Embelin Inhibits Dengue Virus Serotype 2 Infectivity with Nonstructural Protein Helicase as a Potential Molecular Target

Dengue is a viral infectious disease which poses a significant threat to global health, affecting approximately 400 million people on a global scale. Due to the absence of an effective antiviral, the ongoing search for effective anti-dengue therapeutics is imperative. In this study, we aim to evaluate embelin’s infection inhibitory properties against dengue virus serotype 2 using in vitro infectivity and in silico approaches. Embelin showed the highest antiviral activity against dengue virus serotype 2 with lower cytotoxicity on Vero cells compared to others, where MTT assay showed CC₅₀ 9.558 ± 0.229 µM and MNTC₈₀ 2.988 ± 0.360 µM. Subsequently, embelin inhibited dengue virus serotype 2 infectivity in a concentration-dependent manner in all antiviral assays, including direct virus inhibition (IC₅₀ 0.338 ± 0.015 µM; SI 28.28), post-infection inhibition (IC₅₀ 0.442 ± 0.056 µM; SI 21.62), and viral entry (IC₅₀ 0.514 ± 0.023 µM; SI 18.60). In cell protection and viral attachment assays, embelin inhibited dengue virus serotype 2 infectivity in a concentration-dependent manner, with less than 50% inhibition observed. Consistently, molecular docking analysis demonstrated that embelin was predicted to predominantly target the non-structural protein, NS3 helicase, and subordinately for others that are essential for dengue virus replication upon host cell entry, with higher binding affinity in dengue virus serotype 2 and serotype 4 than other proteins. In silico drug-likeness screening showed that embelin possessed good absorption, distribution, metabolism and excretion properties and toxicological profile, making it a potential drug candidate against dengue virus.