Zika virus (ZIKV) pandemic and its implication in congenital malformations and severe neurological disorders had created serious threats to global health. ZIKV is a mosquito-borne flavivirus which spread rapidly and infect a large number of people in a shorter time-span. Due to the lack of effective therapeutics, this had become paramount urgency to discover effective drug molecules to encounter the viral infection. Various anti-ZIKV drug discovery efforts during the past several years had been unsuccessful to develop an effective cure. The NS2B-NS3 protein was reported as an attractive therapeutic target for inhibiting viral proliferation, due to its central role in viral replication and maturation of non-structural viral proteins. Therefore, the current in silico drug exploration aimed to identify the novel inhibitors of Zika NS2B-NS3 protease by implementing an e-pharmacophore-based high-throughput virtual screening. A 3D e-pharmacophore model was generated based on the five-featured (ADPRR) pharmacophore hypothesis. Subsequently, the predicted model is further subjected to the high-throughput virtual screening to reveal top hit molecules from the various small molecule databases. Initial hits were examined in terms of binding free energies and ADME properties to identify the candidate hit exhibiting a favourable pharmacokinetic profile. Eventually, molecular dynamic (MD) simulations studies were conducted to evaluate the binding stability of the hit molecule inside the receptor cavity. The findings of the in silico analysis manifested affirmative evidence for three hit molecules with −64.28, −55.15 and −50.16 kcal/mol binding free energies, as potent inhibitors of Zika NS2B-NS3 protease. Hence, these molecules holds the promising potential to serve as a prospective candidates to design effective drugs against ZIKV and related viral infections.

With increase in number of people suffering from COVID-19, there is a dire need to look for effective remedies against this pandemic. Drug repurposing seems to be the solution for current situation. In our quest for finding potential drug against this virus, 15 anti-malarial drugs including chloroquine, and 2413 FDA approved drugs were investigated against both protease and spike proteins of COVID-19 usingin-silico approach. Molecular docking analysis followed by MD simulation was carried out to estimate the binding and stability of the complexes. In this study, we found a single drug Paromomycin against two targets of COVID-19 i.e. Spike protein (S1) and protease domain. Paromomycin was found to have strong binding affinity against both the targets of coronavirus. The results also showed that no anti-malarial drug exhibited effective binding against either S1 or protease. Current study concluded that Paromomycin is an effective dual targeting drug against coronavirus, as it binds not only to the protease domain of the virion but also with the spike domain with high stability. Furthermore, none of the anti-malarial drugs showed strong binding affinity for either protease or receptor binding domain (RBD).