Virucidal potential of oleuropein identified in Castana sativa shell: insight from in vitro and in silico studies

In this report, Castanea sativa shell extracts have been investigated for their activity against Herpes Virus type 2 (HSV-2). Among four organic extracts only 75% ethanol extract demonstrated activity against HSV-2 with a 50% inhibitory concentration of 6.45 μg/mL. The study of the mechanism underlying the antiviral activity demonstrated this extract strongly inhibits HSV-2 by direct contact and moderately protects the cell from virus recognition and binding. The active compound has been identified as oleuropein by HPLC-DAD-ESI-MSn. This compound which is widely known in the Oleaceae family has been identified in the chestnut shells for the first time. The in vitro results of the mechanism underlying anti HSV-2 action were confirmed by an in silico study which revealed a strong binding free energy of -9.08 kcal/mol between oleuropein and the glycoprotein D of HSV-2. In summary, our findings suggest that C. sativa shells may constitute a promising natural source of anti-HSV-2 agents.