“Inhibition was time and dose dependent, with 52 +/- 5% (mean +/- SE, n = 6) inhibition at 60 min and 82 +/- 9% (n = 3) … starting at 4 h. Low-molecular-mass tannin (1,000-5,000 Da) had no effect on Iso-stimulated cAMP accumulation, whereas N-acetylcysteine , which … of tannin ….”