In vitro multifunctionality of phlorotannin extracts from edible Fucus species on targets underpinning neurodegeneration

A Narrative Review on the Neuroprotective Potential of Brown Macroalgae in Alzheimer's Disease

Systematic Alzheimer's disease (AD) is a neurodegenerative disease increasingly prevalent in the aging population. AD is characterized by pathological features such as β-amyloid (Aβ) plaque accumulation, tau neurofibrillary tangles formation, oxidative stress, an impaired cholinergic system, and neuroinflammation. Many therapeutic drugs have been developed to slow the progression of AD by targeting these pathological mechanisms. However, synthetic drugs, such as donepezil and memantine, can often lead to side effects. In this context, seaweeds have been drawing attention as a nutrient source and a potential source of health-improving metabolites. Studies have shown that extracts from brown macroalgae can potentially reduce the inflammation associated with neurodegenerative diseases by inhibiting proinflammatory cytokine expression. Furthermore, their bioactive compounds exhibit antioxidant properties vital in combating oxidative stress. Antioxidants, mainly carotenoids and phenolic compounds, have been linked to improved cognitive function and a reduced risk of neurodegenerative disorders by protecting neuronal cells through their ability to scavenge free radicals. In addition, omega-3 fatty acids found in certain macroalgae have the potential to support brain health and cognitive function, further enhancing their neuroprotective effects. In conclusion, this review has comprehensively evaluated the research conducted on brown macroalgae in the last five years, covering their potential bioactive compounds, methods of obtaining these compounds, and their neuroprotective properties against AD. The limited number of clinical studies in the literature highlights the need for further research. This narrative review provides a basic framework for new approaches to neuroprotective strategies, such as those associated with brown macroalgae natural resources. Furthermore, they may play an increasingly important role in developing functional foods and nutraceuticals that can support human health in preventing and managing neurodegenerative diseases.

Revealing the Potential of Fucus vesiculosus Linnaeus for Cosmetic Purposes: Chemical Profile and Biological Activities of Commercial and Wild Samples

The natural products industry is gaining increasing interest, not only due to modern lifestyles becoming more aware of environmental and sustainability issues but also because of the loss of efficacy and undesirable side effects of synthetic ingredients. This pioneering study provides a comprehensive comparison between extracts obtained from wild and commercial samples of Fucus vesiculosus Linnaeus, highlighting their multifaceted benefits in cosmetic applications. The antiaging potential of acetone (70 and 90%) and ethanol 60% extracts from wild and commercial samples of F. vesiculosus, focusing on their application in cosmetics, was explored. The extracts were chemically characterized, their carotenoid profiles being established by HPLC, and the total phenolic content and phlorotannins by spectrophotometry. The extracts were evaluated for their antioxidant potential against the physiologic free radicals superoxide anion radical (O2•-) and nitric oxide (•NO), for their ability to inhibit the enzymes hyaluronidase and tyrosinase, and for their anti-inflammatory potential in the macrophage cell model RAW 264.7. The acetone 70% extract of wild F. vesiculosus was the richest in fucoxanthin, which accounted for more than 67% of the total pigments identified, followed by the acetone 90% extract of the same sample, where both fucoxanthin and pheophytin-a represented 40% of the total pigments. The same behavior was observed for phenolic compounds, with the ethanol 60% presenting the lowest values. A chemical correlation could be established between the chemical composition and the biological activities, with acetone extracts from the wild F. vesiculosus, richer in fucoxanthin and phlorotannins, standing out as natural ingredients with anti-aging potential. Acetone 90% can be highlighted as the most effective extraction solvent, their extracts presenting the highest radicals scavenging capacity, ability to inhibit tyrosinase to a greater extent than the commercial ingredient kojic acid, and potential to slow down the inflammatory process.

Cytotoxicity, chemical, and nutritional profile evaluation of biomass extracts of the Lemna aequinoctialis (duckweed) aquatic plant

Lemna aequinoctialis (duckweed) is the smallest and fast-growing aquatic plant species producing protein-rich biomass with high protein nutritional value, phytoremediation capacity, and nutrient removal from wastewater. Duckweed may also be used as a new potential bioreactor for biological products, such as vaccines, antibodies, and pharmaceutical proteins. Based upon the potential importanc of L. aequinoctialis in phytoremediation and as a bioreactor the aim of this study was to (1) characterize the chemical and nutritional profiles of L. aequinoctialis biomass utilizing an integrated multi-trophic aquaculture system (IMTA) and a pond, and (2) investigate the cytotoxic potential of different concentrations of organic extracts and fractions using the MTT bioassay. EDXRF and ICP-MS analyses indicated the presence of trace elements in lower amounts in relation to the biomass of L. aequinoctialis in the lagoon, emphasizing the importance of plant inclusion management to reduce bioaccumulation of these elements. Analysis of mineral profiles, fatty acids, and amino acids indicated a satisfactory nutritional composition for the use of biomass as a bioproduct. Pigment analysis showed a high concentration of carotenoids, especially astaxanthin. After standardizing the controls, the MTT cell viability test was carried out utilizing rat hepatoma cell line (HTC), which are metabolizing cells that were treated with aqueous or ethanolic extracts and the dichloromethane, ethyl acetate, and methanol fractions at different concentrations. No apparent cytotoxic potential was observed following treatments, since there was no significant reduction in cell viability. Therefore, this study provides information regarding the biomass of L. aequinoctialis derived from the IMTA system, which might support further research into the application of this species as a bioproduct.

Red Grape By-Products from the Demarcated Douro Region: Chemical Analysis, Antioxidant Potential and Antimicrobial Activity against Food-Borne Pathogens

Wine production is one of the most important agricultural activities. The winemaking process generates a considerable volume of different residues characterized as by-products, such as pomace, seeds, stems, and skins. By-products are rich in polyphenols with antioxidant and antibacterial properties and may act as bacteriostatic or bactericidal agents against food-borne pathogens, improving food safety by enhancing antibiotic efficacy and reducing bacterial resistance. The aim of this study was to evaluate the phenolic composition and antioxidant activity of grape components (skins, seeds, and stems) from three red grape varieties (Periquita, Gamay, and Donzelinho Tinto) and determine their antibacterial activity against antibiotic-resistant bacteria, including Escherichia coli in food-producing animals and Listeria monocytogenes from food products and food-related environments. Ten phenolic compounds were quantified in these red grape varieties, with specific compounds found in different parts of the grape, including phenolic acids and flavonoids. Flavonoids are abundant in seeds and stems, malvidin-3-O-glucoside being the main anthocyanin in skins. The ethanolic extract from the seeds showed in vitro concentration-dependent activity against reactive species like •NO and O2•-. Gamay extract was the most effective, followed by Donzelinho Tinto and Periquita. Extracts showed varying antibacterial activity against Gram-positive and Gram-negative bacteria, with stronger effects on Gram-positive bacteria. L. monocytogenes was more susceptible, while E. coli was limited to three strains. Seeds exhibited the strongest antibacterial activity, followed by stems. The results of our study provide evidence of the potential of grape by-products, particularly seeds, as sources of bioactive compounds with antioxidant and antibacterial properties, offering promising avenues for enhancing food safety and combating antibiotic resistance in food production and related environments.

Chemical Composition and Antioxidant Potential of Five Algae Cultivated in Fully Controlled Closed Systems

In this study, the chemical composition and antioxidant profile of five edible macroalgae, Fucus vesiculosus, Palmaria palmata, Porphyra dioica, Ulva rigida, and Gracilaria gracilis, cultivated in fully controlled closed systems, were determined. Protein, carbohydrates, and fat contents ranged between 12.4% and 41.8%, 27.6% and 42.0%, and 0.1% and 3.4%, respectively. The tested seaweeds presented considerable amounts of Ca, Mg, K, Mn, and Fe, which reinforce their favorable nutritional profile. Regarding their polysaccharide composition, Gracilaria gracilis and Porphyra dioica were rich in sugars common to agar-producing red algae, and Fucus vesiculosus was composed mainly of uronic acids, mannose, and fucose, characteristic of alginate and fucoidans, whereas rhamnose and uronic acid, characteristic of ulvans, predominated in Ulva rigida. Comparatively, the brown F. vesiculosus clearly stood out, presenting a high polysaccharide content rich in fucoidans, and higher total phenolic content and antioxidant scavenging activity, determined by DPPH and ABTS. The remarkable potential of these marine macroalgae makes them excellent ingredients for a wide range of health, food, and industrial applications.

Marine Macroalgae Polyphenols as Potential Neuroprotective Antioxidants in Neurodegenerative Diseases

Polyphenols are beneficial natural compounds with antioxidant properties that have recently gain a lot of interest for their potential therapeutic applications. Marine polyphenols derived from marine macroalgae have been discovered to possess interesting antioxidant properties; therefore, these compounds can be included in several areas of drug development. Authors have considered the use of polyphenol extracts from seaweeds as neuroprotective antioxidants in neurodegenerative diseases. Marine polyphenols may slow the progression and limit neuronal cell loss due to their antioxidant activity; therefore, the use of these natural compounds would improve the quality of life for patients affected with neurodegenerative diseases. Marine polyphenols have distinct characteristics and potential. Among seaweeds, brown algae are the main sources of polyphenols, and present the highest antioxidant activity in comparison to red algae and green algae. The present paper collects the most recent in vitro and in vivo evidence from investigations regarding polyphenols extracted from seaweeds that exhibit neuroprotective antioxidant activity. Throughout the review, oxidative stress in neurodegeneration and the mechanism of action of marine polyphenol antioxidant activity are discussed to evidence the potential of algal polyphenols for future use in drug development to delay cell loss in patients with neurodegenerative disorders.

Saccorhiza polyschides-A Source of Natural Active Ingredients for Greener Skincare Formulations

The growing knowledge about the harmful effects caused by some synthetic ingredients present in skincare products has led to an extensive search for natural bioactives. Thus, this study aimed to investigate the dermatological potential of five fractions (F1-F5), obtained by a sequential extraction procedure, from the brown seaweed Saccorhiza polyschides. The antioxidant (DPPH, FRAP, ORAC and TPC), anti-enzymatic (collagenase, elastase, hyaluronidase and tyrosinase), antimicrobial (Staphylococcus epidermidis, Cutibacterium acnes and Malassezia furfur), anti-inflammatory (nitric oxide, tumor necrosis factor-α, interleukin-6 and interleukin-10) and photoprotective (reactive oxygen species) properties of all fractions were evaluated. The ethyl acetate fraction (F3) displayed the highest antioxidant and photoprotective capacity, reducing ROS levels in UVA/B-exposed 3T3 fibroblasts, and the highest anti-enzymatic capacity against tyrosinase (IC50 value: 89.1 µg/mL). The solid water-insoluble fraction (F5) revealed the greatest antimicrobial activity against C. acnes growth (IC50 value: 12.4 µg/mL). Furthermore, all fractions demonstrated anti-inflammatory potential, reducing TNF-α and IL-6 levels in RAW 264.7 macrophages induced with lipopolysaccharides. Chemical analysis of the S. polyschides fractions by NMR revealed the presence of different classes of compounds, including lipids, polyphenols and sugars. The results highlight the potential of S. polyschides to be incorporated into new nature-based skincare products.

Effect-directed analysis in food by thin-layer chromatography assays

Thin-layer chromatography (TLC) is widely used for food analysis and quality control. As an open chromatographic system, TLC is compatible with microbial-, biochemical-, and chemical-based derivatization methods. This compatibility makes it possible to run in situ bioassays directly on the plate to obtain activity-profile chromatograms, i.e., the effect-directed analysis of the sample. Many of the properties that can be currently measured using this assay format are related to either desired or undesired features for food related products. The TLC assays can detect compounds related to the stability of foods (antioxidant, antimicrobial, antibrowning, etc.), contaminants (antibiotics, pesticides, estrogenic compounds, etc.), and compounds that affect the absorption, metabolism or excretion of nutrients and metabolites or could improve the consumers health (enzyme inhibitors). In this article, different food related TLC-assays are reviewed. The different detection systems used, the way in which they are applied as well as selected examples are discussed.

Recent advances in biological properties of brown algae-derived compounds for nutraceutical applications

The increasing demand for nutraceuticals in the circular economy era has driven the research toward studying bioactive compounds from renewable underexploited resources. In this regard, the exploration of brown algae has shown significant growth and maintains a great promise for the future. One possible explanation could be that brown algae are rich sources of nutritional compounds (polyunsaturated fatty acids, fiber, proteins, minerals, and vitamins) and unique metabolic compounds (phlorotannins, fucoxanthin, fucoidan) with promising biological activities that make them good candidates for nutraceutical applications with increased value-added. In this review, a deep description of bioactive compounds from brown algae is presented. In addition, recent advances in biological activities ascribed to these compounds through in vitro and in vivo assays are pointed out. Delivery strategies to overcome some drawbacks related to the direct application of algae-derived compounds (low solubility, thermal instability, bioavailability, unpleasant organoleptic properties) are also reviewed. Finally, current commercial and legal statuses of ingredients from brown algae are presented, considering future therapeutical and market perspectives as nutraceuticals.

Biological Potential, Gastrointestinal Digestion, Absorption, and Bioavailability of Algae-Derived Compounds with Neuroprotective Activity: A Comprehensive Review

Currently, there is no known cure for neurodegenerative disease. However, the available therapies aim to manage some of the symptoms of the disease. Human neurodegenerative diseases are a heterogeneous group of illnesses characterized by progressive loss of neuronal cells and nervous system dysfunction related to several mechanisms such as protein aggregation, neuroinflammation, oxidative stress, and neurotransmission dysfunction. Neuroprotective compounds are essential in the prevention and management of neurodegenerative diseases. This review will focus on the neurodegeneration mechanisms and the compounds (proteins, polyunsaturated fatty acids (PUFAs), polysaccharides, carotenoids, phycobiliproteins, phenolic compounds, among others) present in seaweeds that have shown in vivo and in vitro neuroprotective activity. Additionally, it will cover the recent findings on the neuroprotective effects of bioactive compounds from macroalgae, with a focus on their biological potential and possible mechanism of action, including microbiota modulation. Furthermore, gastrointestinal digestion, absorption, and bioavailability will be discussed. Moreover, the clinical trials using seaweed-based drugs or extracts to treat neurodegenerative disorders will be presented, showing the real potential and limitations that a specific metabolite or extract may have as a new therapeutic agent considering the recent approval of a seaweed-based drug to treat Alzheimer’s disease.

Carboxymethyl chitosan incorporated with gliadin/phlorotannin nanoparticles enables the formation of new active packaging films

Advanced carboxymethyl chitosan (CMCS) based functional films were fabricated by involving some amounts of gliadin/phlorotannin nanoparticles (GPNPs) using a solution casting method. GPNPs were synthesized by an antisolvent precipitation approach, and they presented a spherical morphology with a mean diameter of 145.30 ± 2.06 nm. The effect of GPNPs concentration on the structural, physical, antioxidant and antimicrobial properties of CMCS-GPNPs (C-G) functional films was evaluated. It was found that the added GPNPs were homogeneously distributed over the whole CMCS matrix, allowing to reduce the free volume of the nanocomposite matrix and subsequently improve the physical properties of the final film (evidenced by mechanical and water barrier properties). FT-IR spectra indicated the intermolecular interactions, such as hydrogen bonds and electrostatic interaction, within the matrix of the nanocomposite films were increased. Impressively, the anti-ultraviolet properties, antioxidant activity and antimicrobial behaviors of the as-formed C-G functional films were greatly enhanced compared to the pure CMCS film. All these results suggested that our as-prepared C-G nanocomposite films could be a promising food packaging material.

In Vitro Protein Digestibility of Selected Seaweeds

Seaweed biomass is considered a valuable and potential, alternative protein source but it is currently under-exploited. Seaweed or Macroalgae do not require arable land and freshwater for their cultivation, they are fast growing and contain several health ingredients and beneficial macronutrients. In this study, we determined the in vitro k-Protein Digestibility-Corrected Amino Acid Score (k-PDCAAS) values of six different, Irish seaweeds using the rapid k-PDCAAS method. Based on the amino acid profile and protein content of each seaweed, the in vitro protein digestibility and k-PDCAAS scores were calculated. In addition, the limiting amino acid(s) for each of the six seaweeds was/were determined. Results suggest that although the in vitro digestibility was quite similar for all analyzed seaweeds, their k-PDCAAS scores varied significantly. The red seaweed Palmaria palmata had a k-PDCAAS score of 0.69 ± 0.014, while Fucus serratus had a value of 0.63 ± 0.084 and Alaria esculenta a value of 0.59 ± 0.021. The seaweeds were found to be rich in essential amino acids and taurine. Overall, the amino acid composition of the seaweeds studied suggests that they are suitable alternative protein sources for use in human nutrition providing both essential and non-essential amino acids to the consumer.

Phlorotannins-bioactivity and extraction perspectives

Phlorotannins, a seaweed based class of polyphenolic compounds, have proven to possess potential bioactivities such as antioxidant, antimicrobial, anti-allergic, anti-diabetic, anti-inflammatory, anti-cancerous, neuroprotection etc. These bioactivities have further increased demand globally and sustainable techniques such as supercritical fluid extraction, microwave assisted extraction, enzyme assisted extraction, extraction using deep eutectic solvents etc. are being explored currently for production of phlorotannin-rich extracts. In spite of such well documented bioactivities, very few phlorotannin-based nutraceuticals are available commercially which highlights the significance of generating consumer awareness about their physiological benefits. However, for industry level commercialization accurate quantification of phlorotannins with respect to the different classes is vital requiring sophisticated analytical techniques such as mass spectrometry, ¹H-NMR spectroscopy etc. owing to the wide structural diversity. This review summarizes the extraction and bioactivities of phlorotannins based on the findings of in vivo and in vitro studies.

Phlorotannins Derived From the Brown Alga Colpomenia bullosa as Tyrosinase Inhibitors

Tyrosinase catalyzes hydroxylation of L-tyrosine and dehydrogenation of L-DOPA in the melanin biosynthesis pathway. Tyrosinase inhibitors have potential use as cosmetic whitening agents and for preventing seafood deterioration. In this report, tyrosinase inhibitors extracted from brown alga Colpomenia bullosa (Scytosiphonaceae, Scytosiphonales) were investigated. Inhibitory principles were isolated from the extract and identified as phlorotannins, phloroglucinol (1), diphlorethol (2), triphlorethol C (3), which have not been isolated in a free form previously, and fucophlorethol C (4). Compounds 3 and 4 have not been reported previously as tyrosinase inhibitors. Triphlorethol C (3) was the most potent tyrosinase inhibitor among the phlorotannins isolated, whereas isomeric fucophlorethol C (4) displayed the weakest inhibitory activity. The results suggest that molecular structures of phlorotannins strongly affect their tyrosinase inhibitory activity.

Multi-Step Subcritical Water Extracts of Fucus vesiculosus L. and Codium tomentosum Stackhouse: Composition, Health-Benefits and Safety

Mental health and active aging are two of the main concerns in the 21st century. To search for new neuroprotective compounds, extracts of Codium tomentosum Stackhouse and Fucus vesiculosus L. were obtained through multi-step (four step) subcritical water extraction using a temperature gradient. The safety assessment of the extracts was performed by screening pharmaceutical compounds and pesticides by UHPLC-MS/MS, and iodine and arsenic levels by ICP-MS. Although the extracts were free of pharmaceutical compounds and pesticides, the presence of arsenic and high iodine contents were found in the first two extraction steps. Thus, the health-benefits were only evaluated for the fractions obtained in steps 3 and 4 from the extraction process. These fractions were tested against five brain enzymes implicated in Alzheimer’s, Parkinson’s, and major depression etiology as well as against reactive oxygen and nitrogen species, having been observed a strong enzyme inhibition and radical scavenging activities for the step 4 fractions from both seaweed species. Regarding the variation of the chemical composition during the extraction, step 1 fractions were the richest in phenolic compounds. With the increase in temperature, Maillard reaction, caramelization and thermo-oxidation occurred, and the resulting products positively affected the antioxidant capacity and the neuroprotective effects.

A sustainable approach by using microalgae to minimize the eutrophication process of Mar Menor lagoon

The present study evaluates the removal capacity of microalgae photobioreactors of environmental pollutants present in wastewater from the dry riverbed El Albujón, as a way to minimize the eutrophication process of the Mar Menor. Particularly, the capacity of four autochthonous microalgae consortia collected from different locations of the salty lagoon to remove emerging contaminants (simazine, atrazine, terbuthylazine, adenosine and ibuprofen), nitrates, and phosphates, was evaluated. Among the four microalgae consortia, consortium 1 was the best in terms of biomass productivity (0.11 g L^-1 d^-1) and specific growth rate (0.14 d^-1), providing 100% removal of emerging contaminants (simazine, atrazine, terbuthylazine, adenosine and ibuprofen), and a maximal reduction and consumption of macronutrients, especially nitrates and phosphates, reaching levels below 28 mg L^-1, that is, a decrease of 89.90 and 99.70% of nitrates and phosphates, respectively. Therefore, this consortium (Monoraphidium sp., Desmodesmus subspicatus, Nannochloris sp.) could be selected as a green filter for successful large-scale applications. This study is the first one that combines the successful removal of herbicides, ibuprofen and adenosine as emerging contaminants, and nitrate removal.

Polyphenols from Brown Seaweeds (Ochrophyta, Phaeophyceae): Phlorotannins in the Pursuit of Natural Alternatives to Tackle Neurodegeneration

Globally, the burden of neurodegenerative disorders continues to rise, and their multifactorial etiology has been regarded as among the most challenging medical issues. Bioprospecting for seaweed-derived multimodal acting products has earned increasing attention in the fight against neurodegenerative conditions. Phlorotannins (phloroglucinol-based polyphenols exclusively produced by brown seaweeds) are amongst the most promising nature-sourced compounds in terms of functionality, and though research on their neuroprotective properties is still in its infancy, phlorotannins have been found to modulate intricate events within the neuronal network. This review comprehensively covers the available literature on the neuroprotective potential of both isolated phlorotannins and phlorotannin-rich extracts/fractions, highlighting the main key findings and pointing to some potential directions for neuro research ramp-up processes on these marine-derived products.

Characteristics of Polyphenolic Content in Brown Algae of the Pacific Coast of Russia

Water and ethanol brown macroalgal extracts of nine species of Laminariales and four species of Fucales of the Pacific coast of Russia were investigated. It has been shown that brown algae species of Agarum, Thalassiophyllum, Fucus and Cystoseira can be a source of the polyphenolic compounds with antioxidant activity. Phenolic content in the ethanol algal extracts (Undaria pinnatifida, Arthrothamnus bifidus, Thalassiophyllum clathrus and Agarum turneri) was 1.1-3.5 times higher than in the water extracts. In Sargassum pallidum and Kjellmaniella crassifolia, the total polyphenolic content was 2.1 and 1.6 times higher, respectively, in water extracts than in ethanol extracts. The maximum radical scavenging activity has been detected in Agarum turneri ethanol extracts (38.8 mg ascorbic acid/g and 2506.8 µmol Trolox equiv/g dry algae). Phlorotannin content varies from 16.8 μg/g dry sample of Costaria costata to 2763.2 μg/g dry sample of Agarum turneri. It is found the content of polyphenolic compounds in brown algae is determined mainly by their species-specificity and by their belonging to the genus. The presence of major phenols in the extract of Thalassiophyllum clathrus, such as phenolic acid (gallic acid), hydroxycinnamic acids (caffeic acid, chlorogenic acid, coumaric acid) and flavonols (kaempferol, quercetin) has been established.