Transport of harman alkaloids across Caco-2 cell monolayers.

This study examined the intestinal transport of five harman alkaloids using the Caco-2 cell monolayer as a model of the human intestinal mucosa. Transport parameters, permeability coefficients and percent transports, were calculated and compared under identical conditions with atenolol. Permeability coefficients were also compared with the reported values for model compounds like mannitol, propranolol and glucose. Sodium fluorescein was used as the marker for paracellular leakage. These alkaloids, in the concentration range of 250-500 microM, demonstrated substantial transport across the monolayer with moderate to high efflux rates and permeability coefficients. The transport was linear with time and was concentration dependent.