An extract from grape seed forced leukemia cells in a lab to commit cell suicide. In a new study, 76 percent of leukemia cells had died within 24 hours of being exposed to the extract. The researchers were studying chemicals known as proanthocyanidins, which are found in fruits.

The researchers also teased apart the cell signaling pathway associated with use of grape seed extract that led to cell death, also called apoptosis. They found that the extract activates JNK, a protein that regulates the apoptotic pathway.

Grape seed extract has shown activity in a number of laboratory cancer cell lines, including skin, breast, colon, lung, stomach and prostate cancers, but no one had previously tested the extract in hematological cancers, nor had the precise mechanism for activity been found. In the U.S., hematological cancers such as leukemia, lymphoma and myeloma accounted for more than 118,000 new cancer cases and almost 54,000 deaths in 2006.