DHFA

The lower limit of quantification for plasma analysis was defined at 2.1 ng [ml.sup.-1] (CA), 2.0 ng [ml.sup.-1] (DHCA), 2.2 ng [ml.sup.-1] (FA), 2.1 ng [ml.sup.-1] (DHFA), 1.1 ng [ml.sup.-1] (IFA) and 2.1 ng [ml.sup.-1] (LUT) and for urine analysis at 28.8 ng [ml.sup.-1] (CA), 53.6 ng [ml.sup.-1] (DHCA), 110.9 ng [ml.sup.-1] (FA) and 52.2 ng [ml.sup.-1] (DHFA, IFA, LUT).

In spite of a diet free of plant material, analysis of plasma samples showed measurable concentrations for CA, FA, DHFA and LUT before intake of the extracts.

Calculations for CA, DHCA, FA, DHFA based on the total amount of caffeoylquinic acids expressed as caffeic acid equivalents (extract A 107.0 mg; extract B 153.8 mg).

However, after [beta]-glucuronidase treatment CA, its O-methylated products FA and IFA and the hydrogenation products DHCA and DHFA could be identified.

The plasma concentration curves of nonconjugated DHFA and total DHFA after enzymatic hydrolysis of conjugates showed parallel profiles (Fig.

The time courses of total CA, DHCA, FA, DHFA and IFA concentrations found in human plasma after administration of extract A are shown in Fig.

The elimination half-lives of CA, DHCA, DHFA and IFA were between 2 and 3 h after administration of both treatments.

Cumulatively renally excreted amounts of free and conjugated CA, DHCA, FA, DHFA and IFA in 24-h after administration of extracts A and B were 4.74 [+ or -] 1.82% and 4.01 [+ or -] 1.45% of caffeoylquinic acids intake, respectively.