Contraction Of Isolated Guinea Pig Ileum By <i>Tephrosia vogelii</i> Extract

Abstract

An investigation was carried out on the isolated guinea pig ileum, using the crude methanolic leaf extract of Tephrosia vogelii Hook. f., and with the aim of determining its effects on contraction of intestinal smooth muscle. Modified Magnus technique was employed in setting up the tissue. Acetylcholine (ACh), histamine and serotonin (5-hydroxytryptamine, 5-HT) were used as standard agonists with which the effects of the extract of T. vogelii were compared. The extract concentration-dependently (3.2 x 10-5 - 4.10 x 10-3 g/ml) contracted the isolated muscle tissue (n = 7) in a similar fashion as did ACh (4.0 x 10-9 - 5.12 x 10-7 g/ml), histamine (4.0 x 10-9 - 5.12 x 10-7 g/ml) and 5-HT (3.2 x 10-8 - 4.10 x l0-6 g/ml). The maximal contractile effect (Emax) of the extract on the tissue was found to be 48.39 %, 48.61 % and 61.56 % that of ACh, histamine and 5-HT, respectively. The effective concentration of the extract that produced half of its maximal effect (EC50) was calculated to be 2.37 x l0-4 g/ml, whereas the values for ACh, histamine and 5-HT were 2.10 x l0-8, 3.76 x l0-8 and 1.88 x 10-7 g/ml, respectively. In conclusion, the methanolic leaf extract of T. vogelii exerted stimulatory effects on the intestinal smooth muscle which may be likened to those of standard agonists like ACh, histamine and 5-HT. The results provided some scientific basis for the use of T. vogelii leaves as a purgative in traditional medicine.

Keywords: Acetylcholine, Histamine, Ileum, Purgative, Tephrosia vogelii

Nigerian Veterinary Journal Vol. 27 (3) 2006 pp. 46-52