Fig. 1

Identification of brefeldin A as DENV inhibitor. a Fractions of aqueous residue of cultured broth were applied to HPLC. HPLC chromatogram is shown, whereas peak of active molecule (fraction #17) was indicated with an arrow. b Vero cells in 96-well plates were infected with DENV at an MOI of 0.03 in the presence of fraction #17 with increasing dilutions. The cells were incubated for 5 days at 37 °C in 5% CO₂ after which ICFs were harvested and subjected for antigen detection ELISA. In separated experiments, Vero cells in 96-well plates were treated with the fractions with increasing dilutions without virus infection. After 5 days incubation, cell viability was determined by MTT assay as described in the “Materials and methods” section. The error bars represent standard deviation from the means of the results from triplicate determination. c By HR-ESI-MS and NMR methods, the fraction #17 was identified as brefeldin A. Structural formula of BFA is depicted