Downregulation of melanogenesis: drug discovery and therapeutic options.

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.

/pdf/inhibition-of-melanogenesis-by-jineol-from-scolopendra-amqif3si7u.pdf

Inhibition of melanogenesis by jineol from Scolopendra subspinipes mutilans via MAP-Kinase mediated MITF downregulation and the proteasomal degradation of tyrosinase

Diospyros kaki (DK) contains an abundance of flavonoids and has been used in folk medicine in Korea for centuries. Here, we report for the first time the anti-inflammatory activities of Quercetin (QCT) and Quercetin 3-O-β-("2"-galloyl)-glucopyranoside (Q32G) isolated from DK. We have determine the no cytotoxicity of Q32G and QCT against RAW 264.7 cells up to concentration of 50 μM. QCT and Q32G demonstrated potent anti-inflammatory activities by reducing expression of nitric oxide (NO), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 inducible NO synthase (iNOS), cyclooxygenase (COX)-2, and mitogen-activated protein kinase (MAPKs) in mouse RAW 264.7 macrophages activated with lipopolysaccharide (LPS). Both QCT or Q32G could decrease cellular protein levels of COX-2 and iNOS as well as secreted protein levels of NO, PGE2 , and cytokines (TNF-α, IL-1β, and IL-6) in culture medium of LPS-stimulated RAW 264.7 macrophages. Immunoblot analysis showed that QCT and Q32G suppressed LPS-induced MAP kinase pathway proteins p-p38, ERK, and JNK. This study revealed that QCT and Q32G have anti-inflammatory potential, however Q32G possess comparable activity as that of QCT and could be use as adjuvant to treat inflammatory diseases.

Anti-inflammatory Potential of Quercetin-3-O-β-D-(“2”-galloyl)-glucopyranoside and Quercetin Isolated from Diospyros kaki calyx via Suppression of MAP Signaling Molecules in LPS-induced RAW 264.7 Macrophages

Breaking the frontiers of cosmetology with antimicrobial peptides.

Edible insects have been reported to produce metabolites showing various pharmacological activities, recently emerging as rich sources of health functional food. In particular, the larvae of Protaetia brevitarsis seulensis (Kolbe) have been used as traditional Korean medicines for treating diverse diseases, such as breast cancer, inflammatory disease, hepatic cancer, liver cirrhosis, and hepatitis. However, only few chemical investigations were reported on the insect larvae. Therefore, the aim of this study was to discover and identify biologically active chemical components of the larvae of P. brevitarsis seulensis. As a result, a quinoxaline-derived alkaloid (1) was isolated, which was not reported previously from natural sources. In addition, other related compounds (2, 4–10, 15, 16) were also encountered for the first time from the larvae. The structures of all the isolated compounds were established mainly by analysis of HRESIMS, NMR, and electronic circular dichroism data. Compound 5 exhibited inhibition of tyrosinase with IC50 value of 44.8 µM.

Quinoxaline-, dopamine-, and amino acid-derived metabolites from the edible insect Protaetia brevitarsis seulensis.

https://cyberleninka.org/article/n/1213652.pdf

Quercetin-3-O-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside suppresses melanin synthesis by augmenting p38 MAPK and CREB signaling pathways and subsequent cAMP down-regulation in murine melanoma cells

Ultraviolet (UV) exposure is well-known to induce premature aging, which is mediated by matrix metalloproteinase-1 (MMP-1) activity. A 9-mer peptide, CopA3 (CopA3) was synthesized from a natural peptide, coprisin, which is isolated from the dung beetle Copris tripartitus. As part of our continuing search for novel bioactive natural products, CopA3 was investigated for its in vitro anti-skin photoaging activity. UV-induced inhibition of type-I procollagen and induction of MMP-1 were partially prevented in human skin fibroblasts by CopA3 peptide in a dose-dependent manner. At a concentration of 25 μM, CopA3 nearly completely inhibited MMP-1 expression. These results suggest that CopA3, an insect peptide, is a potential candidate for the prevention and treatment of skin aging.

https://www.mdpi.com/1420-3049/19/5/6407/pdf

CopA3 Peptide Prevents Ultraviolet-Induced Inhibition of Type-I Procollagen and Induction of Matrix Metalloproteinase-1 in Human Skin Fibroblasts

The anti-inflammatory effects of Polygonum multiflorum water extracts (PMWs) and Polygonum multiflorum 70 % ethanol extracts(PMEs) were investigated using lipopolysaccharide-induce by inflammatory response. The inhibitory effects of PMWs and PMEs on the production of nitric oxide (NO) and pro inflammatory cytokines in LPS activated Raw 264.7 cells were investigated. The effects were examined after reducing production of Nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein levels. RAW 264.7 cells were cultured with LPS (1 μg/mL) in the presence or absence of PMWs and PMEs for 24 h to determine their NO, iNOS, COX–2 levels. During the entire experimental period 10, 25, 50 and 100 μg/mL of PMWs and PMEs showed no cytotoxicity. At these concentrations, PMWs and PMEs concentration dependently reduced the production of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). PMWs and PMEs were inhibited the activittion of iNOS, COX-2 by 89%, 54%, 91% and 57% respectively, at 100 μg/mL. These results indicate that PMWs and PMEs significantly reduces the effect of oxidative and inflammatory cytokines.

/pdf/anti-inflammatory-effect-of-polygonum-multiflorum-extraction-2v2l3hwcuh.pdf

Eunsu Lee

Papers

Quercetin-3-O-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside suppresses melanin synthesis by augmenting p38 MAPK and CREB signaling pathways and subsequent cAMP down-regulation in murine melanoma cells

CopA3 Peptide Prevents Ultraviolet-Induced Inhibition of Type-I Procollagen and Induction of Matrix Metalloproteinase-1 in Human Skin Fibroblasts

Anti-inflammatory effect of Polygonum multiflorum extraction in activated RAW 264.7 cells with lipopolysaccharide