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. 2021 Oct 17;14(10):1055. doi: 10.3390/ph14101055

Figure 3.

Figure 3

Binding inhibition of S1 spike protein to human HEK293-hACE2 cells by extract pre-incubation. Cells were pre-incubated for the indicated times with 10 mg/mL T. officinale (TO), its HMW fraction, equal to 10 mg/mL extract (HMW), and 10 mg/mL C. intybus (CI) or solvent control (a.d.) and subsequently treated with His-tagged S1 spike protein for 1 h without a washing step in between at 4 °C. Binding inhibition was assessed using flow cytometry. N = 3, bars are means + SD. Upper left: cytogram of gated HEK-hACE2 cells. Middle: overlay of representative fluorescence intensity histograms for ACE2 surface expression. Upper right: overlay of representative fluorescence intensity histograms for spike-binding inhibition by the extracts or a.d.; positive control: 20 µg/mL soluble hACE2. Cells were stained with anti-His-tag Alexa Fluor 647 conjugated monoclonal antibody; ** p < 0.01. Significance of difference was calculated relative to the solvent control by one-way ANOVA.