Characterization and bioactivity of phycocyanin isolated from Spirulina maxima grown under salt stress

Phycobiliprotein from Arthrospira maxima: Conversion to nanoparticles by high-energy ball milling, structural characterization, and evaluation of their anti-inflammatory effect

Arthrospira maxima is a source of phycobiliproteins with different nutraceutical properties, e.g. antioxidant and anti-inflammatory activities. The current study was aimed at the elaboration, characterization, and evaluation of the anti-inflammatory effect of the phycobiliprotein nanoparticles extracted from Arthrospira maxima. Previously freeze-dried phycobiliproteins were milled by high-energy ball milling until reaching a nanometric size (optimal time: 4 h). Microscopy techniques were used for the characterization of the size and morphology of phycobiliproteins nanoparticles. Additionally, a spectroscopic study evidenced that nanosized reduction induced an increase in the chemical functional groups associated with its anti-inflammatory activity that was tested in a murine model, showing an immediate inflammatory effect. The novelty and importance of this contribution was to demonstrate that high energy ball milling is an emerging and green technology that can produce phycobiliprotein nanoparticles on a large-scale, without the use of organic solvents, to test their nutraceutical properties in a biological model by intragastric administration.

Antimicrobial Activity of Arthrospira (Former Spirulina) and Dunaliella Related to Recognized Antimicrobial Bioactive Compounds

With the increasing rate of the antimicrobial resistance phenomenon, natural products gain our attention as potential drug candidates. Apart from being used as nutraceuticals and for biotechnological purposes, microalgae and phytoplankton have well-recognized antimicrobial compounds and proved anti-infectious potential. In this review, we comprehensively outline the antimicrobial activity of one genus of cyanobacteria (Arthrospira, formerly Spirulina) and of eukaryotic microalgae (Dunaliella). Both, especially Arthrospira, are mostly used as nutraceuticals and as a source of antioxidants for health supplements, cancer therapy and cosmetics. Their diverse bioactive compounds provide other bioactivities and potential for various medical applications. Their antibacterial and antifungal activity vary in a broad range and are strain specific. There are strains of Arthrospira platensis with very potent activity and minimum inhibitory concentrations (MICs) as low as 2-15 µg/mL against bacterial fish pathogens including Bacillus and Vibrio spp. Arthrospira sp. has demonstrated an inhibition zone (IZ) of 50 mm against Staphylococcus aureus. Remarkable is the substantial amount of in vivo studies of Arthrospira showing it to be very promising for preventing vibriosis in shrimp and Helicobacter pylori infection and for wound healing. The innovative laser irradiation of the chlorophyll it releases can cause photodynamic destruction of bacteria. Dunaliella salina has exhibited MIC values lower than 300 µg/mL and an IZ value of 25.4 mm on different bacteria, while Dunaliella tertiolecta has demonstrated MIC values of 25 and 50 μg/mL against some Staphylococcus spp. These values fulfill the criteria for significant antimicrobial activity and sometimes are comparable or exceed the activity of the control antibiotics. The bioactive compounds which are responsible for that action are fatty acids including PUFAs, polysaccharides, glycosides, peptides, neophytadiene, etc. Cyanobacteria, such as Arthrospira, also particularly have antimicrobial flavonoids, terpenes, alkaloids, saponins, quinones and some unique-to-them compounds, such as phycobiliproteins, polyhydroxybutyrate, the peptide microcystin, etc. These metabolites can be optimized by using stress factors in a two-step process of fermentation in closed photobioreactors (PBRs).

Membrane inlet—ion mobility spectrometry with automatic spectra evaluation as online monitoring tool for the process control of microalgae cultivation

The cultivation of algae either in open raceway ponds or in closed bioreactors could allow the renewable production of biomass for food, pharmaceutical, cosmetic, or chemical industries. Optimal cultivation conditions are however required to ensure that the production of these compounds is both efficient and economical. Therefore, high-frequency analytical measurements are required to allow timely process control and to detect possible disturbances during algae growth. Such analytical methods are only available to a limited extent. Therefore, we introduced a method for monitoring algae release volatile organic compounds (VOCs) in the headspace above a bioreactor in real time. This method is based on ion mobility spectrometry (IMS) in combination with a membrane inlet (MI). The unique feature of IMS is that complete spectra are detected in real time instead of sum signals. These spectral patterns produced in the ion mobility spectrum were evaluated automatically via principal component analysis (PCA). The detected peak patterns are characteristic for the respective algae culture; allow the assignment of the individual growth phases and reflect the influence of experimental parameters. These results allow for the first time a continuous monitoring of the algae cultivation and thus an early detection of possible disturbances in the biotechnological process.

Biosorption and bioreduction of aqueous chromium (VI) by different Spirulina strains

Spirulina has emerged as a promising microorganism for the treatment of industrial heavy metal ions in wastewater due to their simplicity of cultivation and harvesting, rich functional binding groups, and high bioreductive activity during the uptake process. While the capacities of biosorption and bioreduction for heavy metal ions differ significantly among various algal strains. Therefore, the physiological characteristics were investigated to identify the different Spirulina strains, and the chromium (VI) adsorption capacities of the algal strains were also evaluated. In this study, it was found that algal strains YCX2643 and CLQ1848 performed higher removal efficiency (86.5% and 83.7%) than the other four Spirulina strains (59.4%, 56.3%, 65.6%, and 66.5%, respectively). Moreover, the mechanisms of chromium (VI) ions binding and biotransformation in the Spirulina cell were scrutinized by FTIR (Fourier transform infrared) spectroscopy and scanning electron microscopy (SEM), and it indicated that the varieties of cellular components involved in high binding affinity may cause the higher biosorption and bioreduction of aqueous chromium (VI) in algal strains YCX2643 and CLQ1848, which could be used as promising biosorbents in the removing heavy metal pollutants from wastewaters.

Sustainable Production of Pigments from Cyanobacteria

Pigments are intensely coloured compounds used in many industries to colour other materials. The demand for naturally synthesised pigments is increasing and their production can be incorporated into circular bioeconomy approaches. Natural pigments are produced by bacteria, cyanobacteria, microalgae, macroalgae, plants and animals. There is a huge unexplored biodiversity of prokaryotic cyanobacteria which are microscopic phototrophic microorganisms that have the ability to capture solar energy and CO2 and use it to synthesise a diverse range of sugars, lipids, amino acids and biochemicals including pigments. This makes them attractive for the sustainable production of a wide range of high-value products including industrial chemicals, pharmaceuticals, nutraceuticals and animal-feed supplements. The advantages of cyanobacteria production platforms include comparatively high growth rates, their ability to use freshwater, seawater or brackish water and the ability to cultivate them on non-arable land. The pigments derived from cyanobacteria and microalgae include chlorophylls, carotenoids and phycobiliproteins that have useful properties for advanced technical and commercial products. Development and optimisation of strain-specific pigment-based cultivation strategies support the development of economically feasible pigment biorefinery scenarios with enhanced pigment yields, quality and price. Thus, this chapter discusses the origin, properties, strain selection, production techniques and market opportunities of cyanobacterial pigments.

Progress of Microencapsulated Phycocyanin in Food and Pharma Industries: A Review

Phycocyanin is a blue fluorescent protein with multi-bioactive functions. However, the multi-bioactivities and spectral stability of phycocyanin are susceptible to external environmental conditions, which limit its wide application. Here, the structure, properties, and biological activity of phycocyanin were discussed. This review highlights the significance of the microcapsules' wall materials which commonly protect phycocyanin from environmental interference and summarizes the current preparation principles and characteristics of microcapsules in food and pharma industries, including spray drying, electrospinning, electrospraying, liposome delivery, sharp-hole coagulation baths, and ion gelation. Moreover, the major technical challenge and corresponding countermeasures of phycocyanin microencapsulation are also appraised, providing insights for the broader application of phycocyanin.

Uncovering Research Trends of Phycobiliproteins Using Bibliometric Approach

Phycobiliproteins are gaining popularity as long-term, high-value natural products which can be alternatives to synthetic products. This study analyzed research trends of phycobiliproteins from 1909 to 2020 using a bibliometric approach based on the Scopus database. The current findings showed that phycobiliprotein is a burgeoning field in terms of publications outputs with "biochemistry, genetics, and molecular biology" as the most related and focused subject. The Journal of Applied Phycology was the most productive journal in publishing articles on phycobiliproteins. Although the United States of America (U.S.A.) contributed the most publications on phycobiliproteins, the Chinese Academy of Sciences (China) is the institution with the largest number of publications. The most productive author on phycobiliproteins was Glazer, Alexander N. (U.S.A.). The U.S.A. and Germany were at the forefront of international collaboration in this field. According to the keyword analysis, the most explored theme was the optimization of microalgae culture parameters and phycobiliproteins extraction methods. The bioactivity properties and extraction of phycobiliproteins were identified as future research priorities. Synechococcus and Arthrospira were the most cited genera. This study serves as an initial step in fortifying the phycobiliproteins market, which is expected to exponentially expand in the future. Moreover, further research and global collaboration are necessary to commercialize phycobiliproteins and increase the consumer acceptability of the pigments and their products.

Effect of Arthrospira powders from different producers on the formation of endothelial cell monolayers

Arthrospira platensis (AP) and some of its derived products have well-established biological activities as antioxidants or as agents to reduce cardiovascular disease risk factors. Furthermore, AP products have gained increasing importance as potential anti-cancer agents. However, the ingredients of the available products vary greatly with the origin, the type of production and processing, which could have significant consequences for their biological effects. Therefore, the composition and biological influence of five distinct AP powders, which were acquired commercially or produced at a public biotechnology institute, were investigated in regard to their endothelialization capacity using a cell impedance- (CI) based measurement method. The study revealed that the AP composition and especially the influence on HUVEC proliferation differed significantly between the five AP powders up to 109%.Thus, it could be shown that the method used allows the reliable detection of quantitative differences in biological effects of different AP preparations.

Spirulina platensis Inclusion Reverses Circulating Pro-inflammatory (Chemo)cytokine Profiles in Broilers Fed Low-Protein Diets

Proteins are considered the most expensive nutrients in commercial modern broiler production, and their dietary inclusion at low levels is pivotal to minimize feed costs and reduce nitrogen waste. The quest for an environmentally friendly source of proteins that favor the formulation of low protein diets without compromising broiler health, welfare, and growth performance has become a hotspot in nutrition research. Due to its high protein content, the naturally growing Spirulina microalgae is considered a promising nutrient source. The purpose of the present study was, therefore, to determine the effects of Spirulina supplementation on liver bacterial translocation, hematological profile, and circulating inflammatory and redox markers in broilers fed a low-protein diet. One-day-old Ross 708 male broilers (n = 180) were randomly assigned into one of three experimental treatments: standard diet as a control, low protein diet, and low protein diet supplemented with 100 g/kg of Spirulina. Target molecular markers were measured in the peripheral blood circulation using real-time quantitative PCR. Reducing dietary proteins increased bacterial translocation and systemic inflammation as indicated by proportions of basophils among blood leukocytes. The expression levels of circulating pro-inflammatory cytokines [interleukin (IL)-3, IL-6, IL-4, IL-18, and tumor necrosis factor-α], chemokines (CCL-20), and NOD-like receptor family pyrin domain containing 3 inflammasome were significantly upregulated in birds fed the low protein diet compared with the control. The inclusion of Spirulina reversed these effects, which indicates that Spirulina reduces systemic inflammation- and bacterial translocation-induced by a low protein diet and could be a promising alternative protein source in poultry diets.

Enhancement of Phycobiliprotein Accumulation in Thermotolerant Oscillatoria sp. through Media Optimization

Phycobiliproteins (PBPs) are a group of brilliant pigment proteins found in cyanobacteria and red algae; their synthesis and accumulation depend on several factors such as the type of strain employed, nutrient concentration, light intensity, light regimes, and others. This study evaluates the effect of macronutrients (citrate buffer, NaNO₃, K₂HPO₄, MgSO₄, CaCl₂, Na₂CO₃, and EDTA) and the concentration of trace metals in BG-11 media on the accumulation of PBPs in a thermotolerant strain of Oscillatoria sp. The strain was grown in BG-11 media at 28 °C with a light:dark cycle of 12:12 h at 100 μmol m^-2 s^-1 for 15 days, and the effect of nutrients was evaluated using a Plackett-Burman Design followed by optimization using a response surface methodology. Results from the concentration of trace metals show that it can be reduced up to half-strength in its initial concentration without affecting both biomass and PBPs. Results from the Plackett-Burman Design revealed that only NaNO₃, Na₂CO₃, and K₂HPO₄ show a significant increase in PBP production. Optimization employed a central Non-Factorial Response Surface Design with three levels and four factors (3⁴) using NaNO₃, Na₂CO₃, K₂HPO₄, and trace metals as variables, while the other components of BG-11 media (citrate buffer, MgSO₄, CaCl₂, and EDTA) were used in half of their initial concentration. Results from the optimization show that interaction between Na₂CO₃ and K₂HPO₄ highly increased PBPs' concentration, with values of 15.21, 3.95, and 1.89 (% w/w), respectively. These results demonstrate that identifying and adjusting the concentration of critical nutrients can increase the concentration of PBPs up to two times for phycocyanin and allophycocyanin while four times for phycoerythrin. Finally, the reduction in non-key nutrients' concentration will reduce the production costs of colorants at an industrial scale and increase the sustainability of the process.

Optimization Growth of Spirulina (Arthrospira) Platensis in Photobioreactor Under Varied Nitrogen Concentration for Maximized Biomass, Carotenoids and Lipid Contents

AIMS AND BACKGROUND

Spirulina (Arthrospira) platensis (SP) microalgae were cultured in Zarrouk Medium (ZM), containing three nitrogen concentrations (N-limited, N-optimal and Nrich medium) in ten liter-photo-bioreactor (10 L PBR) for 15-days, in order to study changes in lipid compounds (total carotenoids and total lipids and their effect on fatty acid profile). Based on US patent, the yield of bioactive compounds (such as gamma-linolenic acid GLA, C18:3) extracted from microalgae biomass, mainly depends on the extraction processes (1). GLA has much attention with respect to its therapeutic properties such as its ability to decrease blood cholesterol levels.

METHODS

The impact of the addition of N in cultures of S. platensis in terms of growth, biomasses and induced lipid compounds (total carotenoids and total lipid contents and its fatty acid profile), as well as the Sonication (SON) and Microwave (MIC) process as aiding techniques for lipid extraction compared with a Cold Condition (COL), was examined. GC/MS method was used to determine the fatty acid profile of lipid extract of SP cultures.

RESULTS

In all S. platensis tested culture, the SP was growing successfully, with varying degrees. In N-rich media, the highest cell growth rate and biomass yield were obtained compared with that recorded in other cultures. Under an N-limited condition, SP had higher Total Carotenoids (TCAR, 45.54 mg/g dw) and total lipid contents (TL, 29.51%± 1.92 g/100g dw) compared with that recorded either in N-rich (11.2 mg/g dw) or in N-optimal (6.23 mg/g dw) cultures. Thus, SP copes with the N -stress by altering the metabolic pathways towards inducing lipid biosynthesis. To maximize the TL and TCAR extraction yields, from N-limited cultures, a set of operating process was applied including the Sonication (SON) and Microwave (MIC), which were used as aiding techniques for lipid extraction compared with the Cold Condition (COL) techniques. The results showed that the extraction efficiency of the S. platensis TL increased in the following order: MIC (29.51%± 1.92) > SON (25.46% ± 1.65> COL (20.43% ±1.43). In a comparative study for its fatty acid profiles (FAPs) among all SP cultures, lipids were analyzed by GC/MS. The predominant fatty acids (>10%, of total FA) were found to be myristic acid (C14:0, MA), palmitic acid (C16:0, PA) and oleic acid (C18:1).

CONCLUSION

The study concluded that the N-limited condition was found to have a strong influence on biomass dry weight and lipid contents and total carotenoids in SP cells compared to either Nrich or N-optimal conditions. The use of sonication and the microwave techniques lead to a great increase in the extraction of lipid contents and in high amount Polyunsaturated Fatty Acids (PUFAs) in N-limited cultures, in particular, the omega-6 (ω 6) and omega-3 (ω 3) of the essential C18 fatty acids. It seems that the SP rich in lipid content with a high amount of GLC produced under nitrogen limitation in PBR conditions can be used as a food additive or as a nutritional supplement.

Natural Extracts That Stimulate Adipocyte Browning and Their Underlying Mechanisms

Despite progress in understanding the developmental lineage and transcriptional factors regulating brown and beige adipocytes, the role of environmental modifiers, such as food components and natural extracts, remains to be elucidated. Furthermore, the undesirable pleiotropic effects produced by synthetic drugs targeting adipose tissue browning and thermogenesis necessitate research into alternative natural sources to combat obesity and related metabolic disorders. The current review, therefore, focused on the effects of various extracts from foods, plants, and marine products on adipose tissue browning and obesity. In particular, the recent findings of food components and marine products on adipose tissue browning will be discussed here.

Spirulina maxima reduces inflammation and alveolar bone loss in Porphyromonas gingivalis-induced periodontitis

BACKGROUND

Periodontitis is a common oral disease characterized as inflammation on gingival tissue and alveolar bone resorption. Spirulina maxima has been reported to have anti-oxidative and anti-inflammatory effects on gastric ulcers. However, its effects on gingival inflammation and alveolar bone resorption of periodontitis have not been studied.

PURPOSE

This study was designed to investigate the effects of S. maxima on the P. gingivalis-induced periodontitis and to elucidate its mechanism.

METHODS

The phycocyanin contents in S. maxima were identified by high-performance liquid chromatography. 8-week old SD rats were induced periodontitis by inoculation with P. gingivalis for 14 days. The rats were then orally treated with S. maxima 100, 200, 400 mg/kg, or indomethacin (IND, positive control) 5 mg/kg for an additional 14 days. Inflammatory responses, expressions of collagenases in gingival tissue, osteoclast formation and activation, alveolar bone resorption, osteogenesis-related markers, and BMP2/Smad signaling in alveolar bone were measured.

RESULTS

Pro-inflammatory cytokines such as TNF-α, IL-1β, IL-6, and inflammatory transcription factor NF-κB were decreased in gingival tissue by S. maxima administration. Also, myeloperoxidase (MPO) activity and matrix metalloproteinase (MMPs) expression were decreased by S. maxima administration. Conversely, S. maxima increased IL-4, anti-inflammatory cytokine from Th2 cells. The osteoprotegerin (OPG) / receptor activator of NF-κB ligand (RANKL) expression ratio, which represents osteoclast-osteoblast balance, was increased in S. maxima-treated groups. The alveolar bone loss and the number of TRAP-positive osteoclast cells were also declined in S. maxima-treated groups while the osteoblasts count was increased. Besides, in S. maxima-treated groups, the osteogenesis-related factors were promoted and BMP-2/Smad pathway was up-regulated in a periodontitis condition.

CONCLUSION

S. maxima reduces periodontitis induced by P. gingivalis through anti-inflammatory effect and resultant reduction in bone loss, suggesting that S. maxima might be a potential agent for treating periodontitis.

Efficacy of red light for enhanced cell disruption and fluorescence intensity of phycocyanin

In this study, red LED and urea used as light and nitrogen sources, respectively, for the cultivation of Spirulina to enhance the fluorescence property and purity of phycocyanin. Besides, there is a high concentration of phycocyanin leached out from red light (RL) grown cells than white light (WL) without cell disruption. This type of cultivation reduces the complexity of extraction methods and cost of the downstream process. The fluorescence intensity of C-PC enhanced while using red LEDs and purity ratio improved by single-step cation exchange chromatography. Phycocyanin from red-light-exposed culture exhibited pronounced antibacterial activity against bacteria. The hydrogen peroxide scavenging activity of C-PC (93.7%) is higher than the WL cultures (88.8%). Phycocyanin from RL culture exhibited a strong antiproliferative activity (64.1%) against HeLa cancer cell line. The present study aims to analyze the influence of red light and urea on enhancing the phycocyanin production.

κ-carrageenan-C-phycocyanin based smart injectable hydrogels for accelerated wound recovery and real-time monitoring

Wound healing remains a healthcare challenge in patients suffering from grave tissue damage due to burn injuries and severe medical conditions like diabetes and ischemia. A repeated wound dressing in such cases leads to tissue damage, which could further inflate the wound healing. It is also challenging to analyze the depth of wound bed in these conditions, which could affect the recovery period. To address this need, we have developed an injectable hydrogel from natural polysaccharide κ-carrageenan and a pigmented protein C-phycocyanin. C-phycocyanin has wound healing, antimicrobial, antioxidant and anti-inflammatory properties along with the In-vivo fluorescence imaging ability. Gelling property of κ-carrageenan could be utilized along with C-phycocyanin as an injectable and regenerative wound dressings matrix to monitor wound healing in real-time without upsetting the healing process. The hydrogel presented herein was built from ionic crosslinking of κ-carrageenan monomers along with C-phycocyanin, which provides an interconnected network of porous material with hydrophilic surface and mechanical stiffness. This porosity allows nutrients transportation and gaseous exchange across the wound healing site for the proliferation of various cells. Hydrogel material enhances the proliferation of dermal fibroblasts in vitro without inducing inflammation along with reducing the blood clotting time with no haemolysis. We have found that κ-carrageenan-C-phycocyanin (κ-CRG-C-Pc) hydrogel not only exhibit superior haemostatic capabilities in traumatic injury condition but also provide support for rapid wound healing. Overall, these findings demonstrate the potential of κ-carrageenan-C-phycocyanin hydrogels as a wound-healing and imaging platform towards accelerating tissue repair and real-time monitoring. STATEMENT OF SIGNIFICANCE: Blood clotting and inflammation are the most crucial stages of wound healing along with appropriate monitoring of the healing process. Thus, there is a need of system that could provide point-to-point care and monitoring in this multistage process. Here, we have introduced a self healing, injectable hydrogel system with in vivo imaging abilities from κ-carragenan and C-phycocyanin. C-phycocyanin improves the stability of κ-carragenan matrix and provide support to cellular adhesion, proliferation, and migration. Its anti-inflammatory response and rapid blood clotting ability further empower its applicability in critical medical conditions and wound recovery.

C-Phycocyanin Suppresses the In Vitro Proliferation and Migration of Non-Small-Cell Lung Cancer Cells through Reduction of RIPK1/NF-κB Activity

Phycocyanin, derived from Spirulina platensis, is a type of natural antineoplastic marine protein. It is known that phycocyanin exerts anticancer effects on non-small-cell lung cancer (NSCLC) cells, but its underlying mechanism has not been elucidated. Herein, the antitumor function and regulatory mechanism of phycocyanin were investigated in three NSCLC cell lines for the first time: H358, H1650, and LTEP-a2. Cell phenotype experiments suggested that phycocyanin could suppress the survival rate, proliferation, colony formation, and migration abilities, as well as induce apoptosis of NSCLC cells. Subsequently, transcriptome analysis revealed that receptor-interacting serine/threonine-protein kinase 1 (RIPK1) was significantly down-regulated by phycocyanin in the LTEP-a2 cell, which was further validated by qRT-PCR and Western blot analysis in two other cell lines. Interestingly, similar to phycocyanin-treated assays, siRNA knockdown of RIPK1 expression also resulted in growth and migration inhibition of NSCLC cells. Moreover, the activity of NF-κB signaling was also suppressed after silencing RIPK1 expression, indicating that phycocyanin exerted anti-proliferative and anti-migratory function through down-regulating RIPK1/NF-κB activity in NSCLC cells. This study proposes a mechanism of action for phycocyanin involving both NSCLC apoptosis and down regulation of NSCLC genes.

Effect of Spirulina platensis Biomass with High Polysaccharides Content on Quality Attributes of Common Carp (Cyprinus carpio) and Common Barbel (Barbus barbus) Fish Burgers

Lately, microalgae have been used as natural additives in fish-transformed products to improve their nutritional quality. In this research, the effects of adding Spirulina platensis at concentrations of 0.5, 1 and 1.5% w/v on both the texture and the sensory characteristics of canned burgers were studied. In fact, the addition of Spirulina platensis to fish burgers improves their nutritional composition. Compared to the results of the other fish burger treatments, the treatments that contain 1% of Spirulina platensis had better texture and sensory properties (p < 0.05). Besides, these treatments showed higher swelling ability as well as water and oil holding capacities, due to the important dietary fibers and polysaccharides contents found in Spirulina platensis. No mold or foodborne pathogens were detected in any of the canned burgers up to 8 months of storage at 4 °C. Furthermore, burgers prepared with Spirulina were distinguished by the lowest mean (a* and b*) values (p < 0.05), which shows that the yellow color gradually diminished towards a greenish color. Because of the presence of polysaccharides and pigments (chlorophylls, carotenoids and phycocyanin), Spirulina platensis considerably ameliorates the antioxidant activities of the newly prepared fish burgers. On the whole, we can conclude that Spirulina platensis can be used as a nutritious additive to produce new fish-based products with high alimentary qualities.

Phycocyanin Reduces Proliferation of Melanoma Cells through Downregulating GRB2/ERK Signaling

As a type of functional food additive, phycocyanin is shown to have a potential antineoplastic property. However, its underlying anticancer mechanism in melanoma cells remains unknown. We previously reported a 35S in vivo/vitro labeling analysis for dynamic proteomic (SiLAD) technology. It could exclusively detect protein synthesis rates via pulse labeling of newly expressed proteins by 35S, providing a high time-resolution method for analysis of protein variations. In the present study, we performed a time course analysis in A375 melanoma cells after phycocyanin treatment using SiLAD. Protein expression velocities were specifically visualized and their regulation modes were dynamically traced. Strikingly, novel protein synthesis patterns were discovered in the early phase of phycocyanin treatment, suggesting a possible mechanism of phycocyanin regulation. Furthermore, network analysis and phenotype experiments demonstrated that GRB2-ERK1/2 pathway was involved in phycocyanin-mediated regulation process and responsible for the proliferation suppression of melanoma cell, which could be a therapeutic target for malignant melanoma.

Spirulina maxima Extract Reduces Obesity through Suppression of Adipogenesis and Activation of Browning in 3T3-L1 Cells and High-Fat Diet-Induced Obese Mice

Obesity predisposes animals towards the metabolic syndrome and diseases such as type 2 diabetes, atherosclerosis, and cardiovascular disease. Spirulina maxima is a microalga with anti-oxidant, anti-cancer, and neuroprotective activities, but the anti-obesity effect of Spirulina maxima 70% ethanol extract (SM70EE) has not yet been fully established. We investigated the effect of SM70EE on adipogenesis, lipogenesis, and browning using in vitro and in vivo obesity models. SM70EE treatment reduced lipid droplet accumulation by the oil red O staining method and downregulated the adipogenic proteins C/EBPα, PPARγ, and aP2, and the lipogenic proteins SREBP1, ACC, FAS, LPAATβ, Lipin1, and DGAT1 by western blot analysis. In addition, the index components of SM70EE, chlorophyll a, and C-phycocyanin, reduced adipogenesis and lipogenesis protein levels in 3T3-L1 and C3H10T1/2 cells. High-fat diet (HFD)-fed mice administered with SM70EE demonstrated smaller adipose depots and lower blood lipid concentrations than control HFD-fed mice. The lower body mass gain in treated SM70EE-administrated mice was associated with lower protein expression of adipogenesis factors and higher expression of AMPKα-induced adipose browning proteins PRDM16, PGC1α, and UCP1. SM70EE administration ameliorates obesity, likely by reducing adipogenesis and activating the thermogenic program, in 3T3-L1 cells and HFD-induced obese mice.

Enhancement of cell growth and phycocyanin production in Arthrospira (Spirulina) platensis by metabolic stress and nitrate fed-batch

Arthrospira (Spirulina) platensis is known to have high-quality proteins content and phycocyanin as one of the major pigment constituents of the cells, and the most challenging problem associated with phycocyanin production in Arthrospira is to optimize its intracellular accumulation. The present study evaluated the metabolic stress conditions (by nutrient enrichment) of Arthrospira platensis FACHB-314 for boosting biomass growth and high content phycocyanin accumulation. Experimental results showed that 5 mM sodium glutamate and 7.5 mM succinic acid could enhance biomass yield as well as phycocyanin accumulation compared with that of the control groups. The present study demonstrates that the biomass growth and phycocyanin accumulation were significantly enhanced in fed-batch cultivation of Arthrospira platensis by applying the substrates as metabolic stress agents combined with nitrate feeding strategy. cobA/hemD, hemG and ho genes presented the over-expression level with adding sodium glutamate and succinic acid in cultures, respectively, compared to the control groups.

Anti-obesity effects of Spirulina maxima in high fat diet induced obese rats via the activation of AMPK pathway and SIRT1

Spirulina maxima improved the obese phenotype in high fat diet induced rats by activating AMPK and SIRT1.

Spirulina maxima Extract Prevents Neurotoxicity via Promoting Activation of BDNF/CREB Signaling Pathways in Neuronal Cells and Mice

Spirulina maxima is a microalgae which contains flavonoids and other polyphenols. Although Spirulina maxima 70% ethanol extract (SM70EE) has diverse beneficial effects, its effects on neurotoxicity have not been fully understood. In this study, we investigated the neuroprotective effects of SM70EE against trimethyltin (TMT)-induced neurotoxicity in HT-22 cells. SM70EE inhibited the cleavage of poly-ADP ribose polymerase (PARP). Besides, ROS production was decreased by down-regulating oxidative stress-associated enzymes. SM70EE increased the factors of brain-derived neurotrophic factor (BDNF)/cyclic AMP-responsive element-binding protein (CREB) signalling pathways. Additionally, acetylcholinesterase (AChE) was suppressed by SM70EE. Furthermore, we investigated whether SM70EE prevents cognitive deficits against scopolamine-induced neurotoxicity in mice by applying behavioral tests. SM70EE increased step-through latency time and decreased the escape latency time. Therefore, our data suggest that SM70EE may prevent TMT neurotoxicity through promoting activation of BDNF/CREB neuroprotective signaling pathways in neuronal cells. In vivo study, SM70EE would prevent cognitive deficits against scopolamine-induced neurotoxicity in mice.

Effect of Supercritical Carbon Dioxide Extraction Parameters on the Biological Activities and Metabolites Present in Extracts from Arthrospira platensis

Arthrospira platensis was used to obtain functional extracts through supercritical carbon dioxide extraction (SFE-CO₂). Pressure (P), temperature (T), co-solvent (CX), static extraction (SX), dispersant (Di) and dynamic extraction (DX) were evaluated as process parameters through a Plackett–Burman design. The maximum extract yield obtained was 7.48 ± 0.15% w/w. The maximum contents of bioactive metabolites in extracts were 0.69 ± 0.09 µg/g of riboflavin, 5.49 ± 0.10 µg/g of α-tocopherol, 524.46 ± 0.10 µg/g of β-carotene, 1.44 ± 0.10 µg/g of lutein and 32.11 ± 0.12 mg/g of fatty acids with 39.38% of palmitic acid, 20.63% of linoleic acid and 30.27% of γ-linolenic acid. A. platensis extracts had an antioxidant activity of 76.47 ± 0.71 µg GAE/g by Folin–Ciocalteu assay, 0.52 ± 0.02, 0.40 ± 0.01 and 1.47 ± 0.02 µmol TE/g by DPPH, FRAP and TEAC assays, respectively. These extracts showed antimicrobial activity against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Overall, co-solvent was the most significant factor for all measured effects (p < 0.05). Arthrospira platensis represents a sustainable source of bioactive compounds through SFE using the following extraction parameters P: 450 bar, CX: 11 g/min, SX: 15 min, DX: 25 min, T: 60 °C and Di: 35 g.

Advancement of green process through microwave-assisted extraction of bioactive metabolites from Arthrospira Platensis and bioactivity evaluation

Bioactivity and functional properties of cyanobacterial extract mostly depends on process of extraction, temperature and solvent used (polar or non-polar). To evaluate these parameters a design of experiment (DOE; using a 2^k design) was performed with Arthrospira platensis. Extraction process was optimized through microwave-assisted extraction considering solvent ratio, temperature and time of extraction with polar (PS) and non-polar (NPS). Maximum extract yield obtained was 4.32±0.25% and 5.26±0.11% (w/w) respectively for PS and NPS. Maximum content of bioactive metabolites in PS extracts were thiamine (846.57±14.12μg/g), riboflavin (101.09±1.63μg/g), C-phycocyanin (2.28±0.10μg/g) and A-phycocyanin (4.11±0.03μg/g), while for NPS extracts were α-tocopherol (37.86±0.78μg/g), β-carotene (123.64±1.45μg/g) and 19.44±0.21mg/g of fatty acids. A. platensis PS extracts showed high antimicrobial activity and PS extracts had antioxidant activity of 0.79±0.12μmolTE/g for FRAP assay, while for NPS extracts 1.03±0.08μmol α-TE/g for FRAP assay.

Mycosporine-like Amino Acids and Other Phytochemicals Directly Detected by High-Resolution NMR on Klamath (Aphanizomenon flos-aquae) Blue-Green Algae

This study describes for the first time the use of high-resolution nuclear magnetic resonance (NMR) on Klamath (Aphanizomenon flos-aquae, AFA) blue-green algae directly on powder suspension. These algae are considered to be a "superfood", due to their complete nutritional profile that has proved to have important therapeutic effects. The main advantage of NMR spectroscopy is that it permits the detection of a number of metabolites all at once. The Klamath alga metabolome was revealed to be quite complex, and the most peculiar phytochemicals that can be detected directly on algae by NMR are mycosporine-like amino acids (porphyra-334, P334; shinorine, Shi) and low molecular weight glycosides (glyceryl β-d-galactopyranoside, GalpG; glyceryl 6-amino-6-deoxy-α-d-glucopyranoside, ADG), all compounds with a high nutraceutical value. The presence of cis-3,4-DhLys was revealed for the first time. This molecule could be involved in the anticancer properties ascribed to AFA.

Recent developments in production and biotechnological applications of C-phycocyanin

An extensive range of pigments including phycobiliproteins are present in algae. C-phycocyanin (C-PC), a phycobiliprotein, is one of the key pigments of Spirulina, a microalgae used in many countries as a dietary supplement. Algal pigments have massive commercial value as natural colorants in nutraceutical, cosmetics, and pharmaceutical industries, besides their health benefits. At present, increasing awareness of harmful effects of synthetic compounds and inclination of community towards the usage of natural products have led to the exploitation of microalgae as a source of natural pigments/colors. This review describes recent findings about the sources and production of C-PC, with emphasis on specific techniques for extraction and purification, along with potential industrial applications in diagnostics, foods, cosmetics, and pharmaceutical industries.