Table 1.

ERα and ERβ (iso)flavonoid ER subtype and coactivator affinity^a

Compounds	ERα		ERβ		RBA β/α
	% RBAb	% RREc	% RBAb	% RREc
17β-Estradiol	100	100	100	100	---
Flavanones, Flavones
8-PN	30	94.7	9	51.2	0.3
8-PA	18	43.2	48	47.2	2.7
NRG	<0.002	12.6	0.05	23.0	---
API	<0.002	15.4	0.6	32.8	---
Flavonols
DMI	<0.002	9.1	0.5	16.6	---
ICT	<0.002	10.2	<0.002	11.9	---
KFL	<0.002	31.1	0.2	18.8	---
Isoflavonoids
GEN	5.6	62.7	19.4	50.2	3.5
DGN	<0.002	25.1	14	38.7	---
8-PG	<0.002	33.5	0.9	17.2	---

^aValues are expressed as the mean of at least three independent analytical determinations in triplicate. Method details for the ERα and ERβ competitive binding assay and for the (TR-FRET) assay are described in the Experimental Section.

^b% relative binding affinity (RBA)= (IC_{50 E2}/ IC_{50 (iso)flavonoid)})*100,

^c% relative recruitment efficacy (RRE) = (max FRET efficacy _{(iso)flavonoid)} / max FRET efficacy _E2)*100, E₂ arbitrarily set at 100%.