Yu Ping Feng San, an Ancient Chinese Herbal Decoction, Induces Gene Expression of Anti-viral Proteins and Inhibits Neuraminidase Activity

Yu Ping Feng San (YPFS), a Chinese herbal decoction comprised of Astragali Radix (Huangqi), Atractylodis Macrocephalae Rhizoma (Baizhu) and Saposhnikoviae Radix (Fangfeng), has been used clinically for colds and flus; however, the action mechanism of which is not known. Previously, we had demonstrated that YPFS could modulate inflammatory response and phagocytosis in exerting anti-viral and anti-bacterial effects. Here, we further evaluated the bioactivities of YPFS in gene expression regulated by interferon (IFN) signaling and neuraminidase activity of influenza virus A. Application of YPFS onto cultured murine macrophages, the expressions of mRNAs encoding ribonuclease L (RNaseL), myxovirus (influenza virus) resistance 2 (Mx2), protein kinase R (PKR) and IFN-stimulated gene 15 (ISG15) were induced from 2 to 30 folds in dose-dependent manners. In parallel, the transcriptional activity of IFN-stimulated response element (ISRE), an up stream regulator of the above anti-viral proteins, was also triggered by YPFS treatment. Conversely, YPFS was found to suppress the neuraminidase activity of influenza virus A in cultured epithelial cells, thereby preventing the viral release and spreading. Taken together, YPFS exerted anti-bacterial and anti-viral effects in innate immunity.