Fig. 4

DL analysis of Curcuma aromatica Salisb. samples. a DL decay curves comparison among Curcuma aromatica Salisb. samples. BG = background. b DL properties comparison among Curcuma aromatica Salisb. samples. I0 is the initial intensity of the DL curve, Beta is an index factor associated with the rate of DL decay, and Tau and T represent the DL characteristics and decay time, respectively. *p < 0.05. c PCA score plots of the DL properties obtained from Curcuma aromatica Salisb. samples. d PCA biplot shown how strongly each parameter influence the similarity of DL decay curves