Ellagic acid metabolism and binding to DNA in organ explant cultures of the rat

Ellagic acid (EA) is a plant phenolic compound with postulated antimutagenic and anticarcinogenic activity. In this study, explants of esophagus, forestomach, colon, bladder, trachea, lung and liver from male Sprague-Dawley rats (130-140 g) were incubated in culture medium containing [³H]EA (20 μM, 4.5 μCi/ml) for 24 h at 37°C. After extraction, purification and quantitation of explant DNA significant differences in the binding of EA to the DNA was observed. The most binding occurred in esophagus and the least in lung. Analysis of the organosoluble fraction of the culture medium by high performance liquid chromatography yielded 3 metabolites of EA. None of the metabolites were identified. Elution of water-soluble metabolites from an alumina column showed that there were sulfate ester, glucuronide and glutathione conjugates of EA in the explant culture medium from all the organs. The profile of water-soluble conjugates was very similar between colon and forestomach and between trachea and lung. These results indicate that EA binds to DNA in different tissues and that tissues metabolize EA to both organosoluble and water-soluble products.