Biology Reference
In-Depth Information
apoptotic cell death, and modulating cell cycle kinetics and signal
transduction pathways.
In vitro
studies carried out with cancer cell lines have shown that
strawberries (Meyers
et al.
, 2003, Olsson
et al.
, 2004, Ramos
et al
.,
2005, Wang
et al.
, 2005, Wu
et al
., 2007), raspberries (Liu
et al
., 2002,
Olsson
et al.
, 2004, Wu
et al
., 2007), cloudberries (Wu
et al
., 2007) and
rose hips (Olsson
et al.
, 2004) inhibit cell proliferation, induce apoptosis
and cause cell cycle arrest in human colon, liver, lung, breast or cervical
cancer cells. In the studies mentioned above, the contribution of
ellagitannins on the activities of berry extracts was not assessed.
However, a recent study (Ross
et al
., 2007) suggests that the
antiproliferative activity of raspberries is predominantly associated with
ellagitannins.
Also pomegranate juice and its ellagitannins inhibit proliferation,
induce apoptosis and suppress inflammatory cell signaling in colon
cancer cell lines (Seeram
et al.
, 2005, Adams
et al.
, 2006, Larrosa
et al
.,
2006). The potency of pomegranate juice is higher than its purified
ellagitannins. This indicates synergistic action of ellagitannins and other
bioactive components, such as anthocyanins and flavonols abundant in
pomegranate juice. Likewise, polyphenols in muscadine grape skin
inhibit the growth of colon cancer cells and induce apoptosis (Yi
et al.
,
2005). Fractions isolated from red muscadine grapes and rich in ellagic
acid, ellagic acid glycosides and ellagitannins induce apoptosis, decrease
cell number, and cause alterations in cell cycle kinetics in colon
carcinoma cells (Mertens-Talcott
et al
., 2006b).
Pomegranate fruit juice is effective against prostate cancer cells
in
vitro
, but not against normal prostate epithelial cells. Treatment of highly
aggressive human prostate cancer cells with pomegranate fruit extract
resulted in inhibition of cell growth and viability and induction of
apoptosis (Malik
et al.
, 2005, Malik and Mukhtar, 2006).
The effects of ellagitannins observed in these studies are probably
mainly due to their hydrolysis product, ellagic acid. Pomegranate and
raspberry ellagitannins produce ellagic acid in the cell culture media
(Larrosa
et al
., 2006, Ross
et al
., 2007), and ellagic acid reduces cell
proliferation and induces cell cycle arrest and apoptosis (Narayanan
et
al.
, 1999, Losso
et al
., 2004, Larrosa
et al
., 2006, Wu
et al
., 2007). Also