大黄炮制前后的化学成分变化及其减毒研究

Chemical Components and Toxicity of Radix et Rhizoma Rhei before and after Processing

目的:探究大黄炮制成熟后成分的变化规律及其降低肝毒性的作用机制。方法:分别采用紫外分光光度法、高效液相色谱法分析大黄炮制过程中鞣质、总蒽醌、游离蒽醌含量的变化情况,并采用斑马鱼急性毒性试验评价大黄炮制前后的肝毒性变化。结果:生大黄的鞣质、总蒽醌及游离蒽醌含量分别为3.59%、1.96%和1.03%,经过炮制后,熟大黄的鞣质、总蒽醌及游离蒽醌含量分别为0.33%、1.86%和1.27%,鞣质和结合蒽醌的含量显著降低,而游离蒽醌含量显著升高。3批大黄炮制前后对斑马鱼的半数致死浓度(LC_(50))分别为210.15μg/mL、216.63μg/mL、248.25μg/mL、1082.12μg/mL、1200.98μg/mL和1189.27μg/mL,与生大黄比较,熟大黄水提物的LC_(50)显著升高。与对照组比较,生大黄呈现不同程度的肝脏变性(肝脏萎缩、卵黄囊吸收延迟、肝脏细胞肿大及组织空泡化),而相同浓度下的熟大黄给药组,仅在高浓度条件下呈现轻微的肝脏变性。结论:大黄经过炮制后成分发生明显变化,肝毒性显著降低。

Objective:To explore the changes of the chemical components in Radix et Rhizoma Rhei after processing and the hepatotoxicity-alleviating mechanism.Methods:Ultraviolet spectrophotometry and high-performance liquid chromatography(HPLC)were used to analyze the changes of tannins,total anthraquinones,and free anthraquinones during the processing of Radix et Rhizoma Rhei.In addition,acute toxicity experiment was carried out on zebrafish to evaluate the hepatotoxicity of the medicinal before and after processing.Results:The content of tannins,total anthraquinones,and free anthraquinones in the raw medicinal material was 3.59%,1.96%,and 1.03%,respectively.After processing,the content of tannins,total anthraquinones,and free anthraquinones turned out to be 0.33%,1.86%,and 1.27%,separately.Thus,the content of tannins and bound anthraquinones was significantly reduced,while the content of free anthraquinones was significantly increased after the processing.The median lethal concentration 50(LC_(50)) of three batches of Radix et Rhizoma Rhei before and after processing to zebrafish was 210.15μg/mL,216.63μg/mL,248.25μg/mL,1082.12μg/mL,1200.98μg/mL,and 1189.27μg/mL,respectively.The LC_(50) of the water extract of the processed product increased significantly compared with that that of the raw product.The raw product induced different degrees of liver degeneration(hepatic atrophy,delayed absorption of yolk sac,liver cell enlargement,and tissue vacuolation).For the zebrafish treated with the processed product,only mild liver degeneration was observed in the zebrafish treated with high dose of processed product.Conclusion:In summary,the components of Radix et Rhizoma Rhei change remarkably and the hepatotoxicity significantly reduced after the processing.