Synthesis of analogues of gingerol and shogaol, the active pungent principles from the rhizomes of Zingiber officinale and evaluation of their anti-platelet aggregation effects.

The present study was aimed at discovering novel biologically active compounds based on the skeletons of gingerol and shogaol, the pungent principles from the rhizomes of Zingiber officinale. Therefore, eight groups of analogues were synthesized and examined for their inhibitory activities of platelet aggregation induced by arachidonic acid, collagen, platelet activating factor, and thrombin. Among the tested compounds, [6]-paradol (5b) exhibited the most significant anti-platelet aggregation activity. It was the most potent candidate, which could be used in further investigation to explore new drug leads.

Aciculatin induces p53-dependent apoptosis via MDM2 depletion in human cancer cells in vitro and in vivo.

Aciculatin, a natural compound extracted from the medicinal herb Chrysopogon aciculatus, shows potent anti-cancer potency. This study is the first to prove that aciculatin induces cell death in human cancer cells and HCT116 mouse xenografts due to G1 arrest and subsequent apoptosis. The primary reason for cell cycle arrest and cell death was p53 accumulation followed by increased p21 level, dephosphorylation of Rb protein, PUMA expression, and induction of apoptotic signals such as cleavage of caspase-9, caspase-3, and PARP. We demonstrated that p53 allele-null (-/-) (p53-KO) HCT116 cells were more resistant to aciculatin than cells with wild-type p53 (+/+). The same result was achieved by knocking down p53 with siRNA in p53 wild-type cells, indicating that p53 plays a crucial role in aciculatin-induced apoptosis. Although DNA damage is the most common event leading to p53 activation, we found only weak evidence of DNA damage after aciculatin treatment. Interestingly, the aciculatin-induced downregulation of MDM2, an important negative regulator of p53, contributed to p53 accumulation. The anti-cancer activity and importance of p53 after aciculatin treatment were also confirmed in the HCT116 xenograft models. Collectively, these results indicate that aciculatin treatment induces cell cycle arrest and apoptosis via inhibition of MDM2 expression, thereby inducing p53 accumulation without significant DNA damage and genome toxicity.

DYZ-2-90, a novel neo-tanshinlactone ring-opened compound, induces ERK-mediated mitotic arrest and subsequent apoptosis by activating JNK in human colorectal cancer cells.

Over the past several decades, there has been a considerable and still growing interest in discovering natural products with anticancer potential from traditional Chinese medicine and increasing their anticancer selectivity by chemical modification. In addition, total synthesis of active compounds from natural products can overcome problems related to poor resource availability. DYZ-2-90 is a novel ring-opened compound modified from neo-tanshinlactone, which is isolated from Chinese medicinal herb tanshen. Both in vitro and in vivo tubulin polymerization assays showed that DYZ-2-90 directly bound to microtubules and rapidly induced tubulin depolymerization, inducing ERK-mediated mitotic arrest and subsequent apoptosis by JNK activation in cancer cells, respectively. These results suggest that the fate of cells that undergo mitotic arrest is dictated by two competing networks activated by DYZ-2-90: the cytoprotective ERK pathway and the stress-related JNK pathway. DYZ-2-90 is therefore a novel microtubule-destabilizing agent and a new drug candidate for cancer therapy. This paper provides a new insight into the model of mitotic cell death, which was proposed in order to elucidate how cancer cells respond to microtubule-interfering agents and prolonged cell cycle delay.

Physalin F induces cell apoptosis in human renal carcinoma cells by targeting NF-kappaB and generating reactive oxygen species.

BACKGROUND: The aim of this study was to determine the molecular mechanisms of physalin F, an effective purified extract of Physalis angulata L. (Solanacae), in renal carcinoma A498 cells. METHODOLOGY/PRINCIPAL FINDINGS: Physalin F was observed to significantly induce cytotoxicity of three human renal carcinoma A498, ACHN, and UO-31 cells in a concentration-dependent manner; this was especially potent in A498 cells. The physalin F-induced cell apoptosis of A498 cells was characterized by MTT assay, nuclear DNA fragmentation and chromatin condensation. Using flow cytometry analysis, physalin F induced A498 cell apoptosis as demonstrated by the accumulation of the sub-G1 phase in a concentration- and time-dependent manner. Moreover, physalin F-mediated accumulation of reactive oxygen species (ROS) caused Bcl-2 family proteins, Bcl-2, and Bcl-xL degradation, which led to disruption of mitochondrial membrane potential and release of cytochrome c from the mitochondria into the cytosol. These effects were associated with induction of caspase-3 and caspase-9 activity, which led to poly(ADP-ribose) polymerase cleavage. However, the antioxidant N-acetyl-(L)-cysteine (NAC) and glutathione (GSH) resulted in the inhibition of these events and reversed physalin F-induced cell apoptosis. In addition, physalin F suppressed NF-κB activity and nuclear translocation of p65 and p50, which was reversed by NAC and GSH. CONCLUSION: Physalin F induced cell apoptosis through the ROS-mediated mitochondrial pathway and suppressed NF-κB activation in human renal cancer A498 cells. Thus, physalin F appears to be a promising anti-cancer agent worthy of further clinical development.

Dehydrocostuslactone suppresses angiogenesis in vitro and in vivo through inhibition of Akt/GSK-3ß and mTOR signaling pathways.

The traditional Chinese medicine component dehydrocostuslactone (DHC) isolated from Saussurea costus (Falc.) Lipschitz, has been shown to have anti-cancer activity. Angiogenesis is an essential process in the growth and progression of cancer. In this study, we demonstrated, for the first time, the anti-angiogenic mechanism of action of DHC to be via the induction of cell cycle progression at the G0/G1 phase due to abrogation of the Akt/glycogen synthase kinase-3ß (GSK-3ß)/cyclin D1 and mTOR signaling pathway. First, we demonstrated that DHC has an anti-angiogenic effect in the matrigel-plug nude mice model and an inhibitory effect on human umbilical vein endothelial cell (HUVEC) proliferation and capillary-like tube formation in vitro. DHC caused G0/G1 cell cycle arrest, which was associated with the down-regulation of cyclin D1 expression, leading to the suppression of retinoblastoma protein phosphorylation and subsequent inhibition of cyclin A and cdk2 expression. With respect to the molecular mechanisms underlying the DHC-induced cyclin D1 down-regulation, this study demonstrated that DHC significantly inhibits Akt expression, resulting in the suppression of GSK-3ß phosphorylation and mTOR expression. These effects are capable of regulating cyclin D1 degradation, but they were significantly reversed by constitutively active myristoylated (myr)-Akt. Furthermore, the abrogation of tube formation induced by DHC was also reversed by overexpression of Akt. And the co-treatment with LiCl and DHC significantly reversed the growth inhibition induced by DHC. Taken together, our study has identified Akt/GSK-3ß and mTOR as important targets of DHC and has thus highlighted its potential application in angiogenesis-related diseases, such as cancer.

Moscatilin, a bibenzyl derivative from the India orchid Dendrobrium loddigesii, suppresses tumor angiogenesis and growth in vitro and in vivo.

Attacking angiogenesis is considered an effective strategy for controls the expansion and metastasis of tumors and other related-diseases. The aim of this study was to assess the effects of moscatilin, a bibenzyl derivative, on VEGF and bFGF-induced angiogenesis in cultured human umbilical vein endothelial cells (HUVECs) in vitro and in vivo. Moscatilin significantly inhibited growth of lung cancer cell line A549 (NSCLC) and suppressed growth factor-induced neovascularization. In addition, VEGF- and bFGF-induced cell proliferation, migration, and tube formation of HUVECs was markedly inhibited by moscatilin. Western blotting analysis of cell signaling molecules indicated that moscatilin inhibited ERK1/2, Akt, and eNOS signaling pathways in HUVECs. These results suggest that inhibition of angiogenesis by moscatilin may be a major mechanism in cancer therapy.

Evodiamine represses hypoxia-induced inflammatory proteins expression and hypoxia-inducible factor 1alpha accumulation in RAW264.7.

Inflammation and low oxygen diffusion are recognized characteristics of cardiovascular diseases such as atherosclerosis. Evodiamine, extracted from the traditional Chinese herb, Evodia rutaecarpa, is a bioactive anti-inflammatory alkaloid. The objective of this study was to investigate whether evodiamine could repress hypoxia-induced inflammatory response. We showed that evodiamine repressed not only COX-2 and iNOS expression but also prostaglandin E2 release in a concentration-dependent manner under hypoxic conditions. Furthermore, our studies indicated that COX-2 mRNA was inhibited by evodiamine, implying that transcriptional activity is involved in the mechanistic pathway. It is striking that hypoxia-inducible factor 1alpha (HIF-1alpha) inhibitor, camptothecin, suppressed hypoxia-induced COX-2 expression rather than pyrrolidine dithiocarbamate, a nuclear factor kappaB inhibitor. In addition, our studies have confirmed that evodiamine inhibited HIF-1alpha, which accounted for the transcriptional activity of COX-2, rather than nuclear factor kappaB in RAW264.7 cells. Finally, evodiamine did not affect either the level of HIF-1alpha mRNA or the degradation rate of HIF-1alpha protein, but it regulated the translational process of HIF-1alpha. We found that hypoxia-evoked phosphorylation of Akt and p70S6K was blocked after evodiamine treatment, in addition to the inhibition of phosphorylation of 4E-BP. These results suggest that the mechanism of repression of hypoxia-induced COX-2 expression by evodiamine is through the inhibition of HIF-1alpha at the translational level and is primarily mediated via dephosphorylation of Akt and p70S6K. Therefore, evodiamine could be an effective therapeutic agent against inflammatory diseases involving hypoxia.

Effect of isoquinoline alkaloids of different structural types on antiplatelet aggregation in vitro.

Forty-one isoquinoline alkaloids were tested for antiplatelet aggregation effects. Among them, (-)-discretamine (6), protopine (7), ochotensimine (18), O-methylarmepavinemethine (23), lindoldhamine (25), isotetrandrine (26), thalicarpine (27), papaverine (28), and D-(+)- N-norarmepavine (32) exhibited significant inhibitory activity towards adenosine 5'-diphosphate (ADP)-, arachidonic acid (AA)-, collagen-, and/or platelet-activating factor (PAF)-induced platelet aggregation. The results are discussed on the basis of structure-activity relationships.

Alisol B acetate, a triterpene from Alismatis rhizoma, induces Bax nuclear translocation and apoptosis in human hormone-resistant prostate cancer PC-3 cells.

The anti-tumor potential of components from Chinese herbal medicines has been greatly concerned. Alisol B acetate, a triterpene from Alismatis rhizoma, induced apoptotic cell death in human hormone-resistant prostate cancer PC-3 cells in a time- and concentration-dependent manner. A good correlation between loss of mitochondrial membrane potential and apoptotic cell death was apparent indicating the participation of mitochondria-related mechanism. Alisol B acetate induced Bax up-regulation and nuclear translocation; it also induced the activation of initiator caspase-8 and caspase-9, and executor caspase-3, suggesting the involvement of both extrinsic and intrinsic apoptosis pathways. Taken together, it is suggested that alisol B acetate induces apoptosis in PC-3 cells via a mitochondria-mediated mechanism with activation of caspase-8, -9 and -3. Furthermore, the Bax activation and translocation from the cytosol to nucleus might be a crucial response to the apoptotic effect.

Denbinobin-mediated anticancer effect in human K562 leukemia cells: role in tubulin polymerization and Bcr-Abl activity.

Denbinobin (5-hydroxy-3,7-dimethoxy-1,4-phenanthraquinone) has been reported to exhibit anti-tumor and anti-inflammatory activity. Nevertheless, the anti-tumor mechanism of denbinobin remains unclear. In the present study, we evaluated the anticancer activity of denbinobin in human myelogenous K562 leukemia cells. In accordance with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, we demonstrated that denbinobin inhibited cell viability in a concentration-dependent manner with an IC50 value of 1.84 microM. Cell cycle analysis illustrated that exposure of denbinobin caused a G2/M phase accumulation in a time-dependent manner. Tubulin polymerization in cells was apparently enhanced by denbinobin, implying that denbinobin might have a regulatory role in tubulin/microtubule. Furthermore, denbinobin significantly suppressed the expression of Bcr-Abl and phosphorylation of CrkL, a crucial tyrosine kinase and an adaptor protein in chronic myeloid leukemia, respectively. Denbinobin also markedly enhanced CD11b expression after a long-term treatment, suggesting that denbinobin might play a role in facilitating differentiation in K562 cells. In summary, we have demonstrated that denbinobin displays anticancer effects in K562 cells through the increase of levels of tubulin polymerization and deregulation of Bcr-Abl signaling. Our data demonstrate that denbinobin could be a potential anticancer lead compound for further development.

Three new taxane diterpenoids from Taxus sumatrana.

Phytochemical investigation of taxane diterpenoidal content of an acetone extract of the leaves and twigs of Taxus sumatrana has resulted in the isolation of three new taxoid compounds, tasumatrols E (1), F (2), and G (3) together with 13 known taxanes (5-16). The structures of these taxanes as well as their derivatives were established on the basis of spectroscopic analyses, especially 1D and 2D NMR. Compounds 1, 2, 12, and 16 exhibited significant cytotoxicity against human A-498, NCI-H226, A549, and PC-3 tumor cells.

Antitumor mechanism of evodiamine, a constituent from Chinese herb Evodiae fructus, in human multiple-drug resistant breast cancer NCI/ADR-RES cells in vitro and in vivo.

Drug resistance is one of the main obstacles to the successful treatment of cancer. The availability of agents that are highly effective against drug-resistant cancer cells is therefore essential. The present study was performed to examine the anticancer effects of evodiamine, a major constituent of the Chinese herb Evodiae fructus, in adriamycin-resistant human breast cancer NCI/ADR-RES cells. Evodiamine inhibited the proliferation of NCI/ADR-RES cells in a concentration-dependent manner with a GI50 of 0.59 +/- 0.11 microM. This agent also caused a substantial apoptosis at 1 microM. FACScan flow cytometric analysis of cell cycle progression revealed that a G2/M arrest was initiated after a 12-h exposure to the drug. Evodiamine increased tubulin polymerization as determined by the immunocytochemical and in vivo tubulin polymerization analyses. In a time- and concentration-dependent manner, evodiamine also promoted the phosphorylations of Raf-1 kinase and Bcl-2. The phosphorylation site of Raf-1 kinase was identified to be serine338. The in vivo anticancer effects of evodiamine were evaluated in Balb-c/nude mice following a tumor xenograft implantation of NCI/ADR-RES cells. The antitumor activity of evodiamine against the human multiple-drug resistant tumor xenograft was found to be superior to that of paclitaxel. Evodiamine therefore represents a highly promising chemotherapeutic agent in the treatment of human multiple-drug resistant cancer cells.

Induction of mitotic arrest and apoptosis in human prostate cancer pc-3 cells by evodiamine.

PURPOSE: Although evodiamine, an alkaloid isolated from Evodiae fructus, has been reported to exert anticancer activities, to our knowledge its target and mechanism of action have not yet been explored. We examined the anticancer activities and action mechanism of evodiamine. MATERIALS AND METHODS: Human prostate cancer PC-3 cells were used in this study. The cytotoxic effect and cell growth inhibition were examined using the MTT (3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide) assay and sulforhodamine B assay, respectively. The apoptotic effect was determined using TUNEL assay and the progression of cells through the cell cycle and cell apoptosis were examined by FACScan flow cytometry (Becton Dickinson, Sunnyvale, California). In situ mitotic spindle detection and in vitro tubulin polymerization assay were performed by immunofluorescence staining for beta-tubulin and CytoDYNAMIX ScreenTM3 (CDS-03) kits (Cytoskeleton, Denver, Colorado). RESULTS: It was found that treatment of PC-3 cells with evodiamine decreased the cell number in a concentration and time dependent manner, and effectively inhibited PC-3 cell growth via the induction of cell cycle arrest at the G2/M phase and subsequent apoptosis. In an in situ assay we found that evodiamine inhibited microtubule spindle formation. In a cell-free assay system of tubulin polymerization evodiamine inhibited the polymerization of microtubules in a concentration dependent manner. CONCLUSIONS: These data suggest that evodiamine shows anticancer activity through inhibition of tubulin polymerization. This antitubulin activity might make evodiamine a potential anticancer drug.

Induction of mitotic arrest and apoptosis by evodiamine in human leukemic T-lymphocytes.

Leukemias are a heterogenous group of diseases characterized by uncontrolled proliferation of abnormal blood cells of hematopoietic system. Evodiamine, a characteristic alkaloid extracted from Evodia fruits, has been reported to exhibit inhibitory effect on cell proliferation and migration in several types of cancer cells. However, there is no report elucidating the action target and anti-cancer mechanism of this potential natural compound. In this study, we have defined the anti-proliferative and apoptotic mechanisms of evodiamine in human acute leukemia CCRF-CEM cells. According to the MTT assay, the cell viability was inhibited by evodiamine in a concentration-dependent manner with an IC50 of 0.57 +/- 0.05 microM. Flow cytometry analysis showed that the apoptotic cell death proceeded by evodiamine was accompanied with a cell cycle arrest at the G2/M phase. Using Wright-Giemsa staining, we observed that evodiamine caused the cells to arrest in mitosis. It also profoundly caused an increase in polymerized tubulin levels and Bcl-2 phosphorylation on serine 70 in these cells. These data imply that the microtubular cytoskeleton appears to be one of the cellular targets in response to evodiamine. Moreover, treatment of CCRF-CEM cells with evodiamine was associated with increased levels of pro-apoptotic protein Bax, activation of caspase-3, and proteolytic cleavage of poly (ADP-ribose) polymerase, an endogenous caspase-3 substrate. Taken together, we demonstrate that evodiamine causes the mitotic arrest and a consequent apoptosis in CCRF-CEM cells through the enhancement of polymerized tubulin levels. Furthermore, several biological events including the Bcl-2 phosphorylation, Bax up-regulation and increase of caspase-3 activity could explain evodiamine-induced cell apoptosis.

Modulation of anti-adhesion molecule MUC-1 is associated with arctiin-induced growth inhibition in PC-3 cells.

BACKGROUND: Lignans have been reported to possess anti-tumor activity in various cancer cells. However, their anticancer effects in human prostate cancer have not been well established. Here, we examine the effect of arctiin, a lignan compound, on growth regulation in prostate cancer PC-3 cells. We postulated that arctiin modulates the attachment/detachment of PC-3 cells and we investigated the role of arctiin on MUC-1 expression. METHODS: The effect of arctiin on PC-3 cell growth was examined using an MTT assay method and cell number was calculated by means of a standard regression line. The expressions of MUC-1 and integrins alpha2, alpha5, and beta1 were detected using FACScan flow cytometric analysis. Levels of MUC-1 mRNA were determined using reverse transcriptase PCR (RT-PCR). RESULTS: Treatment of PC-3 cells with arctiin decreased the cell number in a concentration- and time-dependent manner in serum-containing condition. Arctiin preferentially induced cell detachment, but did not have anti-proliferation or cytotoxic effects in PC-3 cells. The arctiin-induced effect was inhibited by cycloheximide, indicating that protein synthesis was required. FACScan flow cytometric analysis demonstrated that arctiin increased the expression of the anti-adhesion mucin MUC-1, but did not affect integrin expression in PC-3 cells. The arctiin-induced increase in MUC-1 protein expression was due to up-regulation of mRNA, as revealed by RT-PCR analysis. CONCLUSIONS: Arctiin significantly induces cell detachment and decreases the cell numbers via the up-regulation of MUC-1 mRNA and protein in PC-3 cells.

A new aristolactam alkaloid and anti-platelet aggregation constituents from Piper taiwanense.

A new alkaloid, piperolactam E, and fourteen known compounds have been isolated from the stem of Piper taiwanense. Bioassay-guided fractionation of the methanolic extract led to the isolation, from the chloroform-soluble part, of 4-allylcatechol, eugenol, trans-caffeic aldehyde, 2-hydroxy-1-methoxy-4 H-dibenzo[ de,g]quinoline-4,5-(6 H)-dione, piperolactam B, piperolactam C, and piperolactam E as the active principles of anti-platelet aggregation in vitro. The derived 1,2-diacetoxy-4-allyl-benzene and eugenol acetate exhibit stronger anti-platelet aggregation activities induced by arachidonic acid than 4-allylcatechol and eugenol, respectively.

Anti-platelet aggregation and chemical constituents from the rhizome of Gynura japonica.

A novel quinonoid terpenoid, (-)- alpha-tocospirone, a new chromanone, (-)-gynuraone, as well as three new steroids, (22 E,24 S)-7 alpha-hydroperoxystigmasta-5,22-dien-3 beta-ol, (22 E,24 S)-stigmasta-1,4,22-trien-3-one, and (24 R)-stigmasta-1,4-dien-3-one, together with 15 known components, were isolated from the rhizome of Formosan Gynura japonica. Structures of the new compounds were determined through spectral analyses and chemical evidence. Several of the isolated compounds, caryophyllene oxide, 6-acetyl-2,2-dimethylchroman-4-one, vanillin, 2,6-dimethoxy-1,4-benzoquinone, and benzoic acid exhibited significant anti-platelet aggregation activity in vitro.

Esculetin inhibits Ras-mediated cell proliferation and attenuates vascular restenosis following angioplasty in rats.

The proliferation of vascular smooth muscle cells (VSMCs) induced by injury to the intima of arteries is an important etiologic factor in vascular proliferative disorders such as atherosclerosis and restenosis. Esculetin, derived from the Chinese herb Artemisia scoparia, is well known as a lipoxygenase inhibitor. We have investigated the inhibitory effects of esculetin on VSMC proliferation and intimal hyperplasia by balloon angioplasty in the rat. We determined, using [3H]thymidine incorporation and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, that esculetin inhibited the proliferation of VSMCs via a lipoxygenase-independent pathway. Three predominant signaling pathways were identified to be inhibited by esculetin: (a) the activation of p42/44 mitogen-activated protein kinase (MAPK) and the downstream effectors of c-fos and c-jun immediate early genes by means of western and reverse transcription-polymerase chain reaction (RT-PCR) analyses; (b) the activation of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1), using the electrophoretic mobility shift assay; and (c) the activation of phosphoinositide 3-kinase (PI 3-kinase) and cell cycle progression, by western blot analysis and flow cytometric detection. Furthermore, esculetin also profoundly inhibited Ras activation, a shared upstream event of the above signaling cascades. In vascular injury studies, intraperitoneal administration of esculetin significantly suppressed intimal hyperplasia induced by balloon angioplasty. We conclude that esculetin blocks cell proliferation via the inhibition of an upstream effector of Ras and downstream events including p42/44 MAPK activation, PI 3-kinase activation, immediate early gene expression, as well as NF-kappaB and AP-1 activation. It also inhibits intimal hyperplasia after balloon vascular injury in the rat, indicating the therapeutic potential for treating restenosis after arterial injury.

Cytotoxic amides from Piper sintenense.

A new alkaloid, pipersintenamide ( 1), together with fourteen known compounds, have been isolated from the whole plant of Piper sintenense. The structures of these compounds were elucidated by spectroscopic analysis. Pipersintenamide, sintenpyridone, sarmentine, and 1-(3,4-methylenedioxyphenyl)-1 E-dodecene at 20 microg/ml exhibited effective cytotoxicities (cell survival < 15 %) against CCRF-CEM, HL-60, PC-3, and HA22T cell lines.

Quinoline alkaloids and anti-platelet aggregation constituents from the leaves of Melicope semecarpifolia.

Three new quinoline alkaloids, melisemine, confusadine, and melicarpinone, together with twelve known compounds have been isolated from the leaves of Melicope semecarpifolia. The structures of these three compounds were determined through spectral analyses. Confusadine was demonstrated to be an anti-platelet aggregation constituent.