Toll-like receptor 4/nuclear factor-κB signaling pathway is involved in ACTG-toxin H-mediated anti-inflammatory effect.

ACTG-toxin H (AH) originates from Alternaria sp. In this study, we explored the molecular mechanism underlying the anti-inflammatory properties of AH. Treatment with AH inhibited lipopolysaccharide (LPS)-induced interleukin-6, IL-1ß, inducible nitric oxide synthase, and cyclooxygenase-2 expression and nitric oxide production. Furthermore, AH inhibited LPS-induced P38 MAPK and Akt activation in RAW264.7 cells. Electrophoretic mobility shift assays (EMSAs) showed that AH inhibited LPS-induced nuclear factor-κB (NFκB) DNA-binding activity. Using transfection assay and measurement of an NFκB-sensitive promoter region, we found that transfection of toll-like receptor 4 (TLR4) increased LPS-induced NFκB transcription activity in 293T cells. AH significantly blocked LPS-induced NFκB activation in TLR4-transfected cells. Taken together, our data indicated that anti-inflammatory properties of AH resulted from the inhibition of proinflammatory cytokines and enzyme production via the TLR4/NFκB signaling pathway.

Toll-like receptor 4-mediated immunoregulation by the aqueous extract of Mori Fructus.

The aqueous extract of Mori Fructus (MF) exerts a change of phenotype and a cytoprotective effect in macrophages. The present study was carried out to investigate the immunomodulating activity of MF on the expression of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), co-stimulatory molecules and also interferon-gamma (IFN-gamma) in macrophages and splenocytes. Toll-like receptor 4 (TLR4) is a promising molecular target for immune-modulating drugs. It was hypothesized that one possible upstream signaling pathway leading to immunoregulation of MF may be mediated by TLRs. Multiple signaling molecules (NF-kappaB, ERK1/2, p38 and JNK) of the TLR4 signaling pathway were also detected. It was found that MF increased NO production and TNF-alpha secretion in RAW 264.7 and peritoneal macrophages, co-stimulatory molecules expression in peritoneal macrophages and IFN-gamma expression in splenocytes. Further studies indicated that MF could significantly induce the phosphorylation of signal molecules of MAPKs and the degradation of IkappaBalpha which finally led to the activation and nuclear translocation of nuclear factor-kappaB (NF-kappaB) for the target gene expression. All those notions disclosed that the aqueous extract MF is a new TLR4 activator, which induces a Th1 immune response as a consequence of induction of cytokines secretion, especially TNF-alpha and IFN-gamma.

In vitro inhibition of coronavirus replications by the traditionally used medicinal herbal extracts, Cimicifuga rhizoma, Meliae cortex, Coptidis rhizoma, and Phellodendron cortex.

BACKGROUND: A search for new anti-coronaviral drugs to treat coronaviral infections was motivated by an outbreak of severe acute respiratory syndrome (SARS). OBJECTIVES: In order to find drugs that treat coronavirus infections, including SARS, we screened traditional medicinal herbal extracts and evaluated their antiviral activities on coronavirus replication. STUDY DESIGN: We employed a plaque assay to evaluate the effect of 22 medicinal herbal extracts on virus replication. We determined the 50% effective concentration (EC50) of each extract that was necessary to inhibit the replication of mouse hepatitis virus A59 (MHV-A59); we also determined 50% cytotoxic concentrations (CC50) for each extract. Northern and Western blot analyzes were performed to investigate antiviral activity in MHV-infected DBT cells, including virus entry, viral RNA and protein expression, and virus release. Coronavirus specific inhibition was also demonstrated using porcine epidemic diarrhea virus (PEDV). RESULTS: Cimicifuga rhizoma, Meliae cortex, Coptidis rhizoma, Phellodendron cortex and Sophora subprostrata radix decreased the MHV production and the intracellular viral RNA and protein expression with EC50 values ranging from 2.0 to 27.5 microg/ml. These extracts also significantly decreased PEDV production and less dramatically decreased vesicular stomatitis virus (VSV) production in vitro. CONCLUSIONS: The extracts selected strongly inhibited MHV replication and could be potential candidates for new anti-coronavirus drugs.

Scopoletin suppresses pro-inflammatory cytokines and PGE2 from LPS-stimulated cell line, RAW 264.7 cells.

Scopoletin (1-50 microg/ml) inhibited the release of PGE2, TNF-alpha, IL-1beta and IL-6 and suppressed the expression of COX-2 in a concentration-dependent manner. These results suggest that scopoletin might suppress the production of such pro-inflammatory cytokines and exert inhibitory activity on LPS-induced PGE2 production through the depression of COX-2 expression.

Anti-hypertensive effect of water extract of danshen on renovascular hypertension through inhibition of the renin angiotensin system.

A study was designed to elucidate the mechanism of anti-hypertensive effects of danshen in the two-kidney, one clip (2K1C) Goldblatt renovascular hypertensive model, which is the renin-angiotensin system (RAS)-dependent hypertensive model. We investigated the effects of water extracts of danshen on the angiotensin converting enzyme (ACE) activities, systolic blood pressure (SBP), and hormone levels in the plasma of 2K1C rats. ACE activity was inhibited by the addition of danshen extract in a dose-dependent manner. SBP was decreased significantly after administration of danshen extract in 2K1C, whereas plasma renin activity (PRA) was not changed. The plasma concentration of aldosterone (PAC) was decreased significantly in 2K1C group administered with Danshen extract, whereas the plasma concentration of ANP was increased by administration of danshen extract for three weeks. These results suggest that danshen has an anti-hypertensive effect through the inhibition of ACE, an essential regulatory enzyme of RAS.

Tongkyutang inhibits mast cell-dependent allergic reactions and inflammatory cytokines secretion.

BACKGROUND: Tongkyutang (TKT) is an Oriental herbal prescription, which has been successfully applied for the treatment of allergic disorders, mainly allergic-rhinitis in clinical medicine. However, its effect in experimental models remains unknown. METHODS: In a mouse model, the role of TKT was examined in mast cell-dependent allergic reactions and secretion of inflammatory cytokines. RESULTS: TKT concentration-dependently inhibited the ear-swelling response induced by intradermal injection of compound 48/80. TKT inhibited the compound 48/80-induced degranulation from mast cells in ear tissue. TKT dose-dependently inhibited the histamine release from the rat peritoneal mast cells by compound 48/80. TKT also showed inhibition of anti-dinitrophenyl IgE antibody-induced passive cutaneous anaphylaxis reaction by oral administration. Furthermore, TKT inhibited both IL-1beta and TNF-alpha secretion induced by PMA and A23187, respectively. CONCLUSIONS: Our findings provide evidence that TKT inhibits the mast cell-dependent allergic reactions and inflammatory cytokines secretion.