Repurposing of FDA-approved drugs to identify potential ns2b/ns3 protease inhibitors against dengue virus: In silico and in vitro evaluation.

Dengue virus (DENV) poses a significant global health burden, affecting many countries and regions worldwide, with no specific antiviral therapy currently available. The NS2B/NS3 protease is a crucial enzyme in viral replication, making it a promising target for the development of antiviral drugs. Drug repurposing offers a rapid and cost-efficient strategy by evaluating FDA-approved compounds for new antiviral indications. The present study aimed to identify potent inhibitors of DENV-2 NS2B/NS3 protease with an integrated in silico and in vitro analysis. Molecular docking was used to screen a library of 3109 FDA-approved drugs in the ZINC database with PyRx software. The three hits, Simeprevir, Saquinavir, and Dolutegravir were subsequently evaluated for their cytotoxicity and antiviral activity in Vero cells, using MTT and infectivity-based assays, respectively. MD simulations confirmed stable binding of Dolutegravir, Saquinavir, and Simeprevir with DENV NS2B/NS3 protease. Although dolutegravir displayed a slightly lower docking affinity, the compound demonstrated the lowest cytotoxicity with CC₅₀ 133.7 µg/mL (318.8 µM), and slightly enhanced antiviral activity with IC₅₀ 22.5 µg/mL (53.7 µM) among the tested compounds. Saquinavir showed CC₅₀ of 118.6 µg/mL (176.8 µM)) and an IC₅₀ 25.0 µg/mL (37.3 µM) and Simeprevir exhibited CC₅₀ 80.9 µg/mL (107.9 µM) with an IC₅₀ 20.0 µg/mL (26.7 µM). This study reflects on the potential of Dolutegravir as a dengue protease inhibitor and also indicates the efficacy of drug repurposing as a drug discovery strategy in the paradigm of antiviral discovery. Dolutegravir was identified as a potential candidate against DENV-2, and additional research is needed with molecular dynamics, mechanistic inquiry, and in vivo support investigation.