Identification and Study on Processing End-point of Raw and Processed Products of Morus alba Based on UPLC Fingerprint and Chromaticity / 中国药房

ABSTRACT

OBJECTIVE：To provide reference for the identification and proces sing end-point determination of raw Morus alba and its processed products （honey-processed M. alba ）. METHODS ：UPLC method was adopted. The determination was performed on Waters BEH Shield RP C 18 column with mobile phase consisted of acetonitrile- 0.1％ phosphoric acid solution （gradient elution ） at the flow rate of 0.30 mL/min. The column temperature was set at 30 ℃. The program wavelengths were set at 280 nm（0-4 min） and 320 nm（4-35 min）. Similarity Evaluation System for Chromatogram Fingerprint of TCM （2012 edition）was used to establish UPLC fingerprint and carry out similarity evaluation of 13 batches of M. alba and honey-processed M. alba . The chromatographic peaks were identified with reference substance fingerprint. The colorimetric value （L，a，b） of 13 batches of M. alba and honey-processed M. alba powder were determined ，and average total colorimetric value （E）was calculated. OPLS-DA and cluster analysis were adopted to analyze the differences in fingerprints and colorimetric values of M. alba before and after processing. At the same time ，the dynamic change rule of fingerprint and colorimetric value of honey-processed M. alba at different processing time points were analyzed to determine the processing end-point. RESULTS ：There were obvious differences in fingerprints before and after processing ，and the similarity of 13 batches of M. alba and honey-processed M. alba were all higher than 0.9. Totally 21 common peaks were calibrated for M. alba ，and 23 common peaks for honey-processed M. alba ；peak 1 and peak 2 were newly produced compounds of honey-processed M. alba . Peak 2，peak 7，peak 14 and peak 19 were identified as 5-hydroxymethylfurfural， mulberry glucoside A ，oxidized resveratrol ，mulberry flavonoids G. Results of OPLS-DA showed that the peak area-sample quantity ratio of peak 1，peak 2，peak 18，peak 20 and the chromaticity values （L，a，b）were the most important factors affecting the difference of raw and processed products of M. alba . When the E ranged 75.84-80.88 as the processing end-point of honey-processed M. alba ，the processing time was determined as 22-34 min. CONCLUSIONS ： The established UPLC fingerprint and colorimetric value determination method can be used to identify the raw and processed products of M. alba as well as determine the processing end-point of honey-processed M. alba .