天南星炮制减毒机理研究（I）

目的：研究天南星炮制减毒机理。方法：通过小鼠急性毒性实验和家兔眼结膜刺激性实验比较天南星生品、炮制品、针晶及不同化学提取部位的毒性；采用扫描电镜观察法研究炮制前后天南星饮片中特殊草酸钙针晶的变化情况，以及明矾所含相关离子对针晶的形态变化的影响。结果：急性毒性实验结果显示，天南星针晶组LD50为42.53mg/kg，生天南星粉末组LD50为1062mg/kg，天南星炮制品粉末组LD50为2788mg/kg。家兔眼刺激实验结果表明，生药粉组和针晶组表现出轻度刺激和中度刺激，而其它各种提取物均无刺激性反应。电镜观察发现，天南星炮制前后饮片中的针晶超微结构发生了明显变化，经KAl(SO4)2?12H2O、AlCl3溶液浸泡12h后，针晶尖端被破坏，而Na2SO4、KCl溶液浸泡后其形态基本没有太大改变，尖端依然存在。结论：天南星针晶是产生刺激性毒性的主要物质基础，天南星针晶的刺激毒性与其结构形态有关，明矾炮制减毒的机制可能是其Al3 加速破坏了草酸钙针晶的形态。

Studies on mechanism of reducing toxicity of processed Rhizoma arisaematis (I)

Abstract] Objective: Studies on mechanism of reducing toxicity of processed Rhizoma arisaematis. Method: Compared the toxicity of dry Rhizoma arisaematis, processed products, raphides and different chemical extracts by acute toxicity experiments in mice and rabbit eye irritation test. Using scanning electron microscopy observed the differences of the raphides between the before and after processing. Results: Acute toxicity test results show that the dry Rhizoma arisaematis group LD50 is 1062mg/kg, processed products group LD50 is 2788mg/kg, raphides group LD50 is 42.53mg/kg. The results of the rabbit eye irritation test showed that the raw powder group and raphides group had low and moderate irritation, and other various extracts had no irritation. Electron microscopy showed that the tip of the raphides is destroyed after soaked in KAl (SO4) 2 ? 12H2O or AlCl3 solution for 12h, but no big change in the Na2SO4 or KCl solution. Conclusion: The irritating toxic material of Rhizoma arisaematis are raphides, and its toxicity was related with its morphology. The mechanism of reducing toxicity of processed Rhizoma arisaematis was that Al3 may accelerate destruction of calcium oxalate crystal morphology.