Purpose: The effects of C-PAC and PP on the infectivity of HAV after exposure from 0 to 1 h were evaluated at ambient temperature and 37°C.
Methods: HAV at ~5 log PFU/ml was mixed with equal volumes of C-PAC at 0.15 mg/ml, PP at 4 mg/ml, or water and incubated for up to 1 h at room temperature or 37°C. Viral infectivity after triplicate treatments was evaluated using standardized plaque assays in duplicate.
Results: The anti-HAV effects of C-PAC and PP were found to be time-dependent. At 37°C, 0.15 mg/ml C-PAC caused an instant HAV reduction of 0.4 log PFU/ml upon mixing and a 1.4 log PFU/ml reduction within the next 10 min of treatment, resulting in a total titer reduction of ~1.9 log PFU/ml within 1 h. At 37°C, no titer reduction of HAV was observed upon immediate mixing of the virus with 4 mg/ml PP, but caused a reduction of 0.4 log PFU/ml within 10 min of treatment, resulting in a total ~1 log PFU/ml reduction within 1 h. Thus, 0.15 mg/ml C-PAC was found to be more effective in HAV reduction than 4 mg/ml PP at 37°C. Comparable reduction of HAV was obtained with 4 mg/ml PP at room temperature and 37°C. However, the anti-HAV effect of C-PAC was found to be temperature-dependent with significantly lesser reduction at room temperature (P < 0.05).
Significance: These results show that C-PAC and PP appear to have promise as natural antivirals for HAV reduction and give an idea of the time-dependence mechanism of action.