Computational design and in vitro assay of lantadene-based novel inhibitors of NS3 protease of dengue virus

Dengue virus (DENV) infection is one of the diseases for which no drug is available for the treatment. The DENV NS2B-NS3 protease is considered to be the prime target for anti-dengue drug development because of its importance in the development of new virus subunits via DENV poly-protein breakdown. Pentacyclic triterpenoids (Lantadenes) from the weed Lantana camara L. and its semi-synthetic congeners have shown a wide array of biological activities in the last two decades. The virtual screening strategy was used on the library of 78 natural and semi-synthetic lantadenes to predict the potent antagonists for the NS2B-NS3 protease enzyme of DENV and their experimental validation by in vitro assay of lead molecules. In the in silico analysis of 78 triterpenoids, two lead molecules (-10.60 and -9.93 kcal/mol) were predicted to be inhibitors of protease (viral) when compared to its reference ligand 1,8-dihydroxy-4,5-dinitroanthraquinone (-5.377 kcal/mol). At the same time, binding affinity, pharmacokinetic, and toxicity profiling, along with molecular dynamics simulations, were studied. The in vitro viral infection inhibition assay inferred that lead molecule 62 exhibited a 60% and 45% reduction in DENV titers at 10 and 5 mu M concentrations, respectively. The lead molecule 62 can further be optimized for its pharmacophore and has the potential to be developed as a drug-like molecule.