Baicalin from Scutellaria baicalensis blocks respiratory syncytial virus (RSV) infection and reduces inflammatory cell infiltration and lung injury in mice

Abstract

The roots of Scutellaria baicalensis has been used as a remedy for inflammatory and infective diseases for thousands of years. We evaluated the antiviral activity against respiratory syncytial virus (RSV) infection, the leading cause of childhood infection and hospitalization. By fractionation and chromatographic analysis, we determined that baicalin was responsible for the antiviral activity of S. baicalensis against RSV infection. The concentration for 50% inhibition (IC50) of RSV infection was determined at 19.9 ± 1.8 μM, while the 50% cytotoxic concentration (CC50) was measured at 370 ± 10 μM. We then used a mouse model of RSV infection to further demonstrate baicalin antiviral effect. RSV infection caused significant lung injury and proinflammatory response, including CD4 and CD8 T lymphocyte infiltration. Baicalin treatment resulted in reduction of T lymphocyte infiltration and gene expression of proinflammatory factors, while the treatment moderately reduced RSV titers recovered from the lung tissues. T lymphocyte infiltration and cytotoxic T lymphocyte modulated tissue damage has been identified critical factors of RSV disease. The study therefore demonstrates that baicalin subjugates RSV disease through antiviral and anti-inflammatory effect.

Rhein Suppresses Lung Inflammatory Injury Induced by Human Respiratory Syncytial Virus Through Inhibiting NLRP3 Inflammasome Activation via NF-κB Pathway in Mice

“…Therefore, it is necessary to find low-toxic and effective drugs to treat excessive inflammation caused by virus. The excessive inflammation caused by RSV infection is worthy of attention (Shi et al, 2016;Mosquera et al, 2018). There is growing evidence that certain natural products may be able to keep mice away from viral pneumonia.…”

Antiviral effect of phytochemicals from medicinal plants: Applications and drug delivery strategies

“…For example, out of 22 different flavonoids, six phytochemicals (apigenin, baicalein, biochanin A, kaempferol, luteolin, naringenin) were active against the avian influenza H5N1 virus in human lung epithelial (A549) cells through inhibiting nucleoprotein production [67]. Baicalin (the glucuronide of baicalein) was also active against a wide range of viruses, including enterovirus [68], dengue virus [69], respiratory syncytial virus [70], Newcastle disease virus [71], human immunodeficiency virus [72], and hepatitis B virus [73], and different mechanisms were suggested for its antiviral actions. For example, baicalin inhibits the production of HBV, the templates for viral proteins and HBV-DNA synthesis [73], and decreases IL-6 and IL-8 production without affecting IP-10 levels, as shown in a study on avian influenza H5N1 virus [67].…”

Standardized Herbal Formula PM014 Inhibits Radiation-Induced Pulmonary Inflammation in Mice

“…Herbs of seven species in PM014 were also evaluated in regards to their therapeutic effects. Among individual herbs, Fruit of Schizandra chinensis and Root of Scutellaria baicalensis showed some attenuation effects on X-ray induced lung inflammation in the mice (Supplementary Figure S2), compared to other herbs, which were reported to exhibit medicinal effects such as renal protective and anti-inflammatory effects, respectively 36,45,46 . Although the therapeutic effective components of PM014 have not yet been fully characterized, we could suggest that PM014 was the most ef-6fective therapeutic agent, compared to the individual herbs, and that PM014 is likely to achieve a more helpful effect based on the synergy of its individual compontents.…”