Intestinal absorption of daphnetin by rats single pass perfusion in situ

This study investigated the effects of concentration, intestinal section, pH and P-gp on the absorption of daphnetin.  The absorptions of three concentrations (10, 20, 40 μg·mL⁻¹) of daphnetin in different intestinal segments were studied with phenol red as the marker by in situ rats single pass perfusion model.  The results showed that daphnetin was stable under pH 6.0 condition and little affected by metabolism enzyme.  There  was upgrade tendency between the P_eff of duodenum, jejunum, ileum and colon in different concentration of daphnetin, and it has obvious difference between the high concentration and low concentration in jejunum and colon, which indicated that the absorption of daphnetin was passive diffusion and no difference in different  segments of rat intestine.  However, compared with colon, the absorption of small intestine was better significantly (P < 0.05).  Daphnetin may be not a substrate of P-gp as verapamil had not significantly affected the absorption of daphnetin in different intestinal segments of rats.