"3. Results
... Based on the results obtained for HCoV-229E, we performed testing for SARS-CoV-2 inhibition. Treatment of Vero E6 cells with lopinavir/ritonavir and chloroquine was toxic and did not allow for the study of their anti-SARS-CoV-2 effect (Figure 4a). The important cell lysis in culture prevented an accurate measure of SARS-CoV-2 replication, giving partial and unreliable results (Figure 4b). In contrast, the cytotoxicity of resveratrol on Vero E6 cells occurred at concentrations higher than 50 µM (Figure 4a). We observed that resveratrol inhibited SARS-CoV-2 replication by 3 logs at 25 µM (Figure 4b). The percentage of inhibition of SARS-CoV-2 ranges from 0 to 99.93% when increasing the concentration of resveratrol from 0 to 25 µM with an EC90 and EC50 of 11.42 µM and 10.66 µM, respectively (Figure 4). A very limited reduction in cell viability was also observed in Vero E6 cells treated with resveratrol at 50 µM, overall leading to a CC50 = 48.21 µM and an SI of 4.52. The inhibition of SARS-CoV-2 replication we observed in cells treated with resveratrol did not follow the reduction in cell viability and was a genuine anti-SARS-CoV-2 effect of resveratrol in vitro...
4. Discussion
... We observed a significant decrease in SARS-CoV-2 replication under non-cytotoxic doses of resveratrol up to 25 µM in vitro."
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