Mechanism of Action of Tephrosia vogelii Leaf Extract on Isolated Rabbit Jejunum

Abstract

ABSTRACT An investigation was carried out on the isolated rabbit jejunum using the crude methanolic leaf extract of Tephrosia vogelii Hook. f. (Fabaceae) with the aim of determining the possible mechanism by which it increases the contractions of intestinal smooth muscle. Atropine concentration-dependently (2.0 × 10−10–6.4 × 10−9 g/ml) blocked the effect of the extract (2.0 × 10−4–4.0 × 10−4 g/ml) on both the frequency and amplitude of contraction of the isolated tissue (n = 4). Similarly, nifedipine concentration-dependently (4.0 × 10−9–8.0 × 10−6 g/ml) blocked the effect of the extract (2.0 × 10−4–4.0 × 10−4 g/ml) on both the frequency and amplitude of contraction of the tissue (n = 4). The extract, apparently, acted through muscarinic cholinergic receptors present in the tissue, and this action probably involved the mobilization of extracellular calcium ions.