ABSTRACT
OBJECTIVE：To stud y the correlatio n 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 0.096 0-0.618 6 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. Category Ⅰ were mainly from Anhui province with higher content of morusin，lower content of total flavonoids ，darker and yellowish brown color ；category Ⅱ were 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. CONCLUS IONS：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.