Assignment of the ¹H and ¹³C NMR of tocotrienols

Abstract

Vitamin E is a family of chromanols that vary by the degree of methylation of the chroman ring as well as the nature of the hydrophobic side chain at C2 that serves to anchor these lipids in biological membranes. The tocopherols contain saturated side chains, whereas the tocotrienols contain three sites of unsaturation and are derived from geranylgeranyl diphosphate. A growing interest in the unique biological activities of the tocotrienols has led us to begin syntheses of isotopically substituted forms and other derivatives that will be useful for probing the metabolism and membrane behavior of the tocotrienols. In order to be certain of our ability to selectively modify sites on the parent molecules it was necessary to make as complete an assignment of the 1H and 13C NMR as possible. Herein we report multidimensional NMR data (HSQC, COSY, ADEQUATE(1,1), C--H HMBC, and NOESY) that have allowed us to assign the identity of almost all the resonances for alpha-, beta-, gamma-, and delta-tocotrienol.

Molecular interaction and localization of tocotrienol-rich fraction (TRF) within the matrices of lipid nanoparticles: Evidence studies by Differential Scanning Calorimetry (DSC) and Proton Nuclear Magnetic Resonance spectroscopy (1H NMR)

“…18 One CH3 (C-2-CH3) a These assignments are based on literature reports [39,40]. With regard to the effect of NLCs on the crystallinity of solid lipids and in contrast to literature reports [36,38], SLN-DYN and SLN-COMP did not display a peak that corresponds to their ␣-polymorph even after reheating of the crystallized SLNs in a second DSC run (data not shown).…”

“…Nonetheless, the distinct signals in the 0.0-2.1 ppm range (Table 5), with the exception of the poloxamer signal at 1.11 ppm, were attributed to methyl signals of TRF components. Literature reports on the NMR analysis of tocopherols and tocotrienols facilitated the assignment of TRF protons [39,40].…”

WRINKLED1 and ACYL‐COA:DIACYLGLYCEROL ACYLTRANSFERASE1 regulate tocochromanol metabolism in Arabidopsis

“…a; Baker & Myers, ). In addition, 13 C chemical shifts of the chromanol substituents (δ(C 7a ) = 11.9 ppm; δ(C 8a ) = 11.9 ppm; δ(C 2a ) = 24.1 ppm) are typical for a γ‐tocochromanol (Baker & Myers, ; Ohnmacht et al ., ). Together, these data show that pumpkin seeds synthesize the 11′‐12′ γ‐tocomonoenol isomer.…”

Countercurrent chromatographic isolation and purification of 11′-α-tocomonoenol from the vitamin E extract of palm oil

“…Due to the three methyl groups and the hydroxyl group on the aromatic part of the 6-chromanol, -T1 does not show resonances between 6 and 7 ppm. Next to the many unresolved signals high-field in the aliphatic range (<2.5 ppm) [8,28], tocomonoenols feature resonances in the olefinic range (~4.5-6 ppm) [8,29]. The -T1 isolate featured the expected complex pattern in the aliphatic range along with one triplet at  = 5.12 ppm ( 3 J = 7 Hz) ( Fig.…”