Antiviral effects of resveratrol against the replication of chikungunya and Japanese encephalitis viruses in vitro.

Chikungunya virus (CHIKV) and Japanese encephalitis virus (JEV) are mosquito-borne arboviruses that pose significant public health risks, especially in tropical regions like Malaysia. CHIKV is linked to joint and muscle pain, while JEV can cause severe neurological illnesses and encephalitis if untreated. With no specific treatments available, research into potential antivirals is crucial. This study investigates the inhibitory potential of resveratrol (RES) against CHIKV and JEV in vitro. Cytotoxicity of RES was assessed on human adenocarcinoma alveolar basal epithelial cells (A549) using the MTS assay, followed by dose-dependent analyses to determine optimal inhibitory concentrations. Antiviral effects were explored through pre-infection, post-infection, virucidal, and anti-adsorption assays, with virus titres measured via plaque and foci-forming assays for CHIKV and JEV, respectively. Results revealed that RES's pre- and post-infection treatments significantly reduced titres of both viruses in a dose-dependent manner. Notably, CHIKV titres were reduced by over 65% (p < 0.01) when treated with 100 µM RES, whether administered pre-infection or post-infection. For JEV, a reduction of over 93% (p < 0.05) was observed only with post-infection treatment, while pre-infection treatment alone did not yield a significant reduction. In addition, both pre-incubation and anti-adsorption assays for CHIKV and JEV showed no significant results. These findings suggest that RES likely inhibits viral replication by modulating host cellular mechanisms rather than directly targeting the viruses. In summary, this study demonstrates that RES exhibits antiviral properties against CHIKV and JEV replication, underscoring its potential as an effective antiviral agent. However, further in vivo studies are needed to fully evaluate its therapeutic potential and efficacy.