Acetic acid suppresses the increase in disaccharidase activity that occursduring culture of Caco-2 cells

To understand how blood glucose level is lowered by oral administration of vinegar, we examined effects of acetic acid on glucose transport and disacc haridase activity in Caco-2 cells. Cells were cultured for 15 d in a medium containing 5 mmol/L of acetic acid. This chronic treatment did not affect cell growth or viability, and furthermore, apoptotic cell death was not obs erved, Glucose transport, evaluated with a nonmetabolizable substrate, 3-O- methyl glucose, also was not affected. However, the increase of sucrase act ivity observed in control cells (no acetic acid) was significantly suppress ed by acetic acid (P < 0.01). Acetic acid suppressed sucrase activity in co ncentration- and time-dependent manners. Similar treatments (5 mmol/L and 1 5 d) with other organic acids such as citric, succinic, L-maric, L-lactic, L-tartaric and itaconic acids, did not suppress the increase in sucrase act ivity. Acetic acid treatment (5 mmol/L and 15 d) significantly decreased th e activities of disaccharidases (sucrase, maltase, trehalase and lactase) a nd angiotensin-I-converting enzyme, whereas the activities of other hydrola ses (alkaline phosphatase, aminopeptidase-N, dipeptidylpeptidase-IV and gam ma-glutamyltranspeptidase) were not affected. To understand mechanisms unde rlying the suppression of disaccharidase activity by acetic acid, Northern and Western analyses of the sucrase-isomaltase complex were performed. Acet ic acid did not affect the de novo synthesis of this complex at either the transcriptional or translational levels. The antihyperglycemic effect of ac etic acid may be partially due to the suppression of disaccharidase activit y. This suppression seems to occur during the post-translational processing .