Fucoxanthin and Rosmarinic Acid Combination Has Anti-Inflammatory Effects through Regulation of NLRP3 Inflammasome in UVB-Exposed HaCaT Keratinocytes

Excessive exposure to ultraviolet (UV) radiation is the main risk factor to develop skin pathologies or cancer because it encourages oxidative condition and skin inflammation. In this sense, strategies for its prevention are currently being evaluated. Natural products such as carotenoids or polyphenols, which are abundant in the marine environment, have been used in the prevention of oxidative stress due to their demonstrated antioxidant activities. Nevertheless, the anti-inflammatory activity and its implication in photo-prevention have not been extensively studied. Thus, we aimed to evaluate the combination of fucoxanthin (FX) and rosmarinic acid (RA) on cell viability, apoptosis induction, inflammasome regulation, and anti-oxidative response activation in UVB-irradiated HaCaT keratinocytes. We demonstrated for the first time that the combination of FX and RA (5 µM RA plus 5 μM FX, designated as M2) improved antioxidant and anti-inflammatory profiles in comparison to compounds assayed individually, by reducing UVB-induced apoptosis and the consequent ROS production. Furthermore, the M2 combination modulated the inflammatory response through down-regulation of inflammasome components such as NLRP3, ASC, and Caspase-1, and the interleukin (IL)-1β production. In addition, Nrf2 and HO-1 antioxidant genes expression increased in UVB-exposed HaCaT cells pre-treated with M2. These results suggest that this combination of natural products exerts photo-protective effects by down-regulating NRLP3-inflammasome and increasing Nrf2 signalling pathway.

Fucoxanthin, A Carotenoid Derived from Phaeodactylum tricornutum Exerts Antiproliferative and Antioxidant Activities In Vitro

Microalgae contain a multitude of nutrients and can be grown sustainably. Fucoxanthin, a carotenoid from Phaeodactylum tricornutum, could have beneficial health effects. Therefore, we investigated the anti-inflammatory, antioxidative and antiproliferative effects of fucoxanthin derived from this diatom in vitro. The effects of purified fucoxanthin on metabolic activity were assessed in blood mononuclear cells and different cell lines. In cell lines, caspase 3/7 activity was also analyzed. Nitrogen monoxide release and mRNA-expression of proinflammatory cytokines were measured. For antioxidant assays, cell free assays were conducted. Additionally, the antioxidant effect in neutrophils was quantified and glutathione was determined in HeLa cells. The results show that neither did fucoxanthin have anti-inflammatory properties nor did it exert cytotoxic effects on mononuclear cells. However, the metabolic activity of cell lines was decreased up to 58% and fucoxanthin increased the caspase 3/7 activity up to 4.6-fold. Additionally, dose-dependent antioxidant effects were detected, resulting in a 63% decrease in chemiluminescence in blood neutrophils and a 3.3-fold increase in the ratio of reduced to oxidized glutathione. Our studies show that fucoxanthin possesses antiproliferative and antioxidant activities in vitro. Hence, this carotenoid or the whole microalgae P. tricornutum could be considered as a food or nutraceutical in human nutrition, showcasing beneficial health effects.

Preventive Effects of Fucoidan and Fucoxanthin on Hyperuricemic Rats Induced by Potassium Oxonate

The purpose of this study was to investigate the preventive effects of fucoidan (Fc) and fucoxanthin (Fx) on hyperuricemic rats. Sprague Dawley (SD) rats were randomly assigned to seven groups: a control group, a hyperuricemia (HUA) group, low- and high-dose Fx groups, a Fc group, a combination Fc and Fx group, and a positive control group. Three weeks after the interventions, each group was given potassium oxonate (PO) and hypoxanthine (HX) to induce HUA in all groups except for the control group, and the rats were then sacrificed. Blood and urine were analyzed for biochemical properties, and differences in urine volume were determined. Livers and kidneys were collected to analyze xanthine oxidase (XO) activity and the expression of uric acid (UA) transporter-related proteins (GLUT9, ABCG2, OAT1, URAT1). The results show that HUA was successfully induced by PO/HX after 4 h of administration. The activity of XO was significantly reduced by a combination of Fc and Fx. In the combination group, both ABCG2 and OAT1 increased significantly, whereas GLUT9 and URAT1 decreased significantly. In summary, the combination of Fc and Fx can inhibit the activity of XO in the liver and regulate the expression of proteins related to UA transporter in the kidney to reduce the UA level in serum.

Marine Carotenoid Fucoxanthin Possesses Anti-Metastasis Activity: Molecular Evidence

Fucoxanthin is commonly found in marine organisms; however, to date, it has been one of the scarcely explored natural compounds. We investigated its activities in human cancer cell culture-based viability, migration, and molecular assays, and found that it possesses strong anticancer and anti-metastatic activities that work irrespective of the p53 status of cancer cells. In our experiments, fucoxanthin caused the transcriptional suppression of mortalin. Cell phenotype-driven molecular analyses on control and treated cells demonstrated that fucoxanthin caused a decrease in hallmark proteins associated with cell proliferation, survival, and the metastatic spread of cancer cells at doses that were relatively safe to the normal cells. The data suggested that the cancer therapy regimen may benefit from the recruitment of fucoxanthin; hence, it warrants further attention for basic mechanistic studies as well as drug development.

Salivary Glycine Is a Significant Predictor for the Attenuation of Polyp and Tumor Microenvironment Formation by Fucoxanthin in AOM/DSS Mice

Background/ Aim: A high polar xanthophyll of Fucoxanthin (Fx) is abundantly contained in edible brown algae, and it has chemopreventive effects in mouse cancer models, however, the underlying mechanisms of these effects are not well understood. Thus, we aimed to investigate the effects of Fx on the tumor microenvironment in cancer model mice.

MATERIALS AND METHODS

We investigated the effect of Fx (30 mg/kg body weight) in a variety of cell types within the tumor microenvironment of α mouse preclinical colorectal cancer model and analyzed the mouse saliva in search of predictors for cancer chemopreventive effects.

RESULTS

Fx administration significantly decreased the number of colorectal polyps and tended to decrease colonic lesions compared to untreated control mice. In addition, Fx administration showed significantly lower numbers of colorectal cancer stem cells-like CD44^high/EpCAM^high cells, cancer-associated fibroblasts-like αSMA^high cells, tumor-associated macrophages-like and dendritic cells-like CD206^high cells by 0.6-, 0.5- and 0.6-fold, respectively, compared to untreated control mice. Moreover, the treatment also showed significantly lower levels of salivary glycine by 0.5-fold.

CONCLUSION

Our results suggest that salivary glycine may be a predictor representing the chemopreventive effect of Fx in mice.

Anti-Obesity Effect of Standardized Extract of Microalga Phaeodactylum tricornutum Containing Fucoxanthin

Fucoxanthin (FX), a marine carotenoid found in macroalgae and microalgae, exhibits several beneficial effects to health. The anti-obesity activity of FX is well documented, but FX has not been mass-produced or applied extensively or commercially because of limited availability of raw materials and complex extraction techniques. In this study, we investigated the anti-obesity effect of standardized FX powder (Phaeodactylum extract (PE)) developed from microalga Phaeodactylum tricornutum as a commercial functional food. The effects of PE on adipogenesis inhibition in 3T3-L1 adipocytes and anti-obesity in high-fat diet (HFD)-fed C57BL/6J mice were evaluated. PE and FX dose-dependently decreased intracellular lipid contents in adipocytes without cytotoxicity. In HFD-fed obese mice, PE supplementation for six weeks decreased body weight, organ weight, and adipocyte size. In the serum parameter analysis, the PE-treated groups showed attenuation of lipid metabolism dysfunction and liver damage induced by HFD. In the liver, uncoupling protein-1 (UCP1) upregulation and peroxisome proliferator activated receptor γ (PPARγ) downregulation were detected in the PE-treated groups. Additionally, micro computed tomography revealed lower fat accumulation in PE-treated groups compared to that in the HFD group. These results indicate that PE exerts anti-obesity effects by inhibiting adipocytic lipogenesis, inducing fat mass reduction and decreasing intracellular lipid content, adipocyte size, and adipose weight.

Fucoxanthin Protects against oxLDL-Induced Endothelial Damage via Activating the AMPK-Akt-CREB-PGC1α Pathway

SCOPE

Atherosclerotic cardiovascular disease is the most prevalent cause of mortality and morbidity. Fucoxanthin (FX) possesses anti-hypertensive and anti-obesity properties. However, the molecular mechanisms underlying the inhibitory effects of FX on oxidized low-density lipoprotein (oxLDL)-induced oxidative injuries in human endothelial cells are still largely unknown. This study aims to test the hypothesis that FX protects against oxLDL-induced oxidative stress by upregulating AMP-activated protein kinase (AMPK) and to explore the roles of cAMP response element binding protein (CREB) and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α).

METHODS AND RESULTS

Human umbilical vein endothelial cells are treated with oxLDL in the presence or absence of FX. FX significantly increases AMPK phosphorylation. In addition, FX diminishes oxLDL-mediated nicotinamide adenine dinucleotide phosphate oxidase activation by inhibiting protein kinase C and subsequently inducing reactive oxygen species generation and impairing the activity of the endogenous antioxidant enzyme superoxidase dismutase. Furthermore, FX restores oxLDL-mediated dephosphorylation of phosphoinositide-3-kinase/Akt and decreases CREB and PGC-1α expression to nearly normal levels. Moreover, FX ameliorates the oxLDL-mediated suppression of mitochondrial function and apoptosis.

CONCLUSION

These findings provide new insights into the possible molecular mechanisms by which FX mitigates oxLDL-induced endothelial oxidative stress and mitochondrial dysfunction.

A Lipophilic Fucoxanthin-Rich Phaeodactylum tricornutum Extract Ameliorates Effects of Diet-Induced Obesity in C57BL/6J Mice

Phaeodactylum tricornutum (P. tricornutum) comprise several lipophilic constituents with proposed anti-obesity and anti-diabetic properties. We investigated the effect of an ethanolic P. tricornutum extract (PTE) on energy metabolism in obesity-prone mice fed a high fat diet (HFD). Six- to eight-week-old male C57BL/6J mice were switched to HFD and, at the same time, received orally placebo or PTE (100 mg or 300 mg/kg body weight/day). Body weight, body composition, and food intake were monitored. After 26 days, blood and tissue samples were collected for biochemical, morphological, and gene expression analyses. PTE-supplemented mice accumulated fucoxanthin metabolites in adipose tissues and attained lower body weight gain, body fat content, weight of white adipose tissue (WAT) depots, and inguinal WAT adipocyte size than controls, independent of decreased food intake. PTE supplementation was associated with lower expression of Mest (a marker of fat tissue expandability) in WAT depots, lower gene expression related to lipid uptake and turnover in visceral WAT, increased expression of genes key to fatty acid oxidation and thermogenesis (Cpt1, Ucp1) in subcutaneous WAT, and signs of thermogenic activation including enhanced UCP1 protein in interscapular brown adipose tissue. In conclusion, these data show the potential of PTE to ameliorate HFD-induced obesity in vivo.

Construction of Fucoxanthin Vector Based on Binding of Whey Protein Isolate and Its Subsequent Complex Coacervation with Lysozyme

In this study, a novel vector for fucoxanthin (FX) was constructed using the ligand-binding property of whey protein isolate and its subsequent heteroprotein complex coacervation with lysozyme. The results showed that FX could quench the intrinsic fluorescence of the whey protein isolate by a static mechanism, indicating that they could spontaneously form a nanocomplex through non-covalent interactions. Moreover, the structural and electrostatic properties of the resulting whey protein were different from those before the binding of FX, and this could be well explained by molecular dynamics simulation. The size and ζ-potential tests showed that when the whey protein isolate was combined with FX and then coacervated with lysozyme, the heteroprotein ratio and pH, which affect the coacervation process, also changed compared to those of the free whey protein isolate. FT-IR spectroscopy results showed that FX was successfully encapsulated into complex coacervates. In addition, the heteroprotein system exhibited a higher loading efficiency and also provided a better protection for FX in heating, storage, and simulated gastrointestinal environments.

Optimization and Formulation of Fucoxanthin-Loaded Microsphere (F-LM) Using Response Surface Methodology (RSM) and Analysis of Its Fucoxanthin Release Profile

Fucoxanthin has interesting anticancer activity, but is insoluble in water, hindering its use as a drug. Microencapsulation is used as a technique for improving drug delivery. This study aimed to formulate fucoxanthin-loaded microspheres (F-LM) for anticancer treatment of H1299 cancer cell lines and optimize particle size (PS) and encapsulation efficiency (EE). Using response surface methodology (RSM), a face centered central composite design (FCCCD) was designed with three factors: Polyvinylalcohol (PVA), poly(d,l-lactic-co-glycolic acid) (PLGA), and fucoxanthin concentration. F-LM was produced using a modified double-emulsion solvent evaporation method. The F-LM were characterized for release profile, release kinetics, and degradation pattern. Optimal F-LM PS and EE of 9.18 µm and 33.09%, respectively, with good surface morphology, were achieved from a 0.5% (w/v) PVA, 6.0% (w/v) PLGA, 200 µg/mL fucoxanthin formulation at a homogenization speed of 20,500 rpm. PVA concentration was the most significant factor (p < 0.05) affecting PS. Meanwhile, EE was significantly affected by interaction between the three factors: PVA, PLGA, and fucoxanthin. In vitro release curve showed fucoxanthin had a high burst release (38.3%) at the first hour, followed by a sustained release stage reaching (79.1%) within 2 months. Release kinetics followed a diffusion pattern predominantly controlled by the Higuchi model. Biodegradability studies based on surface morphology changes on the surface of the F-LM, show that morphology changed within the first hour, and F-LM completely degraded within 2 months. RSM under FCCCD design improved the difference between the lowest and highest responses, with good correlation between observed and predicted values for PS and EE of F-LM.

Protective Effects of Fucoxanthin on Ultraviolet B-Induced Corneal Denervation and Inflammatory Pain in a Rat Model

Fucoxanthin is a carotenoid with many pharmaceutical properties that is found in brown seaweed. However, the effects of fucoxanthin on corneal innervation and intense eye pain have not been extensively examined. To clarify the protective roles and underlying mechanisms of fucoxanthin on ocular lesions, we investigated the beneficial effects and mechanisms by which fucoxanthin ameliorates ultraviolet B (UVB)-induced corneal denervation and trigeminal pain. Treatment with fucoxanthin enhanced the expression of nuclear factor erythroid 2-related factor 2 in the cornea. Inhibition of typical denervation and epithelial exfoliation in the cornea were observed in rats treated with fucoxanthin following UVB-induced nerve disorders. Moreover, the active phosphorylated form of p38 MAP kinase (pp38) and the number of glial fibrillary acidic protein (GFAP)-positive neural cells were significantly reduced. Decreased expression of neuron-selective transient receptor potential vanilloid type 1 (TRPV1) in the trigeminal ganglia neurons was also demonstrated in rats treated with fucoxanthin after UVB-induced keratitis. Symptoms of inflammatory pain, including difficulty in opening the eyes and eye wipe behaviour, were also reduced in fucoxanthin-treated groups. Pre-treatment with fucoxanthin may protect the eyes from denervation and inhibit trigeminal pain in UVB-induced photokeratitis models.

Fucoxanthin inhibits tumour-related lymphangiogenesis and growth of breast cancer

Tumour lymphangiogenesis plays an important role in promoting the growth and lymphatic metastasis of tumours. The process is associated with cell proliferation, migration and tube-like structure formation in lymphatic endothelial cells (LEC), but no antilymphangiogenic agent is currently used in clinical practice. Fucoxanthin is a material found in brown algae that holds promise in the context of drug development. Fucoxanthin is a carotenoid with variety of pharmacological functions, including antitumour and anti-inflammatory effects. The ability of fucoxanthin to inhibit lymphangiogenesis remains unclear. The results of experiments performed as part of this study show that fucoxanthin, extracted from Undaria pinnatifida (Wakame), inhibits proliferation, migration and formation of tube-like structures in human LEC (HLEC). In this study, fucoxanthin also suppressed the malignant phenotype in human breast cancer MDA-MB-231 cells and decreased tumour-induced lymphangiogenesis when used in combination with a conditional medium culture system. Fucoxanthin significantly decreased levels of vascular endothelial growth factor (VEGF)-C, VEGF receptor-3, nuclear factor kappa B, phospho-Akt and phospho-PI3K in HLEC. Fucoxanthin also decreased micro-lymphatic vascular density (micro-LVD) in a MDA-MB-231 nude mouse model of breast cancer. These findings suggest that fucoxanthin inhibits tumour-induced lymphangiogenesis in vitro and in vivo, highlighting its potential use as an antilymphangiogenic agent for antitumour metastatic comprehensive therapy in patients with breast cancer.

The Osteogenic Potential of Brown Seaweed Extracts

Marine drugs hold significantly more promise than their terrestrial counterparts, which could help to solve the current shortfall in treatments for osteoporosis and other bone related diseases. Fucoxanthin is the main carotenoid found in brown seaweed, and has many perceived health benefits, including potential bone therapeutic properties. This study assessed the osteogenic potential of pure fucoxanthin and crude extracts containing both fucoxanthin and phenolic fractions (also cited to have osteogenic potential) isolated from two intertidal species of brown seaweed, Laminaria digitata and Ascophyllum nodosum. In vitro studies were performed using a human foetal osteoblast cell line (hFOBs) and primary human bone marrow stromal cells (hBMSCs). The results found pure fucoxanthin inhibitory to cell proliferation in hFOBs at higher concentrations, whereas, the crude extracts containing both polyphenols and fucoxanthin showed the ability to scavenge free radicals, which masked this effect. None of the extracts tested showed strong pro-osteogenic effects in either cell type tested, failing to support previously reported positive effects.

Induction of Apoptosis in Human Glioma Cells by Fucoxanthin via Triggering of ROS-Mediated Oxidative Damage and Regulation of MAPKs and PI3K-AKT Pathways

Fucoxanthin, a natural carotenoid derived from algae, exhibits novel anticancer potential. However, fucoxanthin with high purity is hard to prepare, and the anticancer mechanism remains elusive. In the present study, fucoxanthin with high purity was prepared and purified from the marine microalgae Nitzschia sp. by silica-gel column chromatography (SGCC), and the underlying mechanism against human glioma cells was evaluated. The results showed that fucoxanthin time- and dose-dependently inhibited U251-human-glioma-cell growth by induction of apoptosis (64.4 ± 4.8, P < 0.01) accompanied by PARP cleavage and caspase activation (244 ± 14.2, P < 0.01). Mechanically, fucoxanthin time-dependently triggered reactive-oxygen-species (ROS)-mediated DNA damage (100 ± 7.38, P < 0.01), as evidenced by the phosphorylation activation of Ser1981-ATM, Ser428-ATR, Ser15-p53, and Ser139-histone. Moreover, fucoxanthin treatment also time-dependently caused dysfunction of MAPKs and PI3K-AKT pathways, as demonstrated by the phosphorylation activation of Thr183-JNK, Thr180-p38, and Thr202-ERK and the phosphorylation inactivation of Ser473-AKT. The addition of kinase inhibitors further confirmed the importance of MAPKs and PI3K-AKT pathways in fucoxanthin-induced cell-growth inhibition (32.5 ± 3.6, P < 0.01). However, ROS inhibition by the antioxidant glutathione (GSH) effectively inhibited fucoxanthin-induced DNA damage, attenuated the dysfunction of MAPKs and PI3K-AKT pathways, and eventually blocked fucoxanthin-induced cytotoxicity (54.3 ± 5.6, P < 0.05) and cell apoptosis (32.7 ± 2.5, P < 0.05), indicating that ROS production, an early apoptotic event, is involved in the fucoxanthin-mediated anticancer mechanism. Taken together, these results suggested that fucoxanthin induced U251-human-glioma-cell apoptosis by triggering ROS-mediated oxidative damage and dysfunction of MAPKs and PI3K-AKT pathways, which validated that fucoxanthin may be a candidate for potential applications in cancer chemotherapy and chemoprevention.

Fucoidan⁻Fucoxanthin Ameliorated Cardiac Function via IRS1/GRB2/ SOS1, GSK3β/CREB Pathways and Metabolic Pathways in Senescent Mice

The effects of low molecular weight fucoidan (LMWF) in combination with high-stability fucoxanthin (HSFUCO) on cardiac function and the metabolic pathways of aging mice (Mus musculus) were investigated. We demonstrated that LMWF and HSFUCO could improve cardiac function in aging mice. Aging mice were treated with LMWF and HSFUCO, either on their own or in combination, on 28 consecutive days. Electrocardiography and whole-cell patch-clamp were used to measure QT interval and action potential duration (APD) of the subjects. Cardiac tissue morphology, reactive oxygen species, and Western blot were also applied. Ultra-high-performance liquid chromatography⁻quadrupole time-of-flight (UPLC-QTOF) mass spectrometry was used for investigating metabolic alterations. The use of LMWF and HSFUCO resulted in improvements in both ventricular rhythms (QT and APD). Treatment with fucoidan and fucoxanthin reduced the expression levels of SOS1 and GRB2 while increasing GSK3β, CREB and IRS1 proteins expression in the aging process. Three main metabolic pathways, namely the TCA cycle, glycolysis, and steroid hormone biosynthesis, were highly enriched in the pathway enrichment analysis. When taken together, the LMWF and HSFUCO treatment improved both the ventricular rhythm and the muscular function of aging subjects by interfering with the metabolism and gene function.

Bioaccessibility of Marine Carotenoids

The benefit of carotenoids to human health is undeniable and consequently, their use for this purpose is growing rapidly. Additionally, the nutraceutical properties of carotenoids have attracted attention of the food industry, especially in a new market area, the 'cosmeceuticals.' Marine organisms (microalgae, seaweeds, animals, etc.) are a rich source of carotenoids, with optimal properties for industrial production and biotechnological manipulation. Consequently, several papers have reviewed the analysis, characterization, extraction and determination methods, biological functions and industrial applications. But, now, the bioaccessibility and bioactivity of marine carotenoids has not been focused of any review, although important achievements have been published. The specific and diverse characteristic of the marine matrix determines the bioavailability of carotenoids, some of them unique in the nature. Considering the importance of the bioavailability not just from the health and nutritional point of view but also to the food and pharmaceutical industry, we consider that the present review responds to an actual demand.

Fucoxanthin-Containing Cream Prevents Epidermal Hyperplasia and UVB-Induced Skin Erythema in Mice

Microalgae represent a source of bio-active compounds such as carotenoids with potent anti-inflammatory and antioxidant properties. We aimed to investigate the effects of fucoxanthin (FX) in both in vitro and in vivo skin models. Firstly, its anti-inflammatory activity was evaluated in LPS-stimulated THP-1 macrophages and TNF-α-stimulated HaCaT keratinocytes, and its antioxidant activity in UVB-irradiated HaCaT cells. Next, in vitro and ex vivo permeation studies were developed to determine the most suitable formulation for in vivo FX topical application. Then, we evaluated the effects of a FX-containing cream on TPA-induced epidermal hyperplasia in mice, as well as on UVB-induced acute erythema in hairless mice. Our results confirmed the in vitro reduction of TNF-α, IL-6, ROS and LDH production. Since the permeation results showed that cream was the most favourable vehicle, FX-cream was elaborated. This formulation effectively ameliorated TPA-induced hyperplasia, by reducing skin edema, epidermal thickness, MPO activity and COX-2 expression. Moreover, FX-cream reduced UVB-induced erythema through down-regulation of COX-2 and iNOS as well as up-regulation of HO-1 protein via Nrf-2 pathway. In conclusion, FX, administered in a topical formulation, could be a novel natural adjuvant for preventing exacerbations associated with skin inflammatory pathologies as well as protecting skin against UV radiation.

Enhancement of the Production of Bioactive Microalgal Metabolites by Ultraviolet Radiation (UVA 365 nm)

Two marine microalgae, Nitzschia closterium and Isochrysis zhangjiangensis, treated for 9 days with photosynthetically active radiation (PAR), were subjected to 3 days of ultraviolet light band A at 365 nm (UVA365) followed by a 3 day post-UVA PAR treatment. Compared with the control that only had PAR treatment, UVA365 treatment significantly ( p < 0.05) increased the amounts of total xanthophylls in N. closterium and I. zhangjiangensis by up to 3.53- and 1.23-fold, respectively, after 3 days of UVA365 irradiation. In particular, UVA365 treatment markedly ( p < 0.05) increased two major bioactive xanthophyll pigments, fucoxanthin in N. closterium and diadinoxanthin in I. zhangjiangensis, by up to 1.97- and 1.52-fold, respectively. UVA365 treatment significantly ( p < 0.05) increased the accumulation of another bioactive microalgal metabolite, total mycosporine-like amino acids, in N. closterium and I. zhangjiangensis by up to 1.40- and 1.30-fold, respectively. UVA365 irradiation has potential as an efficient approach for enhancing the production of valuable microalgal metabolites.

Effects of fucoxanthin on autophagy and apoptosis in SGC-7901cells and the mechanism

Autophagy and apoptosis are involved in the development of a variety of cancers. Fucoxanthin is a natural compound known to have antitumor effects, so we aimed to explore its effects on autophagy and apoptosis in gastric cancer SGC7901 cells. Specifically, we performed methyl thiazolyl tetrazolium assay, transmission electron microscopy, real-time polymerase chain reaction, Western blot analysis, immunofluorescence assay, and cell apoptosis analysis to clarify the role of fucoxanthin in SGC-7901 cells. Our results indicate that fucoxanthin significantly inhibits the viability of SGC-7901 cells, effectively inducing both autophagy and apoptosis by up-regulating the expressions of beclin-1, LC3, and cleaved caspase-3 (CC3), and by down regulating Bcl-2. Fucoxanthin-induced autophagy also seems to occur before, and may promote apoptosis.

Degradation of Fucoxanthin to Elucidate the Relationship between the Fucoxanthin Molecular Structure and Its Antiproliferative Effect on Caco-2 Cells

Fucoxanthin has an antiproliferative effect on cancer cells, but its detailed structure⁻activity correlation has not yet been elucidated. To elucidate this correlation, fucoxanthin was degraded by ozonolysis. The degraded compounds of fucoxanthin obtained by ozonolysis were purified by HPLC and analyzed by NMR. The polyene chain of fucoxanthin was cleaved by ozonolysis, and the fucoxanthin was divided into two types of cyclohexyl derivatives, one with a β,γ-epoxy ketone group and the other with an allenic bond. In order to elucidate the structure⁻activity correlation, Caco-2 cells (human colorectal carcinoma) were treated with fucoxanthin degradation compounds. It was found that the entire structure of fucoxanthin is not essential for its antiproliferative effect and that even a partial structure exerts this effect.

Chemical Mutagenesis and Fluorescence-Based High-Throughput Screening for Enhanced Accumulation of Carotenoids in a Model Marine Diatom Phaeodactylum tricornutum

Diatoms are a major group of unicellular algae that are rich in lipids and carotenoids. However, sustained research efforts are needed to improve the strain performance for high product yields towards commercialization. In this study, we generated a number of mutants of the model diatom Phaeodactylum tricornutum, a cosmopolitan species that has also been found in Nordic region, using the chemical mutagens ethyl methanesulfonate (EMS) and N-methyl-N′-nitro-N-nitrosoguanidine (NTG). We found that both chlorophyll a and neutral lipids had a significant correlation with carotenoid content and these correlations were better during exponential growth than in the stationary growth phase. Then, we studied P. tricornutum common metabolic pathways and analyzed correlated enzymatic reactions between fucoxanthin synthesis and pigmentation or lipid metabolism through a genome-scale metabolic model. The integration of the computational results with liquid chromatography-mass spectrometry data revealed key compounds underlying the correlative metabolic pathways. Approximately 1000 strains were screened using fluorescence-based high-throughput method and five mutants selected had 33% or higher total carotenoids than the wild type, in which four strains remained stable in the long term and the top mutant exhibited an increase of 69.3% in fucoxanthin content compared to the wild type. The platform described in this study may be applied to the screening of other high performing diatom strains for industrial applications.

Anti-Oxidant and Fucoxanthin Contents of Brown Alga Ishimozuku (Sphaerotrichia divaricata) from the West Coast of Aomori, Japan

Fucoxanthin is a specific carotenoid in brown seaweeds with remarkable biological properties. Ishimozuku (Sphaerotrichia divaricata), an edible brown alga from northern Japan, has morphology that is almost identical to that of Okinawa-mozuku (Cladosiphon okamuranus) harvested off Okinawa, Japan. However, because of Ishimozuku's lower availability compared to Okinawa-mozuku, the contents of its nutrient compounds remain unclear. The present study analyzed fucoxanthin and anti-oxidant compound contents of Ishimozuku harvested off the northern coast of Japan from 2014 to 2016. First, 80% ethanol extract solutions were prepared from Ishimozuku harvested from several west coast areas of Aomori, Japan. Then, polyphenol content was analyzed using the Folin⁻Ciocalteu method. Then anti-oxidative effects were analyzed by their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and hydrogen peroxide scavenging activity. Furthermore, fucoxanthin contents were measured using high performance liquid chromatography (HPLC) analysis. Fucoxanthin contents of Ishimozuku were 105.6⁻1148.5 μg/g dry weight. Total polyphenol contents of Ishimozuku were of 0.296⁻0.958 mg/g dry weight: higher than Okinawa-mozuku (0.082 ± 0.011 mg/g dry weight). The anti-oxidation effects of Ishimozuku accompanied the polyphenol content. These results suggest that Ishimozuku contains various anti-oxidant components and has high potential to provide the promotion of human health.

Phycochemical Constituents and Biological Activities of Fucus spp

Seaweeds are known to be a good supply of key nutrients including carbohydrates, protein, minerals, polyunsaturated lipids, as well as several other health-promoting compounds capable of acting on a wide spectrum of disorders and/or diseases. While these marine macroalgae are deeply rooted in the East Asian culture and dietary habits, their major application in Western countries has been in the phycocolloid industry. This scenario has however been gradually changing, since seaweed consumption is becoming more common worldwide. Among the numerous edible seaweeds, members of the genus Fucus have a high nutritional value and are considered good sources of dietary fibers and minerals, especially iodine. Additionally, their wealth of bioactive compounds such as fucoidan, phlorotannins, fucoxanthin and others make them strong candidates for multiple therapeutic applications (e.g., antioxidant, anti-inflammatory, anti-tumor, anti-obesity, anti-coagulant, anti-diabetes and others). This review presents an overview of the nutritional and phytochemical composition of Fucus spp., and their claimed biological activities, as well as the beneficial effects associated to their consumption. Furthermore, the use of Fucus seaweeds and/or their components as functional ingredients for formulation of novel and enhanced foods is also discussed.

Fucoxanthin administration delays occurrence of tumors in xenograft mice by colonospheres, with an anti-tumor predictor of glycine

Fucoxanthin and its major metabolite, fucoxanthinol, have potent anti-cancer properties in carcinogenic model mice and against cancer cells. Evidence has accumulated regarding the diagnostic potential of biological metabolites as invasive and non-invasive obtainable approaches. We recently demonstrated that glycine was an effective predictor of the suppression of sphere formation and epithelial mesenchymal transition by fucoxanthinol in human colorectal cancer stem-like spheroids (colonospheres) under normoxia and hypoxia. In the present study, we investigated the suppressive effect of fucoxanthin on tumorigenesis derived from colonospheres in xenograft mice, and the alteration on the metabolite profiles of mouse tumors by fucoxanthin was evaluated. Fucoxanthin administration at 2.5 mg/kg body weight (p.o.) for 4 weeks significantly inhibited the incidence of tumors by inoculation of colonospheres suspension in BALB/c nu/nu mice compared with control mice, but not tumor sizes. In addition, fucoxanthin down-regulated tumor Cyclin D1 expression by 0.7-fold of that observed in the tumors of the control mice. Moreover, the tumor glycine level in the xenograft mice was decreased by fucoxanthin administration to 0.5-fold. These results imply the possibility of tumor metabolites as a prediction marker of tumorigenicity derived from colorectal cancer stem cells in mice.

Overview on the Antihypertensive and Anti-Obesity Effects of Secondary Metabolites from Seaweeds

Hypertension and obesity are two significant factors that contribute to the onset and exacerbation of a cascade of mechanisms including activation of the sympathetic and renin-angiotensin systems, oxidative stress, release of inflammatory mediators, increase of adipogenesis and thus promotion of systemic dysfunction that leads to clinical manifestations of cardiovascular diseases. Seaweeds, in addition to their use as food, are now unanimously acknowledged as an invaluable source of new natural products that may hold noteworthy leads for future drug discovery and development, including in the prevention and/or treatment of the cardiovascular risk factors. Several compounds including peptides, phlorotannins, polysaccharides, carotenoids, and sterols, isolated from brown, red and green macroalgae exhibit significant anti-hypertensive and anti-obesity properties. This review will provide a comprehensive overview of the recent advances on bioactive pure compounds isolated from different seaweed sources focusing on their potential use as drugs to treat or prevent hypertension and obesity. On the other hand, although it is obvious that macroalgae represent promising sources of antihypertensive and anti-obesity compounds, it is also clear that further efforts are required to fully understand their cellular mechanisms of action, to establish structure-inhibition relationships and mainly to evaluate them in pre-clinical and clinical trials.

A Hetero-Photoautotrophic Two-Stage Cultivation Process for Production of Fucoxanthin by the Marine Diatom Nitzschia laevis

There is currently much interest in fucoxanthin due to its broad beneficial health effects. The major commercial source of fucoxanthin is marine seaweed, which has many shortcomings, and has thus restricted its large-scale production and more diversified applications. In this study, growth characteristics and fucoxanthin accumulation were evaluated to explore the potential of the marine diatom Nitzschia laevis in fucoxanthin production. The results suggested that heterotrophic culture was more effective for cell growth, while the mixotrophic culture was favorable for fucoxanthin accumulation. A two-stage culture strategy was consequently established. A model of exponential fed-batch culture led to a biomass concentration of 17.25 g/L. A mix of white and blue light significantly increased fucoxanthin content. These outcomes were translated into a superior fucoxanthin productivity of 16.5 mg/(L·d), which was more than 2-fold of the best value reported thus far. The culture method established herein therefore represents a promising strategy to boost fucoxanthin production in N. laevis, which might prove to be a valuable natural source of commercial fucoxanthin.

Fucoxanthin and Polyunsaturated Fatty Acids Co-Extraction by a Green Process

By their autotrophic nature and their molecular richness, microalgae are serious assets in the context of current environmental and societal challenges. Some species produce both omega-3 long chain polyunsaturated fatty acids (PUFAs) and xanthophylls, two molecular families widely studied for their bioactivities in the fields of nutrition and cosmetics. Whereas most studies separately deal with the two families, synergies could be exploited with extracts containing both PUFAs and xanthophylls. The purpose of our work was to determine cost effective and eco-friendly parameters for their co-extraction. The effect of several parameters (solvent, solvent/biomass ratio, temperature, duration) were studied, using two microalgal species, the non-calcifying Haptophyta Tisochrysis lutea, and the diatom Phaeodactylum tricornutum, that presents a silicified frustule. Analyses of PUFAs and fucoxanthin (Fx), the main xanthophyll, allowed to compare kinetics and extraction yields between experimental protocols. Co-extraction yields achieved using 96% ethanol as solvent were 100% for Fx and docosahexaenoic acid (DHA) in one hour from T. lutea biomass, and respectively 95% and 89% for Fx and eicosapentaenoic acid (EPA) in eight hours from P. tricornutum. These conditions are compatible with industrial applications.

Fucoxanthin Elicits Epigenetic Modifications, Nrf2 Activation and Blocking Transformation in Mouse Skin JB6 P+ Cells

Nuclear factor erythroid-2-related factor-2 (Nrf2 or NFE2L2) is a master regulator of the anti-oxidative stress response, which is involved in the defense against many oxidative stress/inflammation-mediated diseases, including anticancer effects elicited by an increasing number of natural products. Our previous studies showed that the epigenetic modification of the Nrf2 gene plays a key role in restoring the expression of Nrf2. In this study, we aimed to investigate the epigenetic regulation of Nrf2 by astaxanthin (AST) and fucoxanthin (FX), carotenoids which are abundant in microalgae and seaweeds, in mouse skin epidermal JB6 P+ cells. FX induced the anti-oxidant response element (ARE)-luciferase and upregulated the mRNA and protein levels of Nrf2 and Nrf2 downstream genes in HepG2-C8 cells overexpressing the ARE-luciferase reporter. Both FX and AST decreased colony formation in 12-Otetradecanoylphorbol-13-acetate (TPA)-induced transformation of JB6 P+ cells. FX decreased the methylation of the Nrf2 promoter region in the JB6 P+ cells by the bisulfite conversion and pyrosequencing. Both FX and AST significantly reduced DNA methyltransferase (DNMT) activity but did not affect histone deacetylase (HDAC) activity in JB6 P+ cells. In summary, our results show that FX activates the Nrf2 signaling pathway, induces the epigenetic demethylation of CpG sites in Nrf2 and blocks the TPA-induced transformation of JB6 P+ cells, indicating the potential health-promoting effects of FX in skin cancer prevention.

A Rapid Method for the Determination of Fucoxanthin in Diatom

Fucoxanthin is a natural pigment found in microalgae, especially diatoms and Chrysophyta. Recently, it has been shown to have anti-inflammatory, anti-tumor, and anti-obesityactivity in humans. Phaeodactylum tricornutum is a diatom with high economic potential due to its high content of fucoxanthin and eicosapentaenoic acid. In order to improve fucoxanthin production, physical and chemical mutagenesis could be applied to generate mutants. An accurate and rapid method to assess the fucoxanthin content is a prerequisite for a high-throughput screen of mutants. In this work, the content of fucoxanthin in P. tricornutum was determined using spectrophotometry instead of high performance liquid chromatography (HPLC). This spectrophotometric method is easier and faster than liquid chromatography and the standard error was less than 5% when compared to the HPLC results. Also, this method can be applied to other diatoms, with standard errors of 3-14.6%. It provides a high throughput screening method for microalgae strains producing fucoxanthin.

Marine carotenoids: Bioactivities and potential benefits to human health

Among natural pigments, carotenoids play important roles in physiological functions. The characteristics of carotenoids and their effects on human health have been reported for a long time, but most studies have focused on carotenoids from vegetables, fruits, and other parts of higher plants. Few reports are available on carotenoids from marine sources, such as seaweeds, microalgae, and marine animals, which have attracted attention in recent decades. Hundreds of carotenoids have been identified and isolated from marine organisms and their beneficial physiological functions, such as anticancer, antiobesity, antidiabetic, anti-inflammatory, and cardioprotective activities have been reported. The purpose of this review is to discuss the literature on the beneficial bioactivities of some of the most abundant marine carotenoids, including fucoxanthin, astaxanthin, cantaxanthin, peridinin, fucoxanthinol, and halocynthiaxanthin.

Fucoxanthin and Its Metabolite Fucoxanthinol Do Not Induce Browning in Human Adipocytes

Rodent studies suggest that the antiobesity effects of fucoxanthin relate to activation of brown fat and conversion of white adipocytes to the brown phenotype. To evaluate the browning effect in human adipocytes, we investigated the genes involved in browning and measured the oxygen consumption rate (OCR). Data were analyzed by one way ANOVA. Relative to control, fucoxanthinol (1 μM, 0.1 μM, 0.01 μM, 1 nM, 0.1 nM), the metabolite present in human plasma, stimulated lipolysis acutely (mean ± SEM: 4.2 ± 0.8, 3.1 ± 0.6, 4.1 ± 0.9, 3.8 ± 0.7, 3.8 ± 0.7, respectively, p < 0.01). There was no effect on OCR or the mRNA expression of UCP1, CPT-1β, and GLUT4, the genes associated with browning of adipose tissue, when human adipocytes were treated with fucoxanthin or fucoxanthinol. -mRNA expression of PGC-1α, PPARα, PPARγ, PDK4, FAS, and the lipolytic enzymes was not significantly altered by fucoxanthinol treatment (p > 0.05). Thus, in human adipocytes, fucoxanthin and its metabolite do not stimulate conversion of white adipocytes to the brown phenotype.

Fucoxanthin Inhibits β-Amyloid Assembly and Attenuates β-Amyloid Oligomer-Induced Cognitive Impairments

β-Amyloid (Aβ) can form aggregates through self-assembly and produce neurotoxicity in the early stage of Alzheimer's disease (AD). Therefore, the inhibition of Aβ assembly is considered as the primary target for AD therapy. In this study, we reported that fucoxanthin, a marine carotenoid, potently reduced the formation of Aβ fibrils and oligomers. Moreover, the fucoxanthin-triggered modification significantly reduced the neurotoxicity of Aβ oligomers in vitro. Molecular dynamics simulation analysis further revealed a hydrophobic interaction between fucoxanthin and Aβ peptide, which might prevent the conformational transition and self-assembly of Aβ. Most importantly, fucoxanthin could attenuate cognitive impairments in Aβ oligomer-injected mice. In addition, fucoxanthin significantly inhibited oxidative stress, enhanced the expression of brain-derived neurotrophic factor, and increased ChAT-positive regions in the hippocampus of mice. On the basis of these novel findings, we anticipated that fucoxanthin might ameliorate AD via inhibiting Aβ assembly and attenuating Aβ neurotoxicity.

A marine bio-functional lipid, fucoxanthinol, attenuates human colorectal cancer stem-like cell tumorigenicity and sphere formation

Fucoxanthinol (FuOH), an intestinal metabolite form of fucoxanthin (Fx) isolated from marine algae, is known to possess multiple health benefits, such as prevention of human cancer. However, there is little available information about the effects of FuOH on colorectal cancer stem cells (CCSCs) and their contribution to drug resistance, tumorigenesis and cancer recurrence. In the present study, we investigated the anti-proliferative effect of FuOH on two putative CCSCs, CD44^high/EpCAM^high cells and colonospheres (Csps) formed by HT-29 human colorectal cancer cells, and the suppressive effects of FuOH on the growth of xenografted tumor. FuOH significantly inhibited the growth of CD44^high/EpCAM^high cells and disintegrated Csps and induced many condensed chromatin bodies in the cells in a dose-dependent manner. The IC₅₀ value of FuOH for these changes in Csps was 1.8 µM. FuOH down-regulated pAkt (Ser⁴⁷³), PPARβ/δ and PPARγ in Csps. These proteins play a critical role in cell proliferation, the cell cycle, metastasis and extracellular adhesion. Ten days after the administration of FuOH (5 mg/kg body weight) to the mice every 3 to 4 days significantly suppressed the Csps tumorigenesis when compared to the untreated control mice. Our results suggest that FuOH could be used as a chemopreventive agent against human CCSC.

Effects of Low-Molecular-Weight Fucoidan and High Stability Fucoxanthin on Glucose Homeostasis, Lipid Metabolism, and Liver Function in a Mouse Model of Type II Diabetes

The combined effects of low-molecular-weight fucoidan (LMF) and fucoxanthin (Fx) in terms of antihyperglycemic, antihyperlipidemic, and hepatoprotective activities were investigated in a mouse model of type II diabetes. The intake of LMF, Fx, and LMF + Fx lowered the blood sugar and fasting blood sugar levels, and increased serum adiponectin levels. The significant decrease in urinary sugar was only observed in LMF + Fx supplementation. LMF and Fx had ameliorating effects on the hepatic tissue of db/db mice by increasing hepatic glycogen and antioxidative enzymes, and LMF was more effective than Fx at improving hepatic glucose metabolism. As for glucose and lipid metabolism in the adipose tissue, the expression of insulin receptor substrate (IRS)-1, glucose transporter (GLUT), peroxisome proliferator-activated receptor gamma (PPARγ), and uncoupling protein (UCP)-1 mRNAs in the adipose tissue of diabetic mice was significantly upregulated by Fx and LMF + Fx, and levels of inflammatory adipocytokines, such as adiponectin, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6), were significantly modulated only by LMF + Fx supplementation. The efficacy of LMF + Fx supplementation on the decrease in urinary sugar and on glucose and lipid metabolism in the white adipose tissue of db/db mice was better than that of Fx or LMF alone, indicating the occurrence of a synergistic effect of LMF and Fx.

Antitumor Effects of Laminaria Extract Fucoxanthin on Lung Cancer

Lung cancer is the leading cause of cancer mortality worldwide and non-small-cell lung cancer (NSCLC) is the most common type. Marine plants provide rich resources for anticancer drug discovery. Fucoxanthin (FX), a Laminaria japonica extract, has attracted great research interest for its antitumor activities. Accumulating evidence suggests anti-proliferative effects of FX on many cancer cell lines including NSCLCs, but the detailed mechanisms remain unclear. In the present investigation, we confirmed molecular mechanisms and in vivo anti-lung cancer effect of FX at the first time. Flow cytometry, real-time PCR, western blotting and immunohistochemistry revealed that FX arrested cell cycle and induced apoptosis by modulating expression of p53, p21, Fas, PUMA, Bcl-2 and caspase-3/8. These results show that FX is a potent marine drug for human non-small-cell lung cancer treatment.

Preparation of Fucoxanthin-Loaded Nanoparticles Composed of Casein and Chitosan with Improved Fucoxanthin Bioavailability

To facilitate the utilization of fucoxanthin (FX), a valuable marine carotenoid, in the food industry, FX-loaded casein nanoparticles (FX-CN) and chitosan-coated FX-CN (FX-CS-CN) were developed using the FX-enriched fraction from Phaeodactylum tricornutum. Two nanoscale particles (237 ± 13 nm for FX-CN and 277 ± 26 nm for FX-CN-CN) with spherical and smooth surfaces showed over 71% encapsulation efficiency and polydispersity index (PDI) value of 0.31-0.39 in water. Owing to the chitosan coating, FX-CS-CN showed a positive zeta potential (24.00 mV), whereas that of FX-CN was negative (-12.87 mV). In vitro simulated digestion demonstrated better FX bioaccessibility from the nanoparticles versus P. tricornutum powder (Pt-powder) and from FX-CN versus FX-CS-CN. However, in C57BL/6 mice, fucoxanthinol absorption to the blood circulation was two times higher for FX-CS-CN versus FX-CN, possibly due to increased retention or adsorption to mucin by the cationic biopolymer in the chitosan-coated particles. These results demonstrate that FX-CS-CN can enable the application of FX, with improved bioavailability and water dispersibility, in the food industry.

Marine Algae as a Potential Source for Anti-Obesity Agents

Obesity is a major epidemic that poses a worldwide threat to human health, as it is also associated with metabolic syndrome, type 2 diabetes and cardiovascular disease. Therapeutic intervention through weight loss drugs, accompanied by diet and exercise, is one of the options for the treatment and management of obesity. However, the only approved anti-obesity drug currently available in the market is orlistat, a synthetic inhibitor of pancreatic lipase. Other anti-obesity drugs are still being evaluated at different stages of clinical trials, while some have been withdrawn due to their severe adverse effects. Thus, there is a need to look for new anti-obesity agents, especially from biological sources. Marine algae, especially seaweeds are a promising source of anti-obesity agents. Four major bioactive compounds from seaweeds which have the potential as anti-obesity agents are fucoxanthin, alginates, fucoidans and phlorotannins. The anti-obesity effects of such compounds are due to several mechanisms, which include the inhibition of lipid absorption and metabolism (e.g., fucoxanthin and fucoidans), effect on satiety feeling (e.g., alginates), and inhibition of adipocyte differentiation (e.g., fucoxanthin). Further studies, especially testing bioactive compounds in long-term human trials are required before any new anti-obesity drugs based on algal products can be developed.

Development, Quantification, Method Validation, and Stability Study of a Novel Fucoxanthin-Fortified Milk

To extend the scope of application of fucoxanthin, a marine carotenoid, whole milk (WM) and skimmed milk (SM) were fortified with fucoxanthin isolated from the microalga Phaeodactylum tricornutum to a final 8 μg/mL milk solution concentration. Using these liquid systems, a fucoxanthin analysis method implementing extraction and HPLC-DAD was developed and validated by accuracy, precision, system suitability, and robustness tests. The current method demonstrated good linearity over the range of 0.125-100 μg/mL fucoxanthin with R(2) = 1.0000, and all validation data supported its adequacy for use in fucoxanthin analysis from milk solution. To investigate fucoxanthin stability during milk production and distribution, fucoxanthin content was examined during storage, pasteurization, and drying processes under various conditions. Fucoxanthin in milk solutions showed better stabilizing effect in 1 month of storage period. Degradation rate constant (k) on fucoxanthin during this storage period suggested that fucoxanthin stability might be negatively correlated with decrease of temperature and increase of protein content such as casein and whey protein in milk matrix. In a comparison between SM and WM, fucoxantin in SM always showed better stability than that in WM during storage and three kinds of drying processes. This effect was also deduced to relate with protein content. In the pasteurization step, >91% of fucoxanthin was retained after three pasteurization processes even though the above trend was not found. This study demonstrated for the first time that milk products can be used as a basic food matrix for fucoxanthin application and that protein content in milk is an important factor for fucoxanthin stability.

Undaria pinnatifida and Fucoxanthin Ameliorate Lipogenesis and Markers of Both Inflammation and Cardiovascular Dysfunction in an Animal Model of Diet-Induced Obesity

Brown algae and its carotenoids have been shown to have a positive influence on obesity and its comorbidities. This study evaluated the effect of Undaria pinnatifida and fucoxanthin on biochemical, physiological and inflammation markers related to obesity and on the expression of genes engaged on white adipose tissue lipid metabolism in a murine model of diet-induced obesity. The treatments improved energy expenditure, β-oxidation and adipogenesis by upregulating PPARα, PGC1α, PPARγ and UCP-1. Adipogenesis was also confirmed by image analysis of the retroperitoneal adipose tissue, by measuring cell area, perimeter and cellular density. Additionally, the treatments, ameliorated adipose tissue accumulation, insulin resistance, blood pressure, cholesterol and triglycerides concentration in serum, and reduced lipogenesis and inflammation by downregulating acetyl-CoA carboxylase (ACC) gene expression, increasing serum concentration and expression of adiponectin as well as downregulating IL-6 expression. Both fucoxanthin and Undaria pinnatifida may be considered for treating obesity and other diseases related.

Low-molecular-weight fucoidan and high-stability fucoxanthin from brown seaweed exert prebiotics and anti-inflammatory activities in Caco-2 cells

BACKGROUND

The aim of this study is to investigate the anti-inflammatory effects of low-molecular-weight fucoidan (LMF) and high-stability fucoxanthin (HS-Fucox) in a lipopolysaccharide-induced inflammatory Caco-2 cell line co-culture with B. lactis.

METHODS

We used various methods such as transepithelial resistance (TER) assay, cytokine secretion assay, and tight junction protein mRNA expression assay to examine LMF and HS-Fucox anti-inflammatory properties.

RESULTS

LMF and HS-Fucox activated probiotic growth and reduced the inflammation of the intestinal epithelial cells. Moreover, the combination of LMFHS-Fucox dramatically enhanced the intestinal epithelial barrier and immune function against the lipopolysaccharide effect by inhibiting IL-1β and TNF-α and promoting IL-10 and IFN-γ.

CONCLUSION

These findings suggested that LMF and HS-Fucox, alone or in combination, could be the potential natural compounds to enhance the immune system and have an anti-inflammatory effect on the intestinal cells.

Screening of Diatom Strains and Characterization of Cyclotella cryptica as A Potential Fucoxanthin Producer

Fucoxanthin has been receiving ever-increasing interest due to its broad health beneficial effects. Currently, seaweeds are the predominant source of natural fucoxanthin. However, the disappointingly low fucoxanthin content has impeded their use, driving the exploration of alternative fucoxanthin producers. In the present study, thirteen diatom strains were evaluated with respect to growth and fucoxanthin production potential. Cyclotella cryptica (CCMP 333), which grew well for fucoxanthin production under both photoautotrophic and heterotrophic growth conditions, was selected for further investigation. The supply of nitrate and light individually or in combination were all found to promote growth and fucoxanthin accumulation. When transferring heterotrophic cultures to light, fucoxanthin responded differentially to light intensities and was impaired by higher light intensity with a concomitant increase in diadinoxanthin and diatoxanthin, indicative of the modulation of Diadinoxanthin Cycle to cope with the light stress. Taken together, we, for the first time, performed the screening of diatom strains for fucoxanthin production potential and investigated in detail the effect of nutritional and environmental factors on C. cryptica growth and fucoxanthin accumulation. These results provide valuable implications into future engineering of C. cryptica culture parameters for improved fucoxanthin production and C. cryptica may emerge as a promising microalgal source of fucoxanthin.

Influences of Fucoxanthin on Alveolar Bone Resorption in Induced Periodontitis in Rat Molars

The aim of this study was to evaluate the effects of systemic fucoxanthin treatment on alveolar bone resorption in rats with periodontitis. Thirty rats were divided into control, experimental periodontitis (EP), and experimental periodontitis-fucoxanthin (EP-FUCO) groups. Periodontitis was induced by ligature for four weeks. After removal of the ligature, the rats in the EP-FUCO group were treated with a single dose of fucoxanthin (200 mg/kg bw) per day for 28 consecutive days. At the end of the study, all of the rats were euthanized and intracardiac blood and mandible tissue samples were obtained for biochemical, immunohistochemical, and histometric analyses. Fucoxanthin treatment resulted in a slight decrease in tumor necrosis factor-α, interleukin-1β, and interleukin-6 levels and a significant decrease in oxidative stress index. It was observed that fucoxanthin caused a significant reduction in receptor activator of nuclear factor kappa-β ligand (RANKL) levels and a statistically non-significant elevation in osteoprotegerin and bone-alkaline phosphatase levels. There were no significant differences in alveolar bone loss levels between the EP and EP-FUCO groups. This experimental study revealed that fucoxanthin provides a limited reduction in alveolar bone resorption in rats with periodontitis. One of the mechanisms underlying the mentioned limited effect might be related to the ability of fucoxanthin to inhibit oxidative stress-related RANKL-mediated osteoclastogenesis.

Fucoxanthin, a Marine Carotenoid, Reverses Scopolamine-Induced Cognitive Impairments in Mice and Inhibits Acetylcholinesterase in Vitro

Fucoxanthin, a natural carotenoid abundant in edible brown seaweeds, has been shown to possess anti-cancer, anti-oxidant, anti-obesity and anti-diabetic effects. In this study, we report for the first time that fucoxanthin effectively protects against scopolamine-induced cognitive impairments in mice. In addition, fucoxanthin significantly reversed the scopolamine-induced increase of acetylcholinesterase (AChE) activity and decreased both choline acetyltransferase activity and brain-derived neurotrophic factor (BDNF) expression. Using an in vitro AChE activity assay, we discovered that fucoxanthin directly inhibits AChE with an IC₅₀ value of 81.2 μM. Molecular docking analysis suggests that fucoxanthin likely interacts with the peripheral anionic site within AChE, which is in accordance with enzymatic activity results showing that fucoxanthin inhibits AChE in a non-competitive manner. Based on our current findings, we anticipate that fucoxanthin might exhibit great therapeutic efficacy for the treatment of Alzheimer’s disease by acting on multiple targets, including inhibiting AChE and increasing BDNF expression.

Protective Effect of Fucoxanthin Isolated from Laminaria japonica against Visible Light-Induced Retinal Damage Both in Vitro and in Vivo

With increasingly serious eye exposure to light stresses, such as light-emitting diodes, computers, and widescreen mobile phones, efficient natural compounds for preventing visible light-induced retinal damages are becoming compelling needs in the modern society. Fucoxanthin, as the main light absorption system in marine algae, may possess an outstanding bioactivity in vision protection because of its filtration of blue light and excellent antioxidative activity. In this work, both in vitro and in vivo simulated visible light-induced retinal damage models were employed. The in vitro results revealed that fucoxanthin exhibited better bioactivities than lutein, zeaxanthin, and blueberry anthocyanins in inhibiting overexpression of vascular endothelial growth factor, resisting senescence, improving phagocytic function, and clearing intracellular reactive oxygen species in retinal pigment epithelium cells. The in vivo experiment also confirmed the superiority of fucoxanthin than lutein in protecting retina against photoinduced damage. This excellent bioactivity may be attributed to its unique structural features, including allenic, epoxide, and acetyl groups. Fucoxanthin is expected to be an important ocular nutrient in the future.

Inhibition of Ultraviolet B-Induced Expression of the Proinflammatory Cytokines TNF-α and VEGF in the Cornea by Fucoxanthin Treatment in a Rat Model

Ultraviolet B (UVB) irradiation is the most common cause of radiation damage to the eyeball and is a risk factor for human corneal damage. We determined the protective effect of fucoxanthin, which is a carotenoid found in common edible seaweed, on ocular tissues against oxidative UVB-induced corneal injury. The experimental rats were intravenously injected with fucoxanthin at doses of 0.5, 5 mg/kg body weight/day or with a vehicle before UVB irradiation. Lissamine green for corneal surface staining showed that UVB irradiation caused serious damage on the corneal surface, including severe epithelial exfoliation and deteriorated epithelial smoothness. Histopathological lesion examination revealed that levels of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF), significantly increased. However, pretreatment with fucoxanthin inhibited UVB radiation-induced corneal disorders including evident preservation of corneal surface smoothness, downregulation of proinflammatory cytokine expression, and decrease of infiltrated polymorphonuclear leukocytes from UVB-induced damage. Moreover, significant preservation of the epithelial integrity and inhibition of stromal swelling were also observed after UVB irradiation in fucoxanthin-treated groups. Pretreatment with fucoxanthin may protect against UVB radiation-induced corneal disorders by inhibiting expression of proinflammatory factors, TNF-α, and VEGF and by blocking polymorphonuclear leukocyte infiltration.

Simultaneous Determination of Fucoxanthin and Its Deacetylated Metabolite Fucoxanthinol in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry

Fucoxanthin and its deacetylated metabolite fucoxanthinol are two major carotenoids that have been confirmed to possess various pharmacological properties. In the present study, fucoxanthinol was identified as the deacetylated metabolite of fucoxanthin, after intravenous (i.v.) and intragastric gavage (i.g.) administration to rats at doses of 2 and 65 mg/kg, respectively, by liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis. Next, an accurate and precise LC-MS/MS method was developed to quantitatively determine fucoxanthin and fucoxanthinol in rat plasma. Plasma samples were resolved by LC-MS/MS on a reverse-phase SB-C18 column that was equilibrated and eluted with acetonitrile (A)/aqueous 0.1% formic acid (B; 92/8, v/v) at a flow rate of 0.5 mL/min. Analytes were monitored by multiple-reaction monitoring (MRM) under positive electrospray ionization mode. The precursor/product transitions (m/z) were 659.3→109.0 for fucoxanthin, 617.2→109.0 for fucoxanthinol, and 429.4→313.2 for the internal standard (IS). Calibration curves for fucoxanthin and fucoxanthinol were linear over concentrations ranging from 1.53 to 720 and 1.17 to 600 ng/mL, respectively. The inter- and intraday accuracy and precision were within ±15%. The method was applied successfully in a pharmacokinetic study and the resulting oral fucoxanthin bioavailability calculated.

Photo-Oxidative Stress-Driven Mutagenesis and Adaptive Evolution on the Marine Diatom Phaeodactylum tricornutum for Enhanced Carotenoid Accumulation

Marine diatoms have recently gained much attention as they are expected to be a promising resource for sustainable production of bioactive compounds such as carotenoids and biofuels as a future clean energy solution. To develop photosynthetic cell factories, it is important to improve diatoms for value-added products. In this study, we utilized UVC radiation to induce mutations in the marine diatom Phaeodactylum tricornutum and screened strains with enhanced accumulation of neutral lipids and carotenoids. Adaptive laboratory evolution (ALE) was also used in parallel to develop altered phenotypic and biological functions in P. tricornutum and it was reported for the first time that ALE was successfully applied on diatoms for the enhancement of growth performance and productivity of value-added carotenoids to date. Liquid chromatography-mass spectrometry (LC-MS) was utilized to study the composition of major pigments in the wild type P. tricornutum, UV mutants and ALE strains. UVC radiated strains exhibited higher accumulation of fucoxanthin as well as neutral lipids compared to their wild type counterpart. In addition to UV mutagenesis, P. tricornutum strains developed by ALE also yielded enhanced biomass production and fucoxanthin accumulation under combined red and blue light. In short, both UV mutagenesis and ALE appeared as an effective approach to developing desired phenotypes in the marine diatoms via electromagnetic radiation-induced oxidative stress.

Carotenoids from Marine Microalgae: A Valuable Natural Source for the Prevention of Chronic Diseases

Epidemiological studies have shown a relation between antioxidants and the prevention of several chronic diseases. Microalgae are a potential novel source of bioactive molecules, including a wide range of different carotenoids that can be used as nutraceuticals, food supplements and novel food products. The objective of this review is (i) to update the research that has been carried out on the most known carotenoids produced by marine microalgae, including reporting on their high potentialities to produce other less known important compounds; (ii) to compile the work that has been done in order to establish some relationship between carotenoids and oxidative protection and treatment; (iii) to summarize the association of oxidative stress and the various reactive species including free radicals with several human diseases; and (iv) to provide evidence of the potential of carotenoids from marine microalgae to be used as therapeutics to treat or prevent these oxidative stress-related diseases.

Fucoxanthinol, Metabolite of Fucoxanthin, Improves Obesity-Induced Inflammation in Adipocyte Cells

Fucoxanthin (Fx) is a marine carotenoid found in edible brown seaweeds. We previously reported that dietary Fx metabolite into fucoxanthinol (FxOH), attenuates the weight gain of white adipose tissue of diabetic/obese KK-A^y mice. In this study, to evaluate anti-diabetic effects of Fx, we investigated improving the effect of insulin resistance on the diabetic model of KK-A^y mice. Furthermore, preventing the effect of FxOH on low-grade chronic inflammation related to oxidative stress was evaluated on 3T3-L1 adipocyte cells and a RAW264.7 macrophage cell co-culture system. A diet containing 0.1% Fx was fed to diabetic model KK-A^y mice for three weeks, then glucose tolerance was observed. Fx diet significantly improved glucose tolerance compared with the control diet group. In in vitro studies, FxOH showed suppressed tumor necrosis factor-α (TNF-α), and monocyte chemotactic protein-1 (MCP-1) mRNA expression and protein levels in a co-culture of adipocyte and macrophage cells. These findings suggest that Fx ameliorates glucose tolerance in the diabetic model mice. Furthermore, FxOH, a metabolite of Fx, suppresses low-grade chronic inflammation in adipocyte cells.

Fucoxanthin and Its Metabolite Fucoxanthinol in Cancer Prevention and Treatment

Fucoxanthin is a carotenoid present in the chloroplasts of brown seaweeds. When ingested, it is metabolized mainly to fucoxanthinol by digestive enzymes of the gastrointestinal tract. These compounds have been shown to have many beneficial health effects, including anti-mutagenic, anti-diabetic, anti-obesity, anti-inflammatory and anti-neoplastic actions. In every cancer tested, modulatory actions of fucoxanthinol on viability, cell-cycle arrest, apoptosis and members of the NF-κB pathway were more pronounced than that of fucoxanthin. Anti-proliferative and cancer preventing influences of fucoxanthin and fucoxanthinol are mediated through different signalling pathways, including the caspases, Bcl-2 proteins, MAPK, PI3K/Akt, JAK/STAT, AP-1, GADD45, and several other molecules that are involved in cell cycle arrest, apoptosis, anti-angiogenesis or inhibition of metastasis. In this review, we address the mechanisms of action of fucoxanthin and fucoxanthinol according to different types of cancers. Current findings suggest that these compounds could be effective for treatment and/or prevention of cancer development and aggressiveness.