In Vitro Antiviral Activity of Dried Red Jujube Fruit (Ziziphus jujuba) Ethanol Extract against DENV-2

Dengue infection has become one of the most important mosquito-borne diseases worldwide and is caused by the dengue virus (DENV). Recently, neither patent drug, phytopharmaceutical medicine, nor standardized herbal medicine has been officially available against DENV. Dried red jujube fruit (Ziziphus jujuba) ethanol extract has been proven to have an antiviral effect, anti-inflammatory efficacy, and antioxidant properties, which have potential activity against DENV infection. This research was conducted to analyze the antiviral activity of dried red jujube fruit ethanol extract against DENV-2 in vitro. The halfmaximal cytotoxic concentration (CC50) and half-maximal inhibitory concentration (IC50) were examined on Vero cells by a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, whereas the halfmaximal effective concentration (EC50) was determined using luminescence assay. The selectivity index (SI) value was determined from the ratio of CC50 and EC50. Dried red jujube fruit ethanol extracts inhibited DENV-2 in 24.59%, 22.39%, 17.98%, 14.5%, 6.42%, and 1.28% at 80 μg/mL, 40 μg/mL, 20 μg/mL, 10 μg/ mL, 5 μg/mL, and 2.5 μg/mL, respectively. The extract exhibited antiviral activity against DENV-2, showing a CC50 of 67.73 μg/mL, an IC50 value of 166.18 μg/mL, and an EC50 of 64.87 μg/mL, with an SI of 1.04. The LD50 value was 707.95 mg/kg. Dried red jujube fruit ethanol extract could be a potential candidate for developing an antiviral against DENV-2.