Biology Reference
In-Depth Information
cloudberries against intestinal tumorigenesis in the Min mouse
(Paivarinta
et al.
, 2006). This result raises new questions about the
influence of the animal model on the results of a particular study. There
may be different responses against a specific treatment from animals
with chemically induced tumours and from genetically modified animals
that spontaneously develop a tumor such as the
Apc
-mutated Min mice
used by Paivarinta
et al.
(2006).
Recently, a Phase II clinical trial administering pomegranate juice to
patients with prostate cancer has demonstrated a statistically significant
prolongation of the PSA (prostate serum cancer biomarker) doubling
time (Pantuck
et al.
, 2006). These results suggest some protective effects
of the pomegranate juice in humans. To further understand and reveal the
biological protective effects of ETs, it is essential that we clarify the
bioavailability and metabolism of these compounds, by performing
analysis of ETs and their metabolites
in vivo
in animal and human
studies.
7.4 Is the Analytical Methodology Ready for the Analysis of these
Metabolites
in vivo
?
The analysis of ETs in food products and in biological fluids presents
some limitations. These compounds are present in foods mostly as large
molecules with rather unspecific UV spectra, which hampers their
identification from the chromatographic profile (UV spectra generally do
not show a characteristic maximum in the 250-400 nm range that is
common for other phenolic compounds). Acid hydrolysis of ETs releases
EA, which can be qualitative and quantitative measured, but this
hydrolysis is not always complete and can yield other artefactual
compounds (
e.g.
, EA methyl ethers) hindering the quantification of ETs.
In addition, ETs can interact with proteins and precipitate, hence adding
to the analysis difficulties of ETs and their metabolites in food and in
biological fluids.
The improvement of HPLC detection systems with the introduction
of MS and MS-MS detectors has allowed the determination of different
ETs in food products, and recent publications show that these ETs are
