Grape-seed Extract Kills Laboratory Leukemia Cells

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Grape-seed Extract Kills Laboratory Leukemia Cells, Proving Value Of

Natural Compounds

ScienceDaily (Dec. 31, 2008) — An extract from grape seeds forces

laboratory leukemia cells to commit cell suicide, according to

researchers from the University of Kentucky. They found that within 24

hours, 76 percent of leukemia cells had died after being exposed to

the extract.

The investigators, who report their findings in the January 1, 2009,

issue of Clinical Cancer Research, a journal of the American

Association for Cancer Research, also teased apart the cell signaling

pathway associated with use of grape seed extract that led to cell

death, or apoptosis. They found that the extract activates JNK, a

protein that regulates the apoptotic pathway.

While grape seed extract has shown activity in a number of laboratory

cancer cell lines, including skin, breast, colon, lung, stomach and

prostate cancers, no one had tested the extract in hematological

cancers nor had the precise mechanism for activity been revealed.

" These results could have implications for the incorporation of agents

such as grape seed extract into prevention or treatment of

hematological malignancies and possibly other cancers, " said the

study's lead author, Xianglin Shi, Ph.D., professor in the Graduate

Center for Toxicology at the University of Kentucky.

" What everyone seeks is an agent that has an effect on cancer cells

but leaves normal cells alone, and this shows that grape seed extract

fits into this category, " he said.

Shi adds, however, that the research is not far enough along to

suggest that people should eat grapes, grape seeds, or grape skin in

excess to stave off cancer. " This is very promising research, but it

is too early to say this is chemo-protective. "

Hematological cancers – leukemia, lymphoma and myeloma – accounted for

an estimated 118,310 new cancer cases and almost 54,000 deaths in

2006, ranking these cancers as the fourth leading cause of cancer

incidence and death in the U.S.

Given that epidemiological evidence shows that eating vegetables and

fruits helps prevent cancer development, Shi and his colleagues have

been studying chemicals known as proanthocyanidins in fruits that

contribute to this effect. Shi has found that apple peel extract

contains these flavonoids, which have antioxidant activity, and which

cause apoptosis in several cancer cell lines but not in normal cells.

Based on those studies, and findings from other researchers that grape

seed extract reduces breast tumors in rats and skin tumors in mice,

they looked at the effect of the compound in leukemia cells.

Using a commercially available grape seed extract, Shi exposed

leukemia cells to the extract in different doses and found the marked

effect in causing apoptosis in these cells at one of the higher doses.

They also discovered that the extract does not affect normal cells,

although they don't know why.

The researchers then used pharmacologic and genetic approaches to

determine how the extract induced apoptosis. They found that the

extract strongly activated the JNK pathway, which then led to

up-regulation of Cip/p21, which controls the cell cycle.

They checked this finding by using an agent that inhibited JNK, and

found that the extract was ineffective. Using a genetic approach –

silencing the JNK gene – also disarmed grape seed extract's lethal

attack in leukemia cells.

" This is a natural compound that appears to have relatively important

properties, " Shi said.

http://www.sciencedaily.com/releases/2008/12/081231005257.htm

The question i have is do these and similar compounds survive

digestion to get absorbed into the bloodstream?