Table 2.

Binding affinities of different flavonoids to the FRET nanosensor

Flavonoid	P value* (one-way ANOVA)	R2	KD (μM)
Apigenin	0.00012	0.873	22.99 ± 7.70
Luteolin	0.00031	0.880	131 ± 78.89
Quercetin	0.00002	0.916	126.6 ± 60.18
Kaempferol	0.01873	0.815	27.13 ± 12.24
Apigenin 6-C-glucoside	0.91532	0.897	60.88 ± 24.14
Apigenin 7-O-glucoside	0.73034	0.468	N.B.†
Chrysoeriol	0.10702	0.213	N.B.
Naringenin	0.10737	0.120	N.B.
Eriodyctiol	0.96653	0.233	N.B.
Genistein	0.03077	0.037	N.B.
Flavopiridol	0.99484	0.503	N.B.

Data represent mean ± SEM (n = 3). K_D, dissociation constant; R², coefficient of determination of saturation curves fitted by nonlinear regression (Materials and Methods).

^*Statistical significance of the YFP/CFP ratios over the tested flavonoid concentration range (Fig. 3E and Fig. S7).

^†N.B., no binding.