Fig. 1. Effect of IPA, indole, tryptophan, and propionate at 1, 10, 100, 250, and 500 μM on the viability of Caco-2 cells, following 2 (A), 24 (B), and 72 h treatment periods. Cell viability was determined by the MTT assay. Results are shown as % of control. Data are expressed as mean ± SEM (n = 8).

Ctrl, control; IPA, indole-3-propionic acid; ACN, acetonitrile; FA, formic acid.