Blueberry Leaves Block Replication of the Hepatitis C Virus
Among the areas of especially high hepatitis C incidence is the Miyazaki prefecture of southern Japan, a trend that led researchers in Japan on a search for better treatment options. Currently, there is no vaccine for hepatitis C virus, and though a combination drug regimen can clear hepatitis C virus infection, this treatment is only about 60% effective on average and poses risks of severe side effects.
The researchers believed that since hepatitis C virus is localized in the liver and can take 20 years or more to develop into disease, a dietary supplement might help slow or stop disease progression. So they screened nearly 300 different agricultural products for potential compounds that suppress hepatitis C virus replication and uncovered a strong candidate in the leaves of rabbit-eye blueberry (native to the southeastern US).
They purified the compound and identified it as proanthocyandin (a polyphenol similar to the beneficial chemicals found in grapes and wine). While proanthocyandin can be harmful, the researchers noted its effective concentration against hepatitis C virus was 100 times less than the toxic threshold, and similar chemicals are found in many edible plants, suggesting it should be safe as a dietary supplement. In the meantime, they now hope to explore the detailed mechanisms of how this chemical stops hepatitis C virus replication.
1. Masahiko Takeshita, et al. Proanthocyanidin from Blueberry Leaves Suppresses Expression of Subgenomic Hepatitis C Virus RNA. J. Biol. Chem. 2009 284: 21165-21176.