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Both curcumin and carotenoids are good antioxidants and curcumin has a pleiotropic effect additionally. To combine the beneficial properties carotenoid succinates were coupled to curcumin via ester bond. In another approach hemicurcumin was condensed with apocarotenoid aldehydes to produce a hybrid of the carotenoid and the curcuminoid part. Antioxidant activity of these products was determined with the ABTS-TEAC method in ethanol and in isotonic phosphate buffer saline. Covalent coupling of 8’-apo-β-carotenol, β-cryptoxanthin, capsanthin, and lutein to curcumin via succinate ester significantly increased the antioxidant capacity compared to the parent carotenoids or carotenoid succinates. Derivatization of zeaxanthin, nevertheless, did not improve its properties. The direct merging of hemicurcumin with apocarotenals resulted in extended conjugated polyenes with higher antioxidant activities, that, however, seems to be more effected by the number of phenolic moieties than by the number of conjugated double bonds. The open-chain carotenoid end-group can also contribute to a better antioxidant activity. The lipophilic conjugates and hybrids showed aggregation in aqueous media, thus the determined TEAC values in PBS rather characterize the aggregates than the individual molecules. Based on the drug-prediction studies and TEAC values, bisphenolic hybrids of curcumin with 12,12’-diapo-dialdehyde and crocetindial have the best characteristics for being drug candidates, but an appropriate delivery system is necessary.

BACKGROUND/OBJECTIVES:Capsanthin is a xanthophyll carotenoid from Capsicum species with an extended conjugated polyene chain that underlies both its orange-red color and strong antioxidant potential. In this study, we investigated whether capsanthin protects RA-differentiated SH-SY5Y neuron-like cells against glutamate-induced stress. METHODS:Neuronal dysfunction was induced by glutamate exposure, and capsanthin treatment was evaluated using cell viability, reactive oxygen species (ROS) production, antioxidant defense markers, inflammatory cytokines, mitochondrial energy status, and apoptosis-related endpoints. Antioxidant responses were assessed using superoxide dismutase, catalase, glutathione peroxidase activities, and total antioxidant capacity. Cytokine release (TNFα, IL-6, IL-8, IL-4, IL-10) was quantified by ELISA. Mitochondrial function was monitored using ATP content. Apoptosis-associated genes (BAX, BCL-2, CASP3, and CASP9) were analyzed using SYBR Green-based RT-qPCR, complemented by caspase-9 ELISA and caspase-3 Western blotting. RESULTS:Glutamate increased oxidative stress and shifted the cytokine profile toward a pro-inflammatory state, accompanied by reduced ATP levels and a pro-apoptotic transcriptional pattern. Capsanthin significantly attenuated glutamate-induced ROS production, stabilized antioxidant enzyme activities and total antioxidant capacity, reduced pro-inflammatory cytokines while supporting anti-inflammatory signaling, and preserved ATP levels. CONCLUSIONS:Overall, capsanthin mitigated excitotoxic stress by maintaining redox balance, limiting inflammatory responses, and protecting mitochondrial energy metabolism in neuron-like cells, supporting its potential as a neuroprotective candidate for glutamate-induced neuronal stress.

Lutein and zeaxanthin, prominent carotenoids with antioxidant properties, contribute notably to maintaining of ocular health. These substances reduce the harmful effect of oxidative stress and blue light and ensure the vision quality. Carotenoids-rich dietary could have ophthalmic benefits, such as enhanced contrast perception and reduced eye fatigue, while also show potential in mitigating the risk of age-related macular degeneration (AMD). Nonetheless, ocular administration of carotenoids could enhance the local ophthalmic bioavailability of these compounds. The aim of this study was to investigate ophthalmic applicability of lutein (LutD) and zeaxanthin disuccinates (ZeaD) in aqueous solutions applying cyclodextrins to improve their solubility and permeability. Among the tested cyclodextrins, randomly methylated beta-cyclodextrin (RAMEB) was identified as the most effective solubilizing agent, achieving solubility values of 572±55 μM and 1470±103 μM for LutD and ZeaD, respectively. In vitro corneal-PAMPA and ex vivo porcine eye models demonstrated that RAMEB-based formulations significantly improved the permeability of both carotenoid derivatives by increasing their solubility (corneal concentration at 15 mins), markedly surpassing those of the reference suspensions. The findings suggest that RAMEB may be essential for developing carotenoid-based aqueous eye drops, leveraging its antioxidant properties to improve ocular health and ameliorate various degenerative eye conditions.

Lipophilic substances such as carotenoids show a tendency to aggregate in aqueous medium, that changes the physical and chemical properties of individual molecules. To estimate the antioxidant properties of carotenoids, trolox-equivalent antioxidant capacity (TEAC) values are routinely determined with ABTS+• solutions. As this reagent is a salt, it is generally applied in aqueous solutions to which carotenoids are added in various organic solvents. Here we present a systematic investigation on the solvent dependence of TEAC measurements of 8 carotenoids, as well as the relationship between the aggregation and TEAC values. The aggregation of carotenoids was found to have two opposite effects on the antioxidant capacity: the higher the aggregate size, the lower the TEAC value, however, smaller size (10–20 nm) assemblies surpass the individual molecules in antioxidant capacity. The type of aggregation manner (H or J) seems to have less influence on the antioxidant behaviour.

It has been observed that the leaves of some Zamia species undergo a kind of "reverse ripening"; that is, they change from their original brown color to green during development. We assumed that this strange color change was due to the change in carotenoid composition, so we followed the changes for several weeks. The detailed carotenoid composition and content at different stages of development of the leaves was determined with HPLC-DAD focusing on the changes in red and yellow carotenoids. The total and relative amounts of red and yellow carotenoids were determined simultaneously from one measurement from a saponified and/or unsaponified extract. At the beginning of development, the concentration of red carotenoids was higher than that of the yellow ones; it decreased drastically until 22 days and continued to decrease slowly until they completely disappeared. The concentration of yellow carotenoids decreased at the beginning as well, but after 22 days it started to increase. The amount of red carotenoids started to decrease when the leaflet stopped growing. Lutein is the main component in old leaflets, which is not a red carotenoid precursor. Red carotenoids can always be found in their esterified form in the leaves. These findings support the hypothesis that red and yellow carotenoid accumulation are independent and probably have different functions in the leaflet. The strange color change was explained based on the compartmentalization of red and yellow carotenoids and on the changing activity of the enzyme capsanthin-capsorubin synthase responsible for the synthesis of red carotenoids capsorubin and capsanthin.

The carotenoid composition of petals, florets, and full inflorescences of Calendula officinalis grown in sun and shade was investigated by the HPLC-DAD-MS method. The total carotenoid content of flowers grown in the shade was higher than those grown in the sun (1.154 and 0.872 mg/g in petals), while no differences were found in the proportion of individual carotenoids. In all samples, 29 components were identified, from which the main carotenoids, besides lutein, were 5,8-epoxy-carotenoids with 8S and 8 ' R configurations. The main 5,8-epoxy-carotenoid was chrysanthemaxanthin with the 8S configuration and not flavoxanthin with the 8R configuration, as published earlier. In addition, (all-E,8 ' R)- and (9Z,8 ' R)-luteoxanthin were detected in larger amounts. The 5,8-epoxy-carotenoids (flavoxanthin, chrysanthemaxanthin, and luteoxanthin epimers) were also prepared via an acid-catalyzed reaction of the parent carotenoid 5,6-epoxides. The structures of the epimers were elucidated by NMR measurements.

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.

Lutein and its cis-isomers occur in a lot of plants, including a variety of flowers. In this study, lutein isomers were produced via iodine-catalyzed isomerization, and four cis-isomers (9Z-, 9′Z-, 13Z-, and 13Z′) were isolated by means of column chromatography and semipreparative HPLC. The structures of the 9′Z- and 13′Z-isomers were elucidated via NMR measurements. These compounds were used as standards for the HPLC-DAD-MS determination of the carotenoid composition of the flowers of 20 plant species, in which lutein and its geometrical isomers are the main components. The flowers showed great variation in their cis- and trans-lutein content, and also in the presence or absence of other carotenoids, such as violaxanthin, neoxanthin, β-cryptoxanthin, and β-carotene. Some of the investigated flowers were found to be rich sources of lutein without zeaxanthin.

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine with enzymatic activities. Anti-inflammatory effects of MIF enzyme inhibitors indicate a link between its cytokine- and catalytic activities. Herein the synthesis, docking, and bioactivity of substituted benzylidene-1-indanone and -1-tetralone derivatives as MIF-tautomerase inhibitors is reported. Many of these substituted benzylidene-1-tetralones and -indan-1-ones were potent MIF-tautomerase inhibitors (IC50 < 10 μmol/L), and the most potent inhibitors were the 1-indanone derivatives 16 and 20. Some of these compounds acted as selective enolase or ketonase inhibitors. In addition, compounds 16, 20, 26, 37 and 61 efficiently inhibited NO, TNFα and IL-6 production in lipopolysaccharide-induced macrophages. Compound 20, 37 and 61 also inhibited ROS generation, and compound 26 and 37 abolished activation of NF-κB. Compound 37 significantly augmented hypothermia induced by high dose of lipopolysaccharide in mice. The possible mechanisms of action were explored using molecular modelling and docking, as well as molecular dynamics simulations.

The carotenoid composition of the flower of Telekia speciosa was investigated for the first time by HPLC-DAD-MS. In addition to the main carotenoid lutein and its geometrical isomers, 5,6-epoxy-carotenoids, namely violaxanthin, lutein 5,6-epoxide and antheraxanthin, were detected in larger amounts. In addition, β-carotene 5,6-epoxide and β-carotene 5,6,5′,6′-diepoxide were found, which occurs very rarely in plants. For unambigous identification, β-carotene 5,6-epoxide and β-carotene 5,6,5′,6′-diepoxide were prepared semisynthetically, and they were characterized by 1H and 13C NMR and HPLC-CD methods.

László Zechmeister, one of the most important pioneers of carotenoid chemistry, died 50 years ago. He founded a carotenoid research group in Pécs (Hungary), which is the only place in the world where carotenoid research has been conducted continuously over the past 95 years. This review presents the life of Zechmeister and gives a summary about the evolution of the methods of analysis, isolation, and structure elucidation of carotenoids from the 1930s until today, based on the results of the research group founded by Zechmeister.

The xanthophyll carotenoid lutein has been widely used as supplementation due to its protective effects in light-induced oxidative stress. Its antioxidant and anti-inflammatory features suggest that it has a neuroprotective role as well. Glutamate is a major excitatory neurotransmitter in the central nervous system (CNS), which plays a key role in regulating brain function. Excess accumulation of intracellular glutamate accelerates an increase in the concentration of reactive oxygen species (ROS) in neurons leading to glutamate neurotoxicity. In this study, we focused on the effects of glutamate on SH-SY5Y neuroblastoma cells to identify the possible alterations in oxidative stress, inflammation, and iron metabolism that affect the neurological function itself and in the presence of antioxidant lutein. First, ROS measurements were performed, and then catalase (CAT) and Superoxide Dismutase (SOD) enzyme activity were determined by enzyme activity assay kits. The ELISA technique was used to detect proinflammatory TNFα, IL-6, and IL-8 cytokine secretions. Alterations in iron uptake, storage, and release were followed by gene expression measurements and Western blotting. Total iron level detections were performed by a ferrozine-based iron detection method, and a heme assay kit was used for heme measurements. The gene expression toward lipid-peroxidation was determined by RT-PCR. Our results show glutamate changes ROS, inflammation, and antioxidant enzyme activity, modulate iron accumulation, and may initiate lipid peroxidation in SH-SY5Y cells. Meanwhile, lutein attenuates the glutamate-induced effects on ROS, inflammation, iron metabolism, and lipid peroxidation. According to our findings, lutein could be a beneficial, supportive treatment in neurodegenerative disorders.

Carotenoid succinates were synthesized from hydroxy carotenoids and were coupled to a commercially available derivative of melatonin via amide bond for producing more powerful anti-oxidants and yet new hybrid lipophilic bifunctional molecules with additional therapeutic effects. The coupling reactions produced conjugates in acceptable to good yields. Succinylation increased the water solubility of the carotenoids, while the conjugation with melatonin resulted in more lipophilic derivatives. The conjugates showed self-assembly in aqueous medium and yielded relatively stable colloidal solutions in phosphate-buffered saline. Antioxidant behavior was measured with ABTS and the FRAP methods for the carotenoids, the carotenoid succinates, and the conjugates with melatonin. A strong dependence on the quality of the solvent was observed. TEAC values of the new derivatives in phosphate-buffered saline were found to be comparable to or higher than those of parent carotenoids, however, synergism was observed only in FRAP assays.

Intézetünk szerteágazó nemzetközi és ipari kapcsolatrendszerrel rendelkezve igen széleskörű kutatási feladatokat lát el a biokémia, analitikai kémiai és szintetikus szerves kémia területén. A főbb tudományos témaköröket jól reprezentálja az Intézet keretein belül működő négy Tanszék (Analitikai Biokémia, Orvosi Biokémia, Orvosi Kémia, Patobiokémia). Közleményünkben, a teljesség igénye nélkül, be szeretnénk mutatni néhány olyan kutatási témát, amelyek meghatározó jelentőségűek Intézetünk profiljában. Ezek főként tömegspektrometriára épülő kvantitatív és kvalitatív analitikai vizsgálatok illetve a karotinkémiát érintő területek.

Jipi-japa (Carludovica palmata) and zamia (Zamia dressier() are endemic species and are found mostly in the forests of Central America including Panama. In theory both the jipi-japa fruit and the stem and seeds of zamia are edible, although were only consumed occasionally mostly before modern times. The complete and detailed carotenoid analysis of the fruits of jipi-japa and the brown leaves of zamia was achieved using HPLC-DAD-MS technique, and co-chromatography with authentic samples. Plant extracts were subjected to HPLC separation on both C30 and C18 columns to make possible a better identification. Altogether 22 components were detected and 15 identified from the total extract of jipi-japa, and 32 components were detected and 17 identified from the extract of brown zamia leaves. From the identified carotenoids quite a number has special structures, which have recently been described in some of our previous papers on Central American plants (Murillo et al., 2011a, 2018; Gulyds-Fekete et al., 2013). It was found that almost 50 % of the total carotenoid content can be attributed to capsorubin in both plants. This carotenoid is present usually as a minor (2-3 %) camtenoid in other sources such as red pepper. Other camtenoids with lc end group are present in significant amounts, as well. Total carotenoid content was determined as the sum of yellow and red carotenoids (see Supplement). The main carotenoid, capsorubin, was isolated by open column chromatography on calcium carbonate and aluminium oxide and characterized by UV-vis, H-1 and C-13 NMR methods and compared to literature data. Capsorubin is a potent antioxidant even among carotenoids and have important biological effects. These two plants could be good sources for capsorubin either for isolation in gram amounts or for direct consumption.

Lutein is a tetraterpene carotenoid, which has been reported as an important antioxidant and it is widely used as a supplement. Oxidative stress participates in many human diseases, including different types of neurodegenerative disorders. Microglia, the primary immune effector cells in the central nervous system, are implicated in these disorders by producing harmful substances such as reactive oxygen species (ROS). The protective mechanisms which scavenge ROS include enzymes and antioxidant substances. The protective effects of different carotenoids against oxidative stress have been described previously. Our study focuses on the effects of lutein on antioxidant enzymes, cytokines and iron metabolism under stress conditions in BV-2 microglia. We performed cell culture experiments: BV-2 cells were treated with lutein and/or with H2O2; the latter was used for inducing oxidative stress in microglial cells. Real-time PCR was performed for gene expression analyses of antioxidant enzymes, and ELISA was used for the detection of pro- and anti-inflammatory cytokines. Our results show that the application of lutein suppressed the H2O2-induced ROS (10′: 7.5 ng + 10 µM H2O2, p = 0.0002; 10 ng/µL + 10 µM H2O2, p = 0.0007), influenced iron utilization and changed the anti-inflammatory and pro-inflammatory cytokine secretions in BV-2 cells. Lutein increased the IL-10 secretions compared to control (24 h: 7.5 ng/µL p = 0.0274; 10 ng/µL p = 0.0008) and to 10 µM H2O2-treated cells (24 h: 7.5 ng/µL + H2O2, p = 0.0003; 10 ng/µL + H2O2, p = 0.0003), while it decreased the TNFα secretions compared to H2O2 treated cells (24 h: 7.5 ng/µL + H2O2, p < 0.0001; 10 ng/µL + H2O2, p < 0.0001). These results contribute to understanding the effects of lutein, which may help in preventing or suppressing ROS-mediated microglia activation, which is related to neuronal degeneration in oxidative stress scenario.

The protracted global COVID-19 pandemic urges the development of new drugs against the causative agent SARS-CoV-2. The clinically used glycopeptide antibiotic, teicoplanin, emerged as a potential antiviral, and its efficacy was improved with lipophilic modifications. This prompted us to prepare new lipophilic apocarotenoid conjugates of teicoplanin, its pseudoaglycone and the related ristocetin aglycone. Their antiviral effect was tested against SARS-CoV-2 in Vero E6 cells, using a cell viability assay and quantitative PCR of the viral RNA, confirming their micromolar inhibitory activity against viral replication. Interestingly, two of the parent apocarotenoids, bixin and β-apo-8′carotenoic acid, exerted remarkable anti-SARS-CoV-2 activity. Mechanistic studies involved cathepsin L and B, as well as the main protease 3CLPro, and the results were rationalized by computational studies. Glycopeptide conjugates show dual inhibitory action, while apocarotenoids have mostly cathepsin B and L affinity. Since teicoplanin is a marketed antibiotic and the natural bixin is an approved, cheap and widely used red colorant food additive, these readily available compounds and their conjugates as potential antivirals are worthy of further exploration.

Flavonoids and carotenoids possess beneficial physiological effects, such as high antioxidant capacity, anticarcinogenic, immunomodulatory, and anti-inflammatory properties, as well as protective effects against UV light. The covalent coupling of hydrophobic carotenoids with hydrophilic flavonoids, such as daidzein and chrysin, was achieved, resulting in new amphipathic structures. 7-Azidohexyl ethers of daidzein and chrysin were prepared in five steps, and their azide-alkyne [4 + 2] cycloaddition with pentynoates of 8′-apo-β-carotenol, zeaxanthin, and capsanthin afforded carotenoid–flavonoid conjugates. The trolox-equivalent antioxidant capacity against ABTS•+ radical cation and self-assembly of the final products were examined. The 1:1 flavonoid–carotenoid hybrids generally showed higher antioxidant activity than their parent flavonoids but lower than that of the corresponding carotenoids. The diflavonoid hybrids of zeaxanthin and capsanthin, however, were found to exhibit a synergistic enhancement in antioxidant capacities. ECD (electronic circular dichroism) and UV-vis analysis of zeaxanthin–flavonoid conjugates revealed that they form different optically active J-aggregates in acetone/water and tetrahydrofuran/water mixtures depending on the solvent ratio and type of the applied aprotic polar solvent, while the capsanthin derivatives showed no self-assembly. The zeaxanthin bis-triazole conjugates with daidzein and with chrysin, differing only in the position of a phenolic hydroxyl group, showed significantly different aggregation profile upon the addition of water.

Two new carotenoids, sapotexanthin 5,6-epoxide and sapotexanthin 5,8-epoxide, have been isolated from the ripe fruits of red mamey (Pouteria sapota). Sapotexanthin 5,6-epoxide was also prepared by partial synthesis via epoxidation of sapotexanthin, and the (5R,6S) and (5S,6R) stereoisomers were identified by high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) analysis. Spectroscopic data of the natural and semisynthetic derivatives obtained by acid-catalyzed rearrangement of cryptocapsin 5,8-epoxide stereoisomers were compared for structural elucidation.