| Congresso Brasileiro de Microbiologia 2023 | Resumo: 939-1 | ||||
Resumo:SARS-CoV-2 has become a significant challenge for the world's health systems, affecting around 760 million people, with 6.8 million deaths. Only four antivirals have been approved for emergency use so far and the necessity of studying SARS-CoV-2 in laboratories with biosecurity level III has become a limiting factor in the search for new antivirals. In this study, we aimed to evaluate the antiviral activity of synthetic benzoylguanidine derivatives (RTB18, RTB182, RTB13, and RTB163) selected in silico as potential inhibitors of SARS-CoV-2 RpRd and Mpro. To evaluate the cytotoxicity of the substances, L929 cells were treated and incubated for 72 h with different concentrations of each substance. To verify their antiviral activity, L929 cell line was infected by MHV-3 (murine hepatitis virus-3) and then incubated with varying concentrations of each substance starting from the cytotoxic concentration of 50% (CC50), and the antiviral effect was evaluated at 24 h, and 48 h post-infection (p.i); we also investigated the efficiency of the treatment at different time gaps between the infection and the treatment beginning. Finally, we selected RTB163 and RTB182 to test their synergistic activity by evaluating their combination index (CI) at concentrations below of each isolated inhibition concentration of 50% (IC50). Our results show that the CC50 values found for RTB18 were > 400 μg/mL, RTB13 = 119.91 μg/mL, RTB163 > 400 μg/mL, and 146.49 μg/mL for RTB182. Inhibition of the viral load was detected when infected L929 cells were treated with RTB18 at concentrations of 400, 200, and 100 μg/mL by more than 90% in 24 h p.i (IC50 75.79 μg/mL; SI > 5.28); RTB182 at 50 and 25 μg/mL inhibited above 90% at 24 h p.i (IC50 6.36 μg/mL; SI 23.03); RTB13 at 100 and 50 μg/mL inhibited 100% in 24 h p.i (IC50 21.3 μg/mL; SI 5.63); RTB163 at 25, 12.5 and 6.25 μg/mL inhibited viral load at values close to 90% in 24 h p.i (IC50 5.41 μg/mL; SI > 73.93). All the substances evaluated were able to decrease viral load when the treatment started at 12 h p.i. The therapy with RTB163 and RTB182 in MHV-3 infected cells was able to inhibit 99.9% of viral load at 24 h p.i in lower concentrations when compared to the isolated substances (4 times lower than individual IC50; CI = 0.47). Our results suggest that the treatment with the substances RTB18, RTB13, RTB163, and RTB182 have antiviral activity in L929 cell line infected with murine coronavirus in vitro at the first 24 and 48 h p.i. In addition, all the substances have shown antiviral activity with the treatment beginning until 12h p.i. Hence, we highlight the activity of RTB163 and RTB182 as potential candidates for future in vivo assays. Palavras-chave: Benzoylguanidine, Antiviral, COVID-19, SARS-CoV-2, MHV-3 Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) | |||||