Effect of Muscadine Juice and Elderberry Preparations on Wild‐Type H1N1 Influenza Virus‐Induced Cytotoxicity

Elderberry phenolic compounds have been previously shown to be cytoprotective when cells are incubated with H1N1 influenza virus; the current experiments were designed to examine whether similar beneficial effects can be observed with the muscadine grape. Two commercial elderberry products and a concentrated muscadine juice were added to Manin‐Darby canine kidney cells at various time points relative to the addition of 100 pfu H1N1 influenza virus. Oseltamivir (Tamiflu ® ) was also used as a positive control. After 48 hours, the amount of lactate dehydrogenase released due to cell lysis was employed as the marker for cytotoxicity. All three extracts showed inhibition of cytotoxicity when added to the cells at the same time as the virus at an extract dilution of 1:160; inhibition of cytotoxicity was approximately 50%. A similar pattern of inhibition was observed when the extracts, at a dilution of 1:160, were added to the cells six and twenty‐four hours after viral incubation. When cells were infected with the virus for six hours and, after virus removal, the cells were incubated with the three extracts at a concentration of 40 µg phenolics/ml, cytoprotective activity was also observed. A significant effect was not observed when the experiments were performed by incubating the extracts first and then the virus. Overall, these data suggest that muscadine phenolics act in manner similar to those in the elderberry in providing cytoprotection against the H1N1 virus and this effect can be observed without direct contact between extract and virus.