基于色差原理分析不同产地桑白皮有效成分含量与颜色的相关性

目的:研究桑白皮药材有效成分含量与颜色的相关性,并对不同产地样品进行指纹图谱和聚类分析,为该药材质量控制及品质评价提供依据。方法:分别采用高效液相色谱法(HPLC)和盐酸-镁粉反应比色法测定桑白皮中桑根皮素和总黄酮的含量;肉眼观察桑白皮颜色,采用色差仪测定其色度值(L*、a*、b*)并计算总色差值(E*ab);利用SPSS 21.0软件对桑根皮素和总黄酮的含量与各颜色指标(L*、a*、b*、E*ab)进行Pearson相关性分析。采用HPLC法建立3个不同产地共20批桑白皮药材的指纹图谱,并进行相似度分析。采用SPSS 21.0软件对20批样品进行K-均值聚类分析(基于桑根皮素、总黄酮的含量及颜色指标)和系统聚类分析(基于指纹图谱共有峰相对峰面积)。结果:桑白皮中桑根皮素和总黄酮的平均含量分别为0.0960~0.6186 mg/g、0.48%~1.51%,其各颜色指标均呈显著相关(P<0.01)。其中,L*、b*、E*ab值越小,a*值越大,则桑根皮素含量越高;L*、b*、E*ab值越大,a*值越小,则总黄酮含量越高。20批药材样品的指纹图谱与对照图谱的相似度为0.883~0.983;标定了13个共有峰,并指认1号峰为绿原酸。K-均值聚类分析结果显示,20批样品可聚为2类,Ⅰ类以安徽产样品为主,其桑根皮素含量较高、总黄酮含量偏低,颜色较暗、偏黄棕色;Ⅱ类以四川、贵州产样品为主,其桑根皮素含量偏低、总黄酮含量较高,颜色较明亮、偏黄白色。系统聚类分析结果与其较为一致。结论:桑白皮颜色与其桑根皮素、总黄酮含量密切相关,颜色偏黄棕色的桑白皮中桑根皮素含量较高,颜色偏黄白色的桑白皮中总黄酮含量较高。

Correlation Analysis between Active Ingredient Content and Color of Morus alba from Different Producing Areas Based on Color Difference Principle

OBJECTIVE:To study the correlation between the contents of active ingredients and the color of Morus alba,to establish fingerprint and conduct cluster analysis of samples from different producing areas,so as to provide reference for its quality control and evaluation.METHODS:HPLC and HCl-Mg reaction colorimetry were used to determine the contents of morusin and total flavonoids in M.alba.The color of M.alba was observed by naked eye,and chromaticity values(L*,a*,b*)were measured by color difference meter and color aberration(E*ab)were calculated.Pearson correlation of the contents of morusin and total flavonoids with color indicators(L*,a*,b*,E*ab)were analyzed by SPSS 21.0 software.HPLC method was used to establish the fingerprint of 20 batches of M.alba from 3 different producing areas,and the similarity analysis was carried out.K-means cluster analysis(based on the contents of morusin and total flavonoids and corlor index)and hierarchical cluster analysis(based on relative peak area of common peaks in fingerprint)were performed for 20 batches of samples by SPSS 21.0 software.RESULTS:The average contents of morusin and total flavonoids in M.alba were 0.0960-0.6186 mg/g,0.48%-1.51%,which were significantly correlated with each color index(P<0.01).The smaller L*,b*,E*ab and the larger a*were,the higher the content of morusin was;the higher the value of L*,b*,E*ab and the smaller the value of a*were,the higher the content of total flavonoids was.The similarity between the fingerprints of 20 batches of samples and the control ranged from 0.883 to 0.983;13 common peaks were demarcated,and No.1 peak was identified as chlorogenic acid.K-means cluster analysis showed that 20 batches of samples could be divided into 2 categories.CategoryⅠwere mainly from Anhui province with higher content of morusin,lower content of total flavonoids,darker and yellowish brown color;categoryⅡwere mainly from Sichuan province and Guizhou province,with lower content of morusin,higher content of total flavonoids,lighter and yellowish white color.The results of hierarchical cluster analysis were consistent with the results.CONCLUSIONS:The color of M.alba is closely related to the contents of morusin and total flavonoids.The content of morusin in yellow-brown M.albais is higher,while the content of total flavonoids in yellow-white M.albais is higher.