Study On The Activity And Mechanism Of Two Types Of Natural Products Against H1N1 Influenza Virus In Vitro

Influenza is an acute respiratory infection caused by influenza viruses,which has obvious seasonal and epidemic characteristics.Vaccines and antiviral drugs remain the most effective options for preventing and treating influenza.However,influenza vaccines must be matched to pandemic influenza viruses,and the high mutation of the virus leads to its resistance to some drugs.Therefore,it is urgent to search for novel anti-influenza drugs.In this thesis,MDCK cells infected with A/WSN/33/2009（H1N1）or A/PR/8/34（H1N1）were used as an anti-influenza activity screening model in vitro,and a total of 248 compounds,isolated from the traditional Chinese herbal medicines such as Valeriana jatamansi Jones,Paeoniae radix rubra,Tripterygium wilfordii Hook.f,Osmunda japonica Thunb,Pogostemon cablin Benth,Valeriana officinalis Linn were screened.Thirteen compounds,including phenylpropanoids,diterpenoids,cyclic enol ether terpenoids,sesquiterpenoids and flavonoids,were found to have anti-influenza virus effects.Two types of compound from 13 active compounds were selected for in vitro anti-influenza virus mechanism research.Compound 8,a phenylpropanol compound isolated from Valeriana jatamansi Jones and Paeoniae radix rubra,showed significant anti WSN Influenza virus activity(EC₅₀:19.83±2.03μmol/L).Studies have found that compound 8 exerted inhibitory effects mainly at the replication and release stages of influenza virus life cycle,molecular docking simulation confirms that NP and NA may be its anti-influenza virus targets.It also significantly inhibited the expression of macrophage chemokines and inflammation-related proteins induced by influenza virus.The anti-WSN influenza virus mechanism of another diterpene compound 14,isolated from Tripterygium wilfordii Hook.f,were also investigated.Compound 14 exhibited wonderful inhibitory activity against influenza virus(EC₅₀:23.28±1.72μmol/L)and had low toxicity(CC₅₀>200).Further research has found that 14 may affect the replication process of influenza viruses.In addition,14downregulated influenza virus-induced macrophage inflammatory reaction in a dose-dependent manner by inhibiting MAPK signaling pathway.In conclusion,compound 14 not only achieves anti-influenza virus effects by affecting the replication process of the influenza virus,but also has a mitigating effect on the immune damage caused by influenza virus.