Antidiarrheal properties of Ligusticum chuanxiong Hort's ethanol extract in mice and its impact on the contraction of rabbits' isolated jejunal smooth muscles.

Ligusticum chuanxiong Hort (CR) is the dried rhizome of Ligusticum belongs to the Umbelliferae family. The present study aimed to assess the antidiarrheal effects of ethanol extracts of CR (CR ext.). The mice were administered castor oil to induce diarrhea and the antidiarrheal effects of CR ext (250, 500 and 1000mg/kg) were assessed in vivo. The potential effect of CR ext (0.01-10 mg/mL) was examined on isolated rabbit jejunum smooth muscle in vitro. CR ext exhibited antidiarrheal effects at a dose ranging from 500 to 1000 mg/kg (P <0.01). CR ext (0.01-10 mg/mL) relaxed the smooth muscles in a dose-dependent manner and its median effective concentration (EC₅₀) was 0.55 mg/mL (0.46-0.67, n = 6) (P<0.05; P <0.01). It alleviated jejunal contraction induced by ACh/K+ (60 mM) and EC₅₀ values were 0.35 mg/mL (0.34-0.37) and 0.11 mg/mL (0.10-0.12), respectively. Similar to the effect of verapamil, CR ext shifted the concentration-response curve of CaCl₂ downward to the right. The CR ext exhibits a notable antidiarrheal effect and can inhibit intestinal contraction. This mechanism of action may be based on its ability to inhibit Ca²⁺ channels.