Investigation of the antiviral activity of Carica papaya L. leaf extract against dengue virus serotype 2 (DENV-2) in Vero cells
TL;DR
Limited antiviral activity against dengue virus serotype 2 under the tested conditions is indicated and support further work using wider concentration ranges and fractionation of its bioactive constituents are supported.
Abstract
Indonesia carries one of the highest dengue burdens in ASEAN, where treatment remains largely supportive rather than antiviral, motivating the search for antiviral candidates from natural sources such as papaya. Papaya leaves contain secondary metabolites reported to have antiviral properties. This study evaluated the in vitro antiviral activity of 96% ethanol leaf extract against dengue virus serotype 2 in Vero cells using a post-infection method, and determined its cytotoxic safety in the same cell line. Phytochemical screening detected alkaloids, flavonoids, saponins, steroids, triterpenoids, and tannins. Across four concentrations (125-1000 μg/mL, n = 3 each concentrations) regression gave a fifty percent cytotoxic concentration of 1712.74 μg/mL however, viability did not decline in a dose-dependent manner (R2 = 0.08), so this value is a rough extrapolation rather than a reliable toxicity threshold. Antiviral testing across three concentrations (25-100 μg/mL, n = 3 each concentrations) did not reach fifty percent inhibition of the cytopathic effect within the tested range, the effective concentration was therefore reported as greater than 100 μg/mL, giving a selectivity index below 9.08. These findings indicate limited antiviral activity against dengue virus serotype 2 under the tested conditions and support further work using wider concentration ranges and fractionation of its bioactive constituents.