Nutraceutical and therapeutic potential of Phycocyanobilin for treating Alzheimer’s disease

Enhancing Phycocyanobilin Production Efficiency in Engineered Corynebacterium glutamicum: Strategies and Potential Application

Phycocyanobilin, an algae-originated light-harvesting pigment known for its antioxidant properties, has gained attention as it plays important roles in the food and medication industries and has surged in demand owing to its low-yield extraction from natural resources. In this study, engineered Corynebacterium glutamicum was developed to achieve high PCB production, and three strategies were proposed: reinforcement of the heme biosynthesis pathway with the introduction of two PCB-related enzymes, strengthening of the pentose phosphate pathway to generate an efficient cycle of NADPH, and fed-batch fermentation to maximize PCB production. Each approach increased PCB synthesis, and the final engineered strain successfully produced 78.19 mg/L in a flask and 259.63 mg/L in a 5 L bioreactor, representing the highest bacterial production of PCB reported to date, to our knowledge. The strategies applied in this study will be useful for the synthesis of PCB derivatives and can be applied in the food and pharmaceutical industries.

Exploiting Natural Niches with Neuroprotective Properties: A Comprehensive Review

Natural products from mushrooms, plants, microalgae, and cyanobacteria have been intensively explored and studied for their preventive or therapeutic potential. Among age-related pathologies, neurodegenerative diseases (such as Alzheimer's and Parkinson's diseases) represent a worldwide health and social problem. Since several pathological mechanisms are associated with neurodegeneration, promising strategies against neurodegenerative diseases are aimed to target multiple processes. These approaches usually avoid premature cell death and the loss of function of damaged neurons. This review focuses attention on the preventive and therapeutic potential of several compounds derived from natural sources, which could be exploited for their neuroprotective effect. Curcumin, resveratrol, ergothioneine, and phycocyanin are presented as examples of successful approaches, with a special focus on possible strategies to improve their delivery to the brain.

Progress on the Extraction, Separation, Biological Activity, and Delivery of Natural Plant Pigments

Natural plant pigments are safe and have low toxicity, with various nutrients and biological activities. However, the extraction, preservation, and application of pigments are limited due to the instability of natural pigments. Therefore, it is necessary to examine the extraction and application processes of natural plant pigments in detail. This review discusses the classification, extraction methods, biological activities, and modification methods that could improve the stability of various pigments from plants, providing a reference for applying natural plant pigments in the industry and the cosmetics, food, and pharmaceutical industries.

The Bioactivities of Phycocyanobilin from Spirulina

Phycocyanobilin (PCB) is a linear open-chain tetrapyrrole chromophore that captures and senses light and a variety of biological activities, such as anti-oxidation, anti-cancer, and anti-inflammatory. In this paper, the biological activities of PCB are reviewed, and the related mechanism of PCB and its latest application in disease treatment are introduced. PCB can resist oxidation by scavenging free radicals, inhibiting the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and delaying the activity of antioxidant enzymes. In addition, PCB can also be used as an excellent anti-inflammatory agent to reduce the proinflammatory factors IL-6 and IFN-γ and to up-regulate the production of anti-inflammatory cytokine IL-10 by inhibiting the inflammatory signal pathways NF-κB and mitogen-activated protein kinase (MAPK). Due to the above biological activities of phycocyanobilin PCB, it is expected to become a new effective drug for treating various diseases, such as COVID-19 complications, atherosclerosis, multiple sclerosis (MS), and ischaemic stroke (IS).

Efficient Synthesis of Phycocyanobilin by Combinatorial Metabolic Engineering in Escherichia coli

Phycocyanobilin (PCB) is a kind of light-harvesting pigment which naturally exists in algae and plays important roles in absorbing and transferring energy. Based on its antioxidant and optical properties, PCB has been applied in food, medicine, and cosmetics. Currently, PCB is mainly extracted from Spirulina through complicated steps; thus, the biosynthesis of PCB in Escherichia coli has attracted more attention. However, due to the lower catalytic efficiency of synthetic enzymes and the deficiency of precursors and cofactors, the titer of PCB remains at a low level. Here, we report the efficient synthesis of PCB by the expression of heme oxygenase-1 from Thermosynechococcus elongatus and PCB: ferredoxin oxidoreductase (PcyA) from Synechocystis sp. using a high-copy number plasmid with an inducible T7lac promoter and the assembly of these two enzymes at a suitable ratio of 2:1 with DNA scaffolds. Additionally, the synthesis of PCB was further enhanced by direct supplementation of 5-aminolevulinic acid (ALA), moderate overexpression of key enzymes in the heme biosynthetic pathway (hemB and hemH), and accelerated cycle of cofactors (NADPH) through the expression of NAD⁺ kinase and the addition of a reducing agent. Finally, based on the optimal conditions (Modified R medium with 200 mg/L ALA, 20 mg/L FeSO₄·7H₂O, and 5 g/L vitamin C induced by 0.8 mM isopropylthio-β-galactoside at 30 °C), the highest reported titer of PCB (28.32 mg/L) was obtained at the fermenter level by feeding glucose and FeSO₄·7H₂O. The strategies applied in this study will be useful for the synthesis of other natural pigments and PCB or heme derivatives in E. coli.

Beneficial Effects of Spirulina Consumption on Brain Health

Spirulina is a microscopic, filamentous cyanobacterium that grows in alkaline water bodies. It is extensively utilized as a nutraceutical food supplement all over the world due to its high levels of functional compounds, such as phycocyanins, phenols and polysaccharides, with anti-inflammatory, antioxidant, immunomodulating properties both in vivo and in vitro. Several scientific publications have suggested its positive effects in various pathologies such as cardiovascular diseases, hypercholesterolemia, hyperglycemia, obesity, hypertension, tumors and inflammatory diseases. Lately, different studies have demonstrated the neuroprotective role of Spirulina on the development of the neural system, senility and a number of pathological conditions, including neurological and neurodegenerative diseases. This review focuses on the role of Spirulina in the brain, highlighting how it exerts its beneficial anti-inflammatory and antioxidant effects, acting on glial cell activation, and in the prevention and/or progression of neurodegenerative diseases, in particular Parkinson’s disease, Alzheimer’s disease and Multiple Sclerosis; due to these properties, Spirulina could be considered a potential natural drug.

Challenges and hopes for Alzheimer's disease

Recent drug development efforts targeting Alzheimer's disease (AD) have failed to produce effective disease-modifying agents for many reasons, including the substantial presymptomatic neuronal damage that is caused by the accumulation of the amyloid β (Aβ) peptide and tau protein abnormalities, deleterious adverse effects of drug candidates, and inadequate design of clinical trials. New molecular targets, biomarkers, and diagnostic techniques, as well as alternative nonpharmacological approaches, are sorely needed to detect and treat early pathological events. This article analyzes the successes and debacles of pharmaceutical endeavors to date, and highlights new technologies that may lead to the more effective diagnosis and treatment of the pathologies that underlie AD. The use of focused ultrasound, deep brain stimulation, stem cell therapy, and gene therapy, in parallel with pharmaceuticals and judicious lifestyle adjustments, holds promise for the deceleration, prevention, or cure of AD and other neurodegenerative disorders.

Phycobiliproteins: Structural aspects, functional characteristics, and biotechnological perspectives

Phycobiliproteins (PBPs) are fluorescent proteins of various colors, including fuchsia, purple-blue and cyan, that allow the capture of light energy in auxiliary photosynthetic complexes called phycobilisomes (PBS). PBPs have several highly preserved structural and physicochemical characteristics. In the PBS context, PBPs function is capture luminous energy in the 450–650 nm range and delivers it to photosystems allowing photosynthesis take place. Besides the energy harvesting function, PBPs also have shown to have multiple biological activities, including antioxidant, antibacterial and antitumours, making them an interesting focus for different biotechnological applications in areas like biomedicine, bioenergy and scientific research. Nowadays, the main sources of PBPs are cyanobacteria and micro and macro algae from the phylum Rhodophyta. Due to the diverse biological activities of PBPs, they have attracted the attention of different industries, such as food, biomedical and cosmetics. This is why a large number of patents related to the production, extraction, purification of PBPs and their application as cosmetics, biopharmaceuticals or diagnostic applications have been generated, looking less ecological impact in the natural prairies of macroalgae and less culture time or higher productivity in cyanobacteria to satisfy the markets and applications that require high amounts of these molecules. In this review, we summarize the main structural characteristics of PBPs, their biosynthesys and biotechnological applications. We also address current trends and future perspectives of the PBPs market.

The Effect of C-Phycocyanin on Microglia Activation Is Mediated by Toll-like Receptor 4

The blue-green alga Spirulina platensis is rich in phycocyanins, that exhibit a wide range of pharmacological actions. C-phycocyanin (C-PC), in particular, possesses hepatoprotective, nephroprotective, antioxidant, and anticancer effects. Furthermore, several studies have reported both anti- and proinflammatory properties of this pigment. However, the precise mechanism(s) of action of C-PC in these processes remain largely unknown. Therefore, here we explored the C-PC effect in in vitro microglia activation. The effect of C-PC on the expression and release of IL-1β and TNF-α and the activation of NF-κB was examined in primary microglia by real-time PCR, ELISA, and immunofluorescence. Treatment with C-PC up-regulated the expression and release of IL-1β and TNF-α. C-PC also promoted the nuclear translocation of the NF-κB transcription factor. Then, to elucidate the molecular mechanisms for the immunoregulatory function of C-PC, we focused on investigating the role of Toll-like receptor 4 (TLR4). Accordingly, several TLR4 inhibitors have been used. Curcumin, ciprofloxacin, L48H37, and CLI-095 that suppresses specifically TLR4 signaling, blocked IL-1β and TNF-α. Overall, these results indicate the immunomodulatory effect of C-PC in microglia cultures and show for the first time that the molecular mechanism implicated in this effect may involve TLR4 activation.

Phycocyanin Ameliorates Mouse Colitis via Phycocyanobilin-Dependent Antioxidant and Anti-Inflammatory Protection of Intestinal Epithelial Barrier

Phycocyanin is a typical microalgal active compound with antioxidant and anti-inflammatory efficacy, and the pigment moiety phycocyanobilin has been recently proposed as its active structural component. Here, to explore the...