Apple pectin and polyphenol-rich
apple juice have an anticarcinogenic effect on the colon,
encouraging the production of suspected chemopreventative
metabolite butyrate, say researchers.
Butyrate is a short chain fatty acid (SCFA) that has been
found to be a major factor contributing to healthy colon
mucosa.
The study, published in the April issue of Nutrition,
looked at human faecal matter fermented with apple
constituents and found a significantly increased yield of
SCFA, most notably butyrate.
"Butyrate not only serves as a major nutrient for the
colon epithelia but is also thought to play an important
role in the protective effect of natural fibre against
colorectal cancer," said the German research team, led by
Dieter Schrenk.
This is the not the first study to find benefits of fruits
in cancer prevention and treatment. A recent study in
California found low doses of freeze-dried grape powder
could inhibit the development of colorectal cancer thanks
to the polyphenol resveratrol and synergistic effects
between the grape compounds.
The study
Faecal slurry from healthy individuals was fermented with
apple constituents, such as apple pectin and apple juice
extracts that were high in polyphenols.
The samples that were fermented with pectin were rich in
butyrate and the scientists concluded that this assisted
in colon health because of its effect on histone
deacetylases (HDAC).
When the butyrate content was high, HDAC was inhibited.
With slower production of HDAC, there would be
significantly less growth of precancerous and tumour
cells.
Fermentations with pectin were very active in HDAC
inhibition in nuclear extracts prepared from the colon
tumour cell lines HT-29 and Caco-2 and in intact HeLa Mad
38 cells bearing a reporter gene driven by HDAC
inhibition.
Faecal slurry fermented with apple juice extracts showed
lower butyrate yields but comparable HDAC inhibition.
Combined incubations of pectin with apple juice extracts
resulted in effects similar to those with pectin as the
only substrate added.
The researchers concluded that butyerate is the most
relevant HDAC inhibitor formed in fermentations of human
faecal slurry with apple pectin, whereas addition of apple
juice extracts leads to the formation of butyrate and
other HDAC inhibitors, which are as yet unknown.
The study presents some sound findings to act as a base
for further study into colon cancer prevention, which is
the third most prolific type of cancer in western
industrialised countries, causing 650,000 deaths a year.
Sources
Nutrition
April 2008, 366-374, doi:10.1016/j.nut.2007.12.013
"Histone-deacetylase inhibition and butyrate formation:
Fecal slurry incubations with apple pectin and apple juice
extracts"
Authors: Markus Waldecker, Tanja Kautenburger, Heike
Daumann, Selveraju Veeriah, Frank Will, Helmut Dietrich,
Beactrice Louise Pool-Zobel and Dieter Schrenk |
