Wei-Jern Tsai

Samarangenin B from Limonium sinense Suppresses Herpes Simplex Virus Type 1 Replication in Vero Cells by Regulation of Viral Macromolecular Synthesis

ABSTRACT Inhibitory effects of ethanolic extracts from 10 Chinese herbs on herpes simplex virus type 1 (HSV-1) replication were investigated. By a bioassay-guided fractionation procedure, samarangenin B (Sam B) was isolated from Limonium sinense; Sam B significantly suppressed HSV-1 multiplication in Vero cells without apparent cytotoxicity. Time-of-addition experiments suggested that the inhibitory action of Sam B on HSV-1 replication was not due to the blocking of virus adsorption. In an attempt to further localize the point in the HSV-1 replication cycle where arrest occurred, a set of key regulatory events leading to viral multiplication was examined, including viral immediate-early (α), early (β), and late (γ) gene expression and DNA replication. Results indicated that levels of glycoprotein B (gB), gC, gD, gG, and infected-cell protein 5 (ICP5) expression and gB mRNA expression in Vero cells were impeded by Sam B. Data from PCR showed that replication of HSV-1 DNA in Vero cells was arrested by Sam B. Furthermore, Sam B decreased DNA polymerase, ICP0, and ICP4 gene expression in Vero cells. Results of an electrophoretic mobility shift assay demonstrated that Sam B interrupted the formation of an α-trans-induction factor/C1/Oct-1/GARAT multiprotein complex. The mechanisms of antiviral action of Sam B seem to be mediated, at least in part, by inhibiting HSV-1 α gene expression, including expression of the ICP0 and ICP4 genes, by blocking β transcripts such as DNA polymerase mRNA, and by arresting HSV-1 DNA synthesis and structural protein expression in Vero cells. These results show that Sam B is an antiviral agent against HSV-1 replication.

Immunomodulatory functions of extracts from the Chinese medicinal fungus Cordyceps cicadae

The effects of Cordyceps cicadae extracted fractions on human mononuclear cells (HMNC) proliferation were determined by tritiated thymidine uptake. The results indicated that aqueous methanol (50%) extracts of C. cicadae ascocarps portion (CC-1-2) enhanced HMNC proliferation activated with phytohemagglutinin (PHA) with an EC(50) of 13.8+/-4.6 micro g/ml. By contrast, the methanol (100%) extracts of C. cicadae insect-body portion (CC-2-1) suppressed HMNC proliferation stimulated by PHA with an IC(50) of 32.5+/-5.2 micro g/ml. Cell viability test indicated that inhibitory effects of CC-2-1 on HMNC proliferation were not through direct cytotoxicity. The action mechanisms of CC-1-2 and CC-2-1 may involve the regulation of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production in HMNC. Since CC-2-1 suppressed IL-2 and IFN-gamma production in HMNC induced with PHA. The CC-1-2 enhanced IL-2 and IFN-gamma production of HMNC stimulated with PHA in a concentration dependent manner. Therefore, the results demonstrated that C. cicadae contained growth modulators for HMNC.

Determination of Aristolochic Acid in Rabbit Plasma by High-Performance Liquid Chromatography with Photodiode-Array Ultraviolet Detection and Its Pharmacokinetics Application

Abstract A simple and sensitive high-performance liquid chromatographic method for the determination of aristolochic acid (AA) in rabbit plasma has been developed. Up to 0.1 ml of plasma containing AA was deproteinized by acetonitrile, which contained an internal standard (indomethacin). The supernatant was injected onto a COSMOSIL 5C18-AR column (5 μm) using acetonitrile-0.1 % phosphoric acid (60:40, v/v, pH 2.5–2.8) as the mobile phase. UV detection at 227 nm was followed by ultraviolet spectrum identification (among 200 and 380 nm) with a photodiode-array detector. The method was rapid, easily reproduced, selective and sensitive. It was applied to pharmacokinetic studies of AA in rabbit, after a 5 mg/kg intravenous administration. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration-time curve. Compartmental analyses yielded a two-compartment model.

Lignans from the Aerial Parts of Saururus chinensis: Isolation, Structural Characterization, and Their Effects on Platelet Aggregation

Five new diaryldimethylbutane lignans, saurulignans A-E (1-5), four new tetrahydrofuran lignans, saurufurins A-D (6-9), and one arylnaphthalene lignan, saurunarin (10), were isolated from Saururus chinensis, along with 18 known compounds. Lignan 5 showed significant inhibition of ADP-induced aggregation with an IC50 value of 9.8 μM and AA-induced aggregation with an IC50 value of 14.0 μM. Compound 19 showed significant activity to inhibit PAF-induced aggregation with an IC50 value of 9.1 μM. In addition, five isolated compounds could induce platelet aggregation. These results suggest that secondary metabolites in S. chinensis have bidirectional regulation on blood clotting and anticlotting effects.

Magnolol inhibits collagen-induced platelet serotonin release

Abstract Magnolol is one of the major phenolic constituents of Magnolia bark (1,2). The bark of Magnolia has been used as a folk medicine by Chinese for the treatment of anxiety, neural and cardiovascular disorders (3). Nowadays medicinal herbs have been gaining renewed popularity in the world as an alternative choice in health care very much reminiscent of the pre-pharmacology days. Recent studies indicate that magnolol inhibits intracellular calcium mobilization in platelets (4), relaxes vascular smooth muscle (5), and has antihemostatic and antithrombotic effects (6). For the 5-HT determination, the more commonly used chemical method is spectrophotofluorometric method. However, its detection limit is low (7). Radioimmunoassay and enzymatic assay have higher sensitivity (8,9). The newly developed method of labelling the granule-bound pool by incorporation of radioactive 5-HT then measuring the appearance of radioactivity extracellularly for the quantitation of 5-HT secretion was reported (10). However, they are all complicated and time-consuming. The purpose of this study is to establish a reliable and sensitive microbore HPLC ECD in order to measure platelet 5-HT and evaluate antiplatelet effect of magnolol on collagen-induced 5-HT release.

Seselin from Plumbago zeylanica inhibits phytohemagglutinin (PHA)-stimulated cell proliferation in human peripheral blood mononuclear cells

Effects of seselin (C(14)H(12)O(3); MW 228) identified from Plumbago zeylanica on phytohemagglutinin (PHA)-stimulated cell proliferation were studied in human peripheral blood mononuclear cells (PBMC). The data demonstrated that seselin inhibited PBMC proliferation-activated with PHA with an IC(50) of 53.87+/-0.74 microM. Cell viability test indicated that inhibitory effects of seselin on PBMC proliferation were not through direct cytotoxicity. The action mechanisms of seselin may involve the regulation of cell cycle progression, interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production in PBMC. Since cell cycle analysis indicated that seselin arrested the cell cycle progression of activated PBMC from the G(1) transition to the S phase. Seselin suppressed IL-2 and IFN-gamma production in a concentration-dependent manner. Furthermore, seselin significantly decreased the IL-2 and IFN-gamma gene expression in PHA-activated PBMC. Therefore, results elucidated for the first time that seselin is likely an immunomodulatory agent for PBMC.

Aspirin inhibits collagen-induced platelet serotonin release, as measured by microbore high-performance liquid chromatography with electrochemical detection

A sensitive microbore high-performance liquid chromatographic method with electrochemical detection has been developed for the measurement of small quantities of serotonin (5-hydroxytryptamine; 5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in rabbit platelets. The limit of detection of 5-HT is 0.1 ng/ml. To evaluate the 5-HT release from platelet suspension, the aggregating agent collagen was added at concentrations of 10, 30 and 100 micrograms/ml and the 5-HT concentrations rose from the base level (11.80 +/- 0.42 ng/ml) to 123.97 +/- 11.02, 361.96 +/- 17.90 and 470.45 +/- 35.46 ng/ml, respectively. Further results demonstrated that aspirin inhibits collagen-induced 5-HT release from platelet suspension significantly.

Magnolol Inhibits Arachidonic Acidinduced Rabbit Platelet Serotonin Release, Measure by Microbore HPLC with Electrochemical Detection

Abstract Serotonin (5-hydroxytryptamine; 5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) were determined simultaneously in rabbit platelet by a sensitive microbore high-performance liquid chromatographic method with electrochemical detection. The detection limit of 5-HT in rabbit platelet suspension was 0.1 ng/mL. To evaluate the 5 – HT release from platelet suspension, the aggregating agent arachidonic acid 30 and 100 μM were added and the 5-HT was elevated from basal level 2.96±0.89 ng/mL to 154.72±28.03 and 246.77±24.38 ng/mL, respectively. The results demonstrated that magnolol inhibits arachidonic acid-induced 5-HT release from platelet suspension significantly.