亚临界水萃取紫草中左旋/右旋紫草素的工艺优化(英文)

Optimization of Subcritical Water Extraction of Alkannin and Shikonin from the Dried Roots of Arnebia Boraginaceae

研究了亚临界水萃取技术富集紫草中左旋／右旋紫草素的工艺过程，采用响应曲面法对影响紫草素提取率的工艺参数进行分析优化。考察了萃取温度、萃取时间和固液比对紫草素提取率的影响，结果发现三个因素在各自考察的实验范围内均有显著影响。采用可见分光光度法对亚临界水提取液中紫草素的浓度进行分析，在510nm波长下测得的标准线性方程为y=24．77x＋0．0311，相关系数为0．9905，紫草素浓度的线性范围是0．0084-0．0540mg·mL^-1。响应曲面分析模型预测的最佳提取条件是：固液比为7．875g·L^-1，在20MPa、117．5℃下提取18min，此时紫草素最大提取率是2．02mg·g^-1，与模型预测值基本相符。采用亚临界水萃取紫草素具有高效、环保、操作简便等优势，利用响应曲面设计能够有效地优化萃取过程，为该技术的推广提供了一定的理论支持。

This work reports the subcritical water （SCW） extraction procedure of alkannin and shikonin （A/S） from Arnebia boraginaceae root. The effect of extraction temperature,extraction time,and ratio of solid to liquid were evaluated through single-factor experiment maintaining the pressure of 20 MPa. The extraction process was also optimized using response surface methodology （RSM）. Spectrophotometry was used to calculate the concentration of A/S in water. The standard linear equation is y=24. 77x＋0. 0311 and the coefficient of correlation is 0. 9905 with the linearity range from 0. 0084 mg · mL^-1 to 0. 0540 mg ·mL^-1. SAS 8. 0 was used to make statistical analysis. The optimum extraction conditions given by model were as follows：ratio of solid to liquid,7. 875 g medicinal powder per one liter water; extraction temperature, 117. 5℃ ; and extraction time,18 min. Under the above conditions, the experimental A/S yield was 2.02 mg·g^-1, which was well matched with the predicted value. It could be concluded that SCW extraction is an effective and environment friendly technology for A/S. Extraction temperature,extraction time and ratio of solid to liquid had obvious impact on yield of A/S. The quadratic regression equation could predict yield of A/S under different extraction conditions well with the value for R^2 and small P（probability） （P〈0.05 when significant） of 0. 9490 and O. 0096, respectively.