Ultraviolet B (UVB) irradiation is viewed as the principal inducer of skin photo-aging, associated with acceleration of collagen degradation and upregulation of matrix metalloproteinases (MMPs). The ethnic groups of southern/western China use Fuzhuan brick-tea (FBT) as a beverage and as a nutritional supplement. In this study, we scrutinized the antagonistic effects of aqueous extract of Fuzhuan-brick tea (FBTA) on skin photo-aging in UVB-exposed human keratinocyte (HaCaT) cells. FBTA exhibited strong antioxidant activity and quenched UVB-induced generation of cellular reactive oxygen species (ROS) without showing any toxicity. FBTA was capable of combating oxidative stress by augmenting messenger RNA (mRNA) and protein levels of both phase I and phase II detoxifying enzymes, especially heme oxygenase 1 (HO-1), by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated pathway in HaCaT cells via the phosphorylation of p38 and extracellular signal-regulated kinase (ERK). FBTA also downregulated the expression of matrix metalloproteinase-1 (MMP-1) while upregulating type I procollagen by modulating Nrf2 signaling in UVB-irradiated HaCaT cells. Collectively, our results show that FBTA might be useful as a functional food while being a good candidate in the development of cosmetic products and medicines for the remedy of UVB-induced skin photo-aging.
In this study, the authors investigated the anti-melanogenic effects of 3,8-dihydroxyquinoline (jineol) isolated from Scolopendra subspinipes mutilans, the mechanisms responsible for its inhibition of melanogenesis in melan-a cells, and its antioxidant efficacy. Mushroom tyrosinase activities and melanin contents were determined in melan-a cells, and the protein and mRNA levels of MITF, tyrosinase, TYRP-1, and TYRP-2 were assessed. Jineol exhibited significant, concentration-dependent antioxidant effects as determined by DPPH, ABTS, CUPRAC, and FRAP assays. Jineol significantly inhibited mushroom tyrosinase activity by functioning as an uncompetitive inhibitor, and markedly inhibited melanin production and intracellular tyrosinase activity in melan-a cells. In addition, jineol abolished the expressions of tyrosinase, TYRP-1, TYRP-2, and MITF, thereby blocking melanin production and interfering with the phosphorylations of ERK1/2 and p38. Furthermore, specific inhibitors of ERK1/2 and p38 prevented melanogenesis inhibition by jineol, and the proteasome inhibitor (MG-132) prevented jineol-induced reductions in cellular tyrosinase levels. Taken together, jineol was found to stimulate MAP-kinase (ERK1/2 and p38) phosphorylation and the proteolytic degradation pathway, which led to the degradations of MITF and tyrosinase, and to suppress the productions of melanin.
In this study, the anti-melanogenic effects of Heracleum moellendorffii Hance extract (HmHe) and the mechanisms through which it inhibits melanogenesis in melan-a cells were investigated. Mushroom tyrosinase (TYR) activity and melanin content as well as cellular tyrosinase activity were measured in the cells. mRNA and protein expression of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), TYR-related protein-1 (TYRP-1) and -2 were also examined. The results demonstrate that treatment with HmHe significantly inhibits mushroom tyrosinase activity. Furthermore, HmHe also markedly inhibits melanin production and intracellular tyrosinase activity. By suppressing the expression of TYR, TYRP-1, TYRP-2, and MITF, HmHe treatment antagonized melanin production in melan-a cells. Additionally, HmHe interfered with the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, with reversal of HmHe-induced melanogenesis inhibition after treatment with specific inhibitor U0126. In summary, HmHe can be said to stimulate ERK1/2 phosphorylation and subsequent degradation of MITF, resulting in suppression of melanogenic enzymes and melanin production, possibly due to the presence of polyphenolic compounds.
Glucose deposition in peripheral tissue is an important parameter for the treatment of type 2 diabetes mellitus. The aim of this study was to investigate the effects of Spatholobus suberectus (Ss) on glucose disposal in skeletal muscle cells and additionally explore its in vivo antidiabetic potential. Treatment of ethanolic extract of S. suberectus (EeSs) significantly enhanced the glucose uptake, mediated through the enhanced expression of GLUT4 in skeletal muscle via the stimulation of AKT and AMPK pathways in C2C12 cells. Moreover, EeSs have potential inhibitory action on α-glucosidase activity and significantly lowered the postprandial blood glucose levels in STZ-induced diabetic mice, associated with increased expression of GLUT4 and AKT and/or AMPK-mediated signaling cascade in skeletal muscle. Furthermore, administration of EeSs significantly boosted up the antioxidant enzyme expression and also mitigated the gluconeogenesis enzyme such as PEPCK and G-6-Pase enzyme expression in liver tissue of STZ-induced diabetic mice model. Collectively, these findings suggest that EeSs have a high potentiality to mitigate diabetic symptoms through stimulating glucose uptake in peripheral tissue via the activation of AKT and AMPK signaling cascade and augmenting antioxidant potentiality as well as blocking the gluconeogenesis process in diabetic mice.
The Prunus mume seed is a by-product of the food industry, and we studied its potential as a food biomaterial, particularly for nutraceutical and inner beauty products. Alternative animal tests showed that an extract of P. mume ripened seed (PmRS) was not toxic on the skin. PmRS exhibited protective effects against ultraviolet- (UV-) induced skin aging in mice, confirmed by phenotypic indications, including increased collagen levels and decreased skin thickness. Compared with the UV-saline group, the UV-PmRS group showed increased levels of silent mating type information regulation 2 homolog 1 (SIRT1) and collagen and decreased matrix metalloproteinase- (MMP-) 1 expression. The protective effect of PmRS treatment against UVB-mediated cell viability was observed in vitro without any cytotoxicity, and PmRS prevented UVB-induced reactive oxygen species generation in HaCaT cells. PmRS downregulated MMP-1 and MMP-13 compared with the UVB-irradiated group. However, mRNA expressions of tissue inhibitor of metalloproteinase-1 and SIRT1 were upregulated by PmRS treatment. MMP-1 and SIRT1 treated with PmRS were decreased and increased, respectively, at the protein level. Moreover, PmRS treatment reduced c-Jun N-terminal kinase and p38 phosphorylation compared with the UVB-treated group. We postulate that P. mume seed could be a useful ingredient in nutraceuticals and inner beauty-purpose foods.
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