Induction of Apoptosis and Effect on the FAK/AKT/mTOR Signal Pathway by Evodiamine in Gastric Cancer Cells.

Evodiamine isolated from Evodia rutaecarpa has been known to have anti-tumor activity against various cancer cell types. Although there have been reports showing the inhibitory effect of evodiamine on cell survival of gastric cancer cell, it is not clearly explained how evodiamine affects the expression and modification of proteins associated with apoptosis and upstream signal pathways. We confirmed the cytotoxic activity of evodiamine against AGS and MKN45 cells by a WST assay, cell morphological change, and clonogenic assay. The apoptotic cells were evaluated by Annexin V/PI analysis and Western blot and the expressions of apoptosis-related molecules were confirmed by Western blot. Evodiamine promoted apoptosis of AGS gastric cancer cells through both intrinsic and extrinsic signal pathways in a time- and dose-dependent manner. Evodiamine attenuated the expression of anti-apoptotic proteins, including Bcl-2, XIAP, and survivin, and elevated that of the pro-apoptotic protein Bax. Evodiamine also suppressed the FAK/AKT/mTOR signal pathway. Based on these results, we expect that the results from this study will further elucidate our understanding of evodiamine as an anti-cancer drug.

Zerumbone Inhibits Helicobacter pylori Urease Activity.

Helicobacter pylori (H. pylori) produces urease in order to improve its settlement and growth in the human gastric epithelium. Urease inhibitors likely represent potentially powerful therapeutics for treating H. pylori; however, their instability and toxicity have proven problematic in human clinical trials. In this study, we investigate the ability of a natural compound extracted from Zingiber zerumbet Smith, zerumbone, to inhibit the urease activity of H. pylori by formation of urease dimers, trimers, or tetramers. As an oxygen atom possesses stronger electronegativity than the first carbon atom bonded to it, in the zerumbone structure, the neighboring second carbon atom shows a relatively negative charge (δ-) and the next carbon atom shows a positive charge (δ+), sequentially. Due to this electrical gradient, it is possible that H. pylori urease with its negative charges (such as thiol radicals) might bind to the ß-position carbon of zerumbone. Our results show that zerumbone dimerized, trimerized, or tetramerized with both H. pylori urease A and urease B molecules, and that this formation of complex inhibited H. pylori urease activity. Although zerumbone did not affect either gene transcription or the protein expression of urease A and urease B, our study demonstrated that zerumbone could effectively dimerize with both urease molecules and caused significant functional inhibition of urease activity. In short, our findings suggest that zerumbone may be an effective H. pylori urease inhibitor that may be suitable for therapeutic use in humans.

Evodiamine Inhibits Helicobacter pylori Growth and Helicobacter pylori-Induced Inflammation.

Helicobacter pylori (H. pylori) classified as a class I carcinogen by the World Health Organization (WHO) plays an important role in the progression of chronic gastritis and the development of gastric cancer. A major bioactive component of Evodia rutaecarpa, evodiamine, has been known for its anti-bacterial effect and anti-cancer effects. However, the inhibitory effect of evodiamine against H. pylori is not yet known and the inhibitory mechanisms of evodiamine against gastric cancer cells are yet to be elucidated concretely. In this study, therefore, anti-bacterial effect of evodiamine on H. pylori growth and its inhibitory mechanisms as well as anti-inflammatory effects and its mechanisms of evodiamine on H. pylori-induced inflammation were investigated in vitr. Results of this study showed the growth of the H. pylori reference strains and clinical isolates were inhibited by evodiamine. It was considered one of the inhibitory mechanisms that evodiamine downregulated both gene expressions of replication and transcription machineries of H. pylori. Treatment of evodiamine also induced downregulation of urease and diminished translocation of cytotoxin-associated antigen A (CagA) and vacuolating cytotoxin A (VacA) proteins into gastric adenocarcinoma (AGS) cells. This may be resulted from the reduction of CagA and VacA expressions as well as the type IV secretion system (T4SS) components and secretion system subunit protein A (SecA) protein which are involved in translocation of CagA and VacA into host cells, respectively. In particular, evodiamine inhibited the activation of signaling proteins such as the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and the mitogen-activated protein kinase (MAPK) pathway induced by H. pylori infection. It consequently might contribute to reduction of interleukin (IL)-8 production in AGS cells. Collectively, these results suggest anti-bacterial and anti-inflammatory effects of evodiamine against H. pylori.

Epigallocatechin-3-Gallate Suppresses the Expression of TNF-α-Induced MMP-1 via MAPK/ERK Signaling Pathways in Human Dermal Fibroblasts.

Deeper wrinkles and loss of elasticity are one of the skin-aging symptoms. Collagen breakdown by matrix metalloproteinase-1 (MMP-1), which is induced by reactive oxygen species (ROS) and pro-inflammatory cytokines, has been known to be responsible for these skin-aging symptoms. Therefore, much attention has been paid to chemicals to suppress the MMP-1 activity. Epigallocatechin-3-gallate (EGCG), catechin rich in green tea, has been reported to show antioxidant and protect skin from various stimuli such as UV and chemicals. In this study, we evaluated the inhibitory effect of EGCG on MMP-1 gene expression and secretion in tumor necrosis factor-α (TNF-α)-treated human dermal fibroblast cells (Hs68 cells). Pre-treatment with EGCG (10 and 20 µM) suppressed TNF-α-induced MMP-1 expression and secretion. EGCG also reduced the phosphorylation of extracellular signal regulated kinase (ERK) significantly but not that of p38 activation and c-Jun N-terminal kinase (JNK). Besides, EGCG (10 and 20 µM) showed the inhibitory effect on mitogen-activated protein extracellular kinase (MEK) and Src phosphorylation which is reported to be upstream signal proteins of ERK signal pathway. Based on these results, EGCG might have potential activity to slow down the skin-aging through inhibition of collagen breakdown, which remains to be elucidated.

Neochlorogenic Acid Inhibits Lipopolysaccharide-Induced Activation and Pro-inflammatory Responses in BV2 Microglial Cells.

Microglia is the resident innate immune cells that sense pathogens and tissue injury in the central nervous system. Microglia becomes activated in response to injury, infection, and other stimuli that threaten neuronal survival. Microglia activation plays an important role in neurodegenerative diseases. Neochlorogenic acid (NCA) is a natural polyphenolic compound found in dried fruits and other plants. Although previous studies have shown that phenolic acids including NCA have outstanding antioxidant, antibacterial, antiviral, and antipyretic activities, there has not yet been investigated for anti-inflammatory effects. Therefore, for the first time we have examined the potential of NCA to inhibit microglial activation and pro-inflammatory responses in the brain. We found that lipopolysaccharide-induced inducible nitric oxide synthase, and cyclooxygenase-2 expression, and nitric oxide formation was suppressed by NCA in a dose-dependent manner in BV2 microglia. NCA also inhibited the production of pro-inflammatory mediators, tumor necrosis factor-α and interleukin-1 beta. Furthermore, phosphorylated nuclear factor-kappa B p65 and p38 mitogen-activated protein kinase activation were blocked by NCA. Taken together, these results suggest that NCA exerts neuroprotective effects through the inhibition of pro-inflammatory pathways in activated microglia.

Regulatory Effect of 25-hydroxyvitamin D3 on Nitric Oxide Production in Activated Microglia.

Microglia are activated by inflammatory and pathophysiological stimuli in neurodegenerative diseases, and activated microglia induce neuronal damage by releasing cytotoxic factors like nitric oxide (NO). Activated microglia synthesize a significant amount of vitamin D3 in the rat brain, and vitamin D3 has an inhibitory effect on activated microglia. To investigate the possible role of vitamin D3 as a negative regulator of activated microglia, we examined the effect of 25-hydroxyvitamin D3 on NO production of lipopolysaccharide (LPS)-stimulated microglia. Treatment with LPS increased the production of NO in primary cultured and BV2 microglial cells. Treatment with 25-hydroxyvitamin D3 inhibited the generation of NO in LPS-activated primary microglia and BV2 cells. In addition to NO production, expression of 1-α-hydroxylase and the vitamin D receptor (VDR) was also upregulated in LPS-stimulated primary and BV2 microglia. When BV2 cells were transfected with 1-α-hydroxylase siRNA or VDR siRNA, the inhibitory effect of 25-hydroxyvitamin D3 on activated BV2 cells was suppressed. 25-Hydroxyvitamin D3 also inhibited the increased phosphorylation of p38 seen in LPS-activated BV2 cells, and this inhibition was blocked by VDR siRNA. The present study shows that 25-hydroxyvitamin D3 inhibits NO production in LPS-activated microglia through the mediation of LPS-induced 1-α-hydroxylase. This study also shows that the inhibitory effect of 25-hydroxyvitamin D3 on NO production might be exerted by inhibiting LPS-induced phosphorylation of p38 through the mediation of VDR signaling. These results suggest that vitamin D3 might have an important role in the negative regulation of microglial activation.

A substituted 3,4-dihydropyrimidinone derivative (compound D22) prevents inflammation mediated neurotoxicity; role in microglial activation in BV-2 cells.

A novel synthetic 3,4-dihydropyrimidinone derivative, compound D22 (ethyl 6-methyl-4-(3-phenoxyphenyl)-2-thioxo-3,4-dihydropyrimidine-5-carboxylate), was found to exert anti-inflammatory properties in lipopolysaccharide-stimulated microglial BV-2 cells. Compound D22 reduced the pro-inflammatory factors such as nitric oxide, prostaglandin E(2), tumor necrosis factor-α and interleukin-1ß. Moreover, it suppressed the expressions of inducible NO synthase and cyclooxygenase-2. Compound D22 inhibited the activation of mitogen-activated protein kinases. When compound D22-conditioned media from BV-2 cells were applied to N2a cells, neuronal cell death was inhibited via suppression of caspase-3 activation and regulation of Bcl-2 and Bax proteins expression. These results suggest that compound D22 may be useful for treating neurodegenerative diseases related with neuroinflammation.

Acacetin attenuates neuroinflammation via regulation the response to LPS stimuli in vitro and in vivo.

Under normal conditions in the brain, microglia play roles in homeostasis regulation and defense against injury. However, over-activated microglia secrete proinflammatory and cytotoxic factors that can induce progressive brain disorders, including Alzheimer's disease, Parkinson's disease and ischemia. Therefore, regulation of microglial activation contributes to the suppression of neuronal diseases via neuroinflammatory regulation. In this study, we investigated the effects of acacetin (5,7-dihydroxy-4'-methoxyflavone), which is derived from Robinia pseudoacacia, on neuroinflammation in lipopolysaccharide (LPS)-stimulated BV-2 cells and in animal models of neuroinflammation and ischemia. Acacetin significantly inhibited the release of nitric oxide (NO) and prostaglandin E(2) and the expression of inducible NO synthase and cyclooxygenase-2 in LPS-stimulated BV-2 cells. The compound also reduced proinflammatory cytokines, tumor necrosis factor-α and interleukin-1ß, and inhibited the activation of nuclear factor-κB and p38 mitogen-activated protein kinase. In an LPS-induced neuroinflammation mouse model, acacetin significantly suppressed microglial activation. Moreover, acacetin reduced neuronal cell death in an animal model of ischemia. These results suggest that acacetin may act as a potential therapeutic agent for brain diseases involving neuroinflammation.

Protective effects of standardized Thuja orientalis leaves against 6-hydroxydopamine-induced neurotoxicity in SH-SY5Y cells.

Although the etiology of Parkinson's disease (PD) remains unknown, recent studies have suggested that oxidative stress (OS) and apoptosis, as a result of mitochondrial defects, may play important roles in its pathogenesis. 6-Hydroxydopamine (6-OHDA), a neurotoxin commonly used in models of PD, induces selective catecholaminergic cell death, mediated by reactive oxygen species (ROS) and mitochondrial defects. This study investigated the protective effect of Thuja orientalis leaves (TOFE), a well-known oriental traditional medicine, on 6-OHDA-induced neurotoxicity in SH-SY5Y cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Hoechst staining showed that TOFE attenuated the cell damage caused by 6-OHDA stress. TOFE showed strong radical scavenging effects in 2,2-diphenyl-2-picrylhydrazyl and 2,2-azinobis-(3-ethyl-benzthiazoline-6-sulphonic acid) assays, and it reduced the intracellular ROS and extracellular nitric oxide production induced by 6-OHDA. Additionally, TOFE blocked the reduction in the mitochondrial membrane potential, the release of cytochrome c, and the activation of caspase-3. Moreover, TOFE decreased the phosphorylation of extracellular signal-regulated kinase (pERK), which has pro-apoptotic functions. Taken together, TOFE might protect SH-SY5Y cells from 6-OHDA through the downregulation of OS and mitochondrial-mediated apoptosis, and regulation of pERK.

Ischemia-activated microglia induces neuronal injury via activation of gp91phox NADPH oxidase.

Although glial cells play a major role in the pathogenesis of many neurological diseases by exacerbating neuronal and non-neuronal cell death, the mechanisms involved are unclear. We examined the effects of microglia-(MCM) or astrocyte-(ACM) conditioned media obtained by chemical ischemia on the neuronal injury in SH-SY5Y cells. Chemical ischemia was induced by the treatment with NaN(3) and 2-deoxy-d-glucose for 2h. MCM-treated SH-SY5Y cells showed reduced the viability, increased caspase-3 activity, decreased Bcl-2/Bax ratio, and increased cytochrome c release, increased inflammatory cytokines, and increased reactive oxygen species (ROS) generation. MCM also increased gp91phox nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, which was inhibited by NADPH oxidase inhibitor, apocynin, and gp91phox siRNA. However, ACM did not show any significant changes. The results suggest that microglia activated by ischemic insult may increase reactive oxygen species generation via activation of gp91phox NADPH oxidase, resulting in neuronal injury.

Neurite outgrowth induced by spicatoside A, a steroidal saponin, via the tyrosine kinase A receptor pathway.

Although nerve growth factor (NGF) therapy is an available option for the treatment of Alzheimer's disease, several limitations exist in its medical application. In the present study, we examined the neurotrophic effects of spicatoside A isolated from Liriope platyphylla on PC12 cells as well as the mechanisms involved in this process. Spicatoside A (10 microg/mL) induced neurite outgrowth similar to NGF (50 ng/mL). Furthermore, spicatoside A, a steroidal saponin, activated extracellular signal-regulated kinase 1/2 (ERK 1/2) and phosphatidylinositol 3-kinase (PI 3-kinase/Akt) via tyrosine receptor kinase A (TrkA), which is responsible for the induction of the neuritic process. The effects of NGF and spicatoside A on neurite outgrowth disappeared in TrkA knockdown PC12 cells by siRNA. In conclusion, neuritogenic effects resulting from spicatoside A may be involved in TrkA activation.

Apigenin inhibits the production of NO and PGE2 in microglia and inhibits neuronal cell death in a middle cerebral artery occlusion-induced focal ischemia mice model.

Flavonoids have been intensively studied on their pharmacological activities such as anti-cancer, anti-oxidant and anti-inflammation. However, little is known about their neuroprotective effects. Recent studies suggest that inflammation mediated by microglia may play a role in neurodegenerative diseases. In this study, we evaluated the anti-inflammatory effect of various flavonoid compounds by using BV-2, a murine microglia cell line. Of the compounds that were evaluated, apigenin inhibited the production of nitric oxide and prostaglandin E(2) by suppressing the expression of inducible nitric oxide synthase and cyclooxygenase-2 protein, respectively. Moreover, apigenin suppressed p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK) phosphorylation without affecting the activity of extracellular signal-regulated kinase (ERK). Apigenin was also found to protect neuronal cells from injury in middle cerebral artery occlusion.

Protective effect of (4-methoxybenzylidene)-(3-methoxynophenyl)amine against neuronal cell death induced by oxygen and glucose deprivation in rat organotypic hippocampal slice culture.

Resveratrol (trans-3,4',5-trihydroxystilbene) is a natural phytoalexin found in grape skin, and has been suggested to be an antioxidant agent, an anticancer agent and a cardioprotective agent. In particular, recent experimental evidence has demonstrated that resveratrol exhibits neuroprotective effects in various assay systems. During the study on the resveratrol derivatives, we found that (4-methoxybenzylidene)-(3-methoxyphenyl)amine (MBMPA), which has blocked free phenolic groups, strongly protects neuronal cells against ischemic damage on a higher activity than resveratrol. The MBMPA potently reduced the level of neuronal cell death in an oxygen and glucose deprivation-exposed rat organotypic hippocampal slice culture. In addition, ATP depletion following the onset of oxygen and glucose deprivation in an adult hippocampal slice was blocked by the MBMPA treatment. These results suggest that MBMPA has a neuroprotective effect on an in vitro ischemia model, and may be useful for treating stroke.

Geniposide from Gardenia jasminoides attenuates neuronal cell death in oxygen and glucose deprivation-exposed rat hippocampal slice culture.

Geniposide from Gardenia jasminoides protected neuronal cells from damage in oxygen and glucose deprivation-exposed hippocampal slice culture. Geniposide showed a greater protective effect on the granule cell layer than on the pyramidal cell layer including CA 1 and CA 3. On the basis of the experimental results, geniposide may be a therapeutic agent for ischemia in patients.

15,16-dihydrotanshinone I suppresses the activation of BV-2 cell, a murine microglia cell line, by lipopolysaccharide.

Microglial activation has been implicated in neurodegenerative diseases. Therefore, inhibition of inflammation mediated by microglia is a strategy in neurodegenerative disease therapy. In this study, we isolated cryptotanshinone and 15,16-dihydrotanshinone I from Salvia miltiorrhiza, a traditional Korean herb medicine, by bioactivity-guided fractionation based on inhibitory effect on nitric oxide in a lipopolysaccharide-stimulated BV-2 cells, a murine microglial cell line. 15,16-Dihydotanshinoe I suppressed the expression of not only inducible nitric oxide synthase but also of interleukin-1beta, tumor necrosis factor-alpha, and of TNF-alpha converting enzyme.

Potent inhibitory effects of N-aryl S-alkylthiocarbamate derivatives on the dopa oxidase activity of mushroom tyrosinase.

This study reports the potent inhibitory effect of N-aryl S-alkylthiocarbamate derivatives on mushroom tyrosinase (MT) activity. N-Aryl S-alkylthiocarbamate derivatives were found to exhibit a potent inhibitory effect on the dopa (3,4-dihydroxyphenylalanine) oxidase activity of mushroom tyrosinase. Most of the N-aryl S-alkylthiocarbamate derivatives (compounds from A to J) exhibited higher inhibitory effects than kojic acid (IC50=318 microM), a well known tyrosinase inhibitor. Tyrosinase was the most inhibited by S-phenetyl N-phenylthiocarbamate (compound E, IC50=7.25 microM), and this inhibition was 44 times stronger than that of kojic acid. Compound E exhibited 95.0% of inhibition at 100 microM. A kinetic study of MT inhibition by compound E using the Lineweaver-Burk plots analysis was performed. And the kinetics profiles observed suggest that compound E competitively inhibits MT.

Induction of nerve growth factor by butanol fraction of Liriope platyphylla in C6 and primary astrocyte cells.

Liriope platyphylla (LP) has been used as a tonic, antitussive, and expectorant in Korea for many years. In this study, we found that the buthanol fraction of Liriope platyphylla (BLP)-conditioned media of C6 and primary astrocyte induced the neurite outgrowth of PC12 cells, and that the effect was reversed by addition of nerve growth factor (NGF)-antibody and GF109203X, an inhibitor of protein kinase (PKC). Furthermore, we demonstrated that BLP increased the expression and secretion of NGF. GF109203X also decreased NGF expression in C6 cells. Taken together, our results suggest that astroglial NGF enhanced by BLP in a PKC-dependent pathway contributed to the induction of neurite outgrowth of PC12 cells.

Neuroprotective effect of wogonin in hippocampal slice culture exposed to oxygen and glucose deprivation.

A poor supply of oxygen and glucose to the brain can cause severe brain damage. Therefore, neuroprotective drugs against ischemia need to be developed. In this study, wogonin, a flavone found in Scutellaria baicalensis, had a protective effect on neuronal cells damaged by oxygen and glucose deprivation in rat hippocampal slices in culture. In particular, the protective effect on the pyramidal cell layer was significant. On the basis of these experimental results, wogonin may be a therapeutic agent for treating ischemia in patients.

(-)-3,5-Dicaffeoyl-muco-quinic acid isolated from Aster scaber contributes to the differentiation of PC12 cells: through tyrosine kinase cascade signaling.

Aster scaber T. (Asteraceae) has been used in traditional Korean and Chinese medicine to treat bruises, snakebites, headaches, and dizziness. (-)-3,5-Dicaffeoyl-muco-quinic acid (DQ) isolated from A. scaber induced neurite outgrowth in PC12 cells. It has been reported that the activation of the extracellular signal regulated kinase 1/2 (Erk 1/2) and phosphoinositide 3 (PI3) kinase plays a crucial role in the NGF-induced differentiation of PC12 cells. This study showed that the effect of DQ on neurite outgrowth is mediated via the Erk 1/2 and PI3 kinase-dependent pathways like NGF. Furthermore, DQ stimulated the phosphorylation of Trk A. Overall, DQ elicited the differentiation of PC12 cells through Trk A phosphorylation followed by Erk 1/2 and PI3 kinase activation.

Falcarindiol inhibits nitric oxide-mediated neuronal death in lipopolysaccharide-treated organotypic hippocampal cultures.

Excessive nitric oxide (NO) release from activated microglia has a predominant role in neuronal death. This study investigated the effect of falcarindiol, which was isolated from Cnidium officinale Makino, on the NO-mediated neuronal death in lipopolysaccharide (LPS)-treated organotypic hippocampal cultures. Falcarindiol dose-dependently reduced inducible NO synthase (iNOS)-mediated NO production without cytotoxic effects on LPS-activated BV-2 and microglia. Predictably, falcarindiol inhibited neuronal death by reducing NO production in the LPS-treated organotypic hippocampal cultures. N-monomethyl-L-arginine (NMMA), an iNOS inhibitor, also inhibited neuronal death at 500 microM. In contrast, massive neuronal death was induced by excessive NO production in the LPS-treated alone cultures. These results suggest that excessive NO production plays an important role in the neurotoxic effect, and falcarindiol is a potential inhibitor in NO-mediated neuronal death.