Antidiarrheal Effects of <i>Sophora alopecuroides</i> L. Var. Alopecuroides Seeds and Matrine in a Mouse Model of Castor Oil-Induced Diarrhea

Abstract

Background: Sophora alopecuroides L. var. alopecuroides (SAA) seeds have long been used in Persian medicine to treat diarrhea, although their pharmacological activity has not been adequately validated. Objectives: This study investigated the antidiarrheal effects of a hydroalcoholic SAA seed extract, its alkaloid-rich fraction, and matrine, the principal quinolizidine alkaloid, in a mouse model of castor oil-induced diarrhea. Methods: A total of 110 male Swiss albino mice were randomly assigned to receive the SAA seed extract, alkaloid-rich fraction, matrine, loperamide, or saline before castor oil administration. Antidiarrheal activity was assessed over 4 h by measuring latency to diarrhea, number of wet fecal pellets, wet fecal weight (mg), and total fecal pellet number (including wet and dry pellets). The alkaloid-rich fraction was chemically characterized using gas chromatography–mass spectrometry (MS, gas chromatography–mass spectrometry (GC)–MS). Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey’s multiple-comparison test. Results: The SAA seed extract, alkaloid-rich fraction, and matrine improved diarrheal outcomes compared with saline-treated controls. Effects were statistically significant (Tukey-adjusted P < 0.05) for all treatment-dose combinations, except for total fecal pellet number at the lowest matrine dose (5 mg/kg; adjusted P = 0.169). At 300 mg/kg, the SAA seed extract significantly reduced total fecal pellet number and wet fecal number relative to saline controls and prolonged the latency to diarrhea. Comparisons with loperamide varied according to preparation, dose, and endpoint; therefore, the present findings do not establish equivalent efficacy, noninferiority, or comparable pharmacological potency. Conclusions: Under the conditions of the castor oil–induced diarrhea model, the SAA seed extract, its alkaloid-enriched fraction, and matrine exhibited antidiarrheal activity relative to saline. These findings support further investigation of the SAA seed extract and matrine; however, the relative contributions of individual alkaloids, the underlying mechanisms, safety, and translational relevance require further study.