Biology Reference
In-Depth Information
associated with enhanced atherogenicity. Platelet activation was shown
to be associated with oxidative stress. Following 2 weeks of pomegranate
juice consumption, a significant reduction (11%) in collagen-induced
platelet aggregation was noted (Fuhrman and Aviram, 2006). The
authors link the effects to an interaction of pomegranate polyphenols
with the platelet surface binding sites for collagen and that their
antioxidative properties can attenuate oxidative stress-induced platelet
activation.
It has also been published that pomegranate juice polyphenols can
protect LDL against cell-mediated oxidation via two pathways, a direct
interaction of polyphenols with the lipoprotein, an indirect effect through
polyphenols accumulation in arterial macrophages or both (Fuhrman and
Aviram, 2006). All these antioxidative and antiatherogenic effects of
pomegranate polyphenols have been demonstrated
in vitro
, and
in vivo
in
humans and in atherosclerotic apolipoprotein E-deficient mice.
EA and ETs-containing foodstuffs have also been acknowledged
with cancer chemopreventive activities. There are a number of
in vitro
studies on various cancer cell lines that show the antiproliferative and
pro-apoptotic effects of these compounds. The bioavailability and
metabolism of ETs or EA are however very important issues when it
comes to select the appropriate cell line for a particular study. From a
dietary point of view, if ETs or EA are poorly absorbed from the gut, it
is then not appropriate to test these compounds at μM concentrations
against cell lines representative of systemic organs or tissues. This would
require a high absorption of the compounds into the blood system to
reach the target organ (
e.g.
, breast, brain).
The chemopreventive effect of ETs could result from inhibition of
nuclear-κβ signalling (Kuo
et al.
, 2007), decrease of intracellular redox
status and activation of JNK-1/p38 (Chen
et al.
, 2007), and induction of
apoptosis
via
intrinsic pathway (Larrosa
et al.
, 2006a) among other
reported tentative pathways. Whether the action is promoted by the ETs
themselves or by hydrolysis products such as EA or by valenoic acid
dilactone has not been investigated. In this context, in the case of the
pomegranate ET, punicalagin, a recent work has reported that EA is the
real active component rather than its punicalagin precursor (Larrosa
et al.
, 2006a). Punicalagin and EA provoked the same effects on Caco-2
