Antiviral effects of blackberry extract against herpes simplex virus type 1

Objective: The aim of this study was to evaluate antiviral properties of blackberry extract against herpes simplex virus type 1 (HSV-1) in vitro. Study design: HSV-infected oral epithelial (OKF6) cells and cell-free virus suspensions were treated with blackberry extract (2.24-1,400 μg/mL), and virus yield and infectivity were quantified by direct plaque assay. Results: Blackberry extract <56 μg/mL inhibited HSV-1 replication in oral epithelial cells by >99% (P <.005). Concentrations <280 μg/mL were antiviral when the extract was added after virus adsorption and entry. Exposure of cell-free virus to <280 μg/mL blackberry extract for 15 minutes at room temperature was virucidal (P =.0002). The virucidal effects were not due to pH changes at concentrations up to 1,500 μg/mL. Conclusions: Blackberry extract inhibited the early stages of HSV-1 replication and had potent virucidal activity. These properties suggest that this natural fruit extract could provide advantage as a topical prophylactic/therapeutic agent for HSV infections.