Broad-spectrum antiviral potential of vitexin and isovitexin from Jatropha integerrima: in vitro cytoprotective effects and in silico insights

Abstract

The ongoing emergence of viral infections underscores the need for new antiviral agents with broad-spectrum potential, particularly those derived from natural products. In this study, leaf and flower extracts of Jatropha integerrima, along with two isolated flavone C-glycosides, vitexin, and isovitexin, were evaluated for their antiviral potential against a panel of human DNA and RNA viruses, including hepatitis A virus, herpes simplex virus types 1 and 2, adenovirus, Coxsackievirus B4, and rotavirus A. Cytotoxicity and virus-induced cytopathic effects were assessed in Vero cells using an MTT-based assay, allowing estimation of 50% cytotoxic concentrations (CC₅₀), 50% inhibitory concentrations (IC₅₀), and selectivity indices (SI). The extracts and isolated compounds exhibited variable degrees of cytoprotective effects in infected cells, with vitexin and isovitexin showing favorable selectivity profiles against selected viruses. Morphological observations supported the MTT findings, indicating partial preservation of cell integrity under certain treatment conditions. To explore potential molecular interactions relevant to coronavirus infection, in silico molecular docking was performed against five SARS-CoV-2-related targets, including Mpro, spike glycoprotein, nucleocapsid phosphoprotein, the ACE2 receptor-RBD complex, and nsp10. Both flavonoids generated favorable binding poses within the defined binding regions of the selected proteins, with predicted binding energies suggesting potential structural compatibility with these targets. These computational findings are presented as hypothesis-generating insights and do not constitute experimental evidence of antiviral efficacy against SARS-CoV-2. Overall, the findings suggest that vitexin and isovitexin possess in vitro cytoprotective effects in virus-infected cells and exhibit predicted interactions with viral targets in silico. However, given the indirect nature of the antiviral assays and the absence of direct viral replication measurements, the results should be interpreted cautiously. Further studies employing direct virological endpoints are required to validate the antiviral potential of these compounds and to clarify their mechanisms of action.