T9-01 Temperature and Time-dependence Effects of Cranberry Proanthocyanidins and Pomegranate Polyphenols on Hepatitis A Virus Infectivity

Wednesday, July 25, 2012: 8:30 AM
Room 553 (Rhode Island Convention Center)
Xiaowei Su, University of Tennessee-Knoxville, Knoxville, TN
Amy Howell, Rutgers University, Chatsworth, NJ
Doris D'Souza, University of Tennessee-Knoxville, Knoxville, TN
Introduction: Cranberry proanthocyanidins (C-PAC) and pomegranate polyphenols (PP) are known for their antimicrobial activities against bacteria and also enveloped and non-enveloped viruses. However, their effects on hepatitis A virus (HAV) have not yet been extensively studied.

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 (< 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.