1Laboratoire
de Pharmacodynamie Biochimique, UFR
Biosciences Université d’ Abidjan – Cocody,
22 BP 582 Abidjan 22, 2Laboratoire
des sciences des Aliments, UFR Biosciences
Université d’ Abidjan – Cocody, 22 BP 582
Abidjan 22, 3Laboratoire de
Physiologie Animale, UFR Biosciences
Université d’ Abidjan – Cocody, 22 BP 582
Abidjan 22, Côte d’Ivoire
Tropical
Journal of Pharmaceutical Research, February
2009; 8(1):
11-17
Abstract
Purpose:
In previous studies,
the aqueous extract of Trema guineensis (Ulmaceae) was
shown to increase rabbit duodenal contractions. The aim
of this study was to evaluate the mechanism of the
stimulation of the rabbit duodenum by the aqueous
extract of Trema guineensis (Ulmaceae).
Methods:
The in vitro organ bath method was used in our
experiments. The enzyme was extracted from rabbit
duodenum. The acetylcholinesterase (AChE) activity was
determined by Ellman’s assay using acethylthiocholine
iodide as substrate. The rate of hydrolysis of
acetylcholinesterase was monitored
at 412 nm using a spectrophotometer.
Results:
The effective concentration which induces 50% effect of
Hypo+ (EC50) was obtained with 8 x 10-2
mg/ml of Hypo+. The tests carried out in the presence of
atropine showed a considerable reduction in the
amplitudes of intestinal contractions. Hypo+ exerted
mixed competitive inhibition on acetylcholinesterase (Vmax
= 8.33 µM/min and KM= 6.25 x 10-4
M). These results indicate that the crude extract of
Trema guineensis contains anti-AChE and cholinomimetic
substances. These two properties can explain the
increase of duodenal contraction by Hypo+.
Conclusion:These
results support the use of Trema guineensis as a
laxative due to its stimulating effects on duodenal
contractility.
Key
words:
Trema
guineensis, Myostimulation, Acetylcholinesterase, Hypo+,
Duodenal contraction
