Qingdai-Mabo (QM), a traditional Chinese herbal formula composed of medicinal herb and fungus, has been used for treatment of
cough and
viral pneumonia. However, the underlying mechanism and bioactive components against anti-influenza A virus remain unclear. In the present study,
ethyl acetate (EA) extract of QM decoctions was tested for its biological activity against
acute lung injury (ALI) and its main components were identified using UPLC-MS/MS. In total, 18 bioactive components were identified, including 2-Methylquinaozlin-4(3H)-one (C1), which showed significant
antiviral activity in vitro with an IC50 of 23.8 μg/mL. Furthermore, we validated the efficacy of C1 in ameliorating ALI lesions and
inflammation in influenza A virus-infected mice. The results showed that C1 significantly reduced the lung index, downregulated
neuraminidase (NA) and
nucleoprotein (NP), and decreased the expression of pro-inflammatory molecules IFN-α, TNF-α, MCP-1,
IL-6, and IL-8; however, they enhanced levels of
IL-10 and IFN-γ in lung homogenate from mice infected by influenza A virus. In addition, C1 inhibited the recruitment of macrophages. These in vitro and in vivo studies suggested that the significant anti-influenza A virus activity contributed to its curative effect on lesions and
inflammation of
viral pneumonia in mice. Given its potential
antiviral activity against influenza A virus, C1 is determined to be a main active component in the EA extract of QM. Taken together, the
antiviral activity of C1 suggests its potential as an effective treatment against
viral pneumonia via the inhibition of virus replication, but the mechanism C1 on
antiviral research needs to be explored further.