3.2. Plasma variables
The pharmacokinetic parameters for plasma quercetin and plasma
total flavonols of the participants are given in Table 3. The plasma concentration
time profiles after the 4 different quercetin treatments are
shown in Fig. 1 for the plasma quercetin concentrations and in Fig. 2
for the plasma total flavonol concentrations. Only minor amounts of
kaempferol, isorhamnetin and tamarixetin were detected in plasma.
The comparison between the four quercetin carriers (quercetin
dihydrate capsule as the reference treatment, vacuum impregnated
apple chips, the apple peel extract capsules and the apple peel demonstrated
no significant differences in terms of the areas under the plasma
concentration-time curves (AUC0–1440 min) or maximum plasma peak
concentrations (cmax). However, the plasma concentration time profiles
differed markedly between the quercetin dihydrate capsule (control)
and the apple peel treatment versus treatments with apple peel extract
capsules or vacuum impregnated apple chips. The time between oral
administration and the maximal plasma peak (tmax) was the slowest
after quercetin capsule treatment for the quercetin plasma concentration
(p = 0,017) compared to apple peel extract capsules. Regarding
maximum plasma peak concentration of the total flavonols after
quercetin capsule administration, tmax of the apple peel extract capsules
(p = 0,013) and vacuum impregnated apple chips (p = 0,043) treatments
were reached earlier