Short-term tests of estrogenic potential of plant stanols and plant stanolesters

To test for potential estrogenic activity of plant stanols and plant stanol esters, two short-term tests were performed. These were the E-screen test, which measures a substance's ability to induce proliferation of estrogen-r esponsive human breast adenocarcinoma (MCF-7) cells in culture, and an in v ivo test, which measures uterotrophic activity in immature female rats fed the test substance. Four samples of vegetable oil-derived stanols (containi ng 88-99% stanols) were tested in the E-screen test, and one sample of wood -derived and one of vegetable oil-derived stanol fatty acid eaters were tes ted in the in vivo test. In the E-screen test, the positive control substan ce, 17 beta-estradiol, at 100 pM, produced a statistically significant, 11. 6-fold increase in cell proliferation, as measured by sulforhodamine B stai ning. None of the stanol preparations produced any increase in cell prolife ration when tested at 1, 10, and 100 mu M. The highest dose of each stanol sample was associated with microscopic evidence of cytotoxicity and crystal line precipitation in the culture dishes. In the in vivo test, the positive control compound, diethylstilbestrol, produced a significant, dose-related increase in absolute and relative uterus weight in young female rats (17 d ays old at the start of treatment) fed the compound at 5, 10, and 20 ppb in the diet for 4 days. Neither of the two stanol ester preparations caused a ny significant change in absolute or relative uterus weight when fed at a c oncentration of 8.3% in the diet for 4 days. Thus, under the conditions of testing used, neither the free stanols nor the stanol fatty acid ester prep arations showed evidence of estrogenic or uterotrophic activity. (C) 1999 A cademic Press.