Antiviral and molecular docking analysis of methoxyflavones isolated from Melicope latifolia leaves against HCV

Treatments of hepatitis C virus have been developed and increased the sustained virology response (SVR), however, there are several reports of drug resistance, high-cost issue, and limited access to current hepatitis C virus (HCV) treatment that remain become a problem. This necessitates to search for complementary and alternative drugs against HCV, therefore the investigation of active compounds from plant extracts such as Melicope latifolia, a plant that has been reported as anti-HCV, will be provided in this study. The anti-HCV activities were tested using in vitro cultured cells of hepatocyte cell line Huh 7.5 and HCV genotype 2a (J6/JFH1). Ethanol extract of M. latifolia leaves was separated by chromatographic methods and the chemical structures of the isolated compounds were established based on mass spectrometry, 1D, and 2D nuclear magnetic resonance spectral data, as well as comparison with reported data. The interaction of the compound with the protein, which involves to HCV activity, was determined by docking analysis. Three known methoxyflavone compounds identified as 5,4'-dihydroxy-7-prenyloxy-3,8,5’-trimethoxyflavone (1); 5,3'-dihydroxy-3,7,8,4'-tetramethoxyflavone (2); and 5-hydroxy-3,7,8,3',4'-pentamethoxyflavone (3) were isolated from the ethanolic extract of M. latifolia leaves. Anti-HCV activities revealed that compound (1) strongly inhibited HCV J6/JFH1 with a 50% inhibitory concentration (IC₅₀) value of 6.7±0.4 µg/mL and 50% cytotoxic concentration (CC₅₀) of 19.3 µg/mL. The docking analysis revealed an interaction with the 4GAG, a protein that involves in the entry step of HCV, and the 4EAW protein which plays an important role during HCV replication.