Oseltamivir

The neuraminidase (NA) inhibitors oseltamivir carboxylate (oseltamivir) and zanamivir were purchased from MedChem Express. NA susceptibility was determined by fluorometric assay using the substrate 2′-(4-methylumberlliferyl)-α-D-N-acetylneuraminic acid (MUNANA) (Sigma-Aldrich) with additional modifications^{36 (link), 37 (link)}. Influenza viruses were standardized to equivalent NA activity and incubated with 10-fold dilutions of each NA inhibitor (at concentrations of 5 pM to 50 µM). The fluorescence signal of the released 4-methylumbelliferone was measured using a Synergy H1 microplate reader at excitation/emission (Ex/Em) wavelengths of 360 nM/460 nM. The 50% inhibitory concentrations (IC₅₀s) were estimated from dose-response curves by using the sigmoidal, four-parameter logistic non-linear regression equation (in GraphPad Prism v9). The results are representative of the combined values of at least three independent dose-response curves and include influenza A/Denmark/524/2009 (H1N1)pdm09 (NA H275, NAI susceptible), and A/Denmark/528/2009 (H1N1)pdm09 (NA H275Y, NAI reduced susceptibility) as reference viruses.

Human cervix adenocarcinoma (Hela), adenocarcinomic human alveolar basal epithelial cells (A549), human embryonic kidney cells (HEK293T) and human colon adenocarcinoma cell (Caco2) were obtained from American Type Culture Collection and maintained in complete DMEM medium (containing 2 mmol/L l‐Glutamine, 10% foetal bovine serum (Thermo Fisher Scientific), 100 μg/mL streptomycin and 100 U/mL penicillin) at 37°C with 5% CO₂ incubation. The interferon receptor knockout (IFNAR1 KO) HEK293T cells and retinoic acid‐inducible gene‐I (RIG‐I) KO HEK 293T cells were kept in our laboratory. The influenza virus strains used in this study were A/WSN/33(H1N1) (WSN), which was kept in our laboratory. The IAV‐luc (PR8) strain was a gift from Prof. Ling Chen (Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences). AZ and erythromycin were obtained from BBI Life Sciences. Ribavirin was obtained from Solarbio. Oseltamivir, midecamycin, spiramycin, acetylspiramycin, clarithromycin, dirithromycin, tamoxifen, fluvastatin, fluoxetine and clemastine were obtained from MedChemExpress. Amiodarone, amantadine, roxithromycin, delphinidin and bafilomycin A1 were obtained from Sigma. Chloroquine (CQ) and amlodipine (Norvasc) were obtained from Sangon Biotech.

Acetaminophen (catalog number HY-66005), arbidol hydrochloride (HY-14904A), aspirin (HY-14654), atazanavir sulfate (HY-17367A), baloxavir marboxil (HY-109025), daclatasvir (HY-10466), darunavir (HY-17040), dolutegravir (HY-13238), efavirenz (HY-10572), elbasvir (HY-15789), etravirine (HY-90005), galidesivir (BCX4430, HY-18649A), ganciclovir (HY-13637), glecaprevir (HY-17634), hydroxychloroquine (HY-B1370), indomethacin (HY-14397), ledipasvir (HY-15602), lopinavir (HY-14588), losartan (HY-17512), nafamostat mesylate (HY-B0190A), nitazoxanide (HY-B0217), ombitasvir (HY-13997), oseltamivir (HY-13318), penciclovir (HY-17424), perindopril salt (HY-B0130A), raltegravir (HY-10353), remdesivir (GS-5734, HY-104077), rilpivirine (HY-10574), ritonavir (HY-90001), simeprevir (HY-10241), sofosbuvir (HY-15005), and β-d-N4-hydroxycytidine (HY-125033) were purchased from MedChemExpress (Monmouth Junction, NJ, United States). Amodiaquin dihydrochloride dihydrate (A2799), artesunate (A3731), chloroquine phosphate (PHR1258), mefloquine hydrochloride (PHR1705), peramivir trihydrate (SML2486), ribavirin (R9644), teicoplanin (T0578), and toremifene citrate salt (T7204) were purchased from Sigma-Aldrich (St, Louis, Missouri, United States). Favipiravir (T-705) was provided by the Toyama Chemical Co., Ltd. (Japan). The drug solutions were filtered through a 0.22 μM membrane and were stored at −80°C.