Selective determination of catechin, epicatechin and ascorbic acid in human urine using chiral capillary electrophoresis

Abstract

Chiral CE was successfully applied to the separation and quantification of catechin, epicatechin and ascorbic acid in some commercial drinks and human urine. Analysis involved the separation of analytes in less than 5.0 min at 240 nm with an untreated fused-silica capillary under hydrodynamic injection mode. The running buffer consisted of 50 mM borate buffer with 3 mM beta-CD at pH 8.35. Detection limits for catechin, epicatechin and ascorbic acid were 0.028, 0.011 and 0.004 microg/mL, respectively. Linearity was investigated by selecting the ranges of calibration according to the amount of analytes in urine giving correlation coefficient percent (% r(2)) ranging between 99.4 and 99.6 at 99% confidence level. The maximum urinary excretion of catechin and epicatechin were noted at 2.0 and 4.0 h of the administrated dose. Unchanged catechin, epicatechin and ascorbic acid amounted to about 1.500, 8.696 and 0.003% of the administered dose in the 48.0 h urine collection. The proposed method achieved 99.2% completeness (n = 20) in urine media.

Stereoselective determination of drugs and metabolites in body fluids, tissues and microsomal preparations by capillary electrophoresis (2000–2010)

“…These include two anthelmintic drugs, albendazole and mebendazole. Albendazole becomes oxidized to chiral albendazole sulfoxide [95][96][97][98], and mebendazole is hydroxylated [110]. Analysis of plasma from echinoccocosis patients undergoing pharmacotherapy with these drugs revealed that the two metabolic steps are enantioselective in man.…”

Capillary electrophoresis of natural products: Highlights of the last five years (2006–2010)

“…The wide use of UV detection was also true for food and food contaminants analyses 85, 177, 190, 196–287. However, increasing also were those exploiting CE‐MS 141, 143–145, 146, 148, 288–303.…”

Chiral Separations by Capillary Electrophoresis

“…El-Maali's group [28,29] recently published two papers using β-CD as a chiral selector. (+)-Catechin and (−)-epicatechin were baseline-separated and quantified in aqueous and plasma samples [28].…”

“…The method was applied to a plasma sample after ingestion of green tea, and 2 h after ingestion, 17.4% of catechin and 1.8% of epicatechin, with respect to their concentration in the tea, were found unchanged in plasma. The same enantiomers, along with ascorbic acid, were separated and quantified in urine in the next study by this group [29]. The method developed was validated in terms of selectivity, accuracy, precision, linearity, LOD, LOQ, and robustness.…”