Abstract
The effect of acacetin isolated from Scoparia dulcis and several related flavonoids on herpes simplex virus type 1 (HSV-1) was studied in vitro by the method of plaque yield reduction. Among these compounds, acacetin was shown to be the most potent agent and caused dose-dependent inhibition of virus replication. Acacetin had a weak virucidal activity at higher concentrations. Analysis of early events following infection showed that attachment of the virus to host cells and penetration were unaffected by acacetin. Acacetin was found to exert strong inhibition of protein synthesis in virus-infected cells but not in uninfected cells. The transcription of immediate-early genes and translation of their transcripts were in particular almost stopped by acacetin even at a lower concentration. These selective effects can be attributed mainly to the antiviral activity of acacetin.