Biomedical subjects

Zheng-Tao Wang

Publications and source records attributed to Zheng-Tao Wang.

At least 19 recordsLinked to original sources

PubMed2006

Inhibitory effects of neoandrographolide on nitric oxide and prostaglandin E2 production in LPS-stimulated murine macrophage.

Activated macrophages express inducible isoforms of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), produce excessive amounts of nitric oxide (NO) and prostaglandin E(2) (PGE(2)), which play key roles in the processes of inflammation. Andrographis paniculata Nees is a traditional Chinese herb commonly used for treatment of infection, inflammation, and diarrhea. However, the mechanism of its therapeutic function is not well known. In the present study, the effect of neoandrographolide, one of bioactive components in A. paniculata, on iNOS-mediated NO production and COX-2-mediated PGE(2) in bacterial lipopolysaccharide (LPS) stimulated-murine macrophages was investigated. Neoandrographolide at concentrations (30-90 microM) significantly (p<0.05) inhibited the productions of NO and PGE(2) in LPS stimulated macrophages without inducing cytotoxicity. The effect of neoandrographolide also has been investigated on iNOS and COX-2 expression in activated macrophage by using RT-PCR and immunoblotting. The inhibition of NO release by neoandrographolide can be attributed to the block of iNOS mRNA transcription followed by inhibiting protein expression. However, neoandrographolide inhibited COX-2 protein expression only but without inhibiting COX-2 mRNA expression, which was involved in the inhibitory activity against the PGE(2 )overproduction. This suggests that the effect of neoandrographolide on iNOS expression may occur at the transcriptional level and the inhibition of COX-2 expression occurs at the translational level. Furthermore, we have found that the addition of neoandrographolide inhibited the activation of p38 mitogen-activated protein kinase (MAPKs) instead of JNK, ERK1/2, or NF-kappaB. These results indicated that the anti-inflammatory properties of neoandrographolide might result from the inhibition of iNOS and COX-2 expression through inhibiting p38 MAPKs activation. Therefore, neoandrographolide isolated from A. paniculata could be offered as a leading compound for anti-inflammation.

Animals↗

PubMed2006

Sensitized photooxidation of furanoeremophilane with singlet oxygen and their biogenetic relationship.

In an attempt to explore the biogenetic relationship of furanoeremophilane derivatives and eremophilan-8alpha,12-olides, produced in Ligularia and their structure-activity relationship, we studied the photosensitized oxidation of furanoeremophilane-type sesquiterpenes. Under the condition of several solvents solution Irradiation with a 200 W incandescent lamp of furanoeremophilan-14beta,6alpha-olide isolated from Ligularia vellerea, in various solutions with methylene blue, rose bengal, toluidine blue and safranine T gave several products. The products were isolated by chromatographic procedure and their structures were elucidated as eremophilan-14beta,6alpha,8alpha,12-diolide derivatives by NMR, IR and MS methods. A reaction mechanism has been proposed.

Animals↗

PubMed2006

In vitro anti-tumor activity of isorhamnetin isolated from Hippophae rhamnoides L. against BEL-7402 cells.

Isorhamnetin, a flavonol aglycone, isolated from the traditional Chinese medicine Hippophae rhamnoides L., was investigated in its cytotoxicity and its influence on human hepatocellular carcinoma cells (BEL-7402). The cytotoxic effects of isorhamnetin showed dose- and time-dependency against BEL-7402 cells, with IC(50) equal to 74.4+/-1.13 microg ml(-1) after treatment with isorhamnetin for 72 h. Cytotoxicity of the flavonols on tumor cells depends on cellular accumulation of the drugs. The amount of isorhamnetin accumulated in BEL-7402 cells was assayed by high-performance liquid chromatography (HPLC) and showed that isorhamnetin could permeate the cell membrane into the cell. Staining with Hoechst 33258 showed fragmentation and condensation of chromatin in the cell treated with 50 microg ml(-1) isorhamnetin for 48 h. Flow cytometric analysis was performed to determine hypodiploid cells. The results of flow cytometry assay indicated that the percentage of hypodiploid BEL-7402 cells were 13.77+/-1.05% after 48 h treatment with 50 microg ml(-1) isorhamnetin. The treatment resulted in the appearance of a hypodiploid peak (sub-G(0)/G(1) peak), probably due to the presence of cells in apoptosis and apoptotic bodies with DNA content less than 2n. To our knowledge, this is the first report against human hepatocellular carcinoma cells (BEL-7402) of isorhamnetin.

Antineoplastic Agents, Phytogenic↗

PubMed2006

A new phenanthrene with a spirolactone from Dendrobium chrysanthum and its anti-inflammatory activities.

Investigation of phenolic patterns from the stems of Dendrobium chrysanthum by HPLC-PDA-MS has led to the isolation of a new phenanthrene derivative with a spirolactone ring, dendrochrysanene (1), that proved to suppress the mRNA level of TNF-alpha, IL8, IL10, and iNOS in murine peritoneal macrophages. The structure of 1 was characterized on the basis of various NMR (1H, 13C, 1H-1H COSY, HMQC, and HMBC), mass spectrometry, and X-ray crystal diffraction data.

Animals↗

PubMed2006

A novel bieremophilanolide from Ligularia lapathifolia.

A new bieremophilanolide was isolated from the roots and rhizomes of Ligularia lapathifolia. Its structure was established as 8,8'-bi-3beta-angeloyloxy-eremophil-7(11)-en-12,8alpha(14beta,6alpha)-diolide (1) by IR, MS, 1D, and 2D NMR experiments.

Asteraceae↗

PubMed2006

Andrographolide inhibits the production of TNF-alpha and interleukin-12 in lipopolysaccharide-stimulated macrophages: role of mitogen-activated protein kinases.

Andrographolide has been reported to possess a variety of pharmacological activities. In this study, we have investigated the effect of andrographolide on the production of TNF-alpha and IL-12 (Interleukin-12) in murine peritoneal macrophages. Andrographolide decreased TNF-alpha, IL-12a and IL-12b at mRNA level, and reduced the production of TNF-alpha and IL-12p70 proteins in a concentration-dependent manner. Furthermore, we have found that addition of andrographolide inhibited the activation of ERK1/2 MAP kinase, but not that of JNK, p38 or NF-kappaB. These results suggested that andrographolide inhibit LPS-induced production of TNF-alpha via suppression of the ERK1/2 signaling pathway.

Animals↗

PubMed2006

[Studies on chemical constituents in stem of Dendrobium chrysotoxum].

OBJECTIVE: To investigate the chemical constituents of Dendrobium chrysotoxum. METHOD: The chemical constituents were isolated by various column chromatographic methods and structurally elucidated by spectral evidences. RESULT: Ten compounds were obtained and identified as (+)-syringare sinol (1), 5alpha, 8alpha-epidioxy-24( R)-methycholesta-6, 22-dien-3beta-ol (2), trans-3-(4-hydroxy-3-methoxyphenyl)-acrylic acid octacosyl ester (3), defusin (4), 3, 4-dihydroxy benzoic acid (5), 3, 4-dimethoxy-benzoic acid (6), vanillic acid (7), 3, 4-dimethoxy-benzoic acid methyl ester (8), 3, 5-dibromo-2-aminobenzaldehyde (9), heptadecanoic acid 2, 3-dihydroxy-propyl ester (10). CONCLUSION: Compounds 1, 2 and 6-10 were isolated from this plant for the first time.

Dendrobium↗

PubMed2006

[Study on antithrombotic fraction of Herba Siegesbeckiae].

OBJECTIVE: To analyze the compounds of antithrombotic fraction of Herba Siegesbeckiae. METHODS: The compound type and the content of kirenol of antithrombotic fraction were analyzed by LC/MS and HPLC. RESULTS: In the antithrombotic fraction, the compound type was diterpenoids, and the content of kirenol more than 10 percent. CONCLUSION: Diterpenoids were main compounds in the antithrombotic fraction of Herba Siegesbeckiae.

Asteraceae↗

PubMed2006

[Medicinal species of genus Polygonum s. lat. distributed in Anhui Province].

OBJECTIVE: To clarify the resource of medicinal plants of genus Polygonum s. lat. distributed in Anhui Province. METHOD: Conducting field investigation and consulting related specimens and data. RESULT AND CONCLUSION: The distribution, growing environment and medicinal use of 32 taxa have been clarified. A scientific basis for further study for these medicinal plants has been provided.

Analgesics, Non-Narcotic↗

PubMed2006

[Evaluation of antioxidant activity of Radix Linderae and other two Chinese drugs using TLC-bioautography].

AIM: To evaluate the antioxidant capacity and quality of traditional Chinese medicines using TLC-bioautography. METHODS: Two chromatograms of each crude drug sample were obtained, after developing, by spraying with 1,1-diphenyl-2-picrylhydrazyl (DPPH) solution in ethanol and classical stained reagents, separately. The images sprayed with DPPH solution were captured under light after the plates were heated at 40 degrees C for 30 min, and scanned using video scan software to get peak areas of active compounds. RESULTS: Total peak areas of the spots on TLC were calculated to evaluate the antioxidant capacity of the tested crude drugs from different habitats and sources. The results indicated that Radix Linderae cultivated in Tiantai (Zhejiang province), Cortex Magnoliae Officinalis cultivated in Liangshan (Sichuan province), and Fructus Perillae acquired in Shanghai have the highest scavenging properties towards DPPH in their respective TLC-autographic assays. Norisoboldine, magnolol and honokiol, luteolin, apigenin and an unknown compound "U" proved to be the major antioxidant components in the corresponding crude drugs as they contribute the dominating peak areas to the total ones. CONCLUSION: TLC-bioautography can not only be used for screening of the components with antioxidant potency but also for the purpose of quality evaluation of traditional Chinese medicines at the same time, and the method proved to be selective, simple and reproducible.

Alkaloids↗

PubMed2006

[Advances in research of chemical constituents and pharmacological activites of Ephedra].

The collected information is an attempt to cover the more recent developments in the phytochemistry and pharmacology of this genus. During the past years, alkaloids, flavonoids, volatile oils, organic acids, polysaccharides, tannins and phenolic constituents have been isolated from Ephedra. Pharmacological studies are described according to hypoglycemic effects, anticoagulated blood properties, depressurization, immunosuppressive activity, antioxidation and antivirus activity and so on. The information summarized here is intended to provid a rational foundation for the futher development and utilization of Ephedra which is rich in China.

Alkaloids↗

PubMed2006

[Studies on HPLC fingerprint of cortex moutan].

OBJECTIVE: To establish a HPLC fingerprint for quality evaluation of Cortex Moutan. METHOD: The HPLC chromatographic fingerprinting of 30 lots of Cortex Moutan was established and major peaks were identified by LC-MS and MS-MS. RESULT: The HPLC fingerprint of Cortex Moutan was established, showing 15 characteristic peaks. The areas of these peaks were found to complied with the following rule: paeonol > 1, 2, 3, 4, 6-penta-O-galloyl-glucos > methyl gallate > galloylpaeoniflorin > gallic acid > oxypaeoniflorin > other compounds. CONCLUSION: The chromatographic fingerprinting of Cortex Moutan with high specificity can be used to control its quality and monitor lot to lot consistency.

Acetophenones↗

PubMed2006

[Studies on dynamic variation of six isoflavones contents in rhizomes of Belamcanda chinensis].

OBJECTIVE: To study the monthly dynamic variation of the contents of six isoflavones in the rhizomes of Belamcanda chinensis cultivated in Nanjing, and decide optimum harvesting times. METHOD: HPLC method was used to determine the contents of six isoflavones in the samples collected at different times. RESULT: It was shown that the total contents of six isoflavones in the rhizomes of B. chinensis collected in April were the highest. CONCLUSION: The most optimum collecting time of rhizomes of B. chinensis cultivated in Nanjing should be in April.

Chromatography, High Pressure Liquid↗

PubMed2006

[Studies on chemical constituents in roots of Rumex dentatus].

OBJECTIVE: To investigate the active constituents from Rumex dentatus. METHOD: Compounds were isolated by silica gel, Sephadex LH -20 and ODS column chromatography and identified by chemical and spectroscopic methods. RESULT: Ten compounds were obtained and identified as helonioside A (1), gallic acid (2), isovanillic acid (3), p-hydroxycinnamic acid (4), succinic acid (5), n-butyl-beta-D-fructopyranoside (6), quercetin (7), hexadecanoic acid 2, 3-dihydroxy propyl ester (8), beta-sitosterol (9) and daucosterol (10). CONCLUSION: Compounds 1, 3-6 and 8 were isolated from the genus of Rumex for the first time.

Fructose↗

PubMed2005

A validated stability-indicating HPLC with photodiode array detector (PDA) method for the stress tests of Monascus purpureus-fermented rice, red yeast rice.

A stability-indicating reversed phase high-performance liquid chromatography (RP-HPLC) with photodiode array (PDA) detection method was developed and validated for the assay of monacolin series compounds including monacolin K, L, J and their hydroxyl acid forms as well as dehydroxymonacolin K simultaneously in Monascus purpureus-fermented rice, red yeast rice. Well-resolved peaks of seven main compounds of monacolin family were profiled on a C(18) reverse-phase column using a linear gradient of 0.1% trifluoroacetic acid and acetonitrile as the mobile phase, and the detection wavelength was set at 237nm. The method was validated with respect to specificity, chromatographic parameters, linearity, precision, accuracy, limits of detection and quantitation. The stability stress testing for fermented red yeast rice powder was carried out to show the effects of high temperature (80 degrees C), high humidity at room temperature (92.5% RH, 25 degrees C), high humidity at high temperature (75% RH, 60 degrees C) and light (sunlight) in solid state. The results exhibited that monacolins decreased significantly under the conditions of high humidity at high temperature (75% RH, 60 degrees C) and sunlight. Monacolin K and its hydroxyl acid form would be dehydrolyzed and turned to dehydromonacolin K at high temperature (80 degrees C) while the monacolin K, J and L would be transformed into their corresponding hydroxyl acid forms under the condition of high humidity (92.5% RH, 25 degrees C). The indication is that monacolins in red yeast rice powder are light-sensitive and thermal-sensitive. Therefore, it has been suggested that the preparations containing monacolins be stored in the place of cool and lightproof. The proposed degradation pathways were discussed as well. The multi-components assay for stability of botanical products could provide much more information than the normal marker-orientation method.

Chromatography, High Pressure Liquid↗

PubMed2005

Andrograpanin, a compound isolated from anti-inflammatory traditional Chinese medicine Andrographis paniculata, enhances chemokine SDF-1alpha-induced leukocytes chemotaxis.

Andrographis paniculata is a traditional Chinese medicine (TCM) that has been effectively used for treatment of infection, inflammation, cold, fever, and diarrhea in China. However, mechanism of its therapeutic function is not well known. In the current study, we showed one of its components, andrograpanin, could enhance chemokine stromal cell-derived factor-1alpha (SDF-1alpha) induced chemotaxis in Jurkat and THP-1 cells. Further study demonstrated that this kind of effect was CXC chemokine receptor-4 (CXCR4) specific, since andrograpanin could not enhance other chemokines, such as RANTES, monocyte chemotactic protein-1 (MCP-1), etc. induced cell chemotaxis. Mechanisms of andrograpanin exerting its effect were not directly in the receptor and G protein coupling level because it had no effect on the binding of SDF-1 to CXCR4, SDF-1 induced G protein activation and adenyly cyclase inhibition. However, receptor internalization might be involved, since we found it significantly reduced SDF-1alpha-induced CXCR4 internalization.

Adenylyl Cyclase Inhibitors↗

PubMed2005

Bi-bicyclic and bi-tricyclic compounds from Dendrobium thyrsiflorum.

One bi-bicyclic and two bi-tricyclic derivatives of coumarin-benzofuran, phenanthrene-phenanthrene and phenanthrene-phenanthraquinone, along with seven known compounds, were isolated from stems of Dendrobium thyrsiflorum Rchb.f. (Orchidaceae). On the basis of chemical, NMR (1H, 13C, HMQC, HMBC and NOESY) and mass spectrometry data, their structures were elucidated as denthyrsin [3-(5',6'-dimethoxybenzofuran-2'-yl)-6,7-dimethoxy-2H-chromen-2-one; 1], denthyrsinol (4,5'-dimethoxy-[1,1']biphenanthrenyl-2,5,4',7'-tetraol; 2), and denthyrsinone (7,4',7'-trihydroxy-2,2',8'-trimethoxy-[5,1']biphenanthrenyl-1,4-dione; 3). Compounds 1-3 and denthyrsinin (1,5,7-trimethoxyphenanthrene-2,6-diol; 4) showed significant cytotoxic activities against Hela (13.5, 9.3, 9.9 and 2.7 microM, respectively), K-562 (0.45, 1.6, 6.0 and 2.3 microM, respectively) and MCF-7 (18.1, not tested, 3.5 and 4.8 microM, respectively) cell lines.

Animals↗

PubMed2005

Pyrrolizidine alkaloid clivorine induces apoptosis in human normal liver L-02 cells and reduces the expression of p53 protein.

Clivorine, a pyrrolizidine alkaloid, is a potent toxic compound extracted from a Chinese medicinal plant Ligularia hodgsonii Hook. We have previously shown that clivorine inhibited human normal liver L-02 cells proliferation and induced p38 mitogen-activated protein kinase phosphorylation. The aim of this study is to further observe the mechanism of clivorine-inhibited L-02 cells growth. In this paper we show here that clivorine can induce apoptosis in L-02 cells, reduce the expression of p53 protein but has no effect on the expression of Bcl-2 protein, and clivorine also induces the cleavage of the poly(ADP-ribose) polymerase in L-02 cells. Our results suggest that the anti-proliferative function of clivorine in L-02 cells may be due to its inducing cell apoptosis, and clivorine-induced cell apoptosis is independent of p53 protein.

Apoptosis↗