Antidiarrheal Effect of 80% Methanol Extract and Fractions of Clerodendrum myricoides (Hochst.) Vatke (Lamiaceae) Leaf in Swiss Albino Mice

Background. Diarrhea is one of the tempting symptoms of diseases in the world. In Ethiopian traditional medicine practices, Clerodendrum myricoides is utilized for the treatment of diarrhea without scientific evidence. Objective. This study was aimed to evaluate the antidiarrheal activity of 80% methanol extract and fractions of the leaf of Clerodendrum myricoides in mice. Methods. The crude extract was prepared by maceration in 80% methanol and then fractionated using hexane, chloroform, and distilled water. Antidiarrheal activity was assessed by castor oil-induced diarrhea, enteropooling, and gastrointestinal motility models using onset of diarrhea, number and weight of feces, volume and weight of intestinal contents, and distance travelled by charcoal meal as main parameters. Negative controls received either distilled water or 2% Tween 80 (10 ml/kg), positive controls received 3 mg/kg loperamide or 1 mg/kg atropine, and the test groups received 100, 200, and 400 mg/kg doses of the extract. Results. The crude extract and chloroform fraction significantly prolonged the onset of diarrhea at 200 and 400 mg/kg and decreased the number of wet, total, and weight of fresh feces at all tested doses. Hexane fraction has a significant antidiarrheal effect on the onset, number, and weight of feces at 400 mg/kg. The crude extract and chloroform fraction at all tested doses, as well as aqueous fraction at 200 mg/kg and 100 mg/kg, produced significant reduction in volume and weight of intestinal contents. Additionally, hexane fraction showed significant reduction of volume and weight of the intestinal content at 400 mg/kg. In the gastrointestinal motility test model, both chloroform fraction and crude extract at all tested doses and aqueous fraction at 200 mg/kg and 400 mg/kg showed a significant antidiarrheal effect as compared to the negative control. Conclusion. The leaf of Clerodendrum myricoides showed antidiarrheal activity which supports the traditional use.