龙脷叶总游离氨基酸含量测定

Determination of total free amino acid content in Sauropus spatulifolius Beille

【目的】建立龙脷叶总游离氨基酸含量的测定方法,为龙脷叶药材质量控制及其开发利用提供参考依据。【方法】以谷氨酸为对照品,通过正交试验优化龙脷叶总游离氨基酸的提取条件,并利用紫外—可见分光光度法测定其含量。【结果】龙脷叶总游离氨基酸最佳提取条件为:龙脷叶粉碎过20目筛、液料比25.0∶1、提取时间1.5 h,其中粉碎度和提取时间对龙脷叶总游离氨基酸提取效果的影响显著(P<0.05)。568 nm是龙脷叶供试品溶液和谷氨酸对照品溶液的检测波长;谷氨酸在20.0~60.1μg/m L范围内与吸光值呈良好的线性关系(R2=0.9991)。在最佳提取条件下,测得6批龙脷叶总游离氨基酸含量(以谷氨酸计)在2.82%~6.77%,平均含量为4.50%。【结论】采用紫外—可见分光光度法测定龙脷叶总游离氨基酸含量,操作简便、结果准确,可作为龙脷叶总游离氨基酸的质量控制方法。

[Objective]The determination method of total free amino acid content in Sauropus spatulifolius Beille was established, in order to provide reference for quality control and＇de^elopmefit of S. spatulifolius. [Method ]With glutamic acid was selected as reference substance. The extraction condition of total free amino acid from Sauropus spatulifolius was optimized by orthogonal experiments, and its content was determined by UV-vis spectrophotometry. [ Result ]The resuhs showed that, The optimum extraction process conditions of total free amino acid from S. spatulffolius were as follows： eom- minution with 20-mesh sifter, liquid,material ratio of 25.0：1, extraction time of 1.5 h. The comminution degree and extracting time have significant effects on extraction rate of total free amino acid content in S. spatuli^olius（P〈O.05 ）. As for glutamic acid control solution and S. spatullfolius t6st solution, the detection wavelength was 568 nm. The glutamic acid showed a better linearity and good correlation within a range of 20;0-60.1, μg/mL（R2=0.9991 ）. Under the optimum condi- tions, the content of total free amino acid in six batches of S. spatulifollius ranged from 2.82% to 6.77%, the average was 4.50%. [ Conclusion ]UV-vis spectrophotometry can be used to determinate contqnt of total free amino aq!d：.in S, ;spatuli- folius, which has advantages of simple operation and high accuracy, thus should be taken as quality controlmethod of total free amino acid content in S. spatulifolius.