Bioactive Benzoxazinoids in Rye Bread Are Absorbed and Metabolized in Pigs

Abstract

Recently, bioactive benzoxazinoids were discovered in cereal grains and bakery products. In this study, we studied the uptake, distribution, and metabolism of these secondary metabolites using a pig model. Twelve benzoxazinoid compounds and their 4 transformation products were quantified in the pigs' diets and biofluids using high-performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometry. The 2-β-D-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one (DIBOA-glc) was the most dominant benzoxazinoid (232 nmol/g DM) seconded by the double-hexose derivative of DIBOA (provisionally characterized here as DIBOA-glc-hex) in the rye-based diet. DIBOA-glc (derived from the diet and intestinal deglycosylation of DIBOA-glc-hex) was apparently reduced to 2-β-D-glucopyranosyloxy-1,4-benzoxazin-3-one (HBOA-glc), the most dominant benzoxazinoid in the blood (829 nmol/L). The benzoxazinoid compounds were excreted in the urine, with HBOA-glc (18 μmol/L) as a major metabolite. In this study, we determined for the first time the bioavailability of dietary benzoxazinoids that have high digestibility, distribution, and metabolism in mammals. These findings could be a milestone for the exploitation of healthful and pharmacological properties of benzoxazinoids.

The Postprandial Plasma Rye Fingerprint Includes Benzoxazinoid-Derived Phenylacetamide Sulfates

“…Recently, there were several targeted, quantitative approaches on the characterization of bioavailability and absorption of dietary benzoxazinoids in rats (17), pigs (16), and humans (18). In rats, 3 benzoxazinoid compounds (HBOA, HBOA glucose, and DIBOA glucose) were detected in plasma 3 h after feeding (17).…”

“…Several compounds of the benzoxazinoid class were detected in the plasma and urine of pigs (16) and rats (17) and in a human study showing the postprandial appearance of benzoxazinoids in circulation and urine (18). In addition to these studies using targeted, quantitative assays, a recent nontargeted metabolite profiling study indicated phenylacetamides as the predominant urine metabolites of benzoxazinoids (19).…”

Recent advances in allelopathy for weed control: from knowledge to applications

“…Finally, the presence of these allelochemicals in grain means that they are involved in mammalian and human digestion. Absorption, transformation and excretion have been studied in pig and, in this context, new routes of transformation such as reduction, oxidation, demethoxylation and deglycosylation were described . By contrast, it was found that 2‐β‐ d ‐glucopyranose HBOA 2‐hydroxy‐1,4‐benzoxazin‐3‐one derivative is the principal metabolite in human plasma and urine when 2‐β‐ d ‐glucopyranose DIBOA 2,4‐Dihydroxy‐1,4‐benzoxazin‐3‐one derivative is the principal constituent in the diet.…”

Plant defense and herbivore counter-defense: benzoxazinoids and insect herbivores

“…Ingestion of rye bread which naturally contains a mixture of BXDs has revealed some aspects of BXD metabolism in mammals. For example, in rats and pigs, glucoside hydrolysis, hydroxamic acid reduction to the corresponding lactam, and aglucone conjugation to glucuronic acid were important metabolic reactions (Adhikari et al 2012a, b). In humans, hydroxamic acid reduction and aglucone conjugation with glucuronic acid and sulfate were observed (Adhikari et al 2013).…”