The Impact of the S-Adenosylmethionine Analogue Sinefungin on Viral Life Cycles

DNA and RNA methylation are essential epigenetic modifications that play a crucial role in regulating gene expression and cellular processes. Methylation is also significant in viral infections, influencing various stages of the viral life cycle and immune evasion. In this study, we investigated the antiviral potential of sinefungin, a potent methyltransferase inhibitor, against Herpes Simplex Virus 1 (HSV-1) and SARS-CoV-2. The cytotoxic effect of sinefungin was evaluated on VERO-76 cells by exposing them to concentrations ranging from 12.5 to 200 μg/mL for 24 h. The MTT assay results indicated that sinefungin reduced cell viability by approximately 21.7% at the highest concentration tested, with a CC50 above 200 μg/mL. Our results demonstrated that sinefungin exhibited significant antiviral activity against both HSV-1 and SARS-CoV-2, with IC50 values of 49.5 ± 0.31 μg/mL for HSV-1 and 100.1 ± 2.61 μg/mL for SARS-CoV-2. These results suggest that sinefungin may be a promising therapeutic candidate for treating viral infections, particularly those involving methylation-dependent processes.