Fig. 1.

Cytotoxicity assay of five chemical compounds. A549 cells were infected with or without virus at an MOI of 1.5 at various concentrations of each chemical compound. Cell viability was measured after 3 days by using XTT viability assay. Five chemical compounds included (A) catechin, (B) gallic acid, (C) kaempferol, (D) quercetin, and (E) rutin. To normalize, the relative viability in untreated cells was set as 100%. The results represented the mean ± SD of three independent assays. Asterisk and pound (*, ^#) indicate significant difference (p < 0.05) compared to the control group without or with the treatment of virus infection, respectively.