Antiviral activity of Alpinia katsumadai extracts against rotaviruses.

In vitro anti-rotavirus activity of Alpinia katsumadai (AK) extracts were evaluated against bovine G8P[7] and porcine G5P[7] rotaviruses in two different assay strategies, a mixed treatment assay and a post treatment assay. In the mixed treatment assay, six AK extracts [AK-1 (EtOH extract), AK-3 (H(2)O layer), AK-5 (40% methanol fraction), and AK-9-11 (H(2)O extract, polysaccharide fraction, supernatant fraction)] exhibited inhibitory activities against G5P[7] rotavirus with the EC(50) values ranging from 0.7±0.4 to 33.7±6.5 µg/mL. Extracts AK-1, AK-3, and AK-5 inhibited rotavirus infection against G8P[7] rotavirus, the with EC(50) values of 8.4±2.2 µg/mL, 6.5±0.8 µg/mL and 8.4±5.0 µg/mL, respectively. By hemagglutination inhibition (HI) assay, six AK extracts completely inhibited viral adsorption onto human RBCs in both strains of rotaviruses at less than 11 µg/mL. However, in the post treatment assay, there was no anti activity shown against both strains of rotaviruses. As a result, six AK extracts were attributed mainly to having a strong interaction with hemagglutinin protein on the outer surface of rotavirus, resulting to blockage of viral adsorption.

Manassantin A and B from Saururus chinensis inhibit interleukin-6-induced signal transducer and activator of transcription 3 activation in Hep3B cells.

Inhibition of interleukin-6 (IL-6) has been postulated to be an effective therapy in the pathogenesis of several inflammatory diseases. The current study was performed to examine potential effects of manassantin A and B isolated from Saururus chinensis on the IL-6-induced response to human hepatoma cells. We found that manassantin A and B inhibit signal transducer and activator of transcription 3 (Stat3) activity stimulated by IL-6. We also found that both compounds decreased IL-6-induced Stat3 phosphorylation and nuclear translocation. Both compounds blocked suppressor of cytokine signaling 3 (SOCS-3)-mRNA expression induced by IL-6. In addition, we found that Stat3 inhibitory effects of these compounds could be related to protein tyrosine phosphatase. These findings suggest that manassantin A and B could be useful remedies for treatment of inflammatory diseases by inhibiting IL-6 action.

In vitro inhibitory activity of Alpinia katsumadai extracts against influenza virus infection and hemagglutination.

BACKGROUND: Alpinia katsumadai (AK) extracts and fractions were tested for in vitro antiviral activities against influenza virus type A, specially human A/PR/8/34 (H1N1) and avian A/Chicken/Korea/MS96/96 (H9N2), by means of time-of-addition experiments; pre-treatment, simultaneous treatment, and post treatment. RESULTS: In pre-treatment assay, the AK extracts and AK fractions did not show significant antiviral activity. During the simultaneous treatment assay, one AK extract and five AK fractions designated as AK-1 to AK-3, AK-5, AK-10, and AK-11 showed complete inhibition of virus infectivity against A/PR/8/34 (H1N1) and A/Chicken/Korea/MS96/96 (H9N2). The 50% effective inhibitory concentrations (EC50) of these one AK extracts and five AK fractions with exception of the AK-9 were from 0.8 ± 1.4 to 16.4 ± 4.5 µg/mL against A/PR/8/34 (H1N1). The two AK extracts and three AK fractions had EC50 values ranging from <0.39 ± 0.4 to 2.3 ± 3.6 µg/mL against A/Chicken/Korea/MS96/96 (H9N2). By the hemagglutination inhibition (HI) assay, the two AK extracts and five AK fractions completely inhibited viral adsorption onto chicken RBCs at less than 100 µg/mL against both A/PR/8/34 (H1N1) and A/Chicken/Korea/MS96/96 (H9N2). Interestingly, only AK-3 was found with inhibition for both viral attachment and viral replication after showing extended antiviral activity during the post treatment assay and quantitative real-time PCR. CONCLUSIONS: These results suggest that AK extracts and fractions had strong anti-influenza virus activity that can inhibit viral attachment and/or viral replication, and may be used as viral prophylaxis.

Biflavonoids from Torreya nucifera displaying SARS-CoV 3CL(pro) inhibition.

As part of our search for botanical sources of SARS-CoV 3CL(pro) inhibitors, we selected Torreya nucifera, which is traditionally used as a medicinal plant in Asia. The ethanol extract of T. nucifera leaves exhibited good SARS-CoV 3CL(pro) inhibitory activity (62% at 100µg/mL). Following bioactivity-guided fractionation, eight diterpenoids (1-8) and four biflavonoids (9-12) were isolated and evaluated for SARS-CoV 3CL(pro) inhibition using fluorescence resonance energy transfer analysis. Of these compounds, the biflavone amentoflavone (9) (IC(50)=8.3µM) showed most potent 3CL(pro) inhibitory effect. Three additional authentic flavones (apigenin, luteolin and quercetin) were tested to establish the basic structure-activity relationship of biflavones. Apigenin, luteolin, and quercetin inhibited 3CL(pro) activity with IC(50) values of 280.8, 20.2, and 23.8µM, respectively. Values of binding energy obtained in a molecular docking study supported the results of enzymatic assays. More potent activity appeared to be associated with the presence of an apigenin moiety at position C-3' of flavones, as biflavone had an effect on 3CL(pro) inhibitory activity.

In vitro anti-rotavirus activity of polyphenol compounds isolated from the roots of Glycyrrhiza uralensis.

We evaluated the ability of six polyphenols isolated from the roots of Glycyrrhiza uralensis to inactivate rotaviruses, specially G5P[7] and G8P[7]. Upon finding that all polyphenols possessed anti-rotavirus activity, we evaluated whether these properties were attributable to direct inhibition of the binding of rotavirus to cells and/or to inhibition of viral replication. Using the virucidal assay, we found that all six compounds directly inhibited rotavirus binding, with activity being dependent on the type of virus. The 50% effective inhibitory concentrations (EC(50)) of the six compounds were 18.7-69.5 µM against G5P[7] and 14.7-88.1 µM against G8P[7], respectively. Five of the six compounds inhibited hemagglutination activity. Moreover, the CPE inhibition assay showed that five compounds inhibited viral replication with EC(50) values of 12.1-24.0 µM against G5P[7] and 12.0-42.0 µM against G8P[7], respectively. RT-PCR showed that the compounds suppressed viral RNA synthesis in TF-104 cells. Interestingly, the anti-rotavirus activities of four compounds were attributable to inhibition of both viral absorption and viral replication. These results suggest that compounds isolated from the roots of G. uralensis may be potent anti-rotavirus agents in vivo, acting by inhibiting both viral absorption and viral replication.

Reduction of PKCbetaII activity in smooth muscle cells attenuates acute arterial injury.

OBJECTIVE: The ubiquitous enzyme protein kinase C (PKC) has been linked to the pathogenesis of vascular injury, but the cell-specific and discrete functions of the betaII isoform have yet to be discovered in this setting. Our previous findings demonstrated significantly increased PKCbetaII in the membrane fraction of injured femoral arteries in wild type (WT) mice and revealed reduction of neointimal expansion in PKCbeta(-/-) mice after acute vascular injury. As PKCbeta(-/-) mice are globally devoid of PKCbeta, we established novel transgenic (Tg) mice to test the hypothesis that the action of PKCbetaII specifically in smooth muscle cells (SMCs) mediates the formation of neointimal lesions in response to arterial injury. METHODS: Tg mice expressing SM22alpha promoter-targeted mouse carboxyl-terminal deletion mutant PKCbetaII were produced using standard techniques, subjected to femoral artery injury and compared with littermate controls. Smooth muscle cells (SMCs) were isolated from wild type (WT) and Tg mice and exposed to a prototypic stimulus, tumor necrosis factor (TNF)-alpha. Multiple strategies were employed in vivo and in vitro to examine the molecular mechanisms underlying the specific effects of SMC PKCbetaII in neointimal expansion. RESULTS: In vivo and in vitro analyses demonstrated that PKCbetaII activity in SMCs was critical for neointimal expansion in response to arterial injury, at least in part via regulation of ERK1/2, Egr-1 and induction of MMP-9. CONCLUSIONS: These data identify the SMC-specific regulatory role of PKCbetaII in neointimal expansion in response to acute arterial injury, and suggest that targeted inactivation of PKCbetaII may be beneficial in limiting restenosis via suppression of the neointima-mediating effects of Egr-1 and MMP-9.

Kansuinine A and Kansuinine B from Euphorbia kansui L. inhibit IL-6-induced Stat3 activation.

The current study was performed to examine the mechanisms underlying the potential effects of E. KANSUI on IL-6-induced cellular signaling in human hepatoma cells. We found that two diterpenoids, kansuinine A and B, from E. KANSUI have an inhibitory effect on IL-6-induced Stat3 activation by activating ERK1/2. Inhibition of MEK significantly blocked the effects of kansuinine A and B on IL-6-induced Stat3 activation and tyrosine phosphorylation. These results suggest that blocking of IL-6-induced signal transduction is partially due to the sustained activation of ERK1/2 by kansuinine A and B, which in turn results in an increase of Stat3 serine phosphorylation and SOCS-3 expression. Treatment with kansuinine A and B represents a novel method to block these IL-6-induced effects.

SARS-CoV 3CLpro inhibitory effects of quinone-methide triterpenes from Tripterygium regelii.

Quinone-methide triterpenes, celastrol (1), pristimerin (2), tingenone (3), and iguesterin (4) were isolated from Triterygium regelii and dihydrocelastrol (5) was synthesized by hydrogenation under palladium catalyst. Isolated quinone-methide triterpenes (1-4) and 5 were evaluated for SARS-CoV 3CL(pro) inhibitory activities and showed potent inhibitory activities with IC(50) values of 10.3, 5.5, 9.9, and 2.6 microM, respectively, whereas the corresponding 5 having phenol moiety was observed in low activity (IC(50)=21.7 microM). As a result, quinone-methide moiety in A-ring and more hydrophobic E-ring assist to exhibit potent activity. Also, all quinone-methide triterpenes 1-4 have proven to be competitive by the kinetic analysis.

Inhibition of neuraminidase activity by polyphenol compounds isolated from the roots of Glycyrrhiza uralensis.

We isolated 18 polyphenols with neuraminidase inhibitory activity from methanol extracts of the roots of Glycyrrhiza uralensis. These polyphenols consisted of four chalcones (1-4), nine flavonoids (5-13), four coumarins (14-17), and one phenylbenzofuran (18). When we tested the effects of these individual compounds and analogs thereof on neuraminidase activation, we found that isoliquiritigenin (1, IC(50)=9.0 microM) and glycyrol (14, IC(50)=3.1 microM) had strong inhibitory activity. Structure-activity analysis showed that the furan rings of the polyphenols were essential for neuraminidase inhibitory activity, and that this activity was enhanced by the apioside group on the chalcone and flavanone backbone. In addition, the presence of a five-membered ring between C-4 and C-2' in coumestan was critical for neuraminidase inhibition. All neuraminidase inhibitors screened were found to be reversible noncompetitive inhibitors.

Cancer preventive potential of methanol extracts of Hypsizigus marmoreus.

Hypsizigus marmoreus has recently become a popular edible mushroom in Asia. Despite its extensive use, the underlying mechanisms of the anticarcinogenic effects on the initiation stage are not precisely known. Therefore, methanol extracts from H. marmoreus were prepared and then tested for antiproliferative effects in cancer cells and antimutagenic activities as well as mutagenic capacity using the Ames Salmonella mutagenicity test. In addition, the effects on the phase I drug metabolizing enzymes, phase II detoxifying enzymes, and antioxidative activities were evaluated in livers from mice pretreated with methanol extracts from H. marmoreus and challenged with benzo[a]pyrene (B[a]P). In the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, methanol extracts from H. marmoreus displayed a dose-dependent inhibitory effect against human hepatocarcinoma and colon carcinoma cells. However, equivalent doses did not induce mutagenicity when tested with Salmonella typhimurium TA98 and TA100 while exhibiting antimutagenicity against direct-acting and indirect-acting mutagens. Methanol extracts from H. marmoreus strongly decreased total cytochrome P450 and activity of ethoxyresorufin deethylase after B[a]P challenge. Further investigation revealed that methanol extracts from H. marmoreus decreased protein levels of cytochrome P450 IAI isozyme induced by B[a]P. Methanol extracts from H. marmoreus increased the content of glutathione and activity of glutathione S-transferase. This also induced the activity of quinone reductase, an enzyme well known to be anticarcinogenic. The results of the present study therefore demonstrated that methanol extracts from H. marmoreus may have antimutagenic effects, inhibiting the mutagenicity of some mutagens, particularly indirect-acting B[a]P. The mechanism of this antimutagenicity may be the induction of the activity of phase II enzymes, as well as the ability to reduce phase I metabolic-activating enzymes in mouse liver.

Mice deficient in PKCbeta and apolipoprotein E display decreased atherosclerosis.

Endothelial activation is a central initiating event in atheroma formation. Evidence from our laboratory and others has demonstrated links between activation of early growth response-1 (Egr-1) and atherosclerosis and also has demonstrated that activated protein kinase C (PKC) betaII is a critical upstream regulator of Egr-1 in response to vascular stress. We tested the role of PKCbeta in regulating key events linked to atherosclerosis and show that the aortas of apoE(-/-) mice display an age-dependent increase in PKCbetaII antigen in membranous fractions vs. C57BL/6 animals with a approximately 2-fold increase at age 6 wk and a approximately 4.5-fold increase at age 24 wk. Consistent with important roles for PKCbeta in atherosclerosis, a significant decrease in atherosclerotic lesion area was evident in PKCbeta(-/-)/apoE(-/-) vs. apoE(-/-) mice by approximately 5-fold, in parallel with significantly reduced vascular transcripts for Egr-1 and matrix metalloproteinase (MMP)-2 antigen and activity vs. apoE(-/-) mice. Significant reduction in atherosclerosis of approximately 2-fold was observed in apoE(-/-) mice fed ruboxistaurin chow (PKCbeta inhibitor) vs. vehicle. In primary murine and human aortic endothelial cells, the PKCbeta-JNK mitogen-activated protein kinase pathway importantly contributes to oxLDL-mediated induction of MMP2 expression. Blockade of PKCbeta may be beneficial in mitigating endothelial perturbation and atherosclerosis.

Oxygen deprivation triggers upregulation of early growth response-1 by the receptor for advanced glycation end products.

Myocardial infarction, stroke, and venous thromboembolism are characterized by oxygen deprivation. In hypoxia, biological responses are activated that evoke tissue damage. Rapid activation of early growth response-1 in hypoxia upregulates fundamental inflammatory and prothrombotic stress genes. We probed the mechanisms mediating regulation of early growth response-1 and demonstrate that hypoxia stimulates brisk generation of advanced glycation end products (AGEs) by endothelial cells. Via AGE interaction with their chief signaling receptor, RAGE, membrane translocation of protein kinase C-betaII occurs, provoking phosphorylation of c-Jun NH(2)-terminal kinase and increased transcription of early growth response-1 and its downstream target genes. These findings identify RAGE as a master regulator of tissue stress elicited by hypoxia and highlight this receptor as a central therapeutic target to suppress the tissue injury-provoking effects of oxygen deprivation.

PKCbeta modulates ischemia-reperfusion injury in the heart.

Protein kinase C-betaII (PKCbetaII) is an important modulator of cellular stress responses. To test the hypothesis that PKCbetaII modulates the response to myocardial ischemia-reperfusion (I/R) injury, we subjected mice to occlusion and reperfusion of the left anterior descending coronary artery. Homozygous PKCbeta-null (PKCbeta(-/-)) and wild-type mice fed the PKCbeta inhibitor ruboxistaurin displayed significantly decreased infarct size and enhanced recovery of left ventricular (LV) function and reduced markers of cellular necrosis and serum creatine phosphokinase and lactate dehydrogenase levels compared with wild-type or vehicle-treated animals after 30 min of ischemia followed by 48 h of reperfusion. Our studies revealed that membrane translocation of PKCbetaII in LV tissue was sustained after I/R and that gene deletion or pharmacological blockade of PKCbeta protected ischemic myocardium. Homozygous deletion of PKCbeta significantly diminished phosphorylation of c-Jun NH(2)-terminal mitogen-activated protein kinase and expression of activated caspase-3 in LV tissue of mice subjected to I/R. These data implicate PKCbeta in I/R-mediated myocardial injury, at least in part via phosphorylation of JNK, and suggest that blockade of PKCbeta may represent a potent strategy to protect the vulnerable myocardium.

Vascular and inflammatory stresses mediate atherosclerosis via RAGE and its ligands in apoE-/- mice.

Endothelial dysfunction is a key triggering event in atherosclerosis. Following the entry of lipoproteins into the vessel wall, their rapid modification results in the generation of advanced glycation endproduct epitopes and subsequent infiltration of inflammatory cells. These inflammatory cells release receptor for advanced glycation endproduct (RAGE) ligands, specifically S100/calgranulins and high-mobility group box 1, which sustain vascular injury. Here, we demonstrate critical roles for RAGE and its ligands in vascular inflammation, endothelial dysfunction, and atherosclerotic plaque development in a mouse model of atherosclerosis, apoE-/- mice. Experiments in primary aortic endothelial cells isolated from mice and in cultured human aortic endothelial cells revealed the central role of JNK signaling in transducing the impact of RAGE ligands on inflammation. These data highlight unifying mechanisms whereby endothelial RAGE and its ligands mediate vascular and inflammatory stresses that culminate in atherosclerosis in the vulnerable vessel wall.

7-Ketocholesterol predisposes human aorta smooth muscle cells to Fas-mediated death.

Human vascular smooth muscle cells (HVSMCs) are resistant to Fas-mediated death under normal physiological conditions. However, HVSMC death by activation of the receptor pathway was reported in the atherosclerotic lesions. In this study, we investigated whether 7-ketocholesterol, one of the major cholesterol oxides in the lesions, altered resistance of HVSMC to Fas-mediated death pathway. Cross-linking of Fas receptor with agonistic anti-Fas antibody (CH11) in the presence of 7-ketocholesterol induced death in human aorta smooth muscle cells (HAoSMC) as detected by morphology, viability, and DNA fragmentation. The agonistic anti-Fas antibody, however, did not induce death in the presence of 7alpha-hydroxycholesterol or cholesterol. The HAoSMC death was significantly inhibited by an antagonistic Fas receptor (FasR) antibody and by expression of dominant negative Fas-associated death domain containing protein (DN-FADD) using adenoviruses. Activation of caspase-3 was observed in HAoSMC destined to death. HAoSMC death was significantly inhibited by pharmacological caspase inhibitor, z-VAD and z-DEVD, and baculovirus caspase inhibitor p35. 7-Ketocholesterol impaired mitochondrial transmembrane potential and ATP production. Overexpression of bcl-xL also significantly inhibited HAoSMC death. In dying HAoSMC, bax was translocated from the cytosol to mitochondria and cytochrome c was released from mitochondria into the cytosol. This is the first report demonstrating implication of the oxysterol in Fas-mediated death pathway. The present study proposes that 7-ketocholesterol would contribute to loss of HVSMC in the atherosclerotic lesions by altering resistance to receptor-mediated death pathway.

TNF-alpha activates death pathway in human aorta smooth muscle cell in the presence of 7-ketocholesterol.

This study was undertaken to investigate whether a physiologically compatible concentration of 7-ketocholesterol had any effect on human vascular smooth muscle cells (HVSMCs). We found that 7-ketocholesterol changed the viability of human aorta smooth muscle cells (HAoSMC) not by cytotoxicity but by activation of tumor necrosis factor-alpha receptor (TNFR)-mediated death. Whereas TNF-alpha did not affect the viability in the presence of 7alpha-hydroxycholesterol or cholesterol, the cytokine induced HAoSMC death in the presence of 7-ketocholesterol as detected by morphology, viability, and fragmentation of chromosomal DNA. The HAoSMC death was inhibited by a neutralizing anti-TNF receptor 1 (TNFR1) antibody and by the caspase inhibitors of z-VAD and z-DEVD. Activations of caspase-8 and -3 were detected from dying HAoSMCs. 7-Ketocholesterol inhibited translocation of the nuclear factor kappaB (NF-kappaB) subunits of p65 and p50 from the cytosol into the nucleus, increase of NF-kappaB activity, and expression of caspase-8 homolog Fas ligand interleukin-1-converting enzyme inhibitory protein by TNF-alpha. We also found that X-chromosome-linked inhibitor of apoptosis protein was degraded in dying HAoSMC. The present study proposes that 7-ketocholesterol would contribute to the disappearance of HVSMC in the atherosclerotic lesions by enhancing receptor-mediated death. This is the first report demonstrating induction of TNF-alpha-mediated death by oxysterol in cells.

Kurarinone isolated from Sophora flavescens Ait inhibited MCP-1-induced chemotaxis.

The accumulation of circulating monocytes in the arterial wall is an early in atherosclerotic plaque formation. Monocyte chemoattractant protein-1 (MCP-1) promotes the migration of monocytes and would play a role in the development of atherosclerotic lesions. Searching for inhibitors of MCP-1-induced cell migration from natural sources, we isolated one active compound through active-guided fractionations from the MeOH extracts of Sophora flavescens Ait (Leguminosae). On the basis of spectral evidence, the structure of active compound was identified as kurarinone. It inhibited the migration of THP-1 cells induced by MCP-1 with IC50 value of 19.2 microg/mL. In addition, it inhibited the binding of MCP-1 to THP-1 cells and phosphorylation of p42/44 MARK.

Polyacetylenic compounds, ACAT inhibitors from the roots of Panax ginseng.

Acyl-CoA: cholesterol acyltransferase (ACAT), which plays a role in the absorption, storage, and production of cholesterol, has been explored as a potential target for pharmacological intervention of hyperlipidemia and atherosclerotic disease. In our search for ACAT inhibitors from natural sources, the petroleum ether extract of Panax ginseng showed moderate inhibition of ACAT enzyme from rat liver microsomes. Bioactivity-guided fractionations led to the isolation of one new polyacetylenic compound, (9R,10S)-epoxy-16-heptadecene-4, 6-diyne-3-one (1), in addition to the previously reported polyacetylenic compounds 2 and 3. Their chemical structures were elucidated on the basis of spectroscopic evidence (UV, IR, NMR, and MS). The compounds 1, 2, and 3 showed significant ACAT inhibition with IC(50) values of 35, 47, and 21 microM, respectively.

Capsaicin-induced apoptosis and reduced release of reactive oxygen species in MBT-2 murine bladder tumor cells.

Bladder cancer is a common cancer with high risk of recurrence and mortality. Intravesicle chemotherapy after trans-urethral resection is required to prevent tumor recurrence and progression. It has been known that antioxidants enhance the antitumor effect of bacillus Calmette-Guerin (BCG), the most effective intravesical bladder cancer treatment. Capsaicin, the major pungent ingredient in genus Capsicum, has recently been tried as an intravesical drug for overactive bladder and it has also been shown to induce apoptotic cell death in many cancer cells. In this study, we investigated the apoptosis-inducing effect and alterations in the cellular redox state of capsaicin in MBT-2 murine bladder tumor cells. Capsaicin induced apoptotic MBT-2 cell death in a time- and dose-dependent manner. The capsaicin-induced apoptosis was blocked by the pretreatment with Z-VAD-fmk, a broad-range caspase inhibitor, or Ac-DEVD-CHO, a caspase-3 inhibitor. In addition to the caspase-3 activation, capsaicin also induced cytochrome c release and decrease in Bcl-2 protein expression with no changes in the level of Bax. Furthermore, capsaicin at the concentration of inducing apoptosis also markedly reduced the level of reactive oxygen species and lipid peroxidation, implying that capsaicin may enhance the antitumor effect of BCG in bladder cancer treatment. These results further suggest that capsaicin may be a valuable intravesical chemotherapeutic agent for bladder cancers.

Inhibition of cell cycle progression on HepG2 cells by hypsiziprenol A9, isolated from Hypsizigus marmoreus.

Antiproliferative activities of fractions of Hypsizigus marmoreus were examined using HepG2 cells in vitro. The methanol extract of H. marmoreus markedly induced antiproliferative activity, and an active compound from this mushroom was identified as hypsiziprenol A9. Hypsiziprenol A9 inhibited cell proliferation in a time- and concentration-dependent manner by up to 80% on HepG2 cells by inducing arrest of the G1 phase. Further investigation revealed that hypsiziprenol A9 decreased expression of phosphorylated retinoblastoma protein (ppRb), cyclin D1, and cyclin E in a dose-dependent manner. These results suggest that hypsiziprenol A9 can inhibit the growth of HepG2 cells through inducing G1 phase cell cycle arrest due to the inhibition of pRb phosphorylation.