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Scope In this study, the applicability of several β-carboline, imidazole, and steroidal alkaloids as biomarkers for tomato juice intake is evaluated. Methods and results Over the course of a 2-week crossover dietary intervention study, 14 volunteers were given low and high doses of tomato juice after 3 days of avoiding tomato-based products. On the day of consumption and the following days, volunteers provided urine samples that were quantitatively analyzed by high-performance liquid chromatography-tandem mass spectrometry. Herein, glucose-derived β-carboline alkaloids are determined as supporting, yet non-specific dietary biomarkers for tomato juice intake. Several imidazole alkaloids represent further biomarkers, which are shown to specifically indicate consumption of tomato juice for 24 h and partly >24 h. Additionally, steroidal alkaloids derived from esculeogenin B are determined to be specific biomarkers for tomato juice detectable for at least 48 h after consumption. The intake of low and high amounts of tomato juice is significantly distinguishable based on the urinary excretion of all determined biomarkers as well. Conclusions The dietary intake of tomato juice is conclusively traceable based on urinary excretion of multiple β-carboline, imidazole, and steroidal alkaloids, and can be determined for up to 48 h after consumption. Furthermore, different intake doses can clearly be distinguished based on their urinary excretion.

cope : Urinary biomarkers are used to estimate the nutritional intake of humans. The aim of this study was to distinguish between low, medium and high apple consumption by quantifying possible intake biomarkers in urine samples after apple consumption by HPLC-MS/MS. Apples were chosen as they are the most consumed fruits in Germany. Methods and Results : 30 subjects took part in a seven day study. They abstained from apples and apple products except for one weighed apple portion resembling one, two or four apples. Before apple consumption and during the following days spot urine samples were collected. These urine samples were incubated with β-glucuronidase, diluted and directly measured by HPLC-MS/MS. Phloretin, epicatechin, procyanidin B2 and quercetin were detected in urine using Scheduled MRMTM mode. Phloretin was confirmed as a urinary biomarker of apple intake and had the ability to discriminate between low or medium (1 or 2 apples) and high apple consumption (4 apples). The groups also differ in the excretion of epicatechin and procyanidin B2. Conclusion : Apple consumption can be monitored by urinary biomarkers for a period of at least 12h after consumption. Furthermore the amount of apples consumed can be estimated by the concentration of certain biomarkers. This article is protected by copyright. All rights reserved