Carotenoids are secondary metabolite responsible for colored pigments in plants and microbes (Li et al., 2022). They are a class of C₄₀ tetraterpenoids consisting of eight isoprenoid units, and can be classified into carotenes and xanthophylls on the basis of their functional groups (Saini et al., 2015). Carotenes can be linear (phytoene, phytofluene, and ζ‍-carotene) or branched (β‍-carotene and α‍-carotene). Xanthophylls comprise β,β‍-xanthophylls (β‍-cryptoxanthin, zeaxanthin, violaxanthins, and neoxanthin) and β,ε‍-xanthophylls (α-cryptoxanthin, α-carotene, and lutein). Citrus fruits are complex sources of carotenoids, which are the principal pigments responsible for the typical orange color of most types (Chen, 2020). The difference in total carotenoid content and the diversity of carotenoid isomer proportion also accounts for other colors of citrus fruits, such as yellow, red, and pink (Chen, 2020).
Citrus/metabolism* ; Carotenoids ; Xanthophylls ; Lutein/metabolism* ; Zeaxanthins/metabolism* ; Fruit

The aim of this study was to develop a technical system for high-efficient production of fucoxanthin by photo-fermentation of Phaeodactylum tricornutum. In a 5 L photo-fermentation tank, the effects of initial light intensity, nitrogen source and concentration as well as light quality on biomass concentration and fucoxanthin accumulation in P. tricornutum were investigated systematically under mixotrophic condition. The results showed that the biomass concentration, fucoxanthin content and productivity reached the highest level of 3.80 g/L, 13.44 mg/g and 4.70 mg/(L·d) under the optimal conditions of initial light intensity of 100 μmol/(m²·s), 0.02 mol TN/L of tryptone: urea (1:1, N mol/N mol) as mixed nitrogen source, and a mixed red/blue (R: B=6:1) light, 1.41, 1.33 and 2.05-fold higher than that before optimization, respectively. This study developed a key technology for enhancing the production of fucoxanthin by photo-fermentation of P. tricornutum, facilitating the development of marine natural products.
Fermentation ; Xanthophylls ; Light ; Diatoms ; Nitrogen

The aim of this study was to promote fucoxanthin accumulation in Phaeodactylum tricornutum by photo-fermentation through optimizing the mode of multiple nitrogen supplementation and blue light enhancement. The results showed that the mixed nitrogen source (tryptone: urea=1:1, N mol/N mol; total nitrogen concentration at 0.02 mol/L) added to the culture system by six times was the best mode in shake flasks. Two-phase culture with light adjustment was then carried out in 5 L photo-fermenter with an enhanced blue light (R: G: B=67.1:16.7:16.3) in the second phase, leading to improved cell density (1.12×10⁸ cells/mL), biomass productivity (330 mg/(d·L)), fucoxanthin content (19.62 mg/g), titer (69.71 mg/L) and productivity (6.97 mg/(d·L)). Compared with one-phase culture under red/blue (R: G: B=70.9:18.3:10.9) light and six-times nitrogen supplementation, the fucoxanthin content was significantly increased by 7.68% (P < 0.05) but the productivity did not change significantly (P > 0.05). Compared with one-phase culture under red/blue (R: G: B=70.9:18.3:10.9) light and one-time nitrogen supplementation, the content and productivity of fucoxanthin were significantly increased by 45.98% and 48.30% (P < 0.05), respectively. This study developed a two-phase culture mode with multiple nitrogen supplementation and blue light enhancement, which effectively promoted the accumulation of fucoxanthin and improved the efficiency of nitrogen source utilization, thus providing a new approach for fucoxanthin accumulation in P. tricornutum by photo-fermentation.
Nitrogen ; Light ; Xanthophylls ; Diatoms ; Dietary Supplements

OBJECTIVE: To investigate the protective effect of fucoxanthin (FX) against diabetic cardiomyopathy and explore the underlying mechanism. METHODS: Rat models of diabetes mellitus (DM) induced by intraperitoneal injection of streptozotocin (60 mg/kg) were randomized into DM model group, fucoxanthin treatment (DM+FX) group and metformin treatment (DM+ Met) group, and normal rats with normal feeding served as the control group. In the two treatment groups, fucoxanthin and metformin were administered after modeling by gavage at the daily dose of 200 mg/kg and 230 mg/kg, respectively for 12 weeks, and the rats in the DM model group were given saline only. HE staining was used to examine the area of cardiac myocyte hypertrophy in each group. The expression levels of fibrotic proteins TGF-β1 and FN proteins in rat hearts were detected with Western blotting. In the cell experiment, the effect of 1 μmol/L FX on H9C2 cell hypertrophy induced by exposure to high glucose (HG, 45 mmol/L) was evaluated using FITC-labeled phalloidin. The mRNA expression levels of the hypertrophic factors ANP, BNP and β-MHC in H9C2 cells were detected using qRT-PCR. The protein expressions of Nrf2, Keap1, HO-1 and SOD1 proteins in rat heart tissues and H9C2 cells were determined using Western blotting. The DCFH-DA probe was used to detect the intracellular production of reactive oxygen species (ROS). RESULTS: In the diabetic rats, fucoxanthin treatment obviously alleviated cardiomyocyte hypertrophy and myocardial fibrosis, increased the protein expressions of Nrf2 and HO-1, and decreased the protein expressions of Keap1 in the heart tissue (P < 0.05). In H9C2 cells with HG exposure, fucoxanthin significantly inhibited the enlargement of cell surface area, lowered the mRNA expression levels of ANP, BNP and β-MHC (P < 0.05), promoted Nrf2 translocation from the cytoplasm to the nucleus, and up-regulated the protein expressions its downstream targets SOD1 and HO-1 (P < 0.05) to enhance cellular antioxidant capacity and reduce intracellular ROS production. CONCLUSION Fucoxanthin possesses strong inhibitory activities against diabetic cardiomyocyte hypertrophy and myocardial fibrosis and is capable of up-regulating Nrf2 signaling to promote the expression of its downstream antioxidant proteins SOD1 and HO-1 to reduce the level of ROS.
Animals ; Antioxidants/metabolism* ; Atrial Natriuretic Factor/pharmacology* ; Cardiomegaly ; Diabetes Mellitus, Experimental/metabolism* ; Fibrosis ; Kelch-Like ECH-Associated Protein 1/metabolism* ; Metformin ; NF-E2-Related Factor 2/metabolism* ; Oxidative Stress ; RNA, Messenger/metabolism* ; Rats ; Reactive Oxygen Species/metabolism* ; Superoxide Dismutase-1/pharmacology* ; Xanthophylls

OBJECTIVES: Human periodontal ligament cells (hPDLCs) are important source of periodontal tissue reconstruction. Under chronic inflammation, the multi-directional differentiation potential and chemotaxis in hPDLCs are decreased. Therefore, inhibiting inflammatory microenvironment and improving the functional characteristics of stem cells can better promote periodontal tissue reconstruction. This study was to investigate the effect of astaxanthin (AST) on lipopolysaccharide (LPS)-induced inflammation in hPDLCs and the underlying mechanisms. METHODS: hPDLCs were isolated and cultured in vitro, and vimentin and keratin immunocytochemical staining were used to identify hPDLCs. CCK-8 assay was used to measure the effects of AST (1, 5, 10, 20, 50, 100, and 200 μmol/L) on proliferation of hPDLCs. Quantitative RT-PCR (RT-qPCR) and ELISA were used to measure the mRNA and protein expression of inflammatory factors (IL-6, IL-1β, and TNF-α) in the control (Con) group, the LPS group, and the LPS+AST (5, 10, 20, and 50 μmol/L) group. Western blotting was used to detect the protein expression of IKBα, phosphorylated IKBα (p-IKBα), and p65 in the Con group, the LPS group, the AST (20 μmol/L) group, and the LPS+AST (20 μmol/L) group. After 10 μmol/L PDTC treatment, the mRNA and protein expressions of IL-6, IL-1β, and TNF-α were detected by RT-qPCR and ELISA. RESULTS: Cell morphology and immunocytochemical staining showed that the cells were in line with the characteristics of hPDLCs. Treatment with AST could promote the proliferation of hPDLCs, which reached the peak at 20 μmol/L. The mRNA and protein expressions of IL-6, IL-1β, and TNF-α in the LPS group were higher than those in the Con group (all CONCLUSIONS AST promotes the proliferation of hPDLCs, which is related to suppression of LPS-induced the secretion of inflammatory factors via inhibiting the activation of NF-κB signaling pathway.
Cells, Cultured ; Humans ; Inflammation/chemically induced* ; Lipopolysaccharides ; NF-kappa B ; Periodontal Ligament ; Tumor Necrosis Factor-alpha/genetics* ; Xanthophylls

Aging ; Animals ; Galactose ; Kidney/metabolism* ; NF-E2-Related Factor 2/metabolism* ; Oxidative Stress ; Rats ; Rats, Sprague-Dawley ; Xanthophylls

OBJECTIVE: To observe the effect of astaxanthin (ASTA) on the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in suspended leukocyte-depleted red blood cells stored for transfusion. METHODS: The suspended leukocyte-depleted red blood cells were randomly divided into group A, B, C and D. The ASTA was added into preservation solution of suspended leukocyte-depleted red blood cells of group B, C and D with the final concentration 5, 10 and 20 μmol/L, respectively, while DMSO was added into cells of group A in the same volume. After 7, 14, 28 and 42 days of storage, the reactive oxygen species (ROS) content in red blood cells was detected by fluorescence microplate reader, malondialdehyde (MDA) content was detected by thiobarbituric acid (TBA) method, activity of SOD was detected by xanthine oxidase method, the activity of CAT was detected by visible light method, and activity of GSH-Px was detected by colorimetry. RESULTS: After 7, 14, 28 and 42 days of storage, the contents of ROS and MDA in suspended red blood cells of group B, C and D were significantly lower(P<0.05), while the activities of SOD and GSH-Px were higher than those of group A(P<0.05); and CAT activity in cells treated by ASTA was significantly higher at 28 and 42 days of storage in comparison with that of group A(P<0.05). There were positive correlations between the ROS, MDA content in suspended red blood cells of group A, B, C, D and storage time(P<0.01), while negative correlation between SOD, CAT, GSH-Px activity and storage time(P<0.01). CONCLUSION ASTA can decrease the oxidative stress level and peroxide damage degree by increasing the antioxidant enzyme activities in suspended leukocyte-depleted red blood cells during storage.
Antioxidants ; Catalase/metabolism* ; Erythrocytes ; Leukocytes ; Oxidative Stress ; Superoxide Dismutase/metabolism* ; Xanthophylls

The unicellular green alga Haematococcus pluvialis is the best source of natural astaxanthin (AST) in the world due to its high content under stress conditions. Although high light (HL) can effectively induce AST biosynthesis, the specific mechanisms of light signal perception and transduction are unclear. In the current study, we used transcriptomic data of normal (N), high white light (W), and high blue light (B) to study the mechanisms of light inducing AST accumulation from the point of photoreceptors. The original data of 4.0 G, 3.8 G, and 3.6 G for N, W, and B were obtained, respectively, by the Illumina Hi-seq 2000 sequencing technology. Totally, 51 954 unigenes (at least 200 bp in length) were generated, of which, 20 537 unigenes were annotated into at least one database (NR, NT, KO, SwissProt, Pfam, GO, or KOG). There were 1 255 DEGs in the W vs N, 1 494 DEGs in the B vs N, and 1 008 DEGs in the both W vs N and B vs N. KEGG enrichment analysis revealed that photosynthesis, oxidative phosphorylation, carotenoid biosynthesis, fatty acids biosynthesis, DNA replication, nitrogen metabolism, and carbon metabolism were the significantly enriched pathways. Moreover, a large number of genes encoding photoreceptors and predicted interacting proteins were predicted in Haematococcus transcriptome data. These genes showed significant differences at transcriptional expression levels. In addition, 15 related DEGs were selected and tested by qRT-PCR and the results were significantly correlated with the transcriptome data. The above results indicate that the signal transduction pathway of "light signal - photoreceptors - interaction proteins - (interaction proteins - transcription factor/transcriptional regulator) - gene expression - AST accumulation" might play important roles in the regulation process, and provide reference for further understanding the transcriptional regulation mechanisms of AST accumulation under HL stress.
Chlorophyta/genetics* ; Gene Expression Profiling ; Signal Transduction/genetics* ; Transcriptome/genetics* ; Xanthophylls

The aim of this paper was to study the effect and mechanism of fucoxanthin on insulin resistance of obese mice induced by high-fat diet. Fifty C57 BL/6 J male mice were randomly divided into control group and high-fat diet group. The insulin resistance model was induced with high-fat diet for 12 weeks, and model mice were randomly divided into model group, fucoxanthin-0.2% group, fucoxanthin-0.4% group and metformin group. After dietary treatment for 6 weeks, the body weight and epididymal fat weight in each group were measured. Fasting blood glucose(FBG), fasting insulin(FINS), total cholesterol(TC), triglyceride(TG), low-density lipoprotein(LDL-C) and high-density lipoprotein(HDL-C) were measured, and insulin resistance index(HOMA-IR) was calcula-ted. The pathological morphology in liver was observed by hematoxylin eosin staining, and the expressions of some key proteins in insulin receptor substrate 1(IRS-1)/posphoinositide 3-kinase(PI3 K)/serine-threonine kinase(Akt) and peroxisome proliferators-activated receptor-γ(PPARγ)/sterol regulatory element binding protein-1(SREBP-1)/fatty acid synthetase(FAS) pathways in liver were detected by Western blot. According to the findings, compared with the model group, levels of body weight, epididymal fat weight, FBG, FINS, TC, TG, LDL-C and HOMA-IR, as well as protein expressions of PPARγ, SREBP-1 and FAS in liver were significantly reduced(P<0.05 or P<0.01), while level of HDL-C and protein expressions of p-IRS-1, IRS-1, PI3 K and p-Akt in liver were signi-ficantly increased after treatment with fucoxanthin(P<0.05 or P<0.01). And the pathological changes of liver tissue in fucoxanthin-treated mice were also improved obviously. The results showed that fucoxanthin could improve obesity, hyperglycemia and hyperlipidemia, and alleviate insulin resistance in obese mice, and its mechanism is possibly related to the regulation of IRS-1/PI3 K/Akt and PPARγ/SREBP-1/FAS pathways.
Animals ; Diet, High-Fat/adverse effects* ; Insulin ; Insulin Resistance ; Liver ; Male ; Mice ; Mice, Obese ; Xanthophylls

Objective: To evaluate the efficacy of oral lutein supplementation on macular pigment optical density (MPOD) levels and macular function in pseudophakic eyes that underwent phacoemulsification. Methods: This was a prospective, randomized, parallel-arm, single-masked study comparing oral lutein supplement 20 mg/tablet (Lutax 20) with non-supplementation in pseudophakic eyes. We assessed MPOD, low-luminance deficit (LLD), visual recovery time (VRT) using photostress test, and adverse events. One hundred twenty-eight (128) eyes were enrolled and randomized 1:1 to active treatment (lutein supplementation) or no treatment (no supplementation). The supplementation period was 12 weeks and patients were assessed every 4 weeks over a period of 16 weeks. Results: Sixty-four (64) eyes in each group completed the study. A significant increase in MPOD (p<0.001) was observed in the lutein supplemented group, from 0.36 DU at baseline to 0.55 DU at week 12, with a mean increase of 6.32 ± 1.72% per 4 weeks of supplementation compared with a mean MPOD decrease rate of 0.63 ± 0.48% in the non-supplementation group. A significant reduction in LLD was observed in the lutein-treated group, from LogMAR 0.063 at baseline to LogMAR 0.023 at Week 12 (p=0.003). VRT was also significantly shorter in the treatment from a baseline of 83.06 to 68.80 seconds at Week 12 (p<0.001). Conclusion Lutein supplementation (20 mg/tablet; Lutax 20) demonstrated a significant degree of MPOD augmentation, and reductions in LLD and VRT among patients who underwent phacoemulsification with lens implantation.
Lutein ; Dietary Supplements