Inhibition of Transformation in Cultured Rat Trachéal Epithelial Cells by Potential Chemopreventive Agents1

compounds were /V-acetylcysteine, bismuththiol. calcium glucarate, (±) catechin, diallyl disulfide, glycaric acid, i>-glucaro-l,4-lactone. \-(4hydro\yphenyl)retinamide, n-limonene, mesna, retinole acid, rutin, quercetin, silymarin, and taurine. In examining the nature of compounds that inhibited rat trachea! epithelial cell transformation, several possible chemoprevcntivc mechanisms appeared to be predominant: compounds that »erepositive (a) increased glutathione levels or enhanced conjuga tion; (b) increased cytochrome P-450 activity; (c) displayed nucleophilic activity; or (d) induced differentiation. Thirteen compounds were negative in the rat trachea! epithelial trans formation inhibition assay: crocetin. difluoromethylornithine, ellagic acid, esculetin, enoxalone. ibuprofen, levamisole. nordihydroguaiaretic acid, i 2-oxothia*olidine-4-carboxyIate, piroxicam, sodium butyrate, i>-.. n>copherol acetate, and polyethylene glycol 400. It »asevident from these results that this assay would not detect compounds that »ere(a) antipromoting in nature; (b) glutathione inhibitors; (c) differentiation inhibi tors; (d) O6-methylguanine inhibitors; (<')organ specific; or (/) inactive.