In this study, pharmacological reactivity of rabbit ileum to crude extract of fruits of Xylopia aethiopica in the presence of other agonist and antagonist agents was evaluated. The contractility of the isolated rabbit ileum was recorded using kymograph. The effects of the crude extract of X. aethiopica on rabbit ileum were independently determined using a dose range of 10-8 to 10-4 mg/ml. However, to determine the effects of the extract on rabbit ileum in the presence of other agonist and antagonist a constant dose of 10-4 mg/ml of the extract was used. The result showed that the crude extract of X. aethiopica, nifedipine only and serotonin only produced a significant (p<0.001) dose dependent relaxation of the ileum muscle. Addition of the extract to nifedipine shifted the graph to the right. Administration of CaCl2 alone produce a dose dependent contraction of the rabbit ileum with negative correlation coefficient (p<0.001). Co-administration of CaCl2 with the extract shifted the CaCl2 response curve to the left. Addition of extract to serotonin caused a significant (p<0.01) decreased in the relaxation of the rabbit ileum. In conclusion, this study suggests that X. aethiopica has smooth muscle relaxant effects on rabbit ileum and as such may reduce gastrointestinal motility.
Key word: Xylopia aethiopica, smooth muscle, Ileum, motility, agonist.