目的 对龙利叶的止咳作用进行研究，筛选其活性部位，并初步研究其止咳作用机制。方法 制备龙利叶75%乙醇、石油醚、醋酸乙酯、正丁醇、95%乙醇部位提取物，采用改良寇氏法研究龙利叶不同提取部位的急性毒性；采用氨水引咳法制备小鼠模型，用序贯法求出引起半数小鼠咳嗽的喷雾时间，进行止咳活性部位的筛选；采用辣椒素引咳实验，通过观察龙利叶各部位提取物对小鼠阿片受体激动作用和对ATP敏感性钾通道（KATP）的作用，探讨其作用机制。结果 龙利叶75%乙醇、醋酸乙酯、正丁醇和95%乙醇部位对小鼠的半数致死剂量（LD₅₀）分别为浸膏7.30、17.00、69.68、75.88 g/kg；石油醚部位最大耐受量为浸膏117.71 g/kg；75%乙醇部位和醋酸乙酯部位具有止咳作用，其止咳作用与激动中枢系统的阿片受体和KATP通道有关。结论 75%乙醇和醋酸乙酯部位为龙利叶止咳活性部位，其止咳机制与激动中枢系统的阿片受体和KATP通道有关。

Objective To study the antitussive effect of Sauropus spatulifolius, screen the active part of its antitussive effect, and study its antitussive mechanism. Methods The acute toxicity of different extraction sites of S. spatulifolius were studied by modified Karber's method; The model was made with ammonia liquor to induce cough. The spray time that caused half of the mice to cough was calculated by sequential method with aim to screen the active sites. Capsaicin was used to induce cough, and the mechanism of action of extracts from various parts of S. spatulifolius on opioid receptor and ATP-sensitive potassium channel (KATP) of mice was explored. Results The LD₅₀ of 75% ethanol, ethyl acetate, n-butanol, and 95% ethanol extracts was 7.30, 17.00, 69.68, and 75.88 g/kg, respectively; The maximum tolerance dose (MTD) of petroleum ether extracts was 117.71 g/kg; Extracts from 75% ethanol and ethyl acetate had antitussive effects, and its antitussive effect was related to opioid receptor and KATP pathway. Conclusion The fractions from 75% ethanol and ethyl acetate are the active parts of S. spatulifolius for relieving cough, and its antitussive mechanism is related to the KATP pathway and opioid receptors in the excited central system.

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国家自然科学基金资助项目（81460601）；广西壮族自治区卫生厅中医药科技专项（GZZJ13-03）；2018年广西一流学科建设项目重点课题（2018XK052）；壮瑶-药协同创新中心项目（桂教科研[2013]20号）；广西壮瑶药重点实验室项目（桂科基字[2014]32号）；广西重点学科壮药学项目（桂教科研[2013]16号）；广西八桂学者中药创新理论与药效研究项目（J13162）