Cis-trans isomerizations of β-carotene and lycopene: A theoretical study

Wen Hsin Guo, Cheng Yi Tu, Ching Han Hu

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

The all-trans to mono-cis isomerizations of polyenes and two C 40H56 carotenes, β-carotene and lycopene, at the ground singlet (S0) and triplet (T1) states are studied by means of quantum chemistry computations. At the So state of polyenes containing n acetylene units (Pn), we find that the energy barrier of the central C=C rotation decreases with n. In contrast, however, at the T 1 state, the rotational barrier increases with n. For the C 40H56 carotenes, the rotational barriers of lycopene are lower than those of meir β-carotene counterparts. This difference renders the rotational rates of lycopene to be 1-2 orders of magnitude higher than those of β-carotene at room temperature. For both these carotenes, the barrier is lowest for the rotation toward the 13-cis isomer. The relative abundances are in the following order: all-trans > 9-cis > 13-cis > 15-cis. Although the 5-cis isomer of lycopene has the lowest energy among the cis isomers, its formation from the all-trans form is restricted, owing to a very large rotational barrier. The possible physiological implications of this study are discussed.

Original languageEnglish
Pages (from-to)12158-12167
Number of pages10
JournalJournal of Physical Chemistry B
Volume112
Issue number38
DOIs
Publication statusPublished - 2008 Sep 25

Fingerprint

carotene
Carotenoids
Isomerization
isomerization
Isomers
Polyenes
isomers
Quantum chemistry
Acetylene
Energy barriers
quantum chemistry
acetylene
atomic energy levels
lycopene
energy
room temperature

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Guo, Wen Hsin ; Tu, Cheng Yi ; Hu, Ching Han. / Cis-trans isomerizations of β-carotene and lycopene : A theoretical study. In: Journal of Physical Chemistry B. 2008 ; Vol. 112, No. 38. pp. 12158-12167.
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Cis-trans isomerizations of β-carotene and lycopene : A theoretical study. / Guo, Wen Hsin; Tu, Cheng Yi; Hu, Ching Han.

In: Journal of Physical Chemistry B, Vol. 112, No. 38, 25.09.2008, p. 12158-12167.

Research output: Contribution to journalArticle

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