Analgesic and Anti‐Inflammatory Activities of Sophocarpine from <i>Sophora viciifolia</i> Hance

Abstract

<i>Sophora viciifolia</i> Hance is an edible plant used in traditional Chinese medicine. Sophocarpine, a tetracyclic quinolizidine alkaloid, is one of the most abundant active ingredients in <i>Sophora viciifolia</i> Hance. Here, we study the analgesic and anti-inflammatory effects, as well as the acute toxicity of sophocarpine from <i>Sophora viciifolia</i> Hance in mice. Sophocarpine (20, 40, and 80 mg/kgbw) significantly prolonged the delay period before a hot plate reaction occurred (all <i>P</i> < 0.05), and the delay before a tail-flick response was induced by a warm bath (<i>P</i> < 0.05; <i>P</i> < 0.01). Sophocarpine (40, 80 mg/kg) resulted in dose-dependent inhibition of the writhing reaction induced by acetic acid in mice (<i>P</i> < 0.05; <i>P</i> < 0.001, respectively). Sophocarpine (80 mg/kg) reduced the total duration of a formalin-induced pain response (<i>P</i> < 0.05). Sophocarpine prolonged the foot-licking latency of mice after the hot plate reaction, and this effect was antagonized by calcium chloride and enhanced by verapamil. Sophocarpine (20, 40, and 80 mg/kg) significantly inhibited xylene-induced ear edema (<i>P</i> < 0.01; <i>P</i> < 0.001; <i>P</i> < 0.001, respectively) and the penetration of acetic acid-induced dye into the peritoneal cavity (<i>P</i> < 0.01; <i>P</i> < 0.01; <i>P</i> < 0.001, respectively). It also reduced the levels of proinflammatory cytokine interleukin (IL)-1<i>β</i>, IL-6, and prostaglandin E2 (<i>P</i> < 0.05, <i>P</i> < 0.01, <i>P</i> < 0.001) and those of serum nitric oxide (<i>P</i> < 0.05). The results of this study suggest that sophocarpine possesses certain analgesic and anti-inflammatory activities, which may be related to calcium and inhibition of the secretion of inflammatory factors.