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Hordatines are a characteristic class of secondary metabolites found in barley which have
been reported to be present in barley malt, beer and, recently, brewer ́s spent grain (BSG). However,
little is known about their biological activities such as antioxidative effects in beer or antifungal
activity as their main task within the plants. We conducted an in vitro investigation of the activity
of hordatines isolated from BSG towards enzymes of glucose metabolism. Hordatine-rich fractions
from BSG were prepared by solid-liquid extraction (SLE) with 60% acetone followed by purification
and fractionation. The fractions were characterised and investigated for their in vitro inhibitory
potential on α-glucosidase and glycogen phosphorylase α (GPα). Both enzymes are relevant within
the human glucose metabolism regarding the digestion of carbohydrates as well as the liberation of
glucose from the liver. In total, 10 hordatine-rich fractions varying in the composition of different
hordatines were separated and analysed by mass spectrometry. Hordatine A, B and C, as well as
hydroxylated aglycons and many glycosides, were detected in the fractions. The total hordatine
content was analysed by HPLC-DAD using a semi-quantitative approach and ranged from 60.7 ± 3.1
to 259.6 ± 6.1 μg p-coumaric acid equivalents/mg fraction. Regarding the biological activity of
fractions, no inhibitory effect on GPα was observed, whereas an inhibitory effect on α-glucosidase
was detected (IC50 values: 77.5 ± 6.5–194.1 ± 2.6 μg/mL). Overall, the results confirmed that
hordatines are present in BSG in relatively high amounts and provided evidence that they are potent
inhibitors of α-glucosidase. Further research is needed to confirm these results and identify the active
hordatine structure.
We have investigated urine samples after coffee consumption using targeted and untargeted
approaches to identify furan and 2-methylfuran metabolites in urine samples by UPLC-qToF.
The aim was to establish a fast, robust, and time-saving method involving ultra-performance
liquid chromatography-quantitative time-of-flight tandem mass spectrometry (UPLC-qToF-MS/MS).
The developed method detected previously reported metabolites, such as Lys-BDA, and others that
had not been previously identified, or only detected in animal or in vitro studies. The developed
UPLC-qToF method detected previously reported metabolites, such as lysine-cis-2-butene-1,4-dial
(Lys-BDA) adducts, and others that had not been previously identified, or only detected in animal
and in vitro studies. In sum, the UPLC-qToF approach provides additional information that may be
valuable in future human or animal intervention studies.