumaric acid and consists mainly of low molecular weight (500-900 Da) oligomers of between 3 and 9 monomer units. The tetramer oligomer proved to be dominant. The results of the FT-IR analysis indicated that oat melanin is a fully conjugated aromatic system containing tetrasubstituted aromatic rings linked by C-C coupling. The in vitro preparation of melanin from p-coumaric acid by horseradish peroxidase was performed for comparison. The resulting polymer consisted of oligomers of 4 to 9 monomer units similarly to those in oat melanin. However the building blocks proved to be connected to each other via C-O-C linkages in contrast with the C-C linkages in oat melanin. This is the first demonstration of the structure of melanin originating from plants.

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A novel melanin-like pigment derived from black tea leaves with immuno-stimulating activity

Cited by 98 publications

References 13 publications

Purification and characterisation of a sulphur rich melanin from edible mushroom Termitomyces albuminosus Heim

Purification and characterisation of a sulphur rich melanin from edible mushroom Termitomyces albuminosus Heim

Characterization of melanin extracted from apricot (Armeniaca sibirica) and its effect on hydrazine-induced rat hepatic injury

Structural characterization of allomelanin from black oat

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