Cellular Anti-Inflammatory and Antioxidant Activities of Bamboo Sasa albomarginata Leaf Extract and Its Constituent Coumaric Acid Methyl Ester.

Background: Hot water extract of Sasa albomarginata (Kumazasa) leaves is commercially available and used as a dietary supplement or skincare cream. The extract possesses anti-inflammatory activity on the mouse atopic dermatitis model. To elucidate the mechanism of in vivo activity, we have studied the cellular anti-inflammatory and antioxidant activities of the extract and its constituents. Methods: Secretion of mouse and human IL-6 was measured by ELISA. ROS production was measured by a fluorescent reagent. Ultrahigh performance liquid chromatography (UHPLC)/MS was used for the ingredient analysis. Results: The Sasa albomarginata extract inhibited inflammatory mediators such as LPS-induced NO, IL-6, and ROS production in mouse monocyte leukemia RAW264.7 cells. It also inhibited iNOS, IL-6, and IL-1ß expressions. Moreover, it inhibited LPS-induced IL-6 expression and production in human monocyte leukemia THP-1 cells differentiated into macrophages. The HPLC analysis of the extract revealed the existence of coumaric acid, ferulic acid, and coumaric acid methyl ester. Coumaric acid methyl ester but not coumaric acid or ferulic acid inhibited LPS-induced NO, IL-6, and ROS production in RAW264.7 cells and IL-6 production in differentiated THP-1 cells. Conclusion: The hot water extract of Sasa albomarginata leaves and one of its constituents possess cellular anti-inflammatory and antioxidant activities.

Direct and Indirect Anticancer Activity of Plant-Derived Alkaloid Conophylline.

K-Ras is one of the most important oncogenes in human oncogenesis. K-Ras transfection of normal rat fibroblasts induces phenotypic change from flat to round morphology. Then, we screened compounds inducing flat morphology in K-Ras transformed fibroblasts from microbial culture filtrates and plant extracts. As a result, the alkaloid conophylline was isolated from the leaves of Ervatamia microphylla collected in Thailand. Conophylline induced flat morphology and inhibited cellular invasion in K-Ras-transformed normal rat kidney (K-Ras-NRK) cells. It also inhibited the growth of the K-Ras-NRK tumor in mice. Cancer-associated fibroblasts are now considered to activate cancer growth. Conophylline was found to suppress secretions of various inflammatory cytokines by pancreatic cancer-associated fibroblasts. Moreover, when combined with gemcitabine, it inhibited the growth of pancreatic cancer growth in mice. Conophylline is orally active. Thus, the plant-derived alkaloid conophylline inhibited cancer growth directly and indirectly, and it shows promise as a new anticancer agent.

Therapeutic activity of plant-derived alkaloid conophylline on metabolic syndrome and neurodegenerative disease models.

Increasing metabolic syndromes including type-2 diabetes mellitus, obesity, and steatohepatitis are serious problems in most countries in the world. Neurodegenerative diseases such as Alzheimer, Parkinson's, and Huntington's diseases are increasing in many countries. However, therapy for these diseases is not sufficient yet. Thus, effective chemotherapy for these diseases is being expected. Conophylline is an alkaloid isolated from the leaves of Ervatamia microphylla and related plants. It was found to induce beta-cell differentiation in the precursor pancreatic cells. Oral administration of this compound ameliorated type-2 diabetes mellitus model in mice and rats. Later, fibrosis of the pancreatic islets was found to be greatly reduced by conophylline in the pancreatic islets. It also inhibited chemically induced liver cirrhosis. Further study indicated that conophylline inhibited non-alcoholic steatohepatitis in the model mice. On the one hand, loss of autophagy often causes protein aggregation to give neural cell death. Conophylline was found to activate autophagy in cultured neural cells. Activation of autophagy ameliorated cellular models of Parkinson's and Huntington's diseases. Thus, conophylline is likely to be useful for the development of chemotherapy for metabolic and neurodegenerative diseases.

Determination of topological structure of ARL6ip1 in cells: identification of the essential binding region of ARL6ip1 for conophylline.

Conophylline (CNP) has various biological activities, such as insulin production. A recent study identified ADP-ribosylation factor-like 6-interacting protein 1 (ARL6ip1) as a direct target protein of CNP. In this study, we revealed that ARL6ip1 is a three-spanning transmembrane protein and determined the CNP-binding domain of ARL6ip1 by deletion mutation analysis of ARL6ip1 with biotinyl-amino-CNP. These results suggest that CNP is expected to be useful for future investigation of ARL6ip1 function in cells. Because of the anti-apoptotic function of ARL6ip1, CNP may be an effective therapeutic drug and/or a novel chemosensitizer for human cancers and other diseases.

Earthworm-derived pore-forming toxin lysenin and screening of its inhibitors.

Lysenin is a pore-forming toxin from the coelomic fluid of earthworm Eisenia foetida. This protein specifically binds to sphingomyelin and induces erythrocyte lysis. Lysenin consists of 297 amino acids with a molecular weight of 41 kDa. We screened for cellular signal transduction inhibitors of low molecular weight from microorganisms and plants. The purpose of the screening was to study the mechanism of diseases using the obtained inhibitors and to develop new chemotherapeutic agents acting in the new mechanism. Therefore, our aim was to screen for inhibitors of Lysenin-induced hemolysis from plant extracts and microbial culture filtrates. As a result, we isolated all-E-lutein from an extract of Dalbergia latifolia leaves. All-E-lutein is likely to inhibit the process of Lysenin-membrane binding and/or oligomer formation rather than pore formation. Additionally, we isolated tyrosylproline anhydride from the culture filtrate of Streptomyces as an inhibitor of Lysenin-induced hemolysis.

Inhibition of lysenin-induced hemolysis by all-E-lutein derived from the plant Dalbergia latifolia.

Lysenin is a pore-forming toxin derived from coelomic fluid of the earthworm Eisenia foetida. The model of lysenin-induced hemolysis includes the specific binding of lysenin to sphingomyelin, oligomerization of the pore proteins, and pore formation. Although the mechanism of lysenin-induced hemolysis is unique, its precise mechanism of action and its inhibitors are poorly understood. In the present study, we screened for inhibitors of lysenin-induced hemolysis by using an optimized screening system and found a methanolic extract of Dalbergia latifolia leaves to be a potential candidate. After isolation and identification, all-E-lutein was identified as the hemolysis inhibitor with an effective dose of 0.025-2.5 ng/mL without any toxicity. The inhibition by all-E-lutein is likely to occur during the receptor binding and/or pore-forming protein oligomerization.

Coffee induces breast cancer resistance protein expression in Caco-2 cells.

Coffee is a beverage that is consumed world-wide on a daily basis and is known to induce a series of metabolic and pharmacological effects, especially in the digestive tract. However, little is known concerning the effects of coffee on transporters in the gastrointestinal tract. To elucidate the effect of coffee on intestinal transporters, we investigated its effect on expression of the breast cancer resistance protein (BCRP/ABCG2) in a human colorectal cancer cell line, Caco-2. Coffee induced BCRP gene expression in Caco-2 cells in a coffee-dose dependent manner. Coffee treatment of Caco-2 cells also increased the level of BCRP protein, which corresponded to induction of gene expression, and also increased cellular efflux activity, as judged by Hoechst33342 accumulation. None of the major constituents of coffee tested could induce BCRP gene expression. The constituent of coffee that mediated this induction was extractable with ethyl acetate and was produced during the roasting process. Dehydromethylepoxyquinomicin (DHMEQ), an inhibitor of nuclear factor (NF)-κB, inhibited coffee-mediated induction of BCRP gene expression, suggesting involvement of NF-κB in this induction. Our data suggest that daily consumption of coffee might induce BCRP expression in the gastrointestinal tract and may affect the bioavailability of BCRP substrates.

Inhibition of NF-kappaB and Akt pathways by an antibody-avidin fusion protein sensitizes malignant B-cells to cisplatin-induced apoptosis.

Multiple myeloma (MM) is an incurable disease of malignant plasma cells. Recent therapeutic advancements have resulted in improved response rates, however, there is no improvement in overall survival, therefore, new therapeutics are needed. Since the transferrin receptor is upregulated on the surface of MM cells, we previously developed an antibody fusion protein consisting of an IgG3 specific for the human transferrin receptor 1 (TfR1, CD71) genetically fused to avidin at its carboxy-terminus (ch128.1Av). We have previously shown that ch128.1Av exhibits intrinsic cytotoxicity against certain malignant B-cells by disrupting the cycling of the TfR and decreasing TfR cell surface expression resulting in lethal iron starvation. In addition, ch128.1Av can sensitize malignant cells to apoptosis induced by gambogic acid, a herbal drug used in Chinese medicine. In this study, we hypothesized that ch128.1Av may also sensitize drug-resistant malignant B-cells to chemotherapeutic agents by inhibiting key survival pathways. In this study we show that ch128.1Av sensitizes malignant B-cells to apoptosis induced by cisplatin (CDDP). The sensitization by ch128.1Av resulted in the inhibition of the constitutively activated Akt and NF-kappaB survival/antiapoptotic pathways and downstream decreased expression of antiapoptotic gene products such as BclxL and survivin. The direct role of the inhibition of the Akt and NF-kappaB pathways by ch128.1Av in CDDP-mediated cytotoxicity was demonstrated by the use of specific chemical inhibitors and siRNA which mimicked the effects of ch128.1Av. Overall, this study provides evidence of the therapeutic potential of ch128.1Av as a chemo-sensitizing agent in drug-resistant tumor cells.

Preparation of conophylline affinity nano-beads and identification of a target protein.

Conophylline, a vinca alkaloid extracted from the tropical plant Ervatamia microphylla, has been shown to induce the differentiation of insulin-producing beta-cells in cultured cells and in animals. However, its mechanism of action and the molecular target have remained unclear. Therefore, we prepared a fishing probe with conophylline to identify the target protein by using latex nano-beads, which are newly innovated tools for affinity-purification. With these conophylline-linked nano-beads, we found that conophylline directly interacted with ARL6IP. ARL6IP may thus be involved in the mechanism of cellular differentiation of beta-cells, and this probe should be useful to find other target proteins.

Antitumor effects of dehydroxymethylepoxyquinomicin, a novel nuclear factor-kappaB inhibitor, in human liver cancer cells are mediated through a reactive oxygen species-dependent mechanism.

Activation of the nuclear transcription factor-kappaB (NF-kappaB) has been implicated in liver tumorigenesis. We evaluated the effects of a novel NF-kappaB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), in two human liver cancer cell lines HA22T/VGH and HuH-6. DHMEQ treatment dose dependently decreased the DNA-binding capacity of the NF-kappaB p65 subunit, inhibited cell growth and proliferation, and increased apoptosis as shown by caspase activation, release of cytochrome c, poly(ADP-ribose) polymerase cleavage, and down-regulation of survivin. DHMEQ also induced a dose-dependent activation of mitogen-activated protein kinase kinase/extracellular signal-regulated kinase signaling, and inhibition of this pathway significantly reduced cell growth. It is noteworthy that we observed that DHMEQ stimulated reactive oxygen species (ROS) production in a dose-dependent manner and that pretreatment of the cells with the antioxidant N-acetyl-L-cysteine (NAC) significantly reduced DHMEQ-induced ROS generation. Accordingly, NAC completely reversed the DHMEQ-induced growth inhibition, caspase activation, and cell death. DHMEQ-treated cells exhibited DNA damage, as evaluated by accumulation in nuclear foci of phospho-H2AX, which was completely reversed by NAC. Moreover, DHMEQ induced the expression of genes involved in the endoplasmic reticulum stress response (GRP78, CHOP, TRB3) and promoted the splicing of XBP1 mRNA in a dose-dependent fashion in both cell lines, which was reversed in the presence of NAC. Knockdown of TRB3 mRNA expression by small interference RNA significantly decreased DHMEQ-induced cell growth inhibition. These data suggest that DHMEQ antitumor effects are primarily mediated through ROS generation. Thereby, considering that cancer cells are under increased ER stress and oxidative stress conditions, DHMEQ may greatly improve various anticancer strategies.

Antidiabetic effect of orally administered conophylline-containing plant extract on streptozotocin-treated and Goto-Kakizaki rats.

Conophylline, a vinca alkaloid from Ervatamia microphylla, is known to induce the differentiation of pancreatic precursor cells to insulin-producing cells. In the present research we examined the antidiabetic effects of this alkaloid in vivo by oral administration. Crude conophylline preparations were prepared from the leaves of Tabernaemontana divaricata collected in Okinawa Prefecture, Japan. Conophylline was orally absorbed and showed an increase in its plasma level in both normal and streptozotocin-induced diabetic Sprague-Dawley rats. The plasma conophylline concentration reached its maximum from 1.5 to 3h after a single oral administration and gradually decreased in 24h. The alkaloid decreased the blood glucose level and increased the plasma insulin level in streptozotocin-induced diabetic rats after repetitive administration for 15 days. Fasting blood glucose levels in rats treated orally with conophylline at 0.11 and 0.46 mg/kg/day were 411+/-47 and 381+/-65 mg/dl, respectively; whereas the glucose level of the control rats was 435+/-46 mg/dl. Conophylline also decreased the fasting blood glucose level in Goto-Kakizaki rats in a dose-dependent manner after repetitive administration for 42 days. These results suggest that the extract from conophylline-containing leaves may be useful as a functional food for the treatment of type 2 diabetes mellitus.

Inhibition of Yin Yang 1-dependent repressor activity of DR5 transcription and expression by the novel proteasome inhibitor NPI-0052 contributes to its TRAIL-enhanced apoptosis in cancer cells.

TRAIL promotes apoptotic tumor cell death; however, TRAIL-resistant tumors need to be sensitized to reverse resistance. Proteasome inhibitors potentiate TRAIL apoptosis in vitro and in vivo and correlate with up-regulation of death receptor 5 (DR5) via an unknown mechanism. We hypothesized that the proteasome inhibitor NPI-0052 inhibits the transcription repressor Yin Yang 1 (YY1) which regulates TRAIL resistance and negatively regulates DR5 transcription. Treatment of PC-3 and Ramos cells with NPI-0052 (

DHMEQ, a novel nuclear factor-kappaB inhibitor, induces selective depletion of alloreactive or phytohaemagglutinin-stimulated peripheral blood mononuclear cells, decreases production of T helper type 1 cytokines, and blocks maturation of dendritic cells.

Dehydroxymethylepoxyquinomicin (DHMEQ), a novel nuclear factor kappaB (NF-kappaB) inhibitor, has been shown to be active against variety types of solid tumours as well as haematological malignant cells. This study explored the anti-inflammatory effects of DHMEQ in vitro. DHMEQ inhibited the proliferation of phytohaemagglutinin (PHA)-stimulated or alloreactive peripheral blood mononuclear cells (PBMC) in mixed lymphocyte cultures as measured using a 3-(4,5-dimethylithiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay. In contrast, DHMEQ did not affect the viability of resting PBMC. In addition, real-time polymerase chain reaction showed that DHMEQ decreased PHA-stimulated expression of T helper type 1 (Th1) cytokines, including interleukin-2, interferon-gamma, and tumour necrosis factor alpha, in PBMC as well as Jurkat T-lymphoblastic leukaemia cells, and also decreased levels of p65 isoforms of NF-kappaB in the nucleus. Furthermore, we found that DHMEQ inhibited the endocytic capacity of dendritic cells (DCs) and down-regulated the expression of cell surface antigen CD40, suggesting that DHMEQ blocked the maturation as well as the function of DCs. Taken together, the results suggest that DHMEQ may be useful for treatment of inflammatory diseases, including graft-versus-host disease after allogenic haematopoietic stem cell transplantation.

Macular pigment lutein is antiinflammatory in preventing choroidal neovascularization.

BACKGROUND: Choroidal neovascularization (CNV) is a critical pathogenesis in age-related macular degeneration, the most common cause of blindness in the developed countries. The aim of the current study was to investigate the effect of lutein supplementation on the development of the murine model of laser-induced CNV together with underlying molecular mechanisms. METHODS AND RESULTS: Mice were orally pretreated with lutein daily from 3 days before laser photocoagulation until the end of the study. The index of CNV volume was significantly suppressed by the treatment with lutein, compared with vehicle-treated animals. Lutein treatment led to significant inhibition of macrophage infiltration into CNV and of the in vivo and in vitro expression of inflammation-related molecules including vascular endothelial growth factor, monocyte chemotactic protein -1, and intercellular adhesion molecule-1. Importantly, lutein suppressed IkappaB-alpha degradation and nuclear translocation of nuclear factor (NF)-kappaB p65 both in vivo and in vitro. Additionally, the development of CNV was significantly suppressed by inhibiting NF-kappaB p65 nuclear translocation, to the levels seen in the lutein treatment. CONCLUSIONS: Lutein treatment led to significant suppression of CNV development together with inflammatory processes including NF-kappaB activation and subsequent upregulation of inflammatory molecules, providing molecular evidence of potential validity of lutein supplementation as a therapeutic strategy to suppress CNV.

Screening of bioactive metabolites for pancreatic regeneration chemotherapy.

Plants and microorganisms are the treasury of bioactive metabolites including useful chemical ligands. Chemical ligands that induce beta-cell differentiation may be useful as new therapeutic agents for both type-1 and type-2 diabetes mellitus. We isolated conophylline from the leaves of Ervatamia microphylla as an agent that induce insulin production in rat pancreatic acinar carcinoma cells.

Acute oral selenium intoxication with ten times the lethal dose resulting in deep gastric ulcer.

A 48-year-old woman presented after taking 2000 mg of selenium dioxide, corresponding to 10 times the experimental lethal dose in animals. She presented with mildly altered consciousness and hematemesis. Endoscopy revealed mucosal damage throughout the oral cavity, esophagus, and stomach. There was no evidence of perforation. After intubation and gastric lavage, hemodialysis was performed. The patient was discharged uneventfully on the 16(th) day. This case highlights a very rare acute selenium intoxication. Serum and urinary selenium levels and serum glutathione peroxidase activities during the patient's course were followed, as well as the mucosal corrosive damage caused by the selenium.