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24 pages, 2428 KiB

Open AccessArticle

Protective Effects of 3′-Epilutein and 3′-Oxolutein against Glutamate-Induced Neuronal Damage

by Ramóna Pap, Edina Pandur, Gergely Jánosa, Katalin Sipos, Ferenc Rómeó Fritz, Tamás Nagy, Attila Agócs and József Deli

Int. J. Mol. Sci. 2023, 24(15), 12008; https://doi.org/10.3390/ijms241512008 - 26 Jul 2023

Cited by 2 | Viewed by 1474

Abstract

Dietary lutein can be naturally metabolized to 3′-epilutein and 3′-oxolutein in the human body. The epimerization of lutein can happen in acidic pH, and through cooking, 3′-epilutein can be the product of the direct oxidation of lutein in the retina, which is also present in human serum. The 3′-oxolutein is the main oxidation product of lutein. Thus, the allylic oxidation of dietary lutein can result in the formation of 3′-oxolutein, which may undergo reduction either to revert to dietary lutein or epimerize to form 3′-epilutein. We focused on the effects of 3′-epilutein and 3′-oxolutein itself and on glutamate-induced neurotoxicity on SH-SY5Y human neuroblastoma cells to identify the possible alterations in oxidative stress, inflammation, antioxidant capacity, and iron metabolism that affect neurological function. ROS measurements were performed in the differently treated cells. The inflammatory state of cells was followed by TNFα, IL-6, and IL-8 cytokine ELISA measurements. The antioxidant status of the cells was determined by the total antioxidant capacity kit assay. The alterations of genes related to ferroptosis and lipid peroxidation were followed by gene expression measurements; then, thiol measurements were performed. Lutein metabolites 3′-epilutein and 3′-oxolutein differently modulated the effect of glutamate on ROS, inflammation, ferroptosis-related iron metabolism, and lipid peroxidation in SH-SY5Y cells. Our results revealed the antioxidant and anti-inflammatory features of 3′-epilutein and 3′-oxolutein as possible protective agents against glutamate-induced oxidative stress in SH-SY5Y cells, with greater efficacy in the case of 3′-epilutein. Full article

(This article belongs to the Special Issue The Role of Lutein for Human Health)

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11 pages, 3208 KiB

Open AccessArticle

Physiological Significance of the Heterogeneous Distribution of Zeaxanthin and Lutein in the Retina of the Human Eye

by Wojciech Grudzinski, Rafal Luchowski, Jan Ostrowski, Alicja Sęk, Maria Manuela Mendes Pinto, Renata Welc-Stanowska, Monika Zubik-Duda, Grzegorz Teresiński, Robert Rejdak and Wieslaw I. Gruszecki

Int. J. Mol. Sci. 2023, 24(13), 10702; https://doi.org/10.3390/ijms241310702 - 27 Jun 2023

Cited by 2 | Viewed by 1291

Abstract

Zeaxanthin and lutein are xanthophyll pigments present in the human retina and particularly concentrated in its center referred to as the yellow spot (macula lutea). The fact that zeaxanthin, including its isomer meso-zeaxanthin, is concentrated in the central part of the retina, in contrast to lutein also present in the peripheral regions, raises questions about the possible physiological significance of such a heterogeneous distribution of macular xanthophylls. Here, we attempt to address this problem using resonance Raman spectroscopy and confocal imaging, with different laser lines selected to effectively distinguish the spectral contribution of lutein and zeaxanthin. Additionally, fluorescence lifetime imaging microscopy (FLIM) is used to solve the problem of xanthophyll localization in the axon membranes. The obtained results allow us to conclude that one of the key advantages of a particularly high concentration of zeaxanthin in the central part of the retina is the high efficiency of this pigment in the dynamic filtration of light with excessive intensity, potentially harmful for the photoreceptors. Full article

(This article belongs to the Special Issue The Role of Lutein for Human Health)

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Review

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12 pages, 2036 KiB

Open AccessReview

An Overview of Lutein in the Lipid Membrane

by Justyna Widomska, Witold K. Subczynski, Renata Welc-Stanowska and Rafal Luchowski

Int. J. Mol. Sci. 2023, 24(16), 12948; https://doi.org/10.3390/ijms241612948 - 18 Aug 2023

Cited by 1 | Viewed by 959

Abstract

Lutein, zeaxanthin, and meso-zeaxanthin (a steroisomer of zeaxanthin) are macular pigments. They modify the physical properties of the lipid bilayers in a manner similar to cholesterol. It is not clear if these pigments are directly present in the lipid phase of the membranes, or if they form complexes with specific membrane proteins that retain them in high amounts in the correct place in the retina. The high content of macular pigments in the Henle fiber layer indicates that a portion of the lutein and zeaxanthin should not only be bound to the specific proteins but also directly dissolved in the lipid membranes. This high concentration in the prereceptoral region of the retina is effective for blue-light filtration. Understanding the basic mechanisms of these actions is necessary to better understand the carotenoid–membrane interaction and how carotenoids affect membrane physical properties—such as fluidity, polarity, and order—in relation to membrane structure and membrane dynamics. This review focuses on the properties of lutein. Full article

(This article belongs to the Special Issue The Role of Lutein for Human Health)

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