Tamarix hohenackeri Bunge exerts anti-inflammatory effects on lipopolysaccharide-activated microglia in vitro.

Tamarix species are well known as the main host plants of Herba Cistanches, a valuable Traditional Chinese Medicine. They are also traditional medicinal plants themselves and are used to treat spleen problems, leucoderma and ocular conditions. The aim of the present study was to investigate the anti-inflammatory effect of Tamarix hohenackeri Bunge. In the present study, BV-2 microglial cells were used and stimulated with lipopolysaccharide (LPS). Cell viability was tested using the MTT assay. The release of nitric oxide (NO) was determined using the Griess assay. The mRNA level of inducible nitric oxide synthase (iNOS), tumor necrosis factor α (TNF-α), interleukin (IL)-1β and IL-6 were investigated by quantitative real-time PCR (qRT-PCR). The protein levels of phosphorylated of IκBα, ERK and MEK, as well as the cytoplasmic and nuclear NF-κB p65 were tested by Western blot analysis. The translocation of the NF-κB p65 subunit from the cytosol to the nucleus was investigated by immunofluorescence staining. Ethyl acetate (EtOAc) extract of Tamarix hohenackeri Bunge significantly inhibited the release of NO. Phytochemical research was performed to produce 13 main constituents. Among them, compounds 6, 7, 10 and 13 were identified to be the effective components with anti-inflammatory activity. These compounds significantly inhibited the production of NO by LPS-activated BV-2 microglial cells. qRT-PCR showed that compounds 6 and 7 significantly suppressed the LPS-induced transcription of genes encoding pro-inflammatory mediators, including iNOS, TNF-α, IL-1β and IL-6. Western blot analysis showed that compound 7 inhibited the LPS-induced phosphorylation of IκBα and antagonized the LPS-induced reduction of cytoplasmic NF-κB p65 and the increase of nuclear NF-κB p65. Immunofluorescence staining showed that nuclear translocation of NF-κB p65 was suppressed by compound 7. Western blot analysis showed that compound 7 inhibited the LPS-induced phosphorylation of ERK and MEK. The present study revealed, for the first time, the effective anti-inflammatory agents from T. Hohenackeri. Compound 7 exerted potent anti-inflammatory effects and its underlying mechanism may be associated with its capacity to inhibit NF-κB signaling pathway and the MEK/ERK activation in activated microglia. The compound may be potential candidate therapeutic agent for neurodegenerative diseases.

Chen R ，Yang Y ，Xu J ，Pan Y ，Zhang W ，Xing Y ，Ni H ，Sun Y ，Hou Y ，Li N ... -  《-》

Aspirin-triggered lipoxin A4 attenuates LPS-induced pro-inflammatory responses by inhibiting activation of NF-κB and MAPKs in BV-2 microglial cells.

Wang YP ，Wu Y ，Li LY ，Zheng J ，Liu RG ，Zhou JP ，Yuan SY ，Shang Y ，Yao SL ... -  《Journal of Neuroinflammation》

Attenuation of inflammatory-mediated neurotoxicity by Saururus chinensis extract in LPS-induced BV-2 microglia cells via regulation of NF-κB signaling and anti-oxidant properties.

Kim BW ，Koppula S ，Park SY ，Hwang JW ，Park PJ ，Lim JH ，Choi DK ... -  《BMC Complementary and Alternative Medicine》

Okanin, effective constituent of the flower tea Coreopsis tinctoria, attenuates LPS-induced microglial activation through inhibition of the TLR4/NF-κB signaling pathways.

Hou Y ，Li G ，Wang J ，Pan Y ，Jiao K ，Du J ，Chen R ，Wang B ，Li N ... -  《Scientific Reports》

Anti-inflammatory effects of Polygala tenuifolia root through inhibition of NF-κB activation in lipopolysaccharide-induced BV2 microglial cells.

The root of Polygala tenuifolia Willd is a well-known traditional Oriental medicine and has been prescribed for treatment of dysfunction in memorial systems and various brain inflammatory diseases. The present study was designed to validate the anti-inflammatory effects of the water extract of Polygala tenuifolia root (WEPT). The anti-inflammatory properties of WEPT were studied using lipopolysaccharide (LPS)-stimulated murine BV2 microglia model. As inflammatory parameters, the production of nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase (COX)-2, prostaglandin E(2) (PGE(2)), tumor necrosis factor (TNF)-α, and interleukin (IL)-1β were evaluated. We also examined the extract's effect on the activity of nuclear factor-kappaB (NF-κB), and toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (Myd-88) expression. WEPT suppressed LPS-induced production of NO, PGE(2), and expression of iNOS and COX-2 in a dose-dependent manner, without causing cytotoxicity. It also significantly reduced generation of proinflammatory cytokines, including IL-1β and TNF-α. In addition, WEPT suppressed NF-κB translocation by blockade of IkappaB-α (IκB-α) degradation and inhibited TLR4 and Myd-88 expression in LPS-stimulated BV2 cells. These results indicate that the inhibitory effects of WEPT on LPS-stimulated inflammatory mediator production in BV2 microglia are associated with suppression of the NF-κB and toll-like receptor signaling pathways. Therefore, Polygala tenuifolia extracts may be useful in treatment of neurodegenerative diseases by inhibition of inflammatory mediator production in activated microglia.

Cheong MH ，Lee SR ，Yoo HS ，Jeong JW ，Kim GY ，Kim WJ ，Jung IC ，Choi YH ... -  《-》