Antiviral Activity of Isobutyl Gallate to Dengue Virus Serotype 2 In Vitro

Dengue is one of the most prevalent mosquito-borne diseases in Indonesia that lead to a spectrum of disease, ranging from a flu-like illness to a life-threatening dengue shock syndrome. Despite its high incidence and mortality rate, there is currently no antiviral drug available against dengue virus (DENV). Therefore, research regarding the development of anti-viral to DENV is essential. The aim of this study was to evaluate the antiviral activity of isobutyl gallate, a gallic acid derivative, against DENV in vitro. Various concentration of isobutyl gallate was added to DENV-2 strain New Guinea C (NGC) and infected to Vero cell line. Inhibition of DENV replication as aligned with half inhibitory concentration (IC₅₀) value was determined by focus assay. Furthermore, the toxicity of isobutyl gallate that corresponds with cytotoxic concentration (CC₅₀) value was determined by MTT assay. Selectivity index (SI) value was defined as the ratio of CC₅₀ to IC₅₀. Isobutyl gallate showed no cytotoxic effects against Huh 7 it-1 cells with CC₅₀ values of 167.19 μg/mL and exhibited strong antiviral activity with IC₅₀ of 4.45 μg/mL, hence a significant SI value of 25.69. Isobutyl gallate exerts potent antiviral activity against DENV.