Oxytocic and anti-implantation activities of the leaf extracts of Graptophyllum pictum (Linn.) Griff. (Acanthaceae)

Abstract

This study was aimed at evaluating Graptophyllum pictum aqueous extract (GPAE) and ethanol extract (GPEE) in vitro for oxytocic and in vivo for anti-implantation activities. The oxytocic screening of the extracts was carried out on the isolated strip of gravid rat uterus in mid pregnancy and was compared with the activity of an agonist drug, oxytocin. GPEE exhibited oxytocic activity which is comparable to oxytocin while GPAE was found to reduce the normal contraction of the uterine strip. The antiimplantation
investigation was done using three groups of eight week old virgin female Sprague-Dawley albino rats (eight rats/group). A selected dose (400 mg/kg) of GPEE was orally administered to a group of the rats. The same dose of GPAE was similarly administered to another group while the vehicle of administration (distilled water) was similarly administered to the third group as control. All administrations started on day one of pregnancy and were given daily for seven days. The rats were sacrificed on day 10 of pregnancy. Presence of foetus, implantation sites and number of corporal lutea in the autopsied rats were recorded and used to calculate the percentage anti-implantation effect. GPEE, GPAE and distilled water have percentage anti-implantation value of 93.8 ± 9.1, 16.8 ± 8.5 and 3.9
± 5.4, respectively. The results support the use of this plant in folkloric medicine as a delivery aid and also suggest that the plant can be used very early in pregnancy as a contraceptive.