Bioactive polyketides from the pathogenic fungus of Epicoccum sorghinum.

MAIN CONCLUSION: We discovered and identified a series of characteristic substances, including one new polyketide, epicorepoxydon B, of the important pathogenic fungus, Epicoccum sorghinum, of sorghum. The fungal extract and some isolated polyketides are sensitive to a malignant triple-negative breast cancer cell line, MDA-MB-231. Sorghum (Kaoliang) grain is an important crop with high economic value and several applications. In Taiwan, sorghum has been used in the wine industry, and "Kinmen Kaoliang Liquor" is a well-known Asian brand. Fungal contamination is one of the major threats affecting the production of sorghum grain resulting in economic losses as well as human and animal health problems. Several fungal species can infect sorghum grain and generate some toxic secondary metabolites. Epicoccum sorghinum is one of the major fungal contaminants of sorghum grains and a potent producer of mycotoxins such as tenuazonic acid (TeA). However, except for TeA, few studies focused on chemical compounds produced by this fungus. To explore the potential biological and toxic effects of E. sorghinum, a chemical investigation was carried out on the ethyl acetate extract of the fungus because it showed cytotoxic activity against a triple-negative breast cancer cell line, MDA-MB-231 (54.82% inhibition at 20 µg/mL). One new polyketide, epicorepoxydon B (1), along with six known compounds including 4,5-dihydroxy-6-(6'-methylsalicyloxy)-2-hydroxymethyl-2-cyclohexenl-one (2), epicorepoxydon A (3), 3-hydroxybenzyl alcohol (4), 6-methylsalicylic acid (5), gentisyl alcohol (6), and 6-(hydroxymethyl)benzene-1,2,4-triol (7) were obtained, and their structures were established by the interpretation of their MS and NMR spectroscopic data. The cytotoxic activity of all isolated polyketides 1-7 was evaluated, and compounds 2, 6, and 7 exhibited potent activities against A549, HepG2, and MDA-MB-231 human cancer cell lines with IC50 value ranging from 1.86 to 18.31 µM. The structure-activity relationship of the isolated compounds was proposed.

Developing Lactic Acid Bacteria as an Oral Healthy Food.

Lactic acid bacteria have functions in immunoregulation, antagonism, and pathogen inhibition. The purpose of this study was to evaluate the effectiveness of lactic acid bacteria (LAB) in countering oral pathogens and develop related products. After a series of assays to 450 LAB strains, 8 heat-inactivated strains showed a strong inhibitory effect on a caries pathogen, Streptococcus mutans, and 308 heat-inactivated LAB strains showed a strong inhibitory effect on a periodontal pathogen, Porphyromonas gingivalis. The key reasons for inhibiting oral pathogens were bacteriocins produced by LAB and the coaggregation effect of the inactivated cells. We selected Lacticaseibacillus (Lb) paracasei 111 and Lb.paracasei 141, which had the strongest inhibitory effects on the above pathogens, was the main oral health food source. The optimal cultural conditions of Lb. paracasei 111 and Lb. paracasei 141 were studied. An oral tablet with a shelf life of 446 days made of the above strains was developed. A 40 volunteers' clinical study (CSMUH IRB number: CS05065) was conducted with this tablet in the Periodontological Department of the Stomatology Research Center, Affiliated Hospital of Chung Shan Medical University (Taiwan). After 8 weeks of testing, 95% and 78.9% of patients showed an effect on reducing periodontal pathogens and improving probing pocket depth, respectively, in the oral tablet group.

Anti-inflammatory, Antiplatelet Aggregation, and Antiangiogenesis Polyketides from Epicoccum sorghinum: Toward an Understating of Its Biological Activities and Potential Applications.

The ethyl acetate extract of an endophyte Epicoccum sorghinum exhibited anti-inflammatory activity at a concentration of <10 µg/mL. By bioassay-guided fractionation, one new compound, named epicorepoxydon A (1), and one unusual bioactive compound, 6-(hydroxymethyl)benzene-1,2,4-triol (6), together with six known compounds, were isolated from E. sorghinum. The structures of all isolates were established by spectroscopic analyses. The relative configuration of 1 was deduced by the NOESY spectrum and its absolute configuration was determined by X-ray single-crystal analysis. The biological activities of all isolates were evaluated using four types of bioassays including cytotoxicity, anti-inflammatory, antiplatelet aggregation, and antiangiogenesis activities. Compounds 4 and 6 showed potent anti-inflammatory activity, compound 2 possessed potent antiplatelet aggregation and antiangiogenesis activities, and compound 6 demonstrated antiangiogenesis activity. This fungal species can cause a human hemorrhagic disorder known as onyalai. In this study, we identified the active components with antiplatelet aggregation and antiangiogenesis activities, which may be related to the hemorrhagic disorder caused by this fungus. Moreover, we proposed a biosynthetic pathway of the isolated polyketide secondary metabolites and investigated their structure-activity relationship (SAR). Our results suggested that E. sorghinum is a potent source of biologically active compounds that can be developed as antiplatelet aggregation and anti-inflammatory agents.

YC-1 Prevents Tumor-Associated Tissue Factor Expression and Procoagulant Activity in Hypoxic Conditions by Inhibiting p38/NF-κB Signaling Pathway.

Tissue factor (TF) expressed in cancer cells has been linked to tumor-associated thrombosis, a major cause of mortality in malignancy. Hypoxia is a common feature of solid tumors and can upregulate TF. In this study, the effect of YC-1, a putative inhibitor of hypoxia-inducible factor-1α (HIF-1α), on hypoxia-induced TF expression was investigated in human lung cancer A549 cells. YC-1 selectively prevented hypoxia-induced TF expression and procoagulant activity without affecting the basal TF levels. Surprisingly, knockdown or pharmacological inhibition of HIF-1α failed to mimic YC-1's effect on TF expression, suggesting other mechanisms are involved. NF-κB, a transcription factor for TF, and its upstream regulator p38, were activated by hypoxia exposure. Treatment of hypoxic A549 cells with YC-1 prevented the activation of both NF-κB and p38. Inhibition of p38 suppressed hypoxia-activated NF-κB, and inhibited TF expression and activity to similar levels as treatment with an NF-κB inhibitor. Furthermore, stimulation of p38 by anisomycin reversed the effects of YC-1. Taken together, our results suggest that YC-1 prevents hypoxia-induced TF in cancer cells by inhibiting the p38/NF-κB pathway, this is distinct from the conventional anticoagulants that systemically inhibit blood coagulation and may shed new light on approaches to treat tumor-associated thrombosis.

6-Paradol and 6-Shogaol, the Pungent Compounds of Ginger, Promote Glucose Utilization in Adipocytes and Myotubes, and 6-Paradol Reduces Blood Glucose in High-Fat Diet-Fed Mice.

The anti-diabetic activity of ginger powder (Zingiber officinale) has been recently promoted, with the recommendation to be included as one of the dietary supplements for diabetic patients. However, previous studies presented different results, which may be caused by degradation and metabolic changes of ginger components, gingerols, shogaols and paradols. Therefore, we prepared 10 ginger active components, namely 6-, 8-, 10-paradols, 6-, 8-, 10-shogaols, 6-, 8-, 10-gingerols and zingerone, and evaluated their anti-hyperglycemic activity. Among the tested compounds, 6-paradol and 6-shogaol showed potent activity in stimulating glucose utilization by 3T3-L1 adipocytes and C2C12 myotubes. The effects were attributed to the increase in 5' adenosine monophosphate-activated protein kinase (AMPK) phosphorylation in 3T3-L1 adipocytes. 6-Paradol, the major metabolite of 6-shogaol, was utilized in an in vivo assay and significantly reduced blood glucose, cholesterol and body weight in high-fat diet-fed mice.

Inhibition of the interactions between metastatic human breast cancer cells and platelets by ß-nitrostyrene derivatives.

AIMS: The interactions between cancer cells and platelets have been recognized to play an important role in cancer progress as well as metastasis, and interference with cancer-platelet interactions is an attractive strategy for cancer therapy. In the present study, two ß-nitrostyrene derivatives: 3, 4-methylene-dioxy-ß-nitrostyrene (MNS) and 4-O-benzoyl-3-methoxyl-ß-nitrostyrene (BMNS) have been tested for their inhibitory effect on platelet activation caused by metastatic human breast cancer MDA-MB-231 and Hs578T cells. MAIN METHODS: Washed human platelets were co-incubated with breast cancer cells, and platelet aggregation was determined turbidimetrically. Platelet adhesion to cancer cells and P-selectin expression were measured by flow cytometry. Platelet-derived growth factor (PDGF) released from cancer cell-stimulated platelets was determined by enzyme-linked immunosorbent assay (ELISA). KEY FINDINGS: MNS and BMNS prevented cancer cell-induced platelet aggregation, P-selectin expression, and PDGF secretion. Moreover, the ß-nitrostyrenes reduced platelet adhesion to cancer cells, suggesting the initial cancer-platelet interactions are inhibited. In contrast to current antiplatelet strategies, the glycoprotein IIb/IIIa (GPIIb/IIIa) antagonist RGDS peptide only prevented cancer cells-induced platelet aggregation, but not platelet adhesion and secretion; whereas the cyclooxygenase inhibitor aspirin and the adenosine diphosphate (ADP) scavenger apyrase affected neither platelet aggregation nor platelet secretion. SIGNIFICANCE: The inhibitory effects of the ß-nitrostyrene derivatives on cancer-platelet interactions may offer a potential approach for repressing cancer metastasis.

An epigenetic modifier enhances the production of anti-diabetic and anti-inflammatory sesquiterpenoids from Aspergillus sydowii.

The addition of a DNA methyltransferase inhibitor, 5-azacytidine, to Aspergillus sydowii fungus culture broth changed its secondary metabolites profile. Analysis of the culture broth extract led to the isolation of three new bisabolane-type sesquiterpenoids: (7S)-(+)-7-O-methylsydonol (1), (7S,11S)-(+)-12-hydroxysydonic acid (2) and 7-deoxy-7,14-didehydrosydonol (3), along with eight known compounds. The isolated compounds were evaluated for their anti-diabetic and anti-inflammatory activities. Among the isolates, (S)-(+)-sydonol (4) did not only potentiate insulin-stimulated glucose consumption but also prevented lipid accumulation in 3T3-L1 adipocytes. Additionally, (S)-(+)-sydonol (4) exhibited significant anti-inflammatory activity through inhibiting superoxide anion generation and elastase release by fMLP/CB-induced human neutrophils. This is the first report on isolating a secondary metabolite with anti-diabetic and anti-inflammatory activities from microorganisms.

Combined blockade of thrombin anion binding exosite-1 and PAR4 produces synergistic antiplatelet effect in human platelets.

Thrombin exosite-1 mediates the specific binding of thrombin with fibrinogen and protease-activated receptor (PAR) 1. Exosite-1 inhibitors have been shown to effectively decrease the clotting activity of thrombin, while their antiplatelet effects are relatively weak. In the present study, the inhibitory effects of two exosite-1 inhibitors, hirugen and HD1, but not the exosite-2 inhibitor HD22, on thrombin-induced platelet aggregation and P-selectin expression were dramatically enhanced by a PAR4 antagonist, YD-3. In contrast, the PAR1 antagonist SCH-79797 did not affect the antiplatelet effects of exosite-1 inhibitors. The exosite-1 inhibitors and YD-3 prevented the Ca2+ spike and the prolonged Ca2+ response in thrombin-stimulated platelets, respectively; and combination of these two classes of agents led to abolishment of Ca2+ signal. Unlike exosite-1 inhibitors, the antiplatelet effects of the active site inhibitor PPACK and the bivalent inhibitor bivalirudin were not significantly enhanced by YD-3. In addition, the platelet-stimulating activity of γ-thrombin, an autolytic product of α-thrombin which lacks exosite-1, was inhibited by YD-3. These results suggest that the synergistic antiplatelet effects of exosite-1 inhibitor and PAR4 antagonist are resulted from combined blockade of PAR1 and PAR4 in platelets. In fibrinogen or plasma clotting assay, YD-3 neither prolonged the clotting time on its own nor enhanced the anticoagulant activity of exosite-1 inhibitors. Therefore, the combined blockade of exosite-1 and PAR4 may offer a potential strategy for improving the balance of benefits and risks of antithrombotic therapy.