藏药小大黄的定性定量方法研究

目的：建立藏药小大黄药材的定性定量分析方法，为其质量标准的修订提供参考。方法：采用粉末显微鉴别和薄层色谱法对小大黄药材进行定性鉴别；对药材的水分、总灰分、酸不溶性灰分和乙醇浸出物进行测定。采用高效液相色谱法测定大黄素、大黄酚的含量。高效液相色谱条件：采用SunFire-C₁₈色谱柱（250 mm×4.6 mm，5 μm），以甲醇-0.1%磷酸水溶液（85：15）为流动相，流速1.0 mL·min^-1，检测波长为254 nm，柱温25℃。结果：小大黄显微特征明显；薄层色谱中大黄素、大黄素甲醚、大黄酚斑点分离效果良好；6批样品的水分测定结果为6.02%~8.51%，总灰分为15.21%~21.01%，酸不溶性灰分为0.53%~1.15%，乙醇浸出物为10.56%~21.23%。大黄素、大黄酚进样量分别在0.058~0.576 μg（r=1.000 0）、0.124~1.238 μg（r=1.000 0）的范围内线性关系良好；平均加样回收率（n=6）分别为102.8%和102.6%。6批样品中大黄素、大黄酚的总量为10.24~22.11 mg·g^-1。结论：所建立的方法可用于小大黄药材的质量控制。

Objective:To establish a qualitative and quantitative method for Tibetan medicine roots of Rheum pumilum,and to provide reference for the revision of its quality standard.Methods:Powder microscopy and TLC were used for qualitative identification.The contents of water,total ash,acid-insoluble ash,alcohol-soluble extraction were determined.HPLC was used in the assay of emodin and chrysophanol.Separation was performed on a column of SunFire -C₁₈(250 mm×4.6 mm,5μm) with the mobile phase consisting of methanol -0.1% phosphoric acid at a flow rate of 1.0 mL·min^-1.The detection wavelength was 254 nm and the column temperature was 25.Results:Distinct microscopic characteristic was observed in Rheum pumilum roots.TLC bands of emodin,physcion and chrysophanol ether were separated well.Contents of water,the total ash,the acid-insoluble ash and the alcohol-soluble extraction were 6.02%-8.51%,15.21%-21.01%,0.53%-1.15%,and 10.56%-21.23% in 6 batches of samples,respectively.Emodin and chrysophanol showed good linear relationship in the ranges of 0.058-0.576 μg(r=1.000 0) and 0.124-1.238 μg(r=1.000 0),respectively.The average recoveries (n=6) were 102.8% and 102.6%.The total amount of emodin and chrysophanol in 6 batches of samples were in the range of 10.24 to 22.11 mg·g^-1.Conclusion:The method can be used for the quality control of Rheum pumilum roots.