Fucoxanthin (Fx), a xanthophyll carotenoid abundant in brown algae, possesses several biological functions, such as antioxidant, anti-inflammatory, and cardiac-protective activities. However, the role of Fx in myocardial ischemia/reperfusion (MI/R) is still unclear. Thus, the aim of this study was to investigate the effect of Fx on MI/R-induced injury and explore the underlying mechanisms. Our results showed that in vitro, Fx treatment significantly suppressed inflammatory response, oxidative stress, and apoptosis in rat cardiomyocytes exposed to hypoxia/reoxygenation (H/R). In addition, Fx led to increased phosphorylation of AMPK, AKT, and GSK-3β, and enhanced activation of Nrf2 in cardiomyocytes under H/R conditions. Notably, pretreatment with Compound C (AMPK inhibitor), partially reduced the beneficial effects of Fx in cardiomyocytes exposed to H/R. In vivo, Fx ameliorated myocardial damage, inhibited inflammatory response, oxidative stress, and apoptosis, and activated the AMPK/GSK-3β/Nrf2 signaling in myocardial tissues in MI/R rat model. Taken together, these findings indicated that Fx attenuates MI/R-induced injury by inhibiting oxidative stress, inflammatory response, and apoptosis. The AMPK/GSK-3β/Nrf2 pathway is involved in the cardioprotective effect of Fx in MI/R injury. Thus, Fx may be a promising drug for the treatment of MI/R.

BACKGROUND: Staphylococcus aureus is an infectious bacterium that is frequently found in healthcare settings and the community. This study aimed to prepare rutin-loaded chitosan nanoparticles (Rut-CS NPs) and assess their antibacterial activity against pathogenic strains of S. aureus.
RESULTS: The synthesized Rut-CS NPs exhibited an amorphous morphology with a size ranging from 160 to 240 nm and a zeta potential of 37.3 mV. Rut-CS NPs demonstrated significant antibacterial activity against S. aureus strains. Following exposure to Rut-CS NPs, the production of staphyloxanthin pigment decreased by 43.31-89.63%, leading to increased susceptibility of S. aureus to hydrogen peroxide. Additionally, visual inspection of cell morphology indicated changes in membrane integrity and permeability upon Rut-CS NPs exposure, leading to a substantial increase (107.07-191.08%) in cytoplasmic DNA leakage in the strains. Furthermore, ½ MIC of Rut-CS NPs effectively inhibited the biofilm formation (22.5-37.5%) and hemolytic activity (69-82.59%) in the S. aureus strains.
CONCLUSIONS: Our study showcases that Rut-CS NPs can serve as a novel treatment agent to combat S. aureus infections by altering cell morphology and inhibiting virulence factors of S. aureus.

Antheraxanthin (C40H56O3) is one of fat-soluble carotenoids belonging to natural pigments. Its chemical structure is based on the unsaturated polyene chain skeleton, with a hydroxy-β-ionone ring and an epoxy-β-ionone ring on each side of the skeleton. It is found in a wide range of plants and photosynthetic bacteria, and external stimuli (high temperature, drought, ozone treatment, etc.) can significantly affect its synthesis. It also, like other carotenoids, exhibits a diverse potential pharmacological profile as well as nutraceutical values. However, it is worth noting that various food processing methods (extrusion, puffing, baking, etc.) and storage conditions for fruits and vegetables have distinct impacts on the bioaccessibility and retention of antheraxanthin. This compilation of antheraxanthin includes sources, biosynthesis, chemical analysis, and processing effects.

Fucoxanthin (Fx) has garnered significant interest due to its exceptional biological properties. However, its efficacy in enhancing food quality and human health is contingent upon the solubility of the compound in water and its physicochemical stability. Therefore, nanocarriers must be developed to enhance the stability and biocompatibility of Fx. In this study, oxidized paramylon and Fx self-assembled nanoparticles (Fx-OEP) were prepared via the anti-solvent method, with a loading rate of 82.47 % for Fx. The Fx-OEP exhibited robust storage and photostability. In vitro simulated digestion assays demonstrated that Fx-OEP effectively protected Fx from premature gastric release, while achieving a release efficiency of 72.17 % in the intestinal phase. Fx-OEP has the capacity to scavenge a range of reactive oxygen species (ROS) induced by cellular oxidative stress. Treatment with Fx-OEP resulted in a significant reduction in ROS accumulation in insulin-resistant HepG2 cells, which was attributed to the activation of the nuclear factor E2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway. This, in turn, activated insulin receptor substrate 1/glucose transporter type 4 (IRS1/GLUT4), promoting cellular glucose absorption and utilization. These findings indicate the potential of self-assembled nanoparticles based on oxidized paramylon as a new type of nanocarrier for delivering hydrophobic substances.

Snow (cryotolerant) algae often form red (pink) spots in mountain ecosystems on snowfields around the world, but little is known about their physiology and chemical composition. Content and composition of pigments in the cells of the cryotolerant green microalgae Chloromonas reticulata have been studied. Analysis of carotenoids content in the green (vegetative) cells grown under laboratory conditions and in the red resting cells collected from the snow surface in the Subpolar Urals was carried out. Carotenoids such as neoxanthin, violaxanthin, anteraxanthin, zeaxanthin, lutein, and β-carotene were detected. Among the carotenoids, the ketocarotenoid astaxanthin with high biological activity was also found. It was established that cultivation of the algae at low positive temperature (6°C) and moderate illumination (250 μmol quanta/(m2⋅s) contributed to accumulation of all identified carotenoids, including extraplastidic astaxanthin. In addition to the pigments, fatty acids accumulated in the algae cells. The data obtained allow us to consider the studied microalgae as a potentially promising species for production of carotenoids.

This in vivo study performed in rat adjuvant arthritis aims to advance the understanding of astaxanthin\'s therapeutic properties for the possible treatment of rheumatoid arthritis (RA) in monotherapy and along with the standard RA treatment, methotrexate (MTX), in combination therapy. The main goal was to elucidate astaxanthin\'s full therapeutic potential, evaluate its dose dependency, and compare its effects in monotherapy with other carotenoids such as β-carotene and β-cryptoxanthin (KXAN). Moreover, potential differences in therapeutic activity caused by using different sources of astaxanthin, synthetic (ASYN) versus isolated from Blakeslea trispora (ASTAP), were evaluated using one-way ANOVA (Tukey-Kramer post hoc test). KXAN was the most effective in reducing plasma MMP-9 levels in monotherapy, significantly better than MTX, and in reducing hind paw swelling. The differences in the action of ASTAP and ASYN have been observed across various biometric, anti-inflammatory, and antioxidative parameters. In combined therapy with MTX, the ASYN + MTX combination proved to be better. These findings, especially the significant anti-arthritic effect of KXAN and ASYN + MTX, could be the basis for further preclinical studies.

Fucoxanthin, a carotenoid with remarkable antioxidant properties, has considerable potential for high-value biotechnological applications in the pharmaceutical, nutraceutical, and cosmeceutical fields. However, conventional extraction methods of this molecule from microalgae are limited in terms of cost-effectiveness. This study focused on optimizing biomass and fucoxanthin production from Isochrysis galbana, isolated from the coast of Tadjoura (Djibouti), by testing various culture media. The antioxidant potential of the cultures was evaluated based on the concentrations of fucoxanthin, carotenoids, and total phenols. Different nutrient formulations were tested to determine the optimal combination for a maximum biomass yield. Using the statistical methodology of principal component analysis, Walne and Guillard F/2 media were identified as the most promising, reaching a maximum fucoxanthin yield of 7.8 mg/g. Multiple regression models showed a strong correlation between antioxidant activity and the concentration of fucoxanthin produced. A thorough study of the optimization of I. galbana growth conditions, using a design of experiments, revealed that air flow rate and CO2 flow rate were the most influential factors on fucoxanthin production, reaching a value of 13.4 mg/g. Finally, to validate the antioxidant potential of fucoxanthin, an in silico analysis based on molecular docking was performed, showing that fucoxanthin interacts with antioxidant proteins (3FS1, 3L2C, and 8BBK). This research not only confirmed the positive results of I. galbana cultivation in terms of antioxidant activity, but also provided essential information for the optimization of fucoxanthin production, opening up promising prospects for industrial applications and future research.

Normal-phase (NP) liquid chromatography is one of the most effective methods for separating isomers with sensitive structural features, including xanthophyll isomers. In this work, reverse-phase (RP) and NP liquid chromatography (LC), with silica gel and diol phase, respectively, were evaluated for the separation of xanthophyll isomers. The results showed that RP LC with monomeric C18 phase not only poorly separate all xanthophyll isomers in egg yolk but also requires additional sample preparation to eliminate triacylglycerols in egg yolk. The diol phase of NP-LC provided the highest efficiency for separating lutein, zeaxanthin, and their cis-isomers with isocratic separation using mobile phases consisting of n-hexane and polar modifiers (such as acetone, methyl tert-butyl ether, or ethyl acetate). To determine the xanthophyll content, peak areas from LC and total absorbance from spectrophotometry measurements were used. The approach was applied to analyze the xanthophylls of nine commercial egg samples. The results revealed that five out of nine analyzed samples contained a high level of canthaxanthin, which contributes to color enhancement but not to prevent age-related macular degeneration. Together, it shows that NP LC with diol phase combined with spectrophotometry is a powerful tool to monitor xanthophylls in eggs.

Xanthophyllomyces dendrorhous (X. dendrorhous), previously known as Phaffia rhodozyma, is a red yeast that is widely recognized as a rich source of carotenoids, particularly astaxanthin, which exhibits potent antioxidant activity and other health-promoting functions. However, there is currently a lack of research on the safety of consuming X. dendrorhous. To address this, we conducted an acute toxicity study followed by a 90-day subchronic toxicity trial to evaluate the safety of X. dendrorhous and investigate its in vivo antioxidant activity. In the acute toxicity study, Sprague-Dawley rats were administered a maximum of 12 g/kg body weight of X. dendrorhous powder by gavage and survived without any adverse effects for 14 days. In the subsequent subchronic toxicity test, the rats were randomly divided into five groups, each with free access to their diet adulterated with 0% (control), 2.5% (low), 5% (middle), 10% (high), and 20% (extreme high) X. dendrorhous powder. The rats\' behavior, body weight, and food intake were monitored during the 90-day experiment. At the end of the experiment, urine, blood, and organs were collected from the rats for biochemical testing. Additionally, the antioxidant activity in rat sera was evaluated. The results of the acute toxicity test demonstrated that the LD50 of X. dendrorhous was greater than 12 g/kg body weight, indicating that the substance was not toxic. Throughout the 90-day period of subchronic toxicity, the triglyceride levels of male rats fed with 10 and 20% X. dendrorhous increased to 1.54 ± 0.17 and 1.55 ± 0.25 mmol/L (P < 0.05), respectively. This may be attributed to the elevated fat content of the diet in the high-dose and extreme high-dose groups, which was 5.5 and 2.5% higher than that in the control, respectively. Additionally, the white pulp in the spleen exhibited an increase, and the number of white blood cells in the extreme high-dose group increased by 2.41 × 109/L (P < 0.05), which may contribute to enhanced immunity. Finally, the body weight, food intake, blood and urine indexes, and histopathological examination results of the organs of the rats did not demonstrate any regular toxic effects. With the adulteration of X. dendrorhous, the activity of GSH-Px in male rats increased by 16-36.32%. The activity of GSH-Px in female rats of the extreme high-dose group increased by 14.70% (P < 0.05). The free radical scavenging ability of ABTS in male rats in the two high-dose groups exhibited an increase of 6.5 and 11.41% (P < 0.05). In contrast, the MDA content of male rats in the extreme high-dose group demonstrated a reduction of 2.73 nmol/mL (P < 0.05). These findings indicate that X. dendrorhous has no toxic effects, can be taken in high doses, and has a beneficial antioxidant effect that may enhance the body\'s immunity.

The common presence of glycidyl esters (GEs) in refined vegetable oils has been a concern for food safety. The present study aimed to investigate the inhibitory effects of three carotenoids derived from Haematococcus pluvialis microalga on GE formation in both rice oil and a chemical model during heating. The addition of astaxanthin (AS), lutein (LU), and β-carotene (CA) at 0.6 mg/g in rice oil can reduce GE formation by 65.0%, 57.1%, and 57.5%, respectively, which are significantly higher than those achieved by common antioxidants such as l-ascorbyl palmitate (39.0%), α-tocopherol (18.5%), tert-butyl hydroquinone (42.7%), and quercetin (26.2%). UPLC-Q-TOF-MS/MS analysis showed that two new compounds, that is, propylene glycol monoester and diester of palmitic acid, were formed in the CA-added chemical model, which provided direct experimental evidence for the inhibition of antioxidants including AS, LU, and CA against GE formation not only by indirect antioxidative action but also by direct radical reactions to competitively prevent the formation of cyclic acyloxonium intermediates. Furthermore, it was interestingly found that only AS could react with the GEs. The adduct of AS with GEs, astaxanthin-3-O-propanetriol esters, was preliminarily identified using Q-TOF-MS/MS in the heated AS-GE model, suggesting that reacting with GEs might represent another distinct mechanism of AS to eliminate GEs.