A density functional theory study for the role of end groups on the antioxidative potency of carotenoids

Liao, Fu-Xing; Hu, Ching‐Han

doi:10.1007/s00214-013-1357-5

Cited by 8 publications

(6 citation statements)

References 58 publications

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“…Where Hx stands for the abstracted hydrogen atom and Cx for the carbon atom to which the radical is added to form the adduct. The relative importance of these mechanisms depends on chemical properties of reactives (carotenoid and radical) and the polarity of the solvent used [20,22,23,[29][30][31]. Therefore, the carotenoids can function as a ubiquitous free radical quencher or as an effective preventive of cancers, skin tumors, ophthalmic diseases, heart diseases, cardiovascular and chronic diseases [20][21][22][23][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Insights in the Scavenging Mechanism of Trichloromethyldioxy Radical with Lycopene: a DFT/TD- DFT Study

Taherkhani

Zanjanchi

2022

Preprint

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The antioxidant action of lycopene as an alkyl peroxyl radical (CCl3O•2) scavenger through electron transfer, hydrogen abstraction and radical addition mechanisms has been investigated in the gas, non-polar and polar phases using density functional theory and the conductor like polarizable continuum model, CPCM, to account for solvents effect at the B3LYP/6-31G** level of theory. Results reveal that for fully optimized complexes, there is a stabilizing attraction between CCl3O•2 radical and lycopene that its value in polar phase is more than none-polar phase and in none-polar phase is more than gas phase. Thermodynamic studies reveal that transfer electron process in polar solvent at room temperature is more desirable than other reactions. The global reactivity parameters of ionization potential, IP, electron affinity, EA, electroaccepting, ω+, and electrodonating, ω−, HOMO-LUMO gap, ∆, chemical potential, µ, chemical hardness, η, show that lycopene is considered as a good electron donor compared to CCl3O•2 radical and the antioxidant property of lycopene in polar solvent is more than non-polar solvent and cavity. The calculated λmax via time dependent-density functional theory, TD-DFT, has a bathochromic shift due to interactions of CCl3O•2 radical with lycopene, so that lycopene becomes almost colorless after radical adsorption in polar and non-polar solutions. The calculated values of dipole moment and solubility Gibbs free energy, ∆Gsolv, confirm more solubility of lycopene and its complex with radical in polar phase than non-polar phase. The obtained results can aid in the understanding of different possible mechanisms that may be involved in the prevention of some illness.

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Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Insights in the Scavenging Mechanism of Trichloromethyldioxy Radical with Lycopene: a DFT/TD- DFT Study

Taherkhani

Zanjanchi

2022

Preprint

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“…The effects of the end groups in natural carotenoids on the antioxidant activity were studied theoretically and experimentally. 20 The polarity of the terminal group affected the radical scavenging ability of natural carotenoids: carotenoids (lycopene and β-carotene) > hydroxy-carotenoids (zeaxanthin and lutein) > keto-carotenoids (astaxanthin and canthaxanthin) in phenoxy radical 21 and ABTS cationic radical scavenging experiments. 22 The effective conjugation length is also important in carotenoids' antioxidant activity, 23 and shorter β-apo-8′-carotenal was reported to exhibit poorer radical scavenging activity than β-carotene, 21 which was also demonstrated by our referenced EC 50 values of β-carotene and β-apo-12′-carotenal in Table 2.…”

Section: ■ Results and Discussionmentioning

confidence: 97%

“…The effects of the end groups in natural carotenoids on the antioxidant activity were studied theoretically and experimentally . The polarity of the terminal group affected the radical scavenging ability of natural carotenoids: carotenoids (lycopene and β-carotene) > hydroxy-carotenoids (zeaxanthin and lutein) > keto-carotenoids (astaxanthin and canthaxanthin) in phenoxy radical and ABTS cationic radical scavenging experiments .…”

Section: Resultsmentioning

confidence: 99%

Apocarotenals of Phenolic Carotenoids for Superior Antioxidant Activities

Shi

Jung

et al. 2021

ACS Omega

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A series of para-phenolic carotenes 1 with ortho- and meta-substitutions were respectively prepared utilizing the benzenesulfonyl protection method, which demonstrated the importance of the ring substituents on their effective conjugation, evaluated by their UV absorption values. The corresponding apo-12′-carotenals 2 were devised to improve the conjugation effect of the para-phenolic radical with the polyene chain by the conjugated aldehyde group. Apo-12′-carotenals 2b and 2c without ortho-substituents exhibited superior antioxidant activities to their corresponding symmetrical carotenes 1 as well as β-carotene and apo-12′-β-carotenal in 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assays.

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“…No computational investigations of the absorption spectra of crocin, or of its radicals, have been published. However, several computational studies have been devoted to the structure and antioxidant properties of various other carotenoids [ 21 , 22 , 23 , 24 , 25 , 26 ], and to the conformation studies of fatty acids radicals [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

Unveiling the Intimate Mechanism of the Crocin Antioxidant Properties by Radiolytic Analysis and Molecular Simulations

et al. 2023

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The successive steps of the oxidation mechanism of crocin, a major compound of saffron, by the free OH• radical are investigated by pulse radiolysis, steady-state (gamma) radiolysis methods, and molecular simulations. The optical absorption properties of the transient species and their reaction rate constants are determined. The absorption spectrum of the oxidized radical of crocin resulting from the H-abstraction presents a maximum of 678 nm and a band of 441 nm, almost as intense as that of crocin. The spectrum of the covalent dimer of this radical contains an intense band at 441 nm and a weaker band at 330 nm. The final oxidized crocin, issued from radical disproportionation, absorbs weaker with a maximum of 330 nm. The molecular simulation results suggest that the OH• radical is electrostatically attracted by the terminal sugar and is scavenged predominantly by the neighbor methyl site of the polyene chain as in a sugar-driven mechanism. Based on detailed experimental and theoretical investigations, the antioxidant properties of crocin are highlighted.

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A density functional theory study for the role of end groups on the antioxidative potency of carotenoids

Cited by 8 publications

References 58 publications

WITHDRAWN: Insights in the Scavenging Mechanism of Trichloromethyldioxy Radical with Lycopene: a DFT/TD- DFT Study

WITHDRAWN: Insights in the Scavenging Mechanism of Trichloromethyldioxy Radical with Lycopene: a DFT/TD- DFT Study

Apocarotenals of Phenolic Carotenoids for Superior Antioxidant Activities

Unveiling the Intimate Mechanism of the Crocin Antioxidant Properties by Radiolytic Analysis and Molecular Simulations

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