目的 研究大黄炭炮制过程颜色特征与化学成分的关联性规律，为建立基于颜色量化值的大黄炭炮制过程控制方法和终点判断标准奠定基础。方法 分别在不同温度和时间下制备大黄炭样品，以大黄炭炮制的经验判断为依据，利用视觉分析仪与紫外-可见光谱仪量化大黄炭不同炮制条件的粉末和饮片颜色。同时采用HPLC指纹图谱的方法评价大黄炭炮制过程中化学成分动态变化，利用多元统计学方法对大黄炭炮制过程样品颜色量化值与特征成分进行关联分析。结果 在大黄炭炮制过程中，随着炭化程度的增大，样品表观颜色由淡黄棕色逐渐加深至焦黑色，样品饮片和粉末的明度值（L^*）、红绿色值（a^*）、黄蓝色值（b^*）之间高度相关。HPLC指纹图谱上26个特征峰的面积与色度值均有不同程度的相关性，其中随炭化程度加深而含量递减的5个结合蒽醌类成分（芦荟大黄素-8-O-β-D-葡萄糖苷、大黄酸-8-O-β-D-葡萄糖苷、大黄酚-8-O-β-D-葡萄糖苷、大黄素-8-O-β-D-葡萄糖苷、大黄素甲醚-8-O-β-D-葡萄糖苷）和2个番泻苷类成分（番泻苷A、番泻苷B）与色度值呈线性相关关系，含量先增后减的5个游离蒽醌类成分（芦荟大黄素、大黄酸、大黄酚、大黄素、大黄素甲醚）、没食子酸和5-羟甲基糠醛（5-HMF）与色度值呈二次相关关系。结论 大黄炭炮制过程中的颜色主观判断与量化检测的分析结果一致，颜色量化值与14种已知化学成分的含量具有显著的相关性，初步推断颜色量化值可作为大黄炭炮制过程的质量控制和终点判定指标，以提高大黄炭饮片的质量水平及其一致性。

Objective To study the relationship between the quantitative color value of the powder and the known component content of rhubarb charcoal, and lay the foundation for the establishment of the rhubarb charcoal processing process control and endpoint judgment based on the color quantitative value. Methods Rhubarb charcoal samples were prepared at different temperatures and time. Based on the empirical judgment of the rhubarb charcoal processing, the visual analyzer and UV-Vis were used to quantify the color of the pieces and powder of rhubarb charcoal under different processing conditions. At the same time, the HPLC fingerprint method was used to evaluate the dynamic changes of chemical components during the processing of rhubarb charcoal, and the quantitative value of the color of the sample during the processing of rhubarb charcoal was correlated with the characteristic components of the HPLC fingerprint using the multivariate statistical method. Results During the processing of rhubarb charcoal, as the degree of carbonization increased, the apparent color of the sample changed from light yellowish brown to burnt black. There was a high correlation between the lightness value (L^*), red-green value (a^*) of the sample pieces and powder and the yellow and blue values (b^*). The area of the 26 characteristic peaks had varying degrees of correlation with the chromaticity value. Among the 14 known components, five bound anthraquinones (aloe-emodin-8-O-β-D-glucoside, rhein-8-O-β-D-glucoside, chrysophanol-8-O-β-D-glucoside, emodin-8-O-β-D-glucoside, physcion-8-O-β-D-glucoside), and two sennosides (sennoside A, sennoside B) had a linear positive correlation with the chromaticity value. The content of five free anthraquinones (aloe-emodin, rhein, chrysophanol, emodin, and physcion), gallic acid and 5-hydroxymethylfurfural (5-HMF), whose contents increased first and then decreased, showed a quadratic correlation with the chromaticity value. Conclusion The subjective judgment of rhubarb charcoal in the processing process is consistent with the quantitative color value analysis. The quantitative color value has a clear correlation with the content of 14 active chemical components. It is preliminarily inferred that the color quantitative value can be used as the quality of the rhubarb charcoal processing process control and end-point determination indicators to achieve efficient and rapid identification of the processing quality of rhubarb charcoal, which can provide new ideas for the monitoring and quality control of the rhubarb charcoal processing process.

R283.1

国家自然科学基金资助项目（82003943）；国家中药标准化项目：大黄等6种中药饮片标准化建设（ZYBZH-Y-GS-10-B）