Anti-viral and anti-bacterial activities of an extract of blackcurrants (Ribes nigrum L.).

The inhibitory effects of an extract of the blackcurrant (Ribes nigrum L.) against pathogens associated with oral, nasopharyngeal and upper respiratory infectious diseases; namely respiratory syncytial virus (RSV), influenza virus A and B (IFV-A and IFV-B), adenovirus (AdV), herpes simplex virus type 1, Haemophilus influenzae type B, Streptococcus pneumoniae and Streptococcus mutans, were investigated. Less than 1% concentration of extract of blackcurrant inhibited replication of RSV, IFV-A and -B and HSV-1 by over 50% and a 10% extract inhibited adsorption of these viruses onto the cell surface by over 95%. The effects on AdV were much less pronounced; the half minimal inhibitory concentration of AdV replication was 2.54 ± 0.26, and a 10% concentration of the extract inhibited AdV adsorption on the cell surface by 72.9 ± 3.4%. The antibacterial activities of the blackcurrant were evaluated based on its efficacy as a disinfectant. A 10% extract disinfected 99.8% of H. Influenzae type B and 78.9% of S. pneumoniae in 10 min, but had no demonstrable effect against S. mutans. The blackcurrant extract still showed antiviral and antibacterial activities after the pH had been made neutral with sodium hydroxide, suggesting that these activities are not the result of acidic reactions or of components precipitated at a neutral pH. These findings demonstrate the potential of blackcurrant extract as a functional food for oral care.

The cotton rat model for adenovirus ocular infection: antiviral activity of cidofovir.

To determine the antiviral effects of compounds against ocular adenovirus (AdV) infection, we established an animal model of AdV infection in cotton rat eyes. Cotton rat eyes were inoculated intrastromally and topically with four AdV serotypes 4, 5, 8, and 37, and treated topically with 1% HPMPC (cidofovir) eye drops twice a day. The infected corneas were extracted and homogenized, and virus titers in the cornea specimens were determined by a plaque assay. The virus titer in AdV type 5-inoculated eyes peaked on days 0 through 3 after inoculation and virus shedding was detected for 18.0+/-2.8 days. AdV 5 antigen in the infected corneas was demonstrated in the corneal epithelial cells by immunofluorescence stain. However, for AdV serotypes 4, 8, and 37, no evidence of continued virus replication in cotton rat eyes was noted. Specimens from cidofovir-treated eyes infected with AdV 5 demonstrated a statistically significant reduction in the mean virus titer (days 3-15) (P=0.028) and virus shedding duration (P=0.0014), as compared with those of the control group.