Antiviral activity of Sonchus arvensis L. extracts on dengue virus replication

Objective: To investigate the antiviral potential of Sonchus arvensis L. extracts against dengue virus (DENV)-1 and DENV-2 in vitro , and elucidate its underlying antiviral mechanisms. Methods: The cytotoxicity of the ethanol, ethyl acetate, and n -hexane extracts of Sonchus arvensis L. was determined using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay, followed by post-treatment antiviral assays. Multiple treatment regimens were conducted to assess antiviral effects at different stages of the DENV replication cycle. qRT-PCR analysis was performed to evaluate the effects of the ethanol extract on genes associated with host innate immune and inflammatory responses. Results: The CC 50 values of the ethanol, ethyl acetate, and n -hexane extracts were 391.5 μg/mL, 104.9 μg/mL, and 409.2 μg/mL, respectively. The ethanol and ethyl acetate extracts reduced DENV- 1 and DENV-2 titers by >90% at 30-50 μg/mL, while the n -hexane extract showed comparable activity against DENV-2. The ethanol extract at 30 μg/mL demonstrated potent multi-stage antiviral activity, including direct virucidal, prophylactic, anti-adsorption, and anti-internalization effects. qRT-PCR analysis revealed no significant change in IFN-β expression but marked suppression of NF-κB , TNF-α , and IL-6 expression. Conclusions: Sonchus arvensis L. ethanol extracts demonstrate potent multi-stage antiviral activity against DENV in vitro , highlighting its ability to inhibit viral entry, reduce viral replication, and attenuate excessive inflammatory responses.