Structure determination of partially deuterated carotenoids from intrinsically labeled vegetables by HPLC-MS and 1H NMR.
The structures of biosynthetic deuterated carotenoids in labeled vegetables were investigated: (all-E)-lutein and (all-E)-beta-carotene from spinach, and (all-E)-beta-carotene and (all-E)-alpha-carotene from carrots. The vegetables were grown hydroponically using a nutrient solution enriched with deuterium oxide (D(2)O) and were extracted using matrix solid-phase dispersion (MSPD). Deuterium enrichment in the carotenoid molecules was determined by liquid chromatography-mass spectrometry (LC-MS). (all-E)-Lutein and (all-E)-beta-carotene in spinach showed partial deuteration from (2)H(1) to (2)H(12), with the abundance maximum at (2)H(5). (all-E)-beta-Carotene and (all-E)-alpha-carotene from carrots showed partial deuteration from (2)H(1) to (2)H(17), with the abundance maximum at (2)H(11). The (1)H NMR spectra of the four deuterated carotenoids showed additional signals for all methyl groups and decreased signal intensity for the olefinic protons and the methylene protons in the ring. These differences are due to isotopic effects and are based on the substitution of protons by deuterium atoms. The deuteration was distributed randomly throughout the carotenoid molecules.
Putzbach
Karsten
K
Institute of Organic Chemistry, University of Tübingen, Germany.
Krucker
Manfred
M
Albert
Klaus
K
Grusak
Michael A
MA
Tang
Guangwen
G
Dolnikowski
Gregory G
GG
D002338:Carotenoids / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D018552:Daucus carota / Q000737:chemistry; D003903:Deuterium; D007553:Isotope Labeling; D014975:Lutein / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D018724:Spinacia oleracea / Q000737:chemistry; D014675:Vegetables / Q000737:chemistry*; D019207:beta Carotene / Q000737:chemistry
D019207:beta Carotene; D002338:Carotenoids; D003903:Deuterium; D014975:Lutein