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Published in Michael Hehenberger, Zhi Xia, Huanming Yang, Our Animal Connection, 2020
Michael Hehenberger, Zhi Xia, Huanming Yang
In 1999, the nacre mutation was identified in the zebrafish ortholog of the mammalian MITF transcription factor. Human MITF mutations result in eye defects and loss of pigment. The zebrafish gene responsible for its unusual pigmentation was identified as SLC24A5, a solute carrier required for melanin production. The orthologous human gene was then found to strongly segregate fair-skinned Europeans and dark-skinned Africans.144 Zebrafish with the nacre mutation have since been bred to make fish that are transparent into adulthood. These fish are characterized by uniformly pigmented eyes and translucent skin.
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Published in Michael Hehenberger, Zhi Xia, Our Animal Connection, 2019
In 1999, the nacre mutation was identified in the zebrafish ortholog of the mammalian MITF transcription factor. Human MITF mutations result in eye defects and loss of pigment. The zebrafish gene responsible for its unusual pigmentation was identified as SLC24A5, a solute carrier required for melanin production. The orthologous human gene was then found to strongly segregate fair-skinned Europeans and dark-skinned Africans.144 Zebrafish with the nacre mutation have since been bred to make fish that are transparent into adulthood. These fish are characterized by uniformly pigmented eyes and translucent skin.
Flavonoids from Quercus Genus: Applications in Melasma and Psoriasis
Published in Tatjana Stevanovic, Chemistry of Lignocellulosics: Current Trends, 2018
Esquivel-García Roberto, Velázquez-Hernández María-Elena, Valentín-Escalera Josué, Valencia-Avilés Eréndira, Rodríguez-Orozco Alain-Raimundo, Martha-Estrella García-Pérez
The antimelanogenic effect of catechins has been extensively investigated in vitro and in vivo. Treatment with 5–20 μM of catechins: (–)-epigallocatechin-3- gallate (EGCG), (–)-epigallocatechin (EGC) and (–)-catechin, during five days on B16 murine melanoma cells stimulated with α-MSH resulted in a dose-dependent inhibition of melanin formation and inhibition of tyrosinase expression, with EGCG having the higher antimelanogenic effect (Sato and Toriyama 2009). EGCG (12.5–200 μg/ml) also reduced the melanin level, tyrosinase activity and melanosome maduration in UVA irradiated B16 cells (Liang et al. 2014) and protected human skin fibroblasts from damage induced by UVA, through relieving oxidative stress by an increase in glutathione peroxidase activity (Shin et al. 2014). In mouse melanocyte cell line Mel-Ab, EGCG reduced melanin synthesis by decreasing the protein levels of the transcription factor MITF an important transcriptional regulator of melanogenesis (Kim et al. 2004). A water extract containing EGC, epicatechin (EC), EGCG, epicatechin gallate (ECG) and theaflavins showed higher levels of antimelanogenic activity than EGCG alone. The extract reduced melanin synthesis deposition and dendrite formation in immortalized mouse melanocytes A-melan, and decreased tyrosinase protein levels without affecting mRNA expression (Kim et al., 2015). EGCG has also been shown to induce differentiation and inhibition of proliferation in KCs (Balasubramanian and Eckert 2007) with an antiinflammatory activity on immune cells (Peairs et al. 2010). A significant decrease in the melanin level was determined in 50 melasma patients who used a topical emulsion containing a plant extract enriched with catechins (Khan et al. 2013). Oral administration of low dose catechins (540 mg) for 12 weeks resulted in the incorporation of catechin metabolites into the human skin associated with reduction of proinflammatory eicosanoid 12-hydroxyeicosatetraenoic acid induced by UV irradiation, which may contribute to protection against sunburn inflammation and potentially UV mediated damage (Rhodes et al. 2013).
Antioxidant and anti-tyrosinase activities of quercetin-loaded olive oil nanoemulsion as potential formulation for skin hyperpigmentation
Published in Journal of Dispersion Science and Technology, 2022
Cristiane C. Silva, Rogério B. Benati, Taís N. C. Massaro, Karina C. Pereira, Lorena R. Gaspar, Priscyla D. Marcato
Since melasma and other hyperpigmentation disorders are frequent in regions of the body that are exposed to the sun, ultraviolet radiation (UV) is considered a key factor for their development. The radiation on the skin stimulates the production of melanocyte-stimulating hormone (α-MSH), which in turn induces the modification of the melanocortin receptor (MC1R), leading to an increase in the transcription factor associated with melanogenesis (MITF). This factor activates tyrosinase and tyrosinase-related proteins (TRP) in the Golgi complex, leading to greater production of the pigments eumelanin and pheomelanin.[12,13] Reactive oxygen species (ROS) are also important mediators for the activation of the pathway. Therefore, there is a relationship between oxidative stress and hyperpigmentation disorders.[13,14]