Table 1.

Flavonoids and metabolites inhibit collagen-stimulated function with differential potencies

Flavonoid/metabolite	logIC50±SEM (M)		Rmax±SEM (aggregation-% of control)		Hill slope±SEM
	Aggregation	5-HT secretion	Aggregation	5-HT secretion	Aggregation	5-HT secretion
Quercetin	−5.17 ± 0.04	−5.11 ± 0.02	100 ± 0	96 ± 0	−2.79 ± 0.69	−2.04 ± 0.27
Tamarixetin	−4.75 ± 0.05	−4.66 ± 0.18	96 ± 4	83 ± 3	−2.99 ± 0.80	−1.69 ± 0.60
Quercetin-3′-sulphate	−4.72 ± 0.01	−4.73 ± 0.03	100 ± 0	100 ± 0	−10.71 ± 2.49	−2.48 ± 0.41
Apigenin	−5.31 ± 0.04	−5.36 ± 0.04	100 ± 0	87 ± 2	−2.23 ± 0.43	−2.19 ± 0.32
Catechin	−3.44 ± 0.05	−3.45 ± 0.04	100 ± 0	100 ± 0	−2.91 ± 0.82	−1.51 ± 0.19

Potencies were calculated as the concentration of flavonoids (quercetin, apigenin and catechin) or metabolites (tamarixetin and quercetin-3′-sulphate) that inhibited aggregation or 5-HT secretion by 50% (IC₅₀). LogIC₅₀ values were calculated using non-linear regression and a variable Hill slope with inhibition constants (maximum and minimum % aggregation) individually determined for each compound. The SEM was derived from logIC₅₀ of three individual data sets.