Purification and bioactivities of phycocyanin

A rapid one-step affinity purification of C-phycocyanin from Spirulina platensis

The high-purity phycocyanin has a high commercial value. Most current purification methods of C-phycocyanin involve multiple steps, which are complicated and time-consuming. To solve the problem, this research was studied, and an efficient affinity chromatography purification for C-phycocyanin from Spirulina platensis was developed. Through molecular docking simulation, virtual screening of ligands was performed, and ursolic acid was identified as the specific affinity ligand, which coupled to Affi-Gel 102 gel via 1-ethyl (3-dimethylaminopropyl)-3-carbodiimide, hydrochloride as coupling agent. With this customized and synthesized resin, a high-efficiency one-step purification procedure for C-phycocyanin was developed and optimized, the purity was determined to be 4.53, and the yield was 69 %. This one-step purification protocol provides a new approach for purifying other phycobilin proteins.

Design and preparation of novel antioxidant and antibacterial films containing procyanidins and phycocyanin for food packaging

The purpose of this study was to design a novel antioxidant and antibacterial film for food packaging using food-grade raw materials. The films were designed and fabricated based on carboxymethyl chitosan and pectin incorporated with procyanidins (PCs) and phycocyanin (Phy) by the tape casting method. The effects of different proportions of PCs and Phy on the properties and functions of the prepared films were studied. The results showed that the thickness of films could range from 55 to 70 μm, with dense network structure and uniform distribution of elements. Compared with C-Film group, the film loaded with PCs and Phy had lower water solubility and swelling rate, and higher tensile strength and elongation at break. FITR and XRD spectra revealed the molecular interaction mechanism among carboxymethyl chitosan, pectin, PCs and Phy, which could effectively endow the films with ultraviolet barrier properties. Moreover, the addition of PCs and Phy could effectively improve the antioxidant capacity and antibacterial effect of films, for example, the free radical scavenging abilities of most films were above 80% when the concentration of PCs was 40 μg mL-1. In view of these functional properties, the prepared film containing PCs and Phy have been successfully used in food packaging, which was proved by the preservation experiment of grapes. This study can provide theoretical and technical guidance for the preparation of biodegradable antibacterial films, and their application in the food packaging field.

Natural products for gastric carcinoma prevention and treatment: Focus on their antioxidant stress actions in the Correa's cascade

BACKGROUND

Correa's cascade is a pathological process beginning from gastritis to gastric precancerous lesions, and finally to gastric carcinoma (GC). While the pathogenesis of GC remains unclear, oxidative stress plays a prominent role throughout the entire Correa's cascade process. Studies have shown that some natural products (NPs) could halt and even reverse the development of the Correa's cascade by targeting oxidative stress.

METHODS

To review the effects and mechanism by which NPs inhibit the Correa's cascade through targeting oxidative stress, data were collected from PubMed, Embase, Web of Science, ScienceDirect, and China National Knowledge Infrastructure databases from initial establishment to April 2023. NPs were classified and summarized by their mechanisms of action.

RESULTS

NPs, such as terpenoid, polyphenols and alkaloids, exert multistep antioxidant stress effects on the Correa's cascade. These effects include preventing gastric mucosal inflammation (stage 1), reversing gastric precancerous lesions (stage 2), and inhibiting gastric carcinoma (stage 3). NPs can directly impact the conversion of gastritis to GC by targeting oxidative stress and modulating signaling pathways involving IL-8, Nrf2, TNF-α, NF-κB, and ROS/MAPK. Among which polyphenols have been studied more and are of high research value.

CONCLUSIONS

NPs display a beneficial multi-step action on the Correa's cascade, and have potential value for clinical application in the prevention and treatment of gastric cancer by regulating the level of oxidative stress.

Determination of Heavy Metal Content: Arsenic, Cadmium, Mercury, and Lead in Cyano-Phycocyanin Isolated from the Cyanobacterial Biomass

Cyano-phycocyanin (C-PC) is a light-absorbing biliprotein found in cyanobacteria, commonly known as blue-green algae. Due to its antioxidative, anti-inflammatory, and anticancer properties, this protein is a promising substance in medicine and pharmaceuticals. However, cyanobacteria tend to bind heavy metals from the environment, making it necessary to ensure the safety of C-PC for the development of pharmaceutical products, with C-PC isolated from naturally collected cyanobacterial biomass. This study aimed to determine the content of the most toxic heavy metals, arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in C-PC isolated from different cyanobacterial biomasses collected in the Kaunas Lagoon during 2019-2022, and compare them with the content of heavy metals in C-PC isolated from cultivated Spirulina platensis (S. platensis). Cyanobacteria of Aphanizomenon flos-aquae (A. flos-aquae) dominated the biomass collected in 2019, while the genus Microcystis dominated the biomasses collected in the years 2020 and 2022. Heavy metals were determined using inductively coupled plasma mass spectrometry (ICP-MS). ICP-MS analysis revealed higher levels of the most investigated heavy metals (Pb, Cd, and As) in C-PC isolated from the biomass with the dominant Microcystis spp. compared to C-PC isolated from the biomass with the predominant A. flos-aquae. Meanwhile, C-PC isolated from cultivated S. platensis exhibited lower concentrations of As and Pb than C-PC isolated from naturally collected cyanobacterial biomass.

Microalgae: A Promising Source of Bioactive Phycobiliproteins

Phycobiliproteins are photosynthetic light-harvesting pigments isolated from microalgae with fluorescent, colorimetric and biological properties, making them a potential commodity in the pharmaceutical, cosmetic and food industries. Hence, improving their metabolic yield is of great interest. In this regard, the present review aimed, first, to provide a detailed and thorough overview of the optimization of culture media elements, as well as various physical parameters, to improve the large-scale manufacturing of such bioactive molecules. The second section of the review offers systematic, deep and detailed data about the current main features of phycobiliproteins. In the ultimate section, the health and nutritional claims related to these bioactive pigments, explaining their noticeable potential for biotechnological uses in various fields, are examined.

Coffee Silverskin Cellulose-Based Composite Film with Natural Pigments for Food Packaging: Physicochemical and Sensory Abilities

To promote a circular economy, the use of agricultural by-products as food packaging material has steadily increased. However, designing food packaging films that meet consumers' preferences and requirements is still a challenge. In this work, cellulose extracted from coffee silverskin (a by-product of coffee roasting) and chitosan were combined with different natural pigments (curcumin, phycocyanin, and lycopene) to generate a variety of composite films with different colors for food packaging. The physicochemical and sensory properties of the films were evaluated. The cellulose/chitosan film showed favorable mechanical properties and water sensitivity. Addition of natural pigments resulted in different film colors, and significantly affected the optical properties and improved the UV-barrier, swelling degree, and water vapor permeability (WVP), but there were also slight decreases in the mechanical properties. The various colored films can influence the perceived features and evoke different emotions from consumers, resulting in films receiving different attraction and liking scores. This work provides a comprehensive evaluation strategy for coffee silverskin cellulose-based composite films with incorporated pigments, and a new perspective on the consideration of the hedonic ratings of consumers regarding bio-based films when designing food packaging.

Coassembly of Fiber Hydrogel with Antibacterial Activity for Wound Healing

Wound healing remains a critical challenge due to its vulnerability to bacterial infection and the complicated inflammatory microenvironment. Herein, we report a novel antibacterial hydrogel constructed only by gallic acid (GA) and phycocyanin (PC), which is expected for the treatment of bacteria-infected wounds. These GA/PC hydrogels (GP) was found to coassemble into fibrous networks with a diameter of around 2 μm mainly through noncovalent interactions of hydrogen bonds, van der Waals force, and π interaction. Notably, these GP hydrogels showed excellent rheological properties (i.e., storage modulus of more than 9.0 × 10⁴ Pa) and outstanding biocompatibility and antibacterial activities. Thanks to the incorporation of GA and PC, the GP hydrogels enabled adherence to the moist wound tissue and achieved a sustained release of GA and PC into the wound skin, therefore effectively attenuating inflammation and accelerating wound healing both in normal mice and bacteria-infected mice through regulating the expression of the tight junction protein and the alleviation of oxidative stress. Considering these results, these GP hydrogels are demonstrated to be a promising candidate for bacteria-infected wound healing.

High Purity Grade Phycocyanin Recovery by Decupling Cell Lysis from the Pigment Extraction: an Innovative Approach

Phycocyanin, a phycobiliprotein, is one of the few natural blue pigments available as food colourant, and it is largely used in food industry. We have devised an innovative two-step extraction process which allowed to obtain bright blue phycocyanin crude extracts with high purity grade P (within 2.5 and 3.5) directly from fresh biomass of Arthrospira platensis Gomont 1892 (commonly named Spirulina). We found out and for the first time exploited ammonium sulphate capability to minimize the release of water soluble phycobiliproteins in aqueous medium during ultrasound-assisted cell lysis/purification phase. The conventional sequence which is, extraction followed by purification, was reversed. The extraction phase was decoupled from biomass cell lysis. Cell lysis, accomplished by ultrasonication in ammonium sulphate solution, was merged with purification in a single step, before the pigment extraction/recovering phase. The process was entirely carried out in aqueous solutions. No downstream purification was required to obtain products suitable for the most common phycocyanin applications (i.e. foods, nutraceuticals). Production time, hours instead of days, was reduced to the advantage of the product quality. The process has the great advantages of (1) direct use of extracting solutions that cannot be used in the ordinary ultrasound-assisted extraction of phycocyanin (because of the extensive simultaneous extraction of contaminant molecules), (2) gain of high commercial value phycocyanin due to the elevated purity grade and (3) direct production of highly concentrated bright blue pigment crude extracts (up to about 5 mg mL−1) immediately in hand to the market.

Graphical Abstract

Phycobiliproteins, the pigment-protein complex form of natural food colorants and bioactive ingredients

Currently, the use of synthetic pigments in foods is restricted since synthetic pigments are proven and suspected to be harmful to human health. Phycobiliproteins (PBPs), existed in phycobilisomes (PBSs) of algae, are a kind of pigment-proteins with intense color. The specific color of PBPs (red and blue) is given by the water-soluble open-chained tetrapyrrole chromophore (phycobilin) that covalently attaches to the apo-protein via thioether linkages to cysteine residues. According to the spectral characteristics of PBPs, they can be categorized as phycoerythrins (PEs), phycocyanins (PCs), allophycocyanins (APCs), and phycoerythrocyanins (PECs). PBPs can be used as natural food colorants, fluorescent substances, and bioactive ingredients in food applications owing to their color characteristics and physiological activities. This paper mainly summarizes the extraction and purification methods of the PBPs and reviews their characteristics and applications. Moreover, the use of several strategies such as additives, microencapsulation, electrospray, and cross-linking to improve the stability and bioavailability of PBPs as well as the future outlooks of PBPs as natural colorants in food commercialization are elucidated.

Phycocyanin Ameliorates Colitis-Associated Colorectal Cancer by Regulating the Gut Microbiota and the IL-17 Signaling Pathway

Phycocyanin (PC) is a pigment-protein complex. It has been reported that PC exerts anti-colorectal cancer activities, although the underlying mechanism has not been fully elucidated. In the present study, azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced mice were orally administrated with PC, followed by microbiota and transcriptomic analyses to investigate the effects of PC on colitis-associated cancer (CAC). Our results indicated that PC ameliorated AOM/DSS induced inflammation. PC treatment significantly reduced the number of colorectal tumors and inhibited proliferation of epithelial cell in CAC mice. Moreover, PC reduced the relative abundance of Firmicutes, Deferribacteres, Proteobacteria and Epsilonbacteraeota at phylum level. Transcriptomic analysis showed that the expression of genes involved in the intestinal barrier were altered upon PC administration, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed the IL-17 signaling pathway was affected by PC treatment. The study demonstrated the protective therapeutic action of PC on CAC.

Facile synthesis of food-grade and size-controlled nanocarriers based on self-assembly of procyanidins and phycocyanin

Nanocarriers provide the possibility to overcome the low solubility, poor stability, and low bioavailability of functional factors. However, most nanocarriers do not directly participate in the corresponding effects of functional factors, such as treating inflammatory bowel disease but lack the means to control their size accurately. Herein, nanocarriers were prepared by a one-pot method, using food-grade antioxidant procyanidins, vanillin, and phycocyanin as raw materials. The strategy involved the Mannich reaction among the phenolic hydroxyl groups of procyanidins, the aldehyde groups of vanillin, and the amino groups of phycocyanin. The obtained nanocarriers displayed controllable sizes ranging from 130 to 750 nm, showing good antioxidant capacity in scavenging free radicals and were biocompatible to Caco-2 cells and RAW 264.7 macrophages. Nanocarriers also exhibited an inhibitory effect on cell damage induced by acrylamide and H₂O₂. Moreover, the designed nanocarriers could be used for delivering active ingredients such as lutein, which showed a uniform spherical distribution, high encapsulation efficiency, and good biocompatibility. This work provides a facile synthesis method to prepare food-grade nanocarriers with functional properties, which can be potentially used in the delivery of functional factors.

Photoprotective energy quenching in the red alga Porphyridium purpureum occurs at the core antenna of the photosystem II but not at its reaction center

Photosynthetic organisms have evolved light-harvesting antennae over time. In cyanobacteria, external phycobilisomes (PBSs) are the dominant antennae, whereas in green algae and higher plants, PBSs have been replaced by proteins of the Lhc family that are integrated in the membrane. Red algae represent an evolutionary intermediate between these two systems, as they employ both PBSs and membrane LHCR proteins as light-harvesting units. Understanding how red algae cope with light is not only interesting for biotechnological applications, but is also of evolutionary interest. For example, energy-dependent quenching (qE) is an essential photoprotective mechanism widely used by species from cyanobacteria to higher plants to avoid light damage; however, the quenching mechanism in red algae remains largely unexplored. Here, we used both pulse amplitude-modulated (PAM) and time-resolved chlorophyll fluorescence to characterize qE kinetics in the red alga Porphyridium purpureum. PAM traces confirmed that qE in P. purpureum is activated by a decrease in the thylakoid lumen pH, whereas time-resolved fluorescence results further revealed the quenching site and ultrafast quenching kinetics. We found that quenching exclusively takes place in the photosystem II (PSII) complexes and preferentially occurs at PSII’s core antenna rather than at its reaction center, with an overall quenching rate of 17.6 ± 3.0 ns⁻¹. In conclusion, we propose that qE in red algae is not a reaction center type of quenching, and that there might be a membrane-bound protein that resembles PsbS of higher plants or LHCSR of green algae that senses low luminal pH and triggers qE in red algae.

Seaweeds' pigments and phenolic compounds with antimicrobial potential

Recently, there has been increased interest in the development of novel antimicrobial compounds for utilization in a variety of sectors, including pharmaceutical, biomedical, textile, and food. The use, overuse, and misuse of synthetic compounds or derivatives have led to an increase of pathogenic microorganisms gaining resistance to the traditional antimicrobial therapies, which has led to an increased need for alternative therapeutic strategies. Seaweed are marine organisms that can be cultivated sustainably, and they are a source of polar molecules, such as pigments and phenolic compounds, which demonstrated antimicrobial potential. This review focuses on current knowledge about pigments and phenolic compounds isolated from seaweeds, their chemical characteristics, antimicrobial bioactivity, and corresponding mechanism of action.

Physicochemical degradation of phycocyanin and means to improve its stability: A short review

The cyanobacterium Arthrospira platensis, spirulina, is a source of pigments such as phycobiliprotein and phycocyanin. Phycocyanin is used in the food, cosmetics, and pharmaceutical industries because of its antioxidant, anti-inflammatory, and anticancer properties. The different steps involved in extraction and purification of this protein can alter the final properties. In this review, the stability of phycocyanin (pH, temperature, and light) is discussed, considering the physicochemical parameters of kinetic modeling. The optimal working pH range for phycocyanin is between 5.5 and 6.0 and it remains stable up to 45 °C; however, exposure to relatively high temperatures or acidic pH decreases its half-life and increases the degradation kinetic constant. Phycobiliproteins are sensitive to light; preservatives such as mono- and di-saccharides, citric acid, or sodium chloride appear to be effective stabilizing agents. Encapsulation within nano- or micro-structured materials such as nanofibers, microparticles, or nanoparticles, can also preserve or enhance its stability.

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Phycocyanin is in great demand for industrial application.

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Phycocyanin is sensitive to pH, temperature, and light.

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Optimal stability occurs between pH 5.5–6.0 and at temperatures <45 °C in the dark.

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The use of preservatives or its encapsulation with polymers enhances its stability.

Phycocyanin, a super functional ingredient from algae; properties, purification characterization, and applications

Phycocyanins (PCYs) are a group of luxuriant bioactive compounds found in blue-green algae with an estimated global market of about US$250 million within this decade. The multifarious markets of PCYs noted by form (e.g. powder or aqueous forms), by grade (e.g. analytical, cosmetic, or food grades), and by application (such as biomedical, diagnostics, beverages, foods, nutraceuticals and pharmaceuticals), show that the importance of PCYs cannot be undermined. In this comprehensive study, an overview on PCY, its structure, and health-promoting features are diligently discussed. Methods of purification including chromatography, ammonium sulfate precipitation and membrane filtration, as well as characterization and measurement of PCYs are described. PCYs could have many applications in food colorants, fluorescent markers, nanotechnology, nutraceutical and pharmaceutical industries. It is concluded that PCYs offer significant potentials, although more investigations regarding its purity and safety are encouraged.

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.

Insulin Receptor Substrate 1 Is Involved in the Phycocyanin-Mediated Antineoplastic Function of Non-Small Cell Lung Cancer Cells

Phycocyanin, derived from marine algae, is known to have noteworthy antineoplastic properties. However, the underlying mechanism involved in phycocyanin-mediated anti-growth function on non-small cell lung cancer (NSCLC) cells is still ambiguous. Here, we investigated the mechanism of action of phycocyanin on H1299, A549, and LTEP-a2 cells. According to the results obtained, insulin receptor substrate 1 (IRS-1) expression was reduced by phycocyanin. Cell phenotype tests showed that siRNA knockdown of IRS-1 expression significantly inhibited the growth, migration, colony formation, but promoted the apoptosis of NSCLC cells. Meanwhile, phycocyanin and IRS-1 siRNA treatment both reduced the PI3K-AKT activities in NSCLC cells. Moreover, overexpression of IRS-1 accelerated the proliferation, colony formation, and migration rate of H1299, A549, and LTEP-a2 cells, which was contradicting to the knockdown results. Overall, this study uncovered a regulatory mechanism by which phycocyanin inhibited the growth of NSCLC cells via IRS-1/AKT pathway, laying the foundation for the potential target treatment of NSCLC.

Phycobiliproteins Ameliorate Gonadal Toxicity in Male Mice Treated with Cyclophosphamide

Cyclophosphamide (CP)-which is used to treat autoimmune diseases and cancer-is related to gonadotoxicity attributed to oxidative stress. As phycobiliproteins (PBPs) are strong antioxidants that are unexplored as protective agents against male gonadotoxicity, our work aimed to investigate the effects of PBP crude extract on testicular damage and sperm parameter alterations caused by CP in mice. Three doses of PBP (50, 100, and 200 mg/kg) were tested in the experimental groups (n = 8 per group), administered concomitantly with 100 mg/kg CP. After 42 days receiving PBP daily and CP weekly, body and relative testicular weights, serum testosterone levels, testicular lipoperoxidation and antioxidant enzyme activity levels, and testicular histology and sperm parameter alterations were assessed. The results showed that PBP crude extract at 200 mg/kg prevented testosterone serum reduction, body weight loss, lipoperoxidation and enzyme activity increments, and sperm parameter alterations and partially ameliorated relative testicular weight reductions and histological damage in CP-treated mice. In conclusion, we showed that PBP crude extract (200 mg/kg) mitigated oxidative damage in the testes and ameliorated alterations in sperm parameters in mice treated with CP (100 mg/kg); therefore, PBP extract could be considered as a potential protective agent against CP toxicity.

Lactobionic acid-modified phycocyanin nanoparticles loaded with doxorubicin for synergistic chemo-photodynamic therapy

Phycocyanin (PC) is considered to be an effective natural photosensitizer, but it has not been well utilized as its inefficient biostability and intracellular accumulation. To overcome these limitations, the nano-sized PC particles (LAPC/DOX) were developed by grafting with lactobionic acid (LA) and loading with doxorubicin (DOX). Compared to the PC solution, the storage-stability and photostability of PC particles were remarkably increased, and the formation of nanoparticles further improved its biostability. Besides, CLSM images confirmed that LA could also enhance cellular uptake, resulting in more intracellular PC and DOX accumulation. MTT assay revealed that LAPC/DOX caused the highest cytotoxicity by combined chemo-photodynamic therapy. Finally, LAPC/DOX could efficiently accumulate and spread in tumoral multicellular spheroids, resulting in the enhanced growth inhibition. Overall, the LAPC/DOX is effective in cancer treatment, which provides new insights for the usage of functional proteins in vivo.

Cyanobacterial pigment protein allophycocyanin exhibits longevity and reduces Aβ-mediated paralysis in C. elegans: complicity of FOXO and NRF2 ortholog DAF-16 and SKN-1

The allophycocyanin (APC) protein purified from Phormidium sp. A09DM was investigated for its in vivo antioxidant and anti-aging potential in Caenorhabditis elegans. An increased mean lifespan of APC-treated (100 μg/ml) worms (wild type) were observed from 16 ± 0.2 days (control) to 20 ± 0.1 days (treated). APC-treated worms also showed improved physiological marker of aging such as the rate of pharyngeal pumping and higher rate of survival against oxidative and thermal stress. Furthermore, APC was found to moderate the expression of human amyloid beta (Aβ1-42) as well as associated Aβ-induced paralysis in the transgenic C. elegans CL4176 upon increase in temperature. Furthermore, RNA interference (RNAi)-mediated studies revealed the dependence of downstream regulator daf-16, independent of stress-induced resistance gene skn-1 in the APC treated C. elegans. In the present study, we tried to demonstrate the anti-aging activity, longevity and protective effects of APC against cellular stress in C. elegans, which can lead to the use of this biomolecule in drug development for age-related disorders.

Advances in the Biotechnological Potential of Brazilian Marine Microalgae and Cyanobacteria

Due the worldwide need to improve care for the environment and people, there is a great demand for the development of new renewable, sustainable, and less polluting technologies for food, health, and environmental industries. The marine environment is one of the main areas investigated in the search for alternatives to the raw materials currently used. Thereby, cyanobacteria and marine microalgae are microorganisms that are capable of producing a diverse range of metabolites useful for their cellular maintenance, but that also represent a great biotechnological potential. Due its great potential, they have an enormous appeal in the scientific research where, the biological activity of metabolites produced by these microorganisms, such as the antioxidant action of sterols are, some examples of biotechnological applications investigated around the world. Thereby, Brazil due to its extensive biodiversity, has high potential as a raw material supplier of marine waters, researching cyanobacteria and microalgae metabolites and their applications. Thus, this rapid review intends to present some important contributions and advances from Brazilian researchers, using the biomass of Brazilian cyanobacteria and marine microalgae, in order to illustrate the value of what has already been discovered and the enormous potential of what remains unexplored so far.

A Comprehensive Review of the Nutraceutical and Therapeutic Applications of Red Seaweeds (Rhodophyta)

The red seaweed group (Rhodophyta) is one of the phyla of macroalgae, among the groups Phaeophyceae and Chlorophyta, brown and green seaweeds, respectively. Nowadays, all groups of macroalgae are getting the attention of the scientific community due to the bioactive substances they produce. Several macroalgae products have exceptional properties with nutraceutical, pharmacological, and biomedical interest. The main compounds studied are the fatty acids, pigments, phenols, and polysaccharides. Polysaccharides are the most exploited molecules, which are already widely used in various industries and are, presently, entering into more advanced applications from the therapeutic point of view. The focuses of this review are the red seaweeds' compounds, its proprieties, and its uses. Moreover, this work discusses new possible applications of the compounds of the red seaweeds.

Synthesis, Characterization, and Evaluation of Redox-Sensitive Chitosan Oligosaccharide Nanoparticles Coated with Phycocyanin for Drug Delivery

In this paper, a type of phycocyanin (PC)-functionalized and curcumin (CUR)-loaded biotin-chitosan oligosaccharide-dithiodipropionic acid-curcumin (BCSC) nanoparticles, called CUR-BCSC@PCs, were designed to enhance the biocompatibility of CUR. The structure of BCSC was confirmed using ¹H-NMR. In CUR-BCSC@PCs with an average hydrodynamic diameter of 160.3 ± 9.0 nm, the biomimetic protein corona gave the nanoparticles excellent stability and the potential to avoid protein adsorption in blood circulation. The in vitro release experiment verified that CUR-BCSC@PCs with redox responsive shells were sensitive to high concentrations of glutathione. In addition, CUR-BCSC@PCs were effective at increasing the inhibitory activity on the proliferation of A549 cells by enhancing the intracellular uptake of CUR. These results indicated that CUR-BCSC@PCs have great application prospects in cancer therapy as effective drug delivery carriers.

EU Project of LIFE Programme ‘Algae Service for LIFE’ Develops Ecologicaly Sustainable Bioproducts from Freshwater Cyanobacteria and Macroalgae Biomas

‘Algae Service for LIFE’, the project supported by the European Union, seeks to promote best practices in ecological service and the circular economy by implementing innovative complex system of three interlinked elements: i) prototypes for harvesting of cyanobacteria and macroalgae biomass; ii) distant methods for surveying of the blooms and defining hot-spots of algal agglomerations; and iii) restitution of harvesting costs by redesigning of waste algal biomass into valuable products. The current paper describes application of algal biomass part of the project by providing actions in redesigning of harvested waste biomass of cyanobacteria and macroalgae into potential valuable products for sustainable management and recycling of environmental resources. It also highlights the socio-economic aspects of the project and added value of the project for the European Union.

Phycocyanin Ameliorates Radiation-Induced Acute Intestinal Toxicity by Regulating the Effect of the Gut Microbiota on the TLR4/Myd88/NF-κB Pathway

BACKGROUND

Radiation-induced gastrointestinal syndrome, including nausea, diarrhea, and dehydration, contributes to morbidity and mortality after medical or industrial radiation exposure, which seriously affects patient quality of life after treatment. No safe and effective radiation countermeasure has been approved for clinical therapy. In this study, we aimed to investigate the potential protective effects of phycocyanin (PC) against radiation-induced acute intestinal injury.

MATERIALS AND METHODS

C57BL/6 mice were orally administered 50 mg/kg PC once per day for 1 month before exposure to total-abdominal x-ray irradiation at a single dose of 12 Gy. The effects of PC on intestinal histopathology and integrity, gut microbiota, lipopolysaccharides (LPS), inflammatory cytokines, and Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (Myd88)/nuclear factor κB (NF-κB) signaling were evaluated.

RESULTS

Severe histopathological damage, such as intestinal mucosal epithelial cell apoptosis, necrosis, and nuclear rupture, was most clearly observed 24 hours after total-abdominal x-ray irradiation. Intestinal integrity was damaged by irradiation, which manifested in reduced levels of the tight-junction proteins Claudin-1, Occludin, and zonula occludens-1(ZO-1). PC pretreatment significantly ameliorated radiation-induced intestinal injury. PC also modulated the gut microbiota composition, increasing the proportion of beneficial bacteria and decreasing that of harmful bacteria, which in turn lowered LPS levels and suppressed TLR4/Myd88/NF-κB pathway activation. Finally, levels of corresponding inflammatory cytokines, including tumor necrosis factor α and interleukin-6, were also downregulated.

CONCLUSION

PC protects against mouse intestinal injury from high-dose radiation by regulating the effect of the gut microbiota on the TLR4/Myd88/NF-κB pathway, suggesting PC as a promising natural radiation countermeasure.

Multiproduct biorefinery from Arthrospira spp. towards zero waste: Current status and future trends

Considering the high- and low-value product perspectives, Arthrospira spp. are one of the most industrially exploited microalgae. However, currently, the biomass is being utilized for one specific product resulting in a steep upsurge in the overall production cost. Hence, to boost the economic viability of Arthrospira biorefinery process, every high- and low-value products from it ought to be valorized. Envisioning how costlier can be the multiproduct biorefinery concept owing to the downstream processing at an industrial scale, it is quite essential to look for new trends and encouraging solutions. This article intended to propose a sustainable biorefinery in the wake of the current understanding of the present constraints and challenges associated with Arthrospira biorefinery. The current review aimed at defining the future aspects of this biorefinery including integration and optimization of the culture strategy, and, implementation of new ingenious techniques to improve downstream processing (harvesting, extraction, fractionation, and purification).

Targeted delivery of phycocyanin for the prevention of colon cancer using electrospun fibers

Phycocyanin (PC), a water-soluble biliprotein, exhibits potent anti-colon cancer properties. However, its application in functional foods is limited by the poor stability and low bioavailability of PC. In this study, we successfully encapsulated PC by coaxial electrospinning. The colon targeted release of PC was achieved with retention of the antioxidant activity of PC. The PC-loaded electrospun fiber mat (EFM) obtained inhibited HCT116 cell growth in a dose-dependent and time-dependent manner. In particular, the PC-loaded EFM exerted its anti-cancer activity by blocking the cell cycle at the G0/G1 phase and inducing cell apoptosis involving the decrease of Bcl-2/Bax, activation of caspase 3 and release of cytochrome c. This study suggests that co-axial electrospinning is an efficient and effective way to deliver PC and improve its bioavailability; thus, it represents a promising approach for encapsulating functional ingredients for colon cancer prevention.

Development of a novel method for the purification of C-phycocyanin pigment from a local cyanobacterial strain Limnothrix sp. NS01 and evaluation of its anticancer properties

C-phycocyanin (C-PC) pigment, as a natural blue dye, has particular applications in various fields. It is a water-soluble protein which has anticancer, antioxidant and anti-inflammatory properties. Here, we introduce an efficient procedure for the purification of C-PC pigment, followed by conducting a comprehensive investigation of its cytotoxic effects on human breast cancer (MCF-7) cells and the underlying mechanisms. A novel four-step purification procedure including the adsorption of impurities with chitosan, activated charcoal, ammonium sulfate precipitation, and ion exchange chromatography was employed, achieving a high purity form of C-PC with purity index (PI) of 5.26. SDS-PAGE analysis showed the purified C-PC with two discrete bands, subunit α (17 kD) and β (20 kD), as confirmed its identity by Native-PAGE. A highly purified C-PC was employed to evaluate its anticancer activity and underlying molecular mechanisms of action. The inhibitory effects of highly purified C-PC on the proliferation of human breast cancer cells (MCF-7) have detected by MTT assay. The IC50 values for 24, 48, and 72 hours of exposure to C-PC were determined to be 5.92, 5.66, and 4.52 μg/μl, respectively. Flow cytometric analysis of cells treated with C-PC, by Annexin V/PI double staining, demonstrated to induce MCF-7 cells apoptosis. Also, the results obtained from propidium iodide (PI) staining showed that MCF-7 cells treated with 5.92 μg/μl C-PC for 24 h would arrest at the G2 phase and 5.66 and 4.52 μg/μl C-PC for 48 and 72 h could induce cell cycle arrest at both G2 and S phases. The oxidative damage and mitochondrial dysfunction were evaluated to determine the possible pathways involved in C-PC-induced apoptosis in MCF-7 cells. Our findings clearly indicated that the treatment of MCF-7 cells with C-PC (IC50 for 24 h) increased the production of reactive oxygen species (ROS). Consequently, an increase in the lipid peroxidation (LPO) level and a reduction in the ATP level, mitochondrial membrane potential (MMP), glutathione (GSH) and its oxidized form (GSSG), occurred over time. The reduced expression levels of anti-apoptotic proteins, Bcl2 and Stat3, plus cell cycle regulator protein, Cyclin D1, using Real-Time PCR confirm that the C-PC-induced death of MCF-7 human breast cancer cells occurred through the mitochondrial pathway of apoptosis. Collectively, the analyses presented here suggest that C-PC has the potential so that to develop it as a chemotherapeutic anticancer drug.

Evaluation of the taxonomic and functional variation of freshwater plankton communities induced by trace amounts of the antibiotic ciprofloxacin

Ciprofloxacin (CIP), one of the most frequently detected antibiotics in water systems, has become an aquatic contaminant because of improper disposal and excretion by humans and animals. It is still unknown how trace amounts of CIP affect the aquatic microbial community diversity and function. We therefore investigated the effects of CIP on the structure and function of freshwater microbial communities via 16S/18S rRNA gene sequencing and metatranscriptomic analyses. CIP treatment (7 μg/L) did not significantly alter the physical and chemical condition of the water body as well as the composition of the main species in the community, but slightly increased the relative abundance of cyanobacteria and decreased the relative abundance of eukaryotes. Metatranscriptomic results showed that bacteria enhanced their phosphorus transport and photosynthesis after CIP exposure. The replication, transcription, translation and cell proliferation were all suppressed in eukaryotes, while the bacteria were not affected in any of these aspects. This interesting phenomenon was the exact opposite to both the antibacterial property of CIP and its safety for eukaryotes. We hypothesize that reciprocal and antagonistic interactions in the microcosm both contribute to this result: cyanobacteria may enhance their tolerance to CIP through benefiting from cross-feeding and some secreted substances that withstand bacterial CIP stress would also affect eukaryotic growth. The present study thus indicates that a detailed assessment of the aquatic ecotoxicity of CIP is essential, as the effects of CIP are much more complicated in microbial communities than in monocultures. CIP will continue to be an environmental contaminant due to its wide usage and production and more attention should be given to the negative effects of antibiotics as well as other bioactive pollutants on aquatic environments.

Mexican Microalgae Biodiversity and State-Of-The-Art Extraction Strategies to Meet Sustainable Circular Economy Challenges: High-Value Compounds and Their Applied Perspectives

In recent years, the demand for naturally derived products has hiked with enormous pressure to propose or develop state-of-the-art strategies to meet sustainable circular economy challenges. Microalgae possess the flexibility to produce a variety of high-value products of industrial interests. From pigments such as phycobilins or lutein to phycotoxins and several polyunsaturated fatty acids (PUFAs), microalgae have the potential to become the primary producers for the pharmaceutical, food, and agronomical industries. Also, microalgae require minimal resources to grow due to their autotrophic nature or by consuming waste matter, while allowing for the extraction of several valuable side products such as hydrogen gas and biodiesel in a single process, following a biorefinery agenda. From a Mexican microalgae biodiversity perspective, more than 70 different local species have been characterized and isolated, whereas, only a minimal amount has been explored to produce commercially valuable products, thus ignoring their potential as a locally available resource. In this paper, we discuss the microalgae diversity present in Mexico with their current applications and potential, while expanding on their future applications in bioengineering along with other industrial sectors. In conclusion, the use of available microalgae to produce biochemically revenuable products currently represents an untapped potential that could lead to the solution of several problems through green technologies. As such, if the social, industrial and research communities collaborate to strive towards a greener economy by preserving the existing biodiversity and optimizing the use of the currently available resources, the enrichment of our society and the solution to several environmental problems could be attained.

Synthesizing, characterizing, and toxicity evaluating of Phycocyanin-ZnO nanorod composites: A back to nature approaches

C-Phycocyanin pigment was purified from a native cyanobacterial strain using a novel consecutive multi-step procedure and utilized for the first time for the green synthesis of phycocyanin-zinc oxide nanorods (PHY-ZnO NRs) by a simple, low-cost and eco-friendly approach. The PHY-ZnO NRs were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), zeta potential measurement, FTIR, SEM, TEM, differential scanning calorimetry (DSC), thermogravimetric (TGA), and EDX spectroscopy analysis. The UV-vis spectra showed an absorption band at 364 nm which is characteristic of ZnO nanoparticles (ZnONPs). The rod-shaped PHY-ZnO NRs observed in the TEM and SEM images had an average diameter size of 33 nm, which was in good agreement with the size calculated by XRD. The elemental analysis of PHY-ZnO NRs composition showed that three emission peaks of zinc metal and one emission peak of oxygen comprised 33.88% and 42.50%, respectively. The thermogram of PHY-ZnO NRs sample exhibited the weight loss of biosynthesized nanoparticles registered to be 3%, emphasizing the purity and heat stability of zinc oxide nanorods coated with phycocyanin pigment-protein. MTT assay indicated that PHY-ZnO NRs had a less cytotoxicity on fibroblast L929 compared to the ZnONRs-treated cells. A remarkable increase in ROS level was measured in cells treated with ZnO at final concentrations of 100, 200 and 500 μg/ml (78 ± 7, 99 ± 8 and 116 ± 11, respectively). When it comes to PHY-ZnO NRs, a protective effect for phycocyanin was detected which declined the level of ROS content as confirmed by fluorescent microscopy. The distinctive features of phycocyanin for surface functionalization of ZnO nanoparticles deserve to be deemed as a nano-drug candidate for further researches.

Analytical Grade Purification of Phycocyanin from Cyanobacteria

Phycocyanin is a blue-colored pigment-protein complex that exhibits numerous biofunctions such as anti-inflammation, antioxidation, antitumor, neuroprotective effect, and immunological enhancement. Purified phycocyanin has pharmaceutical and nutraceutical applications. In addition, as a nontoxic and non-carcinogenic natural coloring agent, phycocyanin has many applications in the food and cosmetic industries. This chapter describes a protocol for extraction and analytical grade purification of phycocyanin from cyanobacteria. The purification steps include (1) extraction of phycocyanin from biomass, (2) ammonium sulfate precipitation of phycocyanin and dialysis, and (3) purification of phycocyanin by gel filtration and ion-exchange chromatography.