Fig. 2

Chemometric analysis of normal and orange Danshen. a PCA analysis and score plot of normal and orange Danshen. b S-plot from the loading of the OPLS-DA. The x-axis indicates the variable contributions. The farther a data point lies from 0, the more it contributes to the variance of the sample. The y-axis indicates the samples’ correlations within the same sample group. The farther an exact mass/retention time pair lies from the value 0, the better its correlation with the injections. c Variable averages of ten biomarkers in normal Danshen identified by OPLS-DA