OBJECTIVE To establish HPLC fingerprints of three drying processes (Atmospheric pressure drying, Decompression drying, Freeze-drying) of Danggui Buxue granules, and combine them with antioxidant tests to determine the optimal drying process and main active components of Danggui Buxue granules.

METHODS The fingerprints of multiple batches of Danggui Buxue granules were established by HPLC; the "Fingerprint Similarity Evaluation System of Traditional Chinese Medicine Chromatogram" was used to evaluate the similarity; Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were used to characterize the different drying processes of Danggui Buxue granules; evaluate the antioxidant activity of Danggui Buxue granules in different drying processes using 1,1-diphenyl-2-picrylhydrazy (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging method; the spectrum-effect relationship between Danggui Buxue granules fingerprint and antioxidant activity was analyzed by grey correlation degree and Pearson, Spearman, Kendall's tau-b correlation analysis methods.

RESULTS The results of fingerprint showed that there were 16 common peaks in 30 batches of Danggui Buxue granules, and 6 of them were identified by comparison. The results of Cluster Analysis and Principal Component Analysis showed that 30 batches of Danggui buxue granules were divided into 3 categories, and the difference between the groups of atmospheric pressure drying was the least. The results of oxidation test showed that different drying processes of Danggui Buxue granules had good antioxidant activity, and the atmospheric pressure drying had the lowest IC₅₀ and the strongest antioxidant activity. Finally, combining the results of gray correlation analysis and correlation analysis, the compounds F2, F10, F13 (calycosin), F15 (formononetin), F16 might be important characteristic peaks reflecting the antioxidant activity of Danggui Buxue granules.

CONCLUSION Compared with other drying processes, atmospheric pressure drying has higher batch consistency and stronger antioxidant activity, and can be used as the preferred drying process for Danggui Buxue granules, and components 2, 10, 13, 15 and 16 are the main active ingredients for Danggui Buxue granules to exert antioxidant effects.