Cocoa-Related Flavonoids Inhibit CFTR-Mediated Chloride Transport across T84 Human Colon Epithelia1

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Link to full text:

http://jn.nutrition.org/cgi/content/full/135/10/2320

*ABSTRACT

Cocoa beans have historically been used as a treatment for diarrhea,

leading us to hypothesize that polyphenols contained in cocoa inhibit

intestinal Cl– secretion. In this study, the dose-dependent effects of

flavonoid compounds present in cocoa, or molecularly closely related

compounds, were tested on forskolin-stimulated cystic fibrosis

transmembrane conductance regulator (CFTR)-mediated Cl– secretion across

T84 colonic epithelia in Ussing chambers. Addition of cocoa extract or

cocoa flavanols to the mucosal side of tissues caused partial inhibition

following is-Menten kinetics and resulted in a rank order of

maximum blocker effects as follows: epicatechin > catechin ≥

standardized cocoa preparation ≥ procyanidin B2. Half-maximal blocker

concentrations (Ki) were not substantially different between the tested

preparations and were in the range of 100 µmol/L. For comparison, the

structurally related flavonoids, quercetin and luteolin, caused a total

block of Cl– currents with Ki values similar to the cocoa flavanols

tested. Morin and baicalein were less effective blockers. Effects of

test compounds on mucosal redox potential did not correlate with blocker

activity. These data indicate that cocoa flavanols target intestinal

CFTR Cl– transport and may serve as mild inhibitors of cAMP-stimulated

Cl– secretion in the intestine.*

I noticed this article, and the fact that it involves CTFR raised some

questions in my mind. First, if the research linking PSC to CFTR

deficiency is correct, does this mean that chocolate which seems to

further inhibit CFTR might cause additional problems for us? Or does it

mean that since many of us suffer from diarrhea we should eat more

chocolate (since inhibiting CFTR may help with diarrhea)? Or is there

another conclusion, or no conclusion to be drawn from this?

Just curious!

athan