Effect of secondary metabolites from Streptomyces sp. KSF103 on DENV-2 replication competency in C6/36 cells and identification of potent DENV inhibitors

Streptomyces sp. KSF103 has demonstrated promising insecticidal properties, prompting a subsequent study to evaluate the in vitro effects of its ethyl acetate (EA) extract on dengue virus type 2 (DENV-2) replication in Aedes albopictus C6/36 cells. Pre- and post-treatment assays revealed significant inhibition of viral replication, indicating that the EA extract disrupts both viral entry and adsorption in pre-treated cells, as well as intracellular replication in post-treated cells. Chemical profiling using liquid chromatography-mass spectrometry (LC-MS) identified several bioactive compounds in the extract, including pentanamide, C17 sphinganine, dichamanetin, dodemorph, and antillatoxin B. Further in silico molecular docking analysis targeting DENV-2 NS2B/NS3 protease, NS5 polymerase, and envelope (E) protein revealed that antillatoxin B and dichamanetin exhibit strong binding affinities, supporting their potential antiviral activity. These findings align with the observed inhibitory effects of the EA extract and highlight its potential as a source of potent DENV-2 inhibitors.