藏药小大黄的定性定量方法研究

Qualitative and quantitative study of Tibetan medicine Rheum pumilum roots

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-C_(18)色谱柱(250 mm×4.6 mm,5μm),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0.058~0.576μg(r=1.000 0)、0.124~1.238μg(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 Sun Fire-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.