Astaxanthin, Haematococcus pluvialis and Haematococcus pluvialis Residue Alleviate Liver Injury in D-Galactose-induced Aging Mice through Gut-liver Axis.

Astaxanthin is a keto-based carotenoid mainly obtained from marine organisms, like Haematococcus pluvialis (H. pluvialis). Previous studies indicated the protective effects of Astaxanthin and H. pluvialis on aging related oxidative injury in liver, while the potential mechanisms are largely unknown. In addition, H. pluvialis residue is a by-product after astaxanthin extraction, which is rarely studied and utilized. The present study aimed to compare the effects of astaxanthin, H. pluvialis and H. pluvialis residue on the oxidant injury of liver in D-galactose-induced aging mice and explore the potential mechanisms through gut-liver axis. The results showed that all the three supplements prevented D-galactose-induced tissue injury, oxidative stress and chronic inflammation in liver and improved liver function. Gut microbiota analysis indicated that astaxanthin notably increased fecal levels of Bacteroidetes, unclassified_f__ Lachnospiraceae, norank_f__Lachnospiraceae, norank_f__norank_o__Clostridia_UCG-014, Prevotellaceae_ UCG-001, unclassified_f__Prevotellaceae in D-galactose-fed mice (p < 0.05). Compared to aging mice, H. pluvialis group had higher fecal levels of norank_f__Lachnospiraceae and Lachnospiraceae_UCG-006 (p < 0.05). H. pluvialis residue group displayed higher relative levels of Bacteroidetes, Streptococcus, and Rikenellaceae_RC9_gut_group (p < 0.05). Moreover, the production of fecal microbial metabolites, like SCFAs and LPS was also differently restored by the three supplements. Overall, our results suggest astaxanthin, H. pluvialis and H. pluvialis residue could prevent aging related hepatic injury through gutliver axis and provide evidence for exploiting of H. pluvialis residue as a functional ingredient for the treatment of liver diseases. Future studies are needed to further clarify the effect and mechanism of dominant components of H. pluvialis residue on liver injury, which is expected to provide a reference for the high-value utilization of H. pluvialis resources.

Removal of Fluoride from Aqueous Solution Using Shrimp Shell Residue as a Biosorbent after Astaxanthin Recovery.

Natural astaxanthin has been widely used in the food, cosmetic, and medicine industries due to its exceptional biological activity. Shrimp shell is one of the primary natural biological sources of astaxanthin. However, after astaxanthin recovery, there is still a lot of chitin contained in the residues. In this study, the residue from shrimp (Penaeus vannamei) shells after astaxanthin extraction using ionic liquid (IL) 1-ethyl-3-methyl-imidazolium acetate ([Emim]Ac) was used as a bioadsorbent to remove fluoride from the aqueous solution. The results show the IL extraction conditions, including the solid/liquid ratio, temperature, time, and particle size, all played important roles in the removal of fluoride by the shrimp shell residue. The shrimp shells treated using [Emim]Ac at 100 °C for 2 h exhibited an obvious porous structure, and the porosity showed a positive linear correlation with defluorination (DF, %). Moreover, the adsorption process of fluoride was nonspontaneous and endothermic, which fits well with both the pseudo-second-order and Langmuir models. The maximum adsorption capacity calculated according to the Langmuir model is 3.29 mg/g, which is better than most bioadsorbents. This study provides a low-cost and efficient method for the preparation of adsorbents from shrimp processing waste to remove fluoride from wastewater.

Pigment Composition of Nine Brown Algae from the Iberian Northwestern Coastline: Influence of the Extraction Solvent.

Brown algae are ubiquitously distributed in the NW coastline of the Iberian Peninsula, where they stand as an underexploited resource. In this study, five solvents were applied to the extraction of pigments from nine brown algae, followed by their determination and quantification by HPLC-DAD. A total of 13 compounds were detected: Six were identified as chlorophylls, six were classified as xanthophylls, and one compound was reported as a carotene. Fucoxanthin was reported in all extracts, which is the most prominent pigment of these algae. Among them, L. saccharina and U. pinnatifida present the highest concentration of fucoxanthin (4.5-4.7 mg∙g-1 dry weight). Ethanol and acetone were revealed as the most efficient solvents for the extraction of pigments, showing a maximal value of 11.9 mg of total pigments per gram of dry alga obtained from the ethanolic extracts of H. elongata, followed by the acetonic extracts of L. ochroleuca. Indeed, ethanol was also revealed as the most efficient solvent according to its high extraction yield along all species evaluated. Our results supply insights into the pigment composition of brown algae, opening new perspectives on their commercial exploitation by food, pharmaceutical, and cosmeceutical industries.

Supercritical Fluid Extraction of Fucoxanthin from the Diatom Phaeodactylum tricornutum and Biogas Production through Anaerobic Digestion.

Phaeodactylum tricornutum is the marine diatom best known for high-value compounds that are useful in aquaculture and food area. In this study, fucoxanthin was first extracted from the diatom using supercritical fluid extraction (SFE) and then using the extracted diatom-like substrate to produce bioenergy through anaerobic digestion (AD) processes. Factors such as temperature (30 °C and 50 °C), pressure (20, 30, and 40 MPa), and ethanol (co-solvent concentration from 10% to 50% v/v) were optimized for improving the yield, purity, and recovery of fucoxanthin extracted using SFE. The highest yield (24.41% w/w) was obtained at 30 MPa, 30 °C, and 30% ethanol but the highest fucoxanthin purity and recovery (85.03mg/g extract and 66.60% w/w, respectively) were obtained at 30 MPa, 30 °C, and 40%ethanol. Furthermore, ethanol as a factor had the most significant effect on the overall process of SFE. Subsequently, P.tricornutum biomass and SFE-extracted diatom were used as substrates for biogas production through AD. The effect of fucoxanthin was studied on the yield of AD, which resulted in 77.15 ± 3.85 LSTP CH4/kg volatile solids (VS) and 56.66 ± 1.90 LSTP CH4/kg VS for the whole diatom and the extracted P.tricornutum, respectively. Therefore, P.tricornutuman can be considered a potential source of fucoxanthin and methane and both productions will contribute to the sustainability of the algae-biorefinery processes.

Neoxanthin prevents H2O2-induced cytotoxicity in HepG2 cells by activating endogenous antioxidant signals and suppressing apoptosis signals.

BACKGROUND: The liver has a solid inbuilt antioxidant defense system to regulate oxidative stress. However, exposure to an excessive level of ROS causes liver injury. This study examined the cytoprotective effect of neoxanthin, a xanthophyll antioxidant molecule isolated from Solanum trilobatum in stress-induced HepG2 cells. METHODS AND RESULTS: The cytotoxic effect of H2O2 and cytoprotective potential of ß-carotene, lutein, and neoxanthin was analyzed by WST-1 assay. The intracellular ROS level and mitochondrial membrane potential (MMP) were measured using DCFH-DA (2', 7'-dichlorofluorescin diacetate) and JC-10 MMP assay. The expression of anti-oxidant and apoptotic markers was measured by western blot analysis. Neoxanthin pretreatment exhibited better protection than ß-carotene and lutein against cell death caused by H2O2. It significantly arrested H2O2-mediated elevation of intracellular ROS levels and protected MMP. The intracellular antioxidant enzymes HO-1 and SOD-2 were upregulated by neoxanthin pretreatment. Neoxanthin also activated the protein expression of redox-sensitive transactivation factors, Nrf2 and NF-kB. The cytoprotective effect of neoxanthin was associated with increased expression of the anti-apoptotic protein, Bcl-2 and decreased pro-apoptotic protein Bax. CONCLUSIONS: For the first time, our results demonstrate that neoxanthin offers adequate protection against stress-mediated cytotoxicity in hepatocytes by activating the intracellular antioxidant defense system and blocking apoptosis.

Valorization of Fermented Shrimp Waste with Supercritical CO2 Conditions: Extraction of Astaxanthin and Effect of Simulated Gastrointestinal Digestion on Its Antioxidant Capacity.

Lactic acid fermentation increases the bioactive properties of shrimp waste. Astaxanthin is the principal carotenoid present in shrimp waste, which can be found esterified in the liquid fraction (liquor) after its lactic acid fermentation. Supercritical CO2 technology has been proposed as a green alternative to obtain astaxanthin from fermented shrimp waste. This study aimed to optimize astaxanthin extraction by supercritical CO2 technology from fermented liquor of shrimp waste and study bioaccessibility using simulated gastrointestinal digestion (GD) of the optimized extract. A Box-Behnken design with three variables (pressure, temperature, and flow rate) was used to optimize the supercritical CO2 extraction. The optimized CO2 extract was obtained at 300 bar, 60 °C, and 6 mL/min, and the estimated characteristics showed a predictive extraction yield of 11.17%, antioxidant capacity of 1.965 mmol of Trolox equivalent (TE)/g, and astaxanthin concentration of 0.6353 µg/g. The experiment with optimal conditions performed to validate the predicted values showed an extraction yield of 12.62%, an antioxidant capacity of 1.784 mmol TE/g, and an astaxanthin concentration of 0.52 µg/g. The astaxanthin concentration decreased, and the antioxidant capacity of the optimized extract increased during gastrointestinal digestion. In conclusion, our optimized supercritical CO2 process is suitable for obtaining astaxanthin from shrimp by-products after lactic acid fermentation.

Wolfberry-derived zeaxanthin dipalmitate delays retinal degeneration in a mouse model of retinitis pigmentosa through modulating STAT3, CCL2 and MAPK pathways.

Retinitis pigmentosa (RP) is a group of inherited photoreceptor degeneration diseases that causes blindness without effective treatment. The pathogenesis of retinal degeneration involves mainly oxidative stress and inflammatory responses. Zeaxanthin dipalmitate (ZD), a wolfberry-derived carotenoid, has anti-inflammatory and anti-oxidative stress effects. Here we investigated whether these properties of ZD can delay the retinal degeneration in rd10 mice, a model of RP, and explored its underlying mechanism. One shot of ZD or control vehicle was intravitreally injected into rd10 mice on postnatal day 16 (P16). Retinal function and structure of rd10 mice were assessed at P25, when rods degenerate substantially, using a visual behavior test, multi-electrode-array recordings and immunostaining. Retinal pathogenic gene expression and regulation of signaling pathways by ZD were explored using transcriptome sequencing and western blotting. Our results showed that ZD treatment improved the visual behavior of rd10 mice and delayed the degeneration of retinal photoreceptors. It also improved the light responses of photoreceptors, bipolar cells and retinal ganglion cells. The expression of genes that are involved in inflammation, apoptosis and oxidative stress were up-regulated in rd10 mice, and were reduced by ZD. ZD further reduced the activation of two key factors, signal transducer and activator of transcription 3 and chemokine (C-C motif) ligand 2, down-regulated the expression of the inflammatory factor GFAP, and inhibited extracellular signal regulated protein kinases and P38, but not the JNK pathways. In conclusion, ZD delays the degeneration of the rd10 retina both morphologically and functionally. Its anti-inflammatory function is mediated primarily through the signal transducer and activator of transcription 3, chemokine (C-C motif) ligand 2 and MAPK pathways. Thus, ZD may serve as a potential clinical candidate to treat RP.

Optimization of ultrasonic-assisted extraction of astaxanthin from green tiger (Penaeus semisulcatus) shrimp shell.

This study was aimed at optimizing the astaxanthin extraction efficiency from shrimp shell (green tiger, Penaeus semisulcatus). Astaxanthin was extracted using selected nonpolar/polar solvents (petroleum ether, n-hexane, ethanol, acetone) individually and in ternary mixtures of petroleum ether, acetone, and water in ratios of 15:50:35, 50:45:5, and 15:75:10 for different times (2,4 and 6 h). The results showed that solvents with higher polarity were more suitable for the extraction of astaxanthin, and increasing the extraction time from 2 to 6 h improved the extraction yield. The conditions of extraction of astaxanthin with the desirable solvent were then optimized with the ultrasonic method using the Box-Behnken design [variables included: extraction temperature (25 to 45 °C), extraction time (5 to 15 min), and ultrasound amplitude (20 to 100%)]. Optimal extraction conditions were determined as the ultrasonic amplitude of 23.6%, extraction time of 13.9 min, and extraction temperature of 26.3 °C. Under this optimum condition, the amount of astaxanthin, ferric reducing antioxidant power, and free radical scavenging capacity of the extract were obtained as 51.5%, 1705 µmol of Fe2+/g, and 73.9%, respectively. Extraction and analysis of the extract at the optimum point were used to validate the results.

Comparison of Different Methods for Extracting the Astaxanthin from Haematococcus pluvialis: Chemical Composition and Biological Activity.

In this study, the impact of different cell disruption techniques (high-pressure micro fluidization (HPMF), ionic liquids (ILs), multi-enzyme (ME), and hydrochloric acid (HCl)) on the chemical composition and biological activity of astaxanthin (AST) obtained from Haematococcus pluvialis was investigated. Results indicated that all cell disruption techniques had a significant effect on AST composition, which were confirmed by TLC and UPC2 analysis. AST recovery from HCl (HCl-AST) and ILs (ILs-AST) cell disruption techniques was dominant by free and monoesters AST, while AST recovery from HPMF (HPMF-AST) and ME (ME-AST) cell disruption techniques was composed of monoesters, diesters, and free AST. Further biological activity analysis displayed that HCl-AST showed the highest ABTS and DPPH activity, while ILs-AST showed better results against the ORAC assay. Additionally, ILs-AST exhibits a stronger anti-proliferation of HepG2 cells in a dose-dependent manner, which was ascribed to AST-induced ROS in to inhibit the proliferative of cancer cells.

Isolation and Purification of Fucoxanthin from Brown Seaweed Sargassum horneri Using Open ODS Column Chromatography and Ethanol Precipitation.

As an abundant marine xanthophyll, fucoxanthin (FX) exhibits a broad range of biological activities. The preparation of high-purity FX is in great demand, however, most of the available methods require organic solvents which cannot meet the green chemistry standard. In the present study, a simple and efficient purification approach for the purification of FX from the brown seaweed Sargassum horneri was carried out. The FX-rich ethanol extract was isolated by octadecylsilyl (ODS) column chromatography using ethanol-water solvent as a gradient eluent. The overwhelming majority of FX was successfully eluted by the ethanol-water mixture (9:1, v/v), with a recovery rate of 95.36%. A parametric study was performed to optimize the aqueous ethanol precipitation process by investigating the effects on the purity and recovery of FX. Under the optimal conditions, the purity of FX was 91.07%, and the recovery rate was 74.98%. Collectively, the eco-friendly method was cost-efficient for the purification of FX. The developed method provides a potential approach for the large-scale production of fucoxanthin from the brown seaweed Sargassum horneri.

Distribution of the Water-Soluble Astaxanthin Binding Carotenoprotein (AstaP) in Scenedesmaceae.

Photooxidative stress-inducible water-soluble astaxanthin-binding proteins, designated as AstaP, were identified in two Scenedesmaceae strains, Coelastrella astaxanthina Ki-4 and Scenedesmus obtusus Oki-4N; both strains were isolated under high light conditions. These AstaPs are classified as a novel family of carotenoprotein and are useful for providing valuable astaxanthin in water-soluble form; however, the distribution of AstaP orthologs in other microalgae remains unknown. Here, we examined the distribution of AstaP orthologs in the family Scenedesmaceae with two model microalgae, Chlamydomonas reinhardtii and Chlorella variabilis. The expression of AstaP orthologs under photooxidative stress conditions was detected in cell extracts of Scenedesmaceae strains, but not in model algal strains. Aqueous orange proteins produced by Scenedesmaceae strains were shown to bind astaxanthin. The protein from Scenedesmus costatus SAG 46.88 was purified. It was named ScosAstaP and found to bind astaxanthin. The deduced amino acid sequence from a gene encoding ScosAstaP showed 62% identity to Ki-4 AstaP. The expression of the genes encoding AstaP orthologs was shown to be inducible under photooxidative stress conditions; however, the production amounts of AstaP orthologs were estimated to be approximately 5 to 10 times lower than that of Ki-4 and Oki-4N.

Optimization and kinetic modeling of ultrasonic-assisted extraction of fucoxanthin from edible brown algae Sargassum fusiforme using green solvents.

The development of green and sustainable extraction technologies for various naturally active biomaterials is gaining increasing attention due to their environmentally friendly advantages. In this work, the ultrasonic-assisted extraction of fucoxanthin from edible brown algae Sargassum fusiforme using different green solvents was presented. Ethyl lactate, limonene, soybean oil, and sunflower oil were used in place of traditional organic solvents. Ethyl lactate showed similar performance to organic solvents, whereas limonene and vegetable oil exhibited higher selectivity for fucoxanthin. Moreover, the effects of various extraction factors, including liquid/solid ratio, extraction time, extraction temperature, as well as amplitude were studied. The optimal conditions were optimized as follows: liquid/solid ratio, 40 mL/g; extraction time, 27 min; extraction temperature, 75 ℃; amplitude, 53%; and solvent, ethyl lactate. Optimal model of second-order kinetic parameters (rate constant, equilibrium concentration, and initial extraction rate) was successfully developed for describing the dynamic ultrasonic extraction process under different operating conditions.

Carotenoid Nostoxanthin Production by Sphingomonas sp. SG73 Isolated from Deep Sea Sediment.

Carotenoids are used commercially for dietary supplements, cosmetics, and pharmaceuticals because of their antioxidant activity. In this study, colored microorganisms were isolated from deep sea sediment that had been collected from Suruga Bay, Shizuoka, Japan. One strain was found to be a pure yellow carotenoid producer, and the strain was identified as Sphingomonas sp. (Proteobacteria) by 16S rRNA gene sequence analysis; members of this genus are commonly isolated from air, the human body, and marine environments. The carotenoid was identified as nostoxanthin ((2,3,2',3')-ß,ß-carotene-2,3,2',3'-tetrol) by mass spectrometry (MS), MS/MS, and ultraviolet-visible absorption spectroscopy (UV-Vis). Nostoxanthin is a poly-hydroxy yellow carotenoid isolated from some photosynthetic bacteria, including some species of Cyanobacteria. The strain Sphingomonas sp. SG73 produced highly pure nostoxanthin of approximately 97% (area%) of the total carotenoid production, and the strain was halophilic and tolerant to 1.5-fold higher salt concentration as compared with seawater. When grown in 1.8% artificial sea salt, nostoxanthin production increased by 2.5-fold as compared with production without artificial sea salt. These results indicate that Sphingomonas sp. SG73 is an efficient producer of nostoxanthin, and the strain is ideal for carotenoid production using marine water because of its compatibility with sea salt.

Shrimp Oil Extracted from Shrimp Processing By-Product Is a Rich Source of Omega-3 Fatty Acids and Astaxanthin-Esters, and Reveals Potential Anti-Adipogenic Effects in 3T3-L1 Adipocytes.

The province of Newfoundland and Labrador, Canada, generates tons of shrimp processing by-product every year. Shrimp contains omega (n)-3 polyunsaturated fatty acids (PUFA) and astaxanthin (Astx), a potent antioxidant that exists in either free or esterified form (Astx-E). In this study, shrimp oil (SO) was extracted from the shrimp processing by-product using the Soxhlet method (hexane:acetone 2:3). The extracted SO was rich in phospholipids, n-3 PUFA, and Astx-E. The 3T3-L1 preadipocytes were differentiated to mature adipocytes in the presence or absence of various treatments for 8 days. The effects of SO were then investigated on fat accumulation, and the mRNA expression of genes involved in adipogenesis and lipogenesis in 3T3-L1 cells. The effects of fish oil (FO), in combination with Astx-E, on fat accumulation, and the mRNA expression of genes involved in adipogenesis and lipogenesis were also investigated. The SO decreased fat accumulation, compared to untreated cells, which coincided with lower mRNA expression of adipogenic and lipogenic genes. However, FO and FO + Astx-E increased fat accumulation, along with increased mRNA expression of adipogenic and lipogenic genes, and glucose transporter type 4 (Glut-4), compared to untreated cells. These findings have demonstrated that the SO is a rich source of n-3 PUFA and Astx-E, and has the potential to elicit anti-adipogenic effects. Moreover, the SO and FO appear to regulate adipogenesis and lipogenesis via independent pathways in 3T3-L1 cells.

Xanthophylls from the Sea: Algae as Source of Bioactive Carotenoids.

Algae are considered pigment-producing organisms. The function of these compounds in algae is to carry out photosynthesis. They have a great variety of pigments, which can be classified into three large groups: chlorophylls, carotenoids, and phycobilins. Within the carotenoids are xanthophylls. Xanthophylls (fucoxanthin, astaxanthin, lutein, zeaxanthin, and ß-cryptoxanthin) are a type of carotenoids with anti-tumor and anti-inflammatory activities, due to their chemical structure rich in double bonds that provides them with antioxidant properties. In this context, xanthophylls can protect other molecules from oxidative stress by turning off singlet oxygen damage through various mechanisms. Based on clinical studies, this review shows the available information concerning the bioactivity and biological effects of the main xanthophylls present in algae. In addition, the algae with the highest production rate of the different compounds of interest were studied. It was observed that fucoxanthin is obtained mainly from the brown seaweeds Laminaria japonica, Undaria pinnatifida, Hizikia fusiformis, Sargassum spp., and Fucus spp. The main sources of astaxanthin are the microalgae Haematococcus pluvialis, Chlorella zofingiensis, and Chlorococcum sp. Lutein and zeaxanthin are mainly found in algal species such as Scenedesmus spp., Chlorella spp., Rhodophyta spp., or Spirulina spp. However, the extraction and purification processes of xanthophylls from algae need to be standardized to facilitate their commercialization. Finally, we assessed factors that determine the bioavailability and bioaccesibility of these molecules. We also suggested techniques that increase xanthophyll's bioavailability.

In Vitro Bioactivity of Astaxanthin and Peptides from Hydrolisates of Shrimp (Parapenaeus longirostris) By-Products: From the Extraction Process to Biological Effect Evaluation, as Pilot Actions for the Strategy "From Waste to Profit".

Non-edible parts of crustaceans could be a rich source of valuable bioactive compounds such as the carotenoid astaxanthin and peptides, which have well-recognized beneficial effects. These compounds are widely used in nutraceuticals and pharmaceuticals, and their market is rapidly growing, suggesting the need to find alternative sources. The aim of this work was to set up a pilot-scale protocol for the reutilization of by-products of processed shrimp, in order to address the utilization of this valuable biomass for nutraceutical and pharmaceuticals application, through the extraction of astaxanthin-enriched oil and antioxidant-rich protein hydrolysates. Astaxanthin (AST) was obtained using "green extraction methods," such as using fish oil and different fatty acid ethyl esters as solvents and through supercritical fluid extraction (SFE), whereas bioactive peptides were obtained by protease hydrolysis. Both astaxanthin and bioactive peptides exhibited bioactive properties in vitro in cellular model systems, such as antioxidant and angiotensin I converting enzyme (ACE) inhibitory activities (IA). The results show higher astaxanthin yields in ethyl esters fatty acids (TFA) extraction and significant enrichment by short-path distillation (SPD) up to 114.80 ± 1.23 µg/mL. Peptide fractions of <3 kDa and 3-5 kDa exhibited greater antioxidant activity while the fraction 5-10 kDa exhibited a better ACE-IA. Lower-molecular-weight bioactive peptides and astaxanthin extracted using supercritical fluids showed protective effects against oxidative damage in 142BR and in 3T3 cell lines. These results suggest that "green" extraction methods allow us to obtain high-quality bioactive compounds from large volumes of shrimp waste for nutraceutical and pharmaceutical applications.

Fucoxanthin Suppresses Osteoclastogenesis via Modulation of MAP Kinase and Nrf2 Signaling.

Fucoxanthin (FX), a natural carotenoid present in edible brown seaweed, is known for its therapeutic potential in various diseases, including bone disease. However, its underlying regulatory mechanisms in osteoclastogenesis remain unclear. In this study, we investigated the effect of FX on osteoclast differentiation and its regulatory signaling pathway. In vitro studies were performed using osteoclast-like RAW264.7 cells stimulated with the soluble receptor activator of nuclear factor-κB ligand or tumor necrosis factor-alpha/interleukin-6. FX treatment significantly inhibited osteoclast differentiation and bone resorption ability, and downregulated the expression of osteoclast-specific markers such as nuclear factor of activated T cells 1, dendritic cell-specific seven transmembrane protein, and matrix metallopeptidase 9. Intracellular signaling pathway analysis revealed that FX specifically decreased the activation of the extracellular signal-regulated kinase and p38 kinase, and increased the nuclear translocation of phosphonuclear factor erythroid 2-related factor 2 (Nrf2). Our results suggest that FX regulates the expression of mitogen-activated protein kinases and Nrf2. Therefore, FX is a potential therapeutic agent for osteoclast-related skeletal disorders including osteoporosis and rheumatoid arthritis.

A simple and fast experimental protocol for the extraction of xanthophylls from microalga Chlorella luteoviridis.

This study aimed to optimize the key parameters of extraction methods and to increase the recovery yields of intact xanthophylls (violaxanthin, zeaxanthin, astaxanthin) from microalgae (Chlorella luteoviridis). An effective, simple, and fast extraction protocol is described. It consists of a grinding pretreatment followed by a microwave-assisted extraction, using ethanol 90% as an environmentally preferable extraction solvent. Xanthopylls were quantified using high performance liquid chromatography. Irradiation time of 6 s only resulted in the extraction of violaxanthin (4.479 ± 0.009 mg/g), astaxanthin (4.154 ± 0.013 mg/g), and zeaxanthin (4.776 ± 0.120 mg/g). The described protocol seems to be the fastest extraction method of xantophylls compared to the literature and could be an advantage for industrial scale, while saving time and energy.

Therapeutic attributes and applied aspects of biological macromolecules (polypeptides, fucoxanthin, sterols, fatty acids, polysaccharides, and polyphenols) from diatoms - A review.

Diatoms are ubiquitous, biologically widespread, and have global significance due to their unique silica cell wall composition and noteworthy applied aspects. Diatoms are being extensively exploited for environmental monitoring, reconstruction, and stratigraphic correlation. However, considering all the rich elements of diatoms biology, the current literature lacks sufficient information on the therapeutic attributes and applied aspects of biological macromolecules from diatoms, hampering added advances in all aspects of diatom biology. Diatoms offer numerous high-value compounds, such as fatty acids, polysaccharides, polypeptides, pigments, and polyphenols. Diatoms with a high content of PUFA's are targets of transformation into high-value products through microalgal technologies due to their wide application and growing market as nutraceuticals and food supplements. Diatoms are renewable biomaterial, which can be used to develop drug delivery systems due to biocompatibility, surface area, cost-effective ratio, and ease in surface modifications. Innovative approaches are needed to envisage cost-effective ways for the isolation of bioactive compounds, enhance productivity, and elucidate the detailed mechanism of action. This review spotlights the notable applications of diatoms and their biologically active constituents, such as fucoxanthin and omega 3 fatty acids, among others with unique structural and functional entities.

Fucoxanthin from microalgae Phaeodactylum tricornutum inhibits pro-inflammatory cytokines by regulating both NF-κB and NLRP3 inflammasome activation.

Pro-inflammatory cytokines such as IL-1ß, IL-6, and TNF-α are mediated by the activation of various kinds of signaling pathways in the innate immune system. Particularly, NF-κB and NLRP3 inflammasome signaling are involved in the production and secretion of these cytokines. Each signaling is participated in the two steps necessary for IL-1ß, a representative pro-inflammatory cytokine, to be processed into a form secreted by cells. In the priming step stimulated by LPS, pro-IL-1ß is synthesized through NF-κB activation. Pro-IL-1ß cleavages into mature IL-1ß by formed NLRP3 inflammasome in the activation step induced by ATP. The mature form of IL-1ß is subsequently secreted out of the cell, causing inflammation. Moreover, IL-6 and TNF-α are known to increase in NLRP3 inflammasome-mediated conditions. Here, we found that fucoxanthin, one of the major components of Phaeodactylum tricornutum, has an inhibitory effect on NF-κB and NLRP3 inflammasome activation induced by the combination of LPS and ATP in bone marrow-derived immune cells as well as astrocytes. Fucoxanthin, which is abundant in the EtOH fraction of Phaeodactylum tricornutum extracts, has shown to have less cell toxicity and found to decrease the production of major pro-inflammatory cytokines such as IL-1ß, IL-6, and TNF-α. Fucoxanthin has also shown to suppress the expression of cleaved caspase-1 and the oligomerization of ASC, which are the main components of the NLRP3 inflammasome. Furthermore, phosphorylated IκBα and pro-IL-1ß expression decreased in the presence of fucoxanthin, suggesting that fucoxanthin can negatively regulate the priming step of inflammasome signaling. Thus, our results provide reliable evidence that fucoxanthin may serve as a key candidate in the development of potential therapeutic agents for inflammatory diseases as well as neurodegenerative diseases caused by NF-κB and NLRP3 inflammasome activation.