| ABSTRACT: |
|
Ellagic acid (EA), a plant phenol, is reported to possess
antimutagenic and anticarcinogenic activity. In the present study,
explants of esophagus, trachea, colon, forestomach and bladder from young
male Sprague-Dawley rats were incubated in medium containing [3H]EA (4.5
mu Ci/ml) for 24 h at 37 degrees C. DNA from these explants was extracted,
purified and quantitated to determine [3H]EA binding to the DNA.
Significant covalent binding of [3H]EA to DNA occurred in all the
explants. Calf thymus DNA incubated in 0.05 M sodium phosphate buffer
containing [3H]EA covalently bound [3H]EA in a concentration dependent
manner. Furthermore covalent binding of [3H]EA to calf thymus DNA was
inhibited by the addition of unlabeled EA that was concentration dependent
over a range of 50-150 microM and by the addition of unlabeled adenosine,
cytidine, guanosine or thymidine at a concentration of 1.0 mM. These
results suggest that one of the mechanisms by which EA inhibits
mutagenesis and carcinogenesis is by forming adducts with DNA, thus
masking binding sites to be occupied by the mutagen or carcinogen. |