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Table of Contents | |
FLAVONOIDS
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| Biol Trace Elem Res 1998 Jun;62(3):135-53 |
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Dietary flavonoids interact with trace metals and affect
metallothionein level in human intestinal cells.
Kuo SM, Leavitt PS, Lin CP
Nutrition Program, State University of New York at Buffalo, 14214, USA.
Flavonoids are natural compounds found in food items of plant origin. The
study examined systematically the interaction of structurally diverse
dietary flavonoids with trace metal ions and the potential impact of dietary
flavonoids on the function of intestinal cells. Spectrum analysis was first
performed to determine flavonoid-metal interaction in the buffer. Among the
flavonoids tested, genistein, biochanin-A, naringin, and naringenin did not
interact with any metal ions tested. Members of the flavonol family,
quercetin, rutin, kaempferol, flavanol, and catechin, were found to interact
with Cu(II) and Fe(III). On prolonged exposure, quercetin also interacted
with Mn(II). Quercetin at 1:1 ratio to Cu(II) completely blocked the
Cu-dependent color formation from hematoxylin. When quercetin was added to
the growth medium of cultured human intestinal cells, Caco-2, the level of
metal binding antioxidant protein, metallothionein, decreased. The effect of
quercetin on metallothionein was dose- and time-dependent. Genistein and
biochanin A, on the contrary, increased the level of metallothionein. The
interaction between dietary flavonoids and trace minerals and the effect of
flavonoids on metallothionein level imply that flavonoids may affect metal
homeostasis and cellular oxidative status in a structure-specific fashion.
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