13C-labelling of xanthohumol in hop cones (Humulus lupulus).
Biolabelling conditions in hop cones of xanthohumol (Xn) were studied by feeding [U-13C]glucose, [1-13C]glucose, [ring-13C6]phenylalanine, [2-13C]sodium acetate or [2-13C]malonic acid as biosynthetic precursors to hop sprouts. Quantitative 13C-NMR spectroscopic analysis of the resulting labelled Xn showed different labelling patterns and ratios depending on precursor and feeding concentrations. The highest incorporation rate was achieved with [U-13C]glucose (9.41 +/- 1.22 %). With [ring-13C6]phenylalanine only ring B was labelled (3.51 +/- 0.08 % enrichment). [2-13C]sodium acetate and [2-13C]malonic acid allowed labelling of the A-ring (1.82 +/- 0.02 % and 1.74 +/- 0.03 % enrichment). The specific labelling pattern of the prenyl side chain with [1-13C]glucose (2.36 +/- 0.27 % enrichment) confirmed the biosynthetic origin to be MEP pathway-derived. On the basis of these results radiolabelling of Xn will be performed for in vivo bioavailability studies.
Berwanger
Stefanie
S
Pharmakognosie and Analytische Phytochemie, Universität des Saarlandes, Saarbrücken, Germany.
Zapp
Josef
J
Becker
Hans
H
D002247:Carbon Isotopes / Q000378:metabolism; D005419:Flavonoids; D005947:Glucose / Q000378:metabolism; D006801:Humans; D027582:Humulus / Q000378:metabolism*; D007553:Isotope Labeling; D008517:Phytotherapy; D011427:Propiophenones / Q000302:isolation & purification / Q000378:metabolism*
D002247:Carbon Isotopes; D005419:Flavonoids; D011427:Propiophenones; D005947:Glucose; C104536:xanthohumol