Synthesis of (S)-(+)-decursin and its analogues as potent inhibitors of melanin formation in B16 murine melanoma cells

Suppressive activities of KC1-3 on HMGB1-mediated septic responses

In the present study, several decursin analogues (KC1-3) were synthesized and evaluated in terms of their anti-septic activities on high mobility group box 1 (HMGB1)-mediated septic responses and survival rate in a mouse model of sepsis. KC1 and KC3, but not KC2, significantly reduced HMGB1 release in lipopolysaccharide (LPS)-activated human umbilical vein endothelial cells (HUVECs) and attenuated the cecal ligation and puncture (CLP)-induced release of HMGB1. Additionally, in vitro analyses revealed that KC1 and KC3 both alleviated HMGB1-mediated vascular disruptions and inhibited hyperpermeability in mice, and in vivo analyses revealed that KC1 and KC3 reduced sepsis-related mortality and tissue injury. Taken together, the present results suggest that KC1 and KC3 both reduced HMGB1 release and septic mortality and, thus, may be useful for the treatment of sepsis.

Chemical Constituents Isolated from the Root Bark of Cudrania tricuspidata and Their Potential Neuroprotective Effects

Seventy-five compounds, including 21 new compounds (1-21), were isolated from the root bark of Cudrania tricuspidata. The structures of the isolated compounds were elucidated by interpretation of their spectroscopic data. All isolated compounds were evaluated for their neuroprotective effects against 6-hydroxydopamine (6-OHDA)-induced cell death, and nine compounds had activities with EC50 values of 1.9-30.2 μM. The 75 isolated compounds along with 34 previously reported xanthones were tested also for neuroprotective effects against the 1-methyl-4-phenylpyridinium ion (MPP(+)) and oxygen glucose deprivation (OGD)-induced cell death. Three compounds were active against MPP(+)-induced cell death with EC50 values of 0.2-10.3 μM, and 23 compounds were active in the OGD model with EC50 values of 2.9-35.5 μM.

Computational approaches to predict binding interactions between mammalian tyrosinases and (S)-(+)-decursin and its analogues as potent inhibitors

Using computational methods, we elucidated the binding modes of (S)-(+)-decursin with mouse and human tyrosinases, and thereby provided insight to new tyrosinase inhibitors.

Anti-melanogenic activity of the novel herbal medicine, MA128, through inhibition of tyrosinase activity mediated by the p38 mitogen-activated protein kinases and protein kinase signaling pathway in B16F10 cells

Background:

Recently, our research group developed MA128, a novel herbal medicine, and demonstrated that MA128 is effective for the treatment of asthma and atopic dermatitis (AD). In particular, postinflammatory hyper-pigmentation in AD mice was improved with MA128 treatment. Thus, in this study, we determined the effect of MA128 on melanogenesis and its underlying mechanism in murine B16F10 melanoma cells.

Materials and Methods:

After treatment with MA128 at 100 and 250 μg/mL and/or alpha-melanocyte stimulating hormone (α-MSH) (1 μM), cellular melanin content and tyrosinase activity in B16F10 cells were measured. Using western blotting, expression levels of tyrosinase, tyrosinase-related protein-1 (TRP-1), TRP-2, microphthalmia-associated transcription factor (MITF), and activation of c-AMP-dependent protein kinase (PKA), c-AMP-related element binding protein (CREB) and mitogen-activated protein kinases (MAPKs) were examined.

Results:

MA128 significantly inhibited melanin synthesis and tyrosinase activity in a resting state as well as α-MSH-stimulating condition, and significantly decreased the expression of tyrosinase, TRP-1, TRP-2 and MITF. In addition, phosphorylation of PKA and CREB by α-MSH stimulation was efficiently blocked by MA128 pretreatment. Moreover, MA128 as an herbal mixture showed synergistic anti-melanogenic effects compared with each single constituent herb.

Conclusion:

MA128 showed anti-melanogenic activity through inhibition of tyrosinase activity mediated by p38 MAPK and PKA signaling pathways in B16F10 cells. These results suggest that MA128 may be useful as an herbal medicine for controlling hyper-pigmentation and as a skin-whitening agent.

Ssanghwa-tang, an oriental herbal cocktail, exerts anti-melanogenic activity by suppression of the p38 MAPK and PKA signaling pathways in B16F10 cells

Background

Ssanghwa-tang (SHT) is a widely used medication for the treatment of fatigue, pain, inflammation, hypothermia, erectile dysfunction, cancer, and osteoporosis in Asia, however, role of SHT on the melanin synthesis has not been checked previously. Thus, the present study was designed to determine the effect of SHT on α-melanocyte stimulating hormone (α-MSH)-induced melanogensis and its mechanisms of action in murine B16F10 melanoma cells.

Method

Cellular melanin content and tyrosinase activity in murine B16F10 melanoma cells were determined after α-MSH stimulation with or without pre-treatment of SHT at the concentration of 250 and 500 μg/ml. Expression level of tyrosinase, tyrosinase-related protein 1 (TRP-1), TRP-2, microphthalmia-associated transcription factor (MITF), and activation of c-AMP-dependent protein kinase (PKA), c-AMP-related element binding protein (CREB), and mitogen-activated protein kinases (MAPKs) were examined by Western blot analysis.

Results

SHT significantly inhibited α-MSH-induced melanin synthesis and tyrosinase activity, and also decreased α-MSH-induced expression of MITF, tyrosinase, and TRP-1. In addition, SHT remarkably suppressed tyrosinase, CRE, and MITF luciferase reporter activity in a resting state as well as in α-MSH-stimulating condition. Phosphorylation of p38 MAPK by α-MSH stimulation was efficiently blocked by SHT pre-treatment. Moreover, SHT as an herbal cocktail showed synergistic anti-melanogenic effect compared with that of each single constituent herb.

Conclusion

SHT efficiently inhibited c-AMP-induced melanin synthesis in B16F10 cells via suppression of PKA and p38 MAPK signaling pathways and subsequently decreased the level of CREB phosphorylation, MITF, and melanogenic enzymes. These results indicate that SHT may be useful as herbal medicine for treating hyperpigmentation and cosmetics as a skin-whitening agent.