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The present study was designed to assess the potential inhibitory activity of curcumin on the alpha-melanocyte stimulating hormone (alpha-MSH)-stimulated melanogenesis signal pathway in B16F10 melanoma cells. The molecular mechanism of curcumin-induced inhibitory activity on the alpha-MSH-stimulated melanogenesis signal pathway, including expression of melanogenesis-related proteins and activation of melanogenesis-regulating proteins, was examined in B16F10 cells. Curcumin suppressed the cellular melanin contents and the tyrosinase activity in alpha-MSH-stimulated B16F10 cells. In addition, the expression of melanogenesis-related proteins such as microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein 1 and 2 was suppressed by curcumin in the alpha-MSH-stimulated B16F10 cells. Notably, a melanogenesis-regulating signal such as mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) or phosphatidylinositol 3-kinase (PI3K)/Akt was activated by curcumin in the B16F10 cells treated with or without alpha-MSH. The suppressive activity of curcumin on alpha-MSH-induced melanogenesis was down-regulated by PD98059 and by LY294002. Our results suggest that the suppressive activity of curcumin on alpha-MSH-stimulated melanogenesis may involve the down-regulation of MITF and its downstream signal pathway through the activation of MEK/ERK or PI3K/Akt.

The active fraction of the extract of Asiasari radix, the 60% methanol chromatographic fraction from the ethyl acetate layer (PPAR), was used to investigate the melanogenesis signal pathway in B16F10 melanoma cells. PPAR led to significantly decreased melanin synthesis and tyrosinase activity in a dose-dependent manner. PPAR also reduced the expression of melanogenesis-related proteins including microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein (TRP)s while down-regulating the expression of mRNA of MITF and tyrosinase. Melanogenesis-regulating signals, such as mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K)/Akt and p38 mitogen-activated protein kinase (MAPK) were evaluated, and ERK was activated by PPAR. The selective inhibitor of MEK/ERK, PD98059, abrogated all suppressive activities of PPAR on melanin biosynthesis, tyrosinase activation and expression of melanogenesis-related proteins. These results suggest that ERK activation by PPAR contributes to reduced melanin synthesis via ERK signal pathway-mediated suppression of MITF and its downstream signal pathway.

We investigated the effects of aqueous extract from Platycodi radix (AEPR), a traditional drug used to treat acute lung inflammatory disease, on lipopolysaccharide (LPS)-induced inflammation in A549 human cultured airway epithelial cells. Nuclear factor-kappaB (NF-kappaB) and its inhibitory regulator, inhibitory kappaB (I-kappaB), play crucial roles in LPS-induced inflammatory response. We show that LPS-induced nuclear translocation of NF-kappaBp65 is inhibited by AEPR. LPS-induced expression of I-kappaBalpha, which is expressed by LPS-induced activation of NF-kappaB, is inhibited by AEPR as well. Besides LPS-induced expression of a group of genes, such as tumor necrosis factor-alpha (TNF-alpha), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), are repressed by AEPR. We also found that expression of heat shock protein 70 (Hsp70), which has an anti-inflammatory activity, is increased by AEPR plus LPS. These results suggest that AEPR may act as a therapeutic agent for inflammatory disease through regulating the activity of NF-kappaB and expression of inflammatory genes.

Artemisia capillaris Thunb. has been used for the remedy of liver diseases such as hepatitis, jaundice and fatty liver in traditional oriental medicine. However, despite extensive pharmacological studies, the molecular mechanism of the anti-inflammatory effect of Artemisia capillaris Thunb. has hardly been studied. In the present study, we investigated the pharmacological action mechanism on LPS-induced liver inflammation in HepG2 human hepatocarcinoma cells and rat liver. Aqueous extract from Artemisia capillaris Thunb. (AEAC) inhibits expression of inflammatory proteins including iNOS, COX-2 and TNF-alpha. Also, nuclear translocation of NF-kappaB and degradation of I-kappaBalpha are blocked by AEAC pretreatment. These results suggest that the inhibitory effect of AEAC on the expression of inflammatory proteins involves suppression of NF-kappaB activation.

Aim: To study the anti-inflammatory effects of aqueous extract from Dichroa febrifuga root (AEDF) for suppression in the process of lipopolysaccharide (LPS)-induced sepsis in the rat liver., Methods: The inhibitory effect of AEDF on the alteration of inflammatory proteins was investigated by Western blot and immunohistochemical analysis., Results: Western blot analysis showed that the level of nuclear factor (NF)-kappaBp65 was markedly up-regulated and (I)-kappaBalpha was down-regulated by LPS (8 mg/kg) challenge. However, AEDF 100 mg/kg inhibited induction of NF-kappaBp65 and degradation of I-kappaBalpha in the liver of LPS-challenged rats. Immunohistochemical analysis showed that while the expression of the NF-kappaBp65, tumor necrosis factor (TNF)-alpha and inducible nitric oxide synthase (iNOS) tended to increase, that of I-kappaBalpha was decreased in the hepatocytes of rats challenged with LPS. A slight decline of NF-kappaBp65, TNF-alpha and iNOS, but an increase of I-kappaBalpha were observed in the hepatocytes of the rats pretreated with AEDF., Conclusion: AEDF may act as a therapeutic agent for inflammatory disease through a regulation of inflammation-related proteins.

Tetrandrine, isolated from the root of Stephania tetrandra, has been used in Chinese medicine for the treatment of silicosis and arthritis, and it also has anti-tumor/growth activities. However, the signaling pathways of tetrandrine-induced growth arrest and apoptosis in cancer cells remain unclear. We investigated the molecular mechanisms of tetrandrine-induced apoptosis and growth arrest in human lung carcinoma cells. Upon treatment with tetrandrine, a time-dependent inhibition of cell growth was observed and cells developed many of the hallmark features of apoptosis. Flow cytometry analysis confirmed that tetrandrine increased populations of both apoptotic sub-G1 and G1 phase. Tetrandrine-induced growth inhibition was associated with induction of Cdk inhibitor p21, inhibition of cyclin D1 and activation of caspase-3. Tetrandrine also affected the expression patterns of cytoskeletons including distribution of F-actin and expression level of microtubule. These results suggest that tetrandrine merits further investigation as a cell cycle blocker as well as a cancer chemopreventive agent.