IDENTIFICATION OF A CLASS-3 ALDEHYDE DEHYDROGENASE IN HUMAN SALIVA AND INCREASED LEVELS OF THIS ENZYME, GLUTATHIONE S-TRANSFERASES, AND DT-DIAPHORASE IN THE SALIVA OF SUBJECTS WHO CONTINUALLY INGEST LARGE QUANTITIES OF COFFEE OR BROCCOLI

Human saliva was tested for the presence of cytosolic class 3 aldehyde dehydrogenase, glutathione S-transferases alpha, mu, and pi, and DT-d iaphorase, enzymes that are known to catalyze the biotransformation of many xenobiotics, including some that are carcinogens and some that a re antineoplastic agents, Each of these enzymes was found to be presen t in this fluid, Inducers of these enzymes are known to be abundantly present in the human diet, especially in certain vegetables and fruits , Further investigation revealed that the salivary content of these en zymes rapidly, coordinately, and markedly increased upon daily consump tion of relatively large amounts of coffee or broccoli, The enzyme act ivities of interest rapidly returned to basal levels when these substa nces were removed from the diet, Given the important role that cytosol ic class 3 aldehyde dehydrogenase, the glutathione S-transferases, and DT-diaphorase are thought to play in determining the carcinogenic pot ential of some cancer-producing agents as,yell as the cytotoxic potent ial of some antineoplastic agents, and assuming that their salivary le vels reflect their tissue levels, quantification of the salivary conte nt of one or more of these enzymes, a noninvasive and relatively easy undertaking, could be useful in: (a) preliminarily assessing the chemo preventive potential of various diets and drugs; (b) establishing the optimal dose and schedule in Phase I clinical trials for any putativel y chemopreventive diets or drugs of interest; and (c) the rational sel ection and use of chemotherapeutic agents, since several are inactivat ed, and a few are activated, by these enzymes; alternatively, the anti neoplastic agent could be selected first and then a diet that enables the agent to achieve its full therapeutic potential would be selected based on whether high or low enzyme activity would be favorable in tha t regard, Such measurements may also be useful as an indicator when ex posure to carcinogenic/teratogenic/otherwise toxic environmental/indus trial/dietary agents that induce these enzymes is suspected.