Protective effect of a polyphenolic rich extract from Magnolia officinalis bark on influenza virus-induced pneumonia in mice

Ethnopharmacological relevance: Magnolia officinalis bark is used in traditional Chinese medicine for the treatment of cough, colds, fever, chronic bronchitis and stomach ailments. Aim of the study: To investigate therapeutic effects of polyphenol rich extract from M. officinalis bark (MPE) in influenza virus A-infected mice, and to provide evidence for the inflammation response and immunomodulatory potential during infection. Materials and methods: Mice were infected with influenza virus A (IVA) and MPE at doses of 10 and 20 mg/kg were orally administrated daily for 5 days after challenge. The levels of serum L-6 and TNF-alpha were determined by ELISA while protein expressions of NF-kappa B and TLR3 were detected by western blotting analysis. Results: MPE exhibited significant therapeutical effects on reducing levels of serum NO, IL-6 and TNF-alpha, inhibiting pneumonia, decreasing lung viral titers and sensitizing IVA-induced apoptosis through down-regulation of NF-kappa B and TLR3 protein expression in the lung tissue of IVA-infected mice. Conclusions: MPE could exhibit preventive and therapeutical effects on IVA-infected mice as a suppressor of the production of inflammatory mediators, NO and pro-inflammatory cytokines, TNF-alpha and IL-6. These effects appeared to be mediated, at least in part, by an inhibition of TLR3 and NF-kappa B activation. Therefore. MPE could provide a safe and effective therapeutic approach for influenza and its subsequent viral pneumonia. (C) 2010 Elsevier Ireland Ltd. All rights reserved.