Uterine Contractile Activity and Abortifacient Effect of the Aqueous Extract of Euphorbia heterophylla L. Leaves in Albino Rats

Abstract

Background and Purpose: Euphorbia heterophylla Linn. (Euphorbiaceae) is a promising medicinal plant used as an oxytocic in folkloric medicine. The study investigated the uterotonic and abortifacient effects of the aqueous leaf extract of Euphorbia heterophylla (AEEH).   Methods: GC-MS analysis of AEEH was done. In vitro experiment on the contractile activity of AEEH was conducted on the uterus of nulliparous female Sprague Dawley rats using an isolated organ bath. The abortifacient activity of the extract was determined in pregnant rats orally administered 50, 100, 200, and 400 mg/kg AEEH for five consecutive days. Results: GC-MS analysis of AEEH revealed high amounts of 1-butanol 3-methyl acetate, benzofuran,2,3-dihydro-, 2-methoxy-4-vinyl phenol, and sucrose. Some of the classes of compounds identified in the extract such as phenols, terpenoids, fatty acids, aldehydes, steroid, and glucoside have been associated with uterotonic and abortifacient properties. The extract (0.125-4 mg/mL) was able to enhance the contractile activity of uterine smooth muscles (EC50 = 3.39 × 10-1 mg/mL) similar to oxytocin (EC50 = 3.99 × 10-4 mg/mL) and acetylcholine (EC50=2.68 × 10-4 mg/mL). Pre-treatment with salbutamol, indomethacin, and stimulation in a calcium-deprived medium significantly (P<0.0001) reduced uterine contractions induced by cumulative concentrations of the aqueous extract. However, there was no significant change in uterine contraction in tissues pre-treated with atropine. The aqueous extract induced abortion in 50%, and 83.33% of the animals at 200, and 400 mg/kg respectively when orally administered to pregnant rats for five days.  Conclusions: This study demonstrates the uterotonic and abortifacient effects of AEEH and supports the ethnomedicinal use of the plant as an oxytocic.