Fig. 1. Fluorescence emission spectra of BSA-FA interaction system under different temperature
(a): 298 K; (b): 303 K; (c): 308 K; c_(BSA)=5×10^-7 mol·L^-1;c_(FA)(1—9): (0, 0.6, 1.2, 1.8, 2.4, 3.0, 3.6, 4.2, 4.8)×10^-4 mol·L^-1; pH 7.40

Fig. 2. Overlapping of the fluorescence emission spectra (a) of BSA and with the absorption spectra (b) of FA
c_(BSA)=c_(FA)=5.0×10^-7 mol·L^-1

Fig. 3. The molecular docking result of FA with BSA
(a): Molecular docking simulation of FA and BSA; (b): Streamer shape molecular docking model diagram of FA and BSA;(c): 2D and 3D schematic diagram of amion residues of FA and BSA

Fig. 4. UV-Visible absorption spectroscopy of FA-BSA interaction system
c_(BSA)=5×10^-7 mol·L^-1; c_(FA)(1—9): (0, 0.6, 1.2, 1.8, 2.4, 3.0, 3.6, 4.2, 4.8)×10^-4 mol·L^-1; pH 7.40; T=298 K

Fig. 5. Synchronous fluorescence spectrogram of FA-BSA interaction system
c_(BSA)=5×10^-7 mol·L^-1; c_(FA)(1—9): (0, 0.6, 1.2, 1.8, 2.4, 3.0, 3.6, 4.2, 4.8)×10^-4 mol·L^-1; pH 7.40; T=298 K; (a): Δλ=15 nm, (b): Δλ=60 nm

Fig. 6. Three-dimensional fluorescence spectrum and contour map of BSA
c_(BSA)=2.5×10^-7 mol·L^-1; pH 7.40; T=298 K

Fig. 7. Three-dimensional fluorescence spectrum and contour map of FA-BSA
c_(BSA)=2.5×10^-7 mol·L^-1;c_(FA)=3.0×10^-5 mol·L^-1; pH 7.40; T=298 K

Fig. 8. The circular dichroism spectra of BSA and FA-BSA interaction system
(a): c_(BSA)=1.0×10^-5 mol·L^-1; (b): c_(BSA)=1.0×10^-5 mol·L^-1, c_(FA)=4.0×10^-5 mol·L^-1; T=298 K; pH 7.40