scholarly journals Detection of tyrosine and monitoring tyrosinase activity using an enzyme cascade-triggered colorimetric reaction

RSC Advances ◽  
2020 ◽  
Vol 10 (50) ◽  
pp. 29745-29750
Author(s):  
Huei-Yu Chen ◽  
Yi-Chun Yeh
Keyword(s):  
Yellow Pigment ◽  
Tyrosinase Activity ◽  
Enzyme Cascade ◽  
Betalamic Acid ◽  
Colorimetric Reaction

We developed an enzyme cascade-triggered colorimetric reaction for the detection of tyrosine, based on the formation of yellow pigment (betalamic acid) and red fluorometric betaxanthin.

Melanocyte-stimulating hormone and the regulation of tyrosinase activity in hair follicular melanocytes of the mouse

1986 ◽  
Vol 111 (2) ◽  
pp. 225-232 ◽  
Author(s):  
S. A. Burchill ◽  
A. J. Thody
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Hair Growth ◽  
Yellow Pigment ◽  
Tyrosinase Activity ◽  
Melanocyte Stimulating Hormone ◽  
Golden Yellow ◽  
Skin Explants ◽  
Low Levels ◽  
Old Mice

ABSTRACT Skin tyrosinase activity increases during hair growth in C3H–HeA*vy mice and reaches higher levels in young (30- to 35-day-old) mice when the hair follicular melanocytes synthesize the black pigment, eumelanin, than in older (6-month-old) mice when they produce the golden yellow pigment, phaeomelanin. To examine the regulation of the melanocytes at these different stages we have compared the effect of α-MSH and other agents that act, through cyclic AMP-dependent mechanisms, on skin tyrosinase activity in both young and old mice during hair growth, initiated by plucking. Daily administration of α-MSH, isoprenaline or theophylline increased coat darkness, and skin tyrosinase activity in the younger mice 7–9 days after plucking, but they were ineffective in the older mice. Similarly α-MSH, 8-bromo-cyclic AMP or theophylline increased tyrosinase activity in skin explants from the younger mice incubated for up to 24 h but had no effect in explants from older mice. Cyclic GMP had no effect on tyrosinase activity in skin explants from both young and old mice. It is suggested that whereas cyclic AMP-dependent mechanisms may operate to regulate tyrosinase activity in the hair follicular melanocytes of younger mice that produce eumelanin these systems may not operate in the older mice when these melanocytes synthesize phaeomelanin. Phaeomelanin synthesis, unlike that of eumelanin, may not depend upon tyrosinase and its regulation by cyclic AMP and this could explain the low levels of this enzyme in the skin and its failure to respond to α-MSH and other activators of the cyclic AMP system during periods of phaeomelanin production. J. Endocr. (1986) 111, 225–232

Occurrence and Development of a Dorsal Gland in the Leaves of Twelve Cultivars of Ficus benjamina L. (Weeping Fig)

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 537b-537
Author(s):  
Svoboda V. Pennisi ◽  
Dennis B. McConnell ◽  
Richard W. Henley
Keyword(s):  
Leaf Size ◽  
Dark Spot ◽  
Ficus Benjamina ◽  
Axis Parallel ◽  
Glandular Cells ◽  
Phenolic Substances ◽  
Dark Color ◽  
Columnar Cells ◽  
Dorsal Gland ◽  
Colorimetric Reaction

Ficus benjamina plants are an integral part of most modern interior landscapes. Reports from growers and interiorscape managers have drawn attention to a specific problem related to large F. benjamina plants, namely the occurrence of a dark oval spot on the abaxial surface of the leaf base. Twelve cultivars of F. benjamina were examined: Christine, Citation, Florida Spire, Kelly, Kiki, Midnight, Monique, Stacey, Wintergreen, Dwarf Nikita, Spearmint, and Starlight. Anatomically, the dorsal gland consisted of one to several layers of densely stained, columnar cells. Positive colorimetric reaction for phenolics was obtained in the glandular cells. Developmentally, the gland cells could not be distinguished from the regular epidermal cells until ≈30% of final leaf size was reached. The cells of the outermost glandular layer changed shape from rectangular with long axis parallel to the leaf surface to elongate with long axis perpendicular to the surface. In a mature leaf, the thickness of the glandular layer was between 20 and 30 μm. Externally, at this stage, no dark spot, indicative of the gland's location, could be observed. In older leaves, however, an accumulation of phenolic substances led to appearance of dorsal dark spot. All cultivars possessed glandular layer. However, this area did not darken in all cultivars; Christine, Citation, Florida Spire, Kelly, Kiki, and Stacey developed small dark spots, while Dwarf Nikita and Starlight had numerous, well-pronounced glandular regions. This study showed that the dark spots in F. benjamina cultivars were a normal morphological feature. Although the gland was present in every cultivar, only a few cultivars developed a dark color.

Insight into Mechanistic Action of Thymoquinone Induced Melanogenesis in Cultured Melanocytes

2019 ◽  
Vol 26 (12) ◽  
pp. 910-918
Author(s):  
Kamal U. Zaidi ◽  
Firoz N. Khan ◽  
Sharique A. Ali ◽  
Kausar P. Khan
Keyword(s):  
Western Blot ◽  
Signaling Pathways ◽  
Cell Line ◽  
Melanoma Cell ◽  
Melanoma Cell Line ◽  
Protein Kinase Inhibitors ◽  
Tyrosinase Activity ◽  
Dependent Manner ◽  
B16f10 Melanoma ◽  
B16f10 Melanoma Cell

Background: Melanin plays a crucial role in camouflage, social communication and protection against harmful ultraviolet radiations. Melanin is synthesized by melanocytes through melanogenesis and several intrinsic and extrinsic factors are involved during the process. Any change occuring in the normal melanogenesis process can cause severe pigmentation problems of hypopigmentation or hyperpigmentation. Objective: The present study is based on the evaluation of the effect of thymoquinone on melanogenesis and their possible mechanism of action using the B16F10 melanoma cell line for the production via blocking signaling pathways. Methods: Phase contrast microscopy, cell viability, tyrosinase activity, melanin content and western blot analysis were used in the present study. Results: In the present investigation, cultured melanocytes exhibit that the stimulation of melanin synthesis when treated with thymoquinone. Tyrosinase activity and melanin production in B16F10 melanoma cell line was increased in doze-dependent manner. In western blot, we investigated the involvement of the cAMP/PKA pathway in thymoquinone induced melanogenesis. It was observed protein kinase inhibitors PKA, PKC, PKB and MEK1 decreased the stimulatory effects of thymoquinone from 11.45- fold value to 8.312, 6.631, 4.51, and 7.211-fold value, respectively. However, the results also prove that thymoquinone may partially induce tyrosinase expression via PKA, PKB, PKC and MEK1 signaling pathways. Conclusion: The present finding proposed that thymoquinone is a protective challenger for melanogenesis and it might be useful for the treatment of hypopigmentary disorders.

scholarly journals Inhibitory Effects of Cycloheterophyllin on Melanin Synthesis

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2526
Author(s):  
Joong-Hyun Shim
Keyword(s):  
Functional Materials ◽  
Tyrosinase Activity ◽  
Melanin Synthesis ◽  
Activity Assay ◽  
Inhibitory Effects ◽  
Melanin Production ◽  
Messenger Ribonucleic Acid ◽  
B16f10 Cells ◽  
Cell Line Cell ◽  
Tyrosinase Related Protein

This study was performed to clarify the inhibitory effects of cycloheterophyllin on melanin synthesis. In order to elucidate the inhibitory effects of cycloheterophyllin on the B16F10 cell line, cell viability, messenger ribonucleic acid (mRNA) expressions, tyrosinase activity assay, and melanin production assay were measured. The effects of cycloheterophyllin on tyrosinase-related protein 1 (TYRP1)/TYRP2/tyrosinase (TYR)/microphthalmia-associated transcription factor (MITF) mRNA expressions and melanin content were determined. Quantitative real-time RT-PCR showed that cycloheterophyllin decreased the mRNA expression level of TYRP1/TYRP2/TYR/MITF genes and melanin production contents than α-MSH-treated B16F10 cells. The tyrosinase activity assay revealed that cycloheterophyllin decreased the melanin production in the B16F10 cells. These data show that cycloheterophyllin increases the whitening effects in the B16F10 cells; thus, cycloheterophyllin is a potent ingredient for skin whitening. Thus, further research on the mechanism of action of cycloheterophyllin for the development of functional materials should be investigated.

scholarly journals Novel Chemically Modified Curcumin (CMC) Derivatives Inhibit Tyrosinase Activity and Melanin Synthesis in B16F10 Mouse Melanoma Cells

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 674
Author(s):  
Shilpi Goenka ◽  
Francis Johnson ◽  
Sanford R. Simon
Keyword(s):  
Enzyme Activity ◽  
Parent Compound ◽  
Radical Scavenging ◽  
Melanoma Cells ◽  
Tyrosinase Activity ◽  
Partial Recovery ◽  
Tyrosinase Inhibitor ◽  
Pyrocatechol Violet ◽  
Mouse Melanoma ◽  
Chemically Modified

Skin hyperpigmentation disorders arise due to excessive production of the macromolecular pigment melanin catalyzed by the enzyme tyrosinase. Recently, the therapeutic use of curcumin for inhibiting tyrosinase activity and production of melanin have been recognized, but poor stability and solubility have limited its use, which has inspired synthesis of curcumin analogs. Here, we investigated four novel chemically modified curcumin (CMC) derivatives (CMC2.14, CMC2.5, CMC2.23 and CMC2.24) and compared them to the parent compound curcumin (PC) for inhibition of in vitro tyrosinase activity using two substrates for monophenolase and diphenolase activities of the enzyme and for diminution of cellular melanogenesis. Enzyme kinetics were analyzed using Lineweaver-Burk and Dixon plots and nonlinear curve-fitting to determine the mechanism for tyrosinase inhibition. Copper chelating activity, using pyrocatechol violet dye indicator assay, and antioxidant activity, using a DPPH radical scavenging assay, were also conducted. Next, the capacity of these derivatives to inhibit tyrosinase-catalyzed melanogenesis was studied in B16F10 mouse melanoma cells and the mechanisms of inhibition were elucidated. Inhibition mechanisms were studied by measuring intracellular tyrosinase activity, cell-free and intracellular α-glucosidase enzyme activity, and effects on MITF protein level and cAMP maturation factor. Our results showed that CMC2.24 showed the greatest efficacy as a tyrosinase inhibitor of all the CMCs and was better than PC as well as a popular tyrosinase inhibitor-kojic acid. Both CMC2.24 and CMC2.23 inhibited tyrosinase enzyme activity by a mixed mode of inhibition with a predominant competitive mode. In addition, CMC2.24 as well as CMC2.23 showed a comparable robust efficacy in inhibiting melanogenesis in cultured melanocytes. Furthermore, after removal of CMC2.24 or CMC2.23 from the medium, we could demonstrate a partial recovery of the suppressed intracellular tyrosinase activity in the melanocytes. Our results provide a proof-of-principle for the novel use of the CMCs that shows them to be far superior to the parent compound, curcumin, for skin depigmentation.

scholarly journals Biocompatibility and radioprotection by newly characterized melanin pigment and its production from Dietzia schimae NM3 in optimized whey medium by response surface methodology

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Sahar Eskandari ◽  
Zahra Etemadifar
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Nutrient Broth ◽  
Tyrosinase Activity ◽  
Brown Pigment ◽  
Scavenging Activity ◽  
Protection Factor ◽  
Melanin Production

Abstract Purpose To characterize and optimize the productivity of melanin using an extremotolerant actinobacterium, Dietzia schimae NM3, for the first time. Methods An extracellular brown pigment produced by D. schimae NM3 in the nutrient broth and cheese whey medium by adding L-tyrosine. The extracted melanin was analyzed by UV-visible, HPLC, and FTIR assays. The radical scavenging activity (by DPPH) and sun protection factor (SPF) of the extracted melanin were measured. The melanin cytotoxicity was assayed by MTT and chromate biosorption was measured by atomic absorption spectroscopy. Finally, melanin production by D. schimae NM3 was optimized by response surface methodology (RSM) using Box-Behnken design in the whey medium. Result The purified melanin showed similar peak to the standard melanin (SIGMA) at 3.5 min in HPLC, and C=O bands, NH2, CH, C-N, and aromatic groups by FTIR. The radical scavenging activity (by DPPH) and SPF of the extracted melanin were obtained 188.9% and 20.22, respectively. Using MTT assay, the melanin revealed non-toxic effect on the normal human fibroblast (HFB) cell culture. The melanin yield 790 mg l−1, and tyrosinase activity 3400 U ml−1 were obtained in the medium contained whey powder [5% (w v−1)], L-tyrosine 2.5 g l−1, CuSO4 0.013 g l−1, and pH 10.5, incubated at 32 °C for 3 days. The ANOVA results indicated significant P-value, model F-value, and probability, with insignificant lack of fit. After optimization with mono-factors, the nutrient broth came up with melanin yield as 1.2 g l−1 and tyrosinase activity as 4040 U ml−1. Conclusion This is the first report of melanin production by D. schimae NM3 and this natural melanin showed valuable biological properties such as high antioxidant activity and radioprotection (SPF) and the biocompatibility to human cell line.

Anti-fatigue activity of gardenia yellow pigment and Cistanche phenylethanol glycosides mixture in hypoxia

2021 ◽  
Vol 40 ◽  
pp. 100902
Author(s):  
Maoxing Li ◽  
Xiuyu Tian ◽  
Xiaolin Li ◽  
Ting Mao ◽  
Tianlong Liu
Keyword(s):  
Yellow Pigment

scholarly journals A Redox-Neutral, Two-Enzyme Cascade for the Production of Malate and Gluconate from Pyruvate and Glucose

2021 ◽  
Vol 11 (11) ◽  
pp. 4877
Author(s):  
Ravneet Mandair ◽  
Pinar Karagoz ◽  
Roslyn M. Bill
Keyword(s):  
Malate Dehydrogenase ◽  
Closed System ◽  
Glucose Dehydrogenase ◽  
Sulfolobus Solfataricus ◽  
Cofactor Regeneration ◽  
Triple Mutant ◽  
Thermococcus Kodakarensis ◽  
Platform Chemicals ◽  
Enzyme Cascade

A triple mutant of NADP(H)-dependent malate dehydrogenase from thermotolerant Thermococcus kodakarensis has an altered cofactor preference for NAD+, as well as improved malate production compared to wildtype malate dehydrogenase. By combining mutant malate dehydrogenase with glucose dehydrogenase from Sulfolobus solfataricus and NAD+/NADH in a closed reaction environment, gluconate and malate could be produced from pyruvate and glucose. After 3 h, the yield of malate was 15.96 mM. These data demonstrate the feasibility of a closed system capable of cofactor regeneration in the production of platform chemicals.

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