The Postprandial Plasma Rye Fingerprint Includes Benzoxazinoid-Derived Phenylacetamide Sulfates

Abstract

The bioavailability of whole-grain rye-derived phytochemicals has not yet been comprehensively characterized, and different baking and manufacturing processes can modulate the phytochemical composition of breads and other rye products. The aim of our study was to find key differences in the phytochemical profile of plasma after the consumption of 3 breads containing rye bran when compared with a plain white wheat bread control. Plasma metabolite profiles of 12 healthy middle-aged men and women were analyzed using LC quadrupole time-of-flight mass spectrometry metabolomics analysis while fasting and at 60 min, 120 min, 240 min, and 24 h after consuming a meal that contained either 100% whole-grain sourdough rye bread or white wheat bread enriched with native unprocessed rye bran or bioprocessed rye bran. White wheat bread was used as the control. The meals were served in random order after a 12-h overnight fast, with at least 3 d between each occasion. Two sulfonated phenylacetamides, hydroxy-N-(2-hydroxyphenyl) acetamide and N-(2-hydroxyphenyl) acetamide, potentially derived from the benzoxazinoid metabolites, were among the most discriminant postprandial plasma biomarkers distinguishing intake of breads containing whole-meal rye or rye bran from the control white wheat bread. Furthermore, subsequent metabolite profiling analysis of the consumed breads indicated that different bioprocessing/baking techniques involving exposure to microbial metabolism (e.g., sourdough fermentation) have a central role in modulating the phytochemical content of the whole-grain and bran-rich breads.

Discovery of urinary biomarkers of whole grain rye intake in free‐living subjects using nontargeted LC‐MS metabolite profiling

“…This metabolite was therefore conclusively identified as HPAA‐sulfate. The present findings are in line with recent research showing that metabolized forms of benzoxazinoids such as phenylacetamides and aminophenol sulfate increase in response to recent intake of WG rye products . Evaluation of their stability over time is needed before using them as biomarkers.…”

“…However, it is not yet known whether dietary phenylacetamides are similarly formed from benzoxazinoid precursors, or at which stages of food processing or digestion such conversion could potentially occur. Additionally, a feature with m/z 168.065 was identified as free form of HHPAA based on identical fragmentation and retention time as in earlier analysis . Another ion, namely m/z 108.045 eluting at 2.5 min was included among the top‐ranked metabolites.…”

Urinary Biomarkers of Whole Grain Wheat Intake Identified by Non-targeted and Targeted Metabolomics Approaches

“…1) were attributed to wheat phytochemicals ARs and BXs3839. Other altered compounds linked to WG consumption are phenolic acids and related metabolites, such as ferulic acid (FA) sulfate, 1,2,3-benzenetriol sulfates degraded from gallic acid40, 3-methoxycatechol sulfate derived probably from 3-methylgallic acid40, 3-methylcatechol41, and 4-acetylphenol42 (Table 1 and Supplementary Fig.…”

The genetic background of benzoxazinoid biosynthesis in cereals

“…Moreover, they have antiallergic properties (Otsuka et al1988;Poupaert et al 2005), appetite suppression and weight reduction effects (Rosenfeld and Forsberg 2009). However, the content of BXs in final food products strongly depends on the type of grain processing (Tanwir et al 2013;Hanhineva et al 2014). …”