To determine if blackberry extract has antiviral properties, its ability to inhibit the HSV-1
replication cycle in oral epithelial cells was evaluated. To broadly evaluate possible antiviral
activities cultures were maintained in the presence of increasing concentrations of
blackberry extract (0, 2.24, 11.2, 56, 280 and 1400 μg/ml) throughout the entire replication
cycle (i.e. adsorption, entry and production of progeny). As shown in Figure 1, blackberry
extract at 56 μg/ml significantly reduced HSV-1 yield by more than 99% (p = 0.004) and
progeny virus was not detectable in cultures treated with extract at concentrations ≥ 280 μg/
ml.