Antiviral Activity of Benzavir-2 against Emerging Flaviviruses

Gwon, Yong-Dae; Strand, Mårten; Lindqvist, Richard; Nilsson, Emma; Saleeb, Michael; Elofsson, Mikael; Överby, Anna K.; Evander, Magnus

The inhibitory effect of the compounds ( Figure 1A ) on rZIKV-ZsGreen expression was assessed in a dose-dependent manner ( Figure 2 and Table 1 ). Benzavir-2 displayed the highest potency among the compounds, with an EC 50 value of 0.8 ± 0.1 µM (EC 90 of 1.2 ± 0.3 µM). The EC 50 value of ribavirin was 45.5 ± 13.5 µM (EC 90 of 114.5 ± 18.0 µM), while no antiviral activity of favipiravir was detected in the tested concentration range (highest concentration was 100 µM). Benzavir-1, the precursor to benzavir-2, displayed at a lower potency (EC 50 of 3.0 ± 0.1 µM and EC 90 of 3.3 ± 0.1 µM) compared to benzavir-2, while the two structurally-related analogs, 17d and 35f, showed no antiviral activity or reduced potency (EC 50 of 6.1 ± 0.1 µM and EC 90 of 14.9 ± 0.9 µM, respectively). The results for benzavir-1, benzavir-2, 17d, and 35f are in line with our previous observations with herpes simplex virus (HSV) [18] , human adenovirus (HAdV) [17] , and Rift Valley fever virus (RVFV) [19] .