The Assessment on Synergistic Activity of Ebselen and Silver Ion Against Yersinia pseudotuberculosis.

Yersinia pseudotuberculosis is a foodborne zoonotic bacterium that is pathogenic to guinea pigs, rabbits, and mice. It also causes pseudotuberculosis in humans. However, it still lacked the scientific basis for control. Here, we found out that Ebselen (EbSe) exhibited synergistic antibacterial activity with silver nitrate (Ag+) against Y. pseudotuberculosis YpIII strain with high efficacy in vitro using UV-visible light absorption spectrum, 5,5'-dithiobis-(2-nitrobenzoic acid), laser scanning confocal microscope, flow cytometry, transmission electron microscopy and Western blotting assays. The depletion of total glutathione (GSH) amount and inhibition of thioredoxin reductase (TrxR) activity in thiol-dependent redox system revealed the destructiveness of EbSe-Ag+-caused intracellular oxidative stress. Furthermore, a YpIII-caused mice gastroenteritis model was constructed. EbSe-Ag+ significantly reduced bacterial loads with low toxicity. It also down-regulated the expression levels of interferon (IL)-1ß and tumor necrosis factor-α, up-regulated the expression level of IL-10 on-site. All the in vivo results demonstrated the antibacterial activity and immune-modulatory property of EbSe-Ag+. Collectively, these results provided academic fundament for further analysis and development of EbSe-Ag+ as the antibacterial agents for pseudotuberculosis control.

The standardized extract of Ziziphus jujuba fruit (jujube) regulates pro-inflammatory cytokine expression in cultured murine macrophages: suppression of lipopolysaccharide-stimulated NF-κB activity.

The fruit of Ziziphus jujuba Mill., known as jujube or Chinese date, is commonly consumed as a health supplement or herbal medicine worldwide. To study the beneficial role of jujube in regulating immune response, we investigated its roles on the expressions of pro-inflammatory cytokines in cultured macrophages. Application of chemically standardized jujube water extract for 24 h stimulated the transcriptional expression of interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α in cultured RAW 264.7 macrophages. In contrast, the pretreatment with jujube water extract suppressed the expression of IL-1ß and IL-6, but not for TNF-α in lipopolysaccharide (LPS)-stimulated macrophages. The IL-1ß and IL-6 cytokines in LPS-induced macrophages were suppressed by jujube water extract in both mRNA and protein levels. In parallel, the inhibition of jujube water extract on the transcriptional activity of nuclear factor-kappa B was revealed in LPS-induced macrophages. These results verified the bidirectional immune-modulatory roles of jujube by regulating the expressions of pro-inflammatory cytokines in macrophages.