BACKGROUND: Rotavirus is the leading cause of severe diarrhea disease in 
newborns and young children worldwide, estimated to be responsible for over 
300,000 childhood deaths every year, mostly in developing countries. 
Rotavirus-related deaths represent approximately 5% of all deaths in children 
younger than 5 years of age worldwide. Saponins are readily soluble in water and 
are approved by the US FDA for inclusion in beverages intended for human 
consumption. The addition of saponins to existing water supplies offers a new 
form of intervention into the cycle of rotavirus infection. We believe that 
saponins will 'coat' the epithelium of the host's small intestine and prevent 
attachment of rotavirus.
DISCUSSION: This experiment provides in vitro data for the possibility of 
including saponin in drinking water to prevent infections of rotavirus. We 
demonstrate that microgram amounts of extract, while exhibiting no cell 
cytotoxicity or direct virucidal activity, prevent rotavirus from infecting its 
host cells. In addition, the presence of residual amounts of extract continue to 
block viral infection and render cells resistant to infection for at least 16 h 
after the removal of the extract from the cell culture media.
CONCLUSION: We demonstrate that two Quillaja extracts possess strong antiviral 
activity at concentrations more than 1000-fold lower than concentrations 
exhibiting cell cytotoxicity. Extract concentrations as high as 1000 μg/ml are 
not cytotoxic, but concentrations as low as 1.0 μg/ml are able to block 
rotavirus and reovirus attachment and infection.