The Effects of Crude Extracts and Fractions of Alchemilla abyssinica on Smooth Muscle of Guinea-pig Ileum: An in Vitro Study

Background: Alchemilla abyssinica is a plant widely used in traditional medicine. Its wide use among the community plus already established scientific evidences for medicinal values of other Alchemilla species provided good ground for this investigation. Methods: In this research, CHCl3/EtoAc 1:1 extract of dried aerial parts of Alchemilla abyssinica, methanolic extract of the CHCl3/ EtoAc residue and fractions of the methanolic extract were tested on isolated guinea-pig ileum (GPI) for possible presence of spasmogenic or spasmolytic effects. Concentrations of each extract and fraction ranging from 20-600 μg/ml final organ bath concentration were tested. The effects of these test samples on the basal rhythmic contractions of the GPI as well as on its contraction elicited using the agonist, histamine, were determined. The antagonist, Papaverine, was also used as a control smooth muscle relaxant. Results: While the CHCl3/EtoAc 1:1 extract showed neither spasmogenic nor spasmolytic result, the methanolic extract showed marked spasmolytic effect. This methanolic extract was fractionated using column chromatography and the fraction eluted using Hexane/EtoAc 1:2 gave greatest spasmolytic result. This fraction produced significant (P<0.05) dose-dependent spasmolytic effects on the agonist induced contractions of the GPI to 95.7% at 20 μg/ml, 43.6% at 70 μg/ml and 14.2% at 120 μg/ml in the organ bath. Conclusions: The results of the present study showed that Alchemilla abyssinica possesses spasmolytic property. The oral acute toxicity study showed Alchemilla abyssinica exhibited no toxicity up to doses of 1,000 mg/kg body weight in Swiss albino mice. Further chemical work to identify the compound(s) responsible for the activity is recommended.