Ellagic acid

Oseltamivir carboxylate was purchased from AOBIOUS Inc. (Gloucester, MA, USA). Gallic and protocatechuic acids were purchased from Sigma-Aldrich (St. Louis, MO, USA). Corilagin, GN, ellagic acid, kaempferitrin, kaempferol-7-O-rhamnoside, quercetin, and kaempferol were purchased from ChemFaces (Wuhan, China), and antibodies targeting influenza proteins (PA, HA, NA, NP, PB1, PB2, M1, M2, NS-1, and NS-2) were procured from GeneTex (San Antonio, TX, USA). Anti-β-actin was purchased from Cell Signaling Technology (Cell Signaling Technology, Boston, MA, USA).

HPLC analysis was performed using a Waters e2695 liquid chromatography system (Waters Co., Milford, MA, USA) equipped with a Waters 2998 photodiode array detector. All analyses were performed using Empower software v3 (Waters Co., Milford, MA, USA). Chromatographic separation was conducted on a Waters Xselect C18 column (250 mm × 4.6 mm; 5 μm, Milford). An elution system with 0.1% aqueous trifluoroacetic acid (A) and acetonitrile (B) was used at the following gradients: 0–5 min, 10%–20% B; 5–40 min, 20%–45% B. After each analysis, the equilibration time used to return to the initial mobile phase composition (10% B) was 8 min. The flow rate of the mobile phase was 1.0 mL/min, and the injection volume was 20 µL. The detection wavelength selected for quantitative analysis of the samples was 250 nm. SHE was dissolved in methanol (10 mg/mL) and passed through 0.2 μm syringe filters before HPLC analysis. Two reference compounds with > 98% purity were used for the analysis; ellagic acid was purchased from ChemFaces Biochemical (Wuhan, China), and quercetin was purchased from Biopurify Phytochemicals (Chengdu, China).