Biology Reference
In-Depth Information
it increased adenoma size in the duodenum. Animal and human studies
have provided promising evidence on the potential of pomegranate juice
in the chemoprevention of prostate cancer. Athymic nude mice were
implanted with androgen-sensitive cells, which form rapid and
reproducible prostate carcinoma tumors in nude mice and secrete PSA
(prostate-specific antigen, a marker of prostate cancer progression) in the
blood of the host. Oral administration of a human acceptable dose of
pomegranate fruit extract to the animals resulted in inhibition of tumor
growth and concomitant decrease in the serum PSA levels (Malik
et al.
,
2005, Malik and Mukhtar, 2006).
A clinical trial has been conducted to investigate the effects of
pomegranate juice consumption in patients with recurrent prostate cancer
(Pantuck
et al.
, 2006). Men with rising PSA levels after surgery or
radiotherapy consumed 240 mL of commercial pomegranate juice daily
until disease progression. A significant prolongation of PSA doubling
time was observed, suggesting delayed progression of the disease. Serum
antioxidant status was also improved, and
in vitro
assays of the patients'
sera showed decreased proliferation and increased apoptosis of prostate
cancer cells.
8.5
Conclusions
According to the present knowledge, berries of
Rubus
,
Fragaria
and
Rosa
species, as well as pomegranate and muscadine grape products and
walnuts are the best dietary sources of ellagitannins. Due to limited food
sources, the dietary intake of ellagitannins and ellagic acid is probably
low compared to many other polyphenols. Experimental studies on
ellagitannin-rich foods have demonstrated potential for health benefits,
and dietary interventions are being conducted in patients at increased risk
for cancer development. In addition to high levels of ellagitannins,
berries, pomegranates and walnuts also contain a variety of other
phytochemicals, essential fatty acids and other nutrients, and may
therefore be regarded as “health foods” or even “superfoods”. Research
is progressing in many laboratories and will eventually provide new
evidence on the health effects of dietary ellagitannins. Meanwhile,
