EFFECTS OF SESAMUM RADIATUM AQUEOUS LEAF EXTRACT ON RHYTHMIC CONTRACTIONS OF UTERINE SMOOTH MUSCLE BUNDLES FROM PREGNANT RATS

Abstract

Sesamum radiatum is employed in traditional medicine for parturient women to facilitate deliveries. In this study, the effects of the aqueous leaf extract were examined on the contractile activity of uterine smooth muscle isolated from pregnant Wistar rats (19-21 days). The isometric contractile force of the uterine smooth muscle bundles was recorded by using a strain gauge. S. radiatum aqueous leaf extracts (ESera, 1×10 -4 µg/ml - 100µg/ml) showed uterotonic properties. These uterotonic effects were characterized by the increase of the amplitude, the frequency and the basal tone of the uterine smooth muscle strips in normal Mac Ewen solution and by the development of contracture in depolarizing solution and in solution without calcium. Similar effects were observed with Oxytocin (OT, 2.5×10 -14 µg/ml - 2.5×10 -9 µg/ml) and misoprostol (Miso, 1×10 -3 µg/ml - 0.08µg/ml). In Ca 2+ -free solution, the addition of the ESera (10 µg / ml) elicited the development of contracture in the presence of EGTA (0.1 mM). This result suggests that ESera could act on the double calcium flux (intracellular and extracellular) like misoprostol, a synthetic analogue of prostaglandin E1. In conclusion, the aqueous leaf extract of S. radiatum (ESera) had uterotonic effects (prostaglandin-like activity) on uterine contraction in pregnant rats.