| ABSTRACT: |
|
Fruits and vegetables are a good source of bioflavonoids, compounds
that exhibit a wide range of biological activities, including
anti-tumorigenic effects. Some flavonoids possess
estrogenic/antiestrogenic activity which may be responsible for the
significantly lowered risk of hormone-dependent cancers among vegetarians.
Using the expression of pS2 mRNA in MCF-7 cells as an indicator of
estrogenic or antiestrogenic activity, we have identified curcumin,
dimethoxycoumarin, ellagic acid, epigallocatechin, genkwanin, pinocembrin
and tangeretin, at 10(-6) M, as being estrogenic. We observed a
differential response when each flavonoid was added along with estradiol,
with a few having an additive effect on pS2 expression while others were
competitive. The effect of these compounds on the proliferation of MCF-7
cells was also examined. While most of the estrogenic flavonoids
stimulated growth, tangeretin and dimethoxycoumarin did not, despite being
estrogenic at similar concentrations. Our results suggest that there are
qualitative differences in the biological activities of the various
flavonoids tested. |