Fig. 6

DL analysis of Glycyrrhizae Radix et Rhizoma samples. a DL decay curves comparison among Glycyrrhizae Radix et Rhizoma samples. BG = background. b DL properties comparison among Glycyrrhizae Radix et Rhizoma samples. I0 is the initial intensity of the DL curve. All five samples’ I0 parameter were significantly different (p < 0.05) from each other, except G.g_2018–G.g_1929 group and G.g_2018–G.u_2018 group. Beta is an index factor associated with the rate of DL decay. The Beta parameter of G.g_1929 was significantly different (p < 0.05) from the other four samples. Tau represent the DL characteristics. The Tau parameter of G.g_1900 and G.g_1929–G.i_2018 group and G.g_1929–G.u_2018 group were significantly different (p < 0.05). T describes the DL decay time. T parameter of G.g_1900 was significantly different (p < 0.05) from the other four samples. c PCA clustering of DL properties obtained from Glycyrrhizae Radix et Rhizoma samples. d PCA biplot showing how each parameter influences the similarity of DL decay curves