Table 1.

The concentration of flavonoids introduced into the TP and TAC assays changes TAC values of flavonoid standards.

Assay	Compound	Dilution range (μmol/L)	Standard equivalents μmol/μmol	% difference in TAC between concentrationsb
TP	Catechin	70 to 340	3.6	−4
	Daidzein	1000 to 4000	0.38	7
	Luteolin	146 to 1747	1.7	−98
	Naringenin	367 to 3060	1.0	−43
	Quercetin	170 to 660	1.8	8
DPPHa	Catechin	34 to 450	2.16	−51
	Luteolin	30 to 220	2.9	−38
	Quercetin	66 to 330	1.36	105
FRAP	Catechin	34 to 340	3.3	−16
	Daidzein	250 to 7900	0.13	−82
	Luteolin	28 to 440	2.5	−33
	Naringenin	11 to 92	11	−34
	Quercetin	66 to 660	1.2	59
ORAC	Catechin	8.3 to 19	14	126
	Daidzein	0.82 to 2.5	15	−3
	Luteolin	1.1 to 2.9	18	−6
	Naringenin	1.0 to 8.3	37	−68
	Quercetin	0.83 to 6.6	11	51

^aDaidzein and naringenin did not have a measurable responses in the DPPH assay.

^bThe percent change is the maximum difference between final TAC values of the tested flavonoid concentrations observed experimentally using the routine assay conditions.