"San-Bai Decoction" (SBD) has been a traditional Chinese medicine compound preparation for replenishing Qi and promoting blood circulation, whitening skin, and removing blemishes since ancient times. However, its chemical composition and antioxidant activity are not clear thus far, which limits the in-depth study on its pharmacodynamic material basis and efficacy. The objective of this study was to establish the fingerprint profile of SBD, assess its antioxidant activity by measuring 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, and find the spectrum-effect relationship of SBD by Grey Relation Analysis (GRA) and Partial Least Squares Regression (PLS). In this study, the fingerprint of SBD was established by high performance liquid chromatography (HPLC), and 20 common peaks were found, among which 6 peaks were designated. The similarities between the fingerprints of 12 batches of SBD and the reference fingerprint (R) were all greater than 0.900. Meanwhile, the antioxidant activities of all batches were concentration-dependent in their linear regression equation. The result of GRA showed that the correlation order of 20 common peaks for DPPH radical scavenging was X13 X7 X3 X6 X10 X11 X4 X12 X2 X18 X9 X5 X19 X1 X20 X16 X17 X15 X8 X14. At the same time, PLS study demonstrated that the contribution of six identified characteristic peaks to DPPH radical scavenging ability was X1 = X7 X6 X19 X20 X16. In this study, the spectrum-effect relationship of SBD between its HPLC fingerprint and the antioxidant activity can be used to screen the pharmacodynamic substance basis of its antioxidant action and lay the foundation for establishing quality standards and product development.
