Seaweed-based natural ingredients: Stability of phlorotannins during extraction, storage, passage through the gastrointestinal tract and potential incorporation into functional foods

Effects of Brown Seaweed (Ascophyllum nodosum) Supplementation on Enteric Methane Emissions, Metabolic Status and Milk Composition in Peak-Lactating Holstein Cows

The dairy industry contributes significantly to anthropogenic methane emissions, which have an impact on global warming. This study aimed to investigate the effects of a dietary inclusion of brown seaweed Ascophyllum nodosum on enteric methane emissions (EMEs), hematological and blood biochemical profiles, and milk composition in dairy cows. Eighteen Holstein cows were divided into three groups: CON (non-supplemented cows), BS50 (50 mL of 10% A. nodosum), and BS100 (100 mL of 10% A. nodosum). In each cow, measurements of EME, dry matter intake (DMI), and milk yield (MY), as well as blood and milk sampling with respective analyzes, were performed before supplementation (P1), after 15 (P2) days, and after 30 (P3) days of supplementation. A. nodosum reduced (p < 0.05) methane production, methane yield, and methane intensity in both BS50 and BS100, and raised DMI (p < 0.05) only in BS50. Total bilirubin (p < 0.05) was higher in BS50 compared to CON cows in P2, and triacylglycerols were lower (p < 0.05) in BS50 than in CON cows in P3. Higher milk fat content was found in BS50 than in CON cows in P3. C16:0 proportions were higher (p < 0.05) in BS50 and BS100 than in CON cows, while C18:3n-3 was higher (p < 0.05) in BS100 than in BS50 and CON cows in P3. Dietary treatment with A. nodosum reduced EMEs and showed the potential to increase DMI and to improve energy status as well as milk composition in peak-lactating dairy cows.

Phytochemical compounds with promising biological activities from Ascophyllum nodosum extracts using microwave-assisted extraction

Phytochemical-rich antioxidant extracts were obtained from Ascophyllum nodosum (AN) using microwave-assisted extraction (MAE). Critical extraction factors such as time, pressure, and ethanol concentration were optimized by response surface methodology with a circumscribed central composite design. Under the optimal MAE conditions (3 min, 10.4 bar, 46.8 % ethanol), the maximum recovery of phytochemical compounds (polyphenols and fucoxanthin) with improved antioxidant activity from AN was obtained. In addition, the optimized AN extract showed significant biological activities as it was able to scavenge reactive oxygen and nitrogen species, inhibit central nervous system-related enzymes, and exhibit cytotoxic activity against different cancer cell lines. In addition, the optimized AN extract showed antimicrobial, and anti-quorum sensing activities, indicating that this extract could offer direct and indirect protection against infection by pathogenic microorganisms. This work demonstrated that the sustainably obtained AN extract could be an emerging, non-toxic, and natural ingredient with potential to be included in different applications.

The Potential of Using Cochayuyo (Durvillaea incurvata) Extract Obtained by Ultrasound-Assisted Extraction to Fight against Aging-Related Diseases

The world's population is in a demographical transition, with an increase in the number of older adults and prevalence of diseases related to aging. This study evaluated in vitro the potential of using Durvillaea incurvata extract (extracted using ultrasound-assisted extraction) to inhibit key enzymes associated with the development of age-related diseases. Our results show that an extract extracted via ultrasound-assisted extracted, as well as an extract conventional extracted from Durvillaea incurvata, presented antidiabetes potential by exhibiting inhibitory activity against α-glucosidase (91.8 ± 1.0% and 93.8 ± 0.3%, respectively, at 500 µg/mL) and α-amylase (42.2 ± 1.4% and 61.9 ± 0.9%, respectively, at 1500 µg/mL) enzymes related to starch digestion and postprandial glycemic response. Also, the extracts showed inhibitory activity against the enzymes acetylcholinesterase (51.5% and 50.8%, respectively, at 500 µg/mL) and butyrylcholinesterase (32.8% and 34.4%, respectively, at 0.5 mg/mL), the biomarkers associated with Alzheimer's disease, and angiotensin-converting enzyme (98.7 ± 7.4% and 93.0 ± 3.4%, respectively, at 2.0 mg/mL), which is key in the regulation of vascular tone and blood pressure and helps to prevent the development of hypertension. In conclusion, the extract of Durvillaea incurvata obtained from ultrasound-assisted extraction has the potential to prevent the development of age-related pathologies such as diabetes, Alzheimer's disease, and hypertension.

From Ocean to Medicine: Harnessing Seaweed's Potential for Drug Development

Seaweed, a miscellaneous group of marine algae, has long been recognized for its rich nutritional composition and bioactive compounds, being considered nutraceutical ingredient. This revision delves into the promising role of seaweed-derived nutrients as a beneficial resource for drug discovery and innovative product development. Seaweeds are abundant sources of essential vitamins, minerals, polysaccharides, polyphenols, and unique secondary metabolites, which reveal a wide range of biological activities. These bioactive compounds possess potential therapeutic properties, making them intriguing candidates for drug leads in various medical applications and pharmaceutical drug development. It explores their pharmacological properties, including antioxidant, anti-inflammatory, antimicrobial, and anticancer activities, shedding light on their potential as therapeutic agents. Moreover, the manuscript provides insights into the development of formulation strategies and delivery systems to enhance the bioavailability and stability of seaweed-derived compounds. The manuscript also discusses the challenges and opportunities associated with the integration of seaweed-based nutrients into the pharmaceutical and nutraceutical industries. Regulatory considerations, sustainability, and scalability of sustainable seaweed sourcing and cultivation methods are addressed, emphasizing the need for a holistic approach in harnessing seaweed's potential. This revision underscores the immense potential of seaweed-derived compounds as a valuable reservoir for drug leads and product development. By bridging the gap between marine biology, pharmacology, and product formulation, this research contributes to the critical advancement of sustainable and innovative solutions in the pharmaceutical and nutraceutical sectors.

Structural basis of EHEP-mediated offense against phlorotannin-induced defense from brown algae to protect akuBGL activity

The defensive-offensive associations between algae and herbivores determine marine ecology. Brown algae utilize phlorotannin as their chemical defense against the predator Aplysia kurodai, which uses β-glucosidase (akuBGL) to digest the laminarin in algae into glucose. Moreover, A. kurodai employs Eisenia hydrolysis-enhancing protein (EHEP) as an offense to protect akuBGL activity from phlorotannin inhibition by precipitating phlorotannin. To underpin the molecular mechanism of this digestive-defensive-offensive system, we determined the structures of the apo and tannic acid (TNA, a phlorotannin analog) bound forms of EHEP, as well as the apo akuBGL. EHEP consisted of three peritrophin-A domains arranged in a triangular shape and bound TNA in the center without significant conformational changes. Structural comparison between EHEP and EHEP-TNA led us to find that EHEP can be resolubilized from phlorotannin precipitation at an alkaline pH, which reflects a requirement in the digestive tract. akuBGL contained two GH1 domains, only one of which conserved the active site. Combining docking analysis, we propose the mechanisms by which phlorotannin inhibits akuBGL by occupying the substrate-binding pocket, and EHEP protects akuBGL against this inhibition by binding with phlorotannin to free the akuBGL pocket.

Phlorotannins: Novel Orally Administrated Bioactive Compounds That Induce Mitochondrial Dysfunction and Oxidative Stress in Cancer

Mitochondrial dysfunction is an interesting therapeutic target to help reduce cancer deaths, and the use of bioactive compounds has emerged as a novel and safe approach to solve this problem. Here, we discuss the information available related to phlorotannins, a type of polyphenol present in brown seaweeds that reportedly functions as antioxidants/pro-oxidants and anti-inflammatory and anti-tumorigenic agents. Specifically, available evidence indicates that dieckol and phloroglucinol promote mitochondrial membrane depolarization and mitochondria-dependent apoptosis. Phlorotannins also reduce pro-tumorigenic, -inflammatory, and -angiogenic signaling mechanisms involving RAS/MAPK/ERK, PI3K/Akt/mTOR, NF-κB, and VEGF. In doing so, they inhibit pathways that favor cancer development and progression. Unfortunately, these compounds are rather labile and, therefore, this review also summarizes approaches permitting the encapsulation of bioactive compounds, like phlorotannins, and their subsequent oral administration as novel and non-invasive therapeutic alternatives for cancer treatment.

Cochayuyo (Durvillaea incurvata) Extracts: Their Impact on Starch Breakdown and Antioxidant Activity in Pasta during In Vitro Digestion

Seaweeds, notably cochayuyo (Durvillaea incurvata), are recognized for their rich macro- and micronutrient content, along with their inhibitory effects on the α-glucosidase enzyme. The present study aims to evaluate the effectiveness of this inhibition in actual starchy food products under in vitro gastrointestinal conditions. This study utilized freeze-dried cochayuyo, extracted using hot pressurized liquid extraction with 50% ethanol at 120 °C and 1500 psi. The inhibition mechanism of α-glucosidase was determined, and the polyphenol composition of the extract was analyzed using Ultra-High-Performance Liquid Chromatography. This study further evaluated the extract's impact on starch digestibility, total phenolic content, and antioxidant capacity in pasta (noodles) as representative starchy food under gastrointestinal conditions. The results indicate that the α-glucosidase inhibition mechanism is of mixed type. Phenolic compounds, primarily tetraphloroethol, could contribute to this anti-enzymatic activity. The extract was observed to decrease starch digestibility, indicated by a lower rate constant (0.0158 vs. 0.0261 min-1) and digested starch at an infinite time (77.4 vs. 80.5 g/100 g). A significant increase (~1200 vs. ~390 µmol TROLOX/100 g) in antioxidant activity was also noted during digestion when the extract was used. Thus, this study suggests that the cochayuyo extract can reduce starch digestion and enhance antioxidant capacity under gastrointestinal conditions.

Algae Incorporation and Nutritional Improvement: The Case of a Whole-Wheat Pasta

Algae contain high-quality proteins, dietary fiber, minerals, and phenolic compounds, making them promising alternative ingredients. Since pasta is consumed worldwide, it can be an effective vehicle for incorporating algae. This study compares the nutritional and antioxidant composition of whole-wheat pasta without and with enrichment of an algae mixture (containing Himanthalia elongata and Spirulina) and ascertains the influence of the cooking procedure on their features. Spirulina and H. elongata were also analyzed in parallel for comparison purposes. Macronutrients, chlorides and salt, total and free amino acid profiles, and antioxidant properties (total phenolic content and ferric reducing antioxidant power) were analyzed using AOAC, Mohr's, high performance liquid chromatography with fluorescence detection, and spectrophotometric methods, respectively. The results show a significant increase in fat (70.4%), protein (29.7%), ash (26.5%), and total amino acid (except for serine, tryptophan, isoleucine, and threonine) contents in the raw algae-enriched pasta. The antioxidant activity was also higher (4.15 versus 3.68 g ferrous sulfate eq./g dw, respectively). After cooking, protein, dietary fiber, total amino acids (except threonine) and antioxidant activity were stable in the algae-enriched pasta. Thus, algae can be an excellent ingredient for food applications with health benefits.

Algal nutraceuticals: A perspective on metabolic diversity, current food applications, and prospects in the field of metabolomics

The current consumers' demand for food naturalness is urging the search for new functional foods of natural origin with enhanced health-promoting properties. In this sense, algae constitute an underexplored biological source of nutraceuticals that can be used to fortify food products. Both marine macroalgae (or seaweeds) and microalgae exhibit a myriad of chemical constituents with associated features as a result of their primary and secondary metabolism. Thus, primary metabolites, especially polysaccharides and phycobiliproteins, present interesting properties to improve the rheological and nutritional properties of food matrices, whereas secondary metabolites, such as polyphenols and xanthophylls, may provide interesting bioactivities, including antioxidant or cytotoxic effects. Due to the interest in algae as a source of nutraceuticals by the food and related industries, novel strategies should be undertaken to add value to their derived functional components. As a result, metabolomics is considered a high throughput technology to get insight into the full metabolic profile of biological samples, and it opens a wide perspective in the study of algae metabolism, whose knowledge is still little explored. This review focuses on algae metabolism and its applications in the food industry, paying attention to the promising metabolomic approaches to be developed aiming at the functional characterization of these organisms.

Brown algae and their multiple applications as functional ingredient in food production

Brown algae are considered one of the resources that can contribute to transforming our global food system by promoting healthier diets and reducing environmental impact. In this sense, this review article aims to provide up-to-date information on the nutritional and functional improvement of brown algae when they are applied to different food matrices. Brown algae present sulfated polysaccharides (alginates, fucoidans, and laminarins), proteins, minerals, vitamins, dietary fibers, fatty acids, pigments, and bioactive compounds that can positively contribute to the development of highly nutritious food products, as well as used reformulate products already existing, to remove, reduce, increase, add and/or replace different components and obtain products that confer health-promoting properties. This review demonstrates that there is a tendency to use seaweed for the production of functional foods and that the number of commercially produced products from seaweed is increasing, that is, seaweed is a sector whose global market is expanding.

Antioxidant and chemotherapeutic efficacies of seaweed-derived phlorotannins in cancer treatment: A review regarding novel anticancer drugs

The ineffectiveness of traditional cancer therapies due to drug resistance, nontargeted delivery, and chemotherapy-associated adverse side effects has shifted attention to bioactive phytochemicals. Consequently, research efforts toward screening and identification of natural compounds with anticancer properties have increased in recent years. Marine seaweed-derived bioactive compounds, such as polyphenolic compounds, have exhibited anticancer properties. Phlorotannins (PTs), a major group of seaweed-derived polyphenolic compounds, have emerged as powerful chemopreventive and chemoprotective compounds, regulating apoptotic cell death pathways both in vitro and in vivo. In this context, this review focuses on the anticancer activity of polyphenols isolated from brown algae, with a special reference to PTs. Furthermore, we highlight the antioxidant effects of PTs and discuss how they can impact cell survival and tumor development and progression. Moreover, we discussed the potential therapeutic application of PTs as anticancer agents, having molecular mechanisms involving oxidative stress reduction. We have also discussed patents or patent applications that apply PTs as major components of antioxidant and antitumor products. With this review, researcher may gain new insights into the potential novel role of PTs, as well as uncover a novel cancer-prevention mechanism and improve human health.

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.

Pressurized Liquid Extraction for the Recovery of Bioactive Compounds from Seaweeds for Food Industry Application: A Review

Seaweeds are an underutilized food in the Western world, but they are widely consumed in Asia, with China being the world’s larger producer. Seaweeds have gained attention in the food industry in recent years because of their composition, which includes polysaccharides, lipids, proteins, dietary fiber, and various bioactive compounds such as vitamins, essential minerals, phenolic compounds, and pigments. Extraction techniques, ranging from more traditional techniques such as maceration to novel technologies, are required to obtain these components. Pressurized liquid extraction (PLE) is a green technique that uses high temperatures and pressure applied in conjunction with a solvent to extract components from a solid matrix. To improve the efficiency of this technique, different parameters such as the solvent, temperature, pressure, extraction time and number of cycles should be carefully optimized. It is important to note that PLE conditions allow for the extraction of target analytes in a short-time period while using less solvent and maintaining a high yield. Moreover, the combination of PLE with other techniques has been already applied to extract compounds from different matrices, including seaweeds. In this way, the combination of PLE-SFE-CO2 seems to be the best option considering both the higher yields obtained and the economic feasibility of a scaling-up approximation. In addition, the food industry is interested in incorporating the compounds extracted from edible seaweeds into food packaging (including edible coating, bioplastics and bio-nanocomposites incorporated into bioplastics), food products and animal feed to improve their nutritional profile and technological properties. This review attempts to compile and analyze the current data available regarding the application of PLE in seaweeds to determine the use of this extraction technique as a method to obtain active compounds of interest for food industry application.

Biomolecules from Macroalgae-Nutritional Profile and Bioactives for Novel Food Product Development

Seaweed is in the spotlight as a promising source of nutrition for humans as the search for sustainable food production systems continues. Seaweed has a well-documented rich nutritional profile containing compounds such as polyphenols, carotenoids and polysaccharides as well as proteins, fatty acids and minerals. Seaweed processing for the extraction of functional ingredients such as alginate, agar, and carrageenan is well-established. Novel pretreatments such as ultrasound assisted extraction or high-pressure processing can be incorporated to more efficiently extract these targeted ingredients. The scope of products that can be created using seaweed are wide ranging: from bread and noodles to yoghurt and milk and even as an ingredient to enhance the nutritional profile and stability of meat products. There are opportunities for food producers in this area to develop novel food products using seaweed. This review paper discusses the unique properties of seaweed as a food, the processes involved in seaweed aquaculture, and the products that can be developed from this marine biomass. Challenges facing the industry such as consumer hesitation around seaweed products, the safety of seaweed, and processing hurdles will also be discussed.

Antibacterial, Antifungal and Algicidal Activity of Phlorotannins, as Principal Biologically Active Components of Ten Species of Brown Algae

Marine seaweeds synthesize a plethora of bioactive metabolites, of which phlorotannins of brown algae currently attract special attention due to their high antibiotic and cytotoxic capacities. Here we measured the minimum inhibitory concentrations (MICs) of several semi-purified phlorotannin preparations of different origins and molecular composition using a set of model unicellular organisms, such as Escherichia coli, Saccharomyces cerevisiae, Chlamydomonas reinhardtii, etc. For the first time, MIC values were evaluated for phlorotannin-enriched extracts of brown algae of the orders Ectocarpales and Desmarestiales. Phlorotannin extracts of Desmarestia aculeata, Fucus vesiculosus, and Ectocarpus siliculosus showed the lowest MIC values against most of the treated organisms (4-25 μg/mL for bacteria and yeast). Analysis of the survival curves of E. coli showed that massive loss of cells started after 3-4 h of exposure. Microalgae were less susceptible to activity of phlorotannin extracts, with the highest MIC values (≥200 µg/mL) measured for Chlorella vulgaris cells. D. aculeata, E. siliculosus, and three fucalean algae accumulate considerable amounts (4-16% of dry weight) of phlorotannins with MIC values similar to those widely used antibiotics. As these species grow abundantly in polar and temperate seas and have considerable biomass, they may be regarded as promising sources of phlorotannins.

Effect of brown and green seaweeds on diet digestibility, ruminal fermentation patterns and enteric methane emissions using the rumen simulation technique

Inclusion of the red seaweed Asparagopsis taxiformis as a feed additive, has led to significant reductions in methane (CH4) production from ruminants. However, dietary supplementation with this seaweed is negatively associated with health and environmental concerns mainly due to its bromoform content, a compound with potential carcinogenic properties. Thus, there is renewed focus on ascertaining the anti-methanogenic potential of locally grown brown and green seaweeds, which typically do not contain bromoform. The objective of this study was to investigate the effects of selected brown and green seaweeds on diet digestibility, ruminal fermentation patterns, total gas (TGP) and CH4 production in vitro, using the rumen simulation technique system. In experiment 1, Pelvetia canaliculata (PEC) was examined. In experiment 2, Cystoseira tamariscifolia (CYT), Bifurcaria bifurcata (BIB), Fucus vesiculosus (FUV), Himanthalia elongata (HIM) and Ulva intestinalis (ULI) were analysed. Ascophyllum nodosum (ASC) was included in both experiments. A diet containing A. taxiformis (ASP1; ASP2) and an unsupplemented diet (CON) were included as positive and negative controls, respectively in both experiments. All seaweeds were included at a rate of 10 g/kg dry matter (DM) into a control diet of 50:50 (w:w) forage:concentrate. The seven brown and green seaweeds assessed failed to affect absolute CH4 emissions or alter fermentation patterns. In experiment 1, seaweed treatment had no effect on diet digestibility, CH4%, CH4 mmol/d or CH4 L/d (P&gt;0.1), however ASP1 reduced CH4 mmol/g DOM by 49% (P&lt;0.01) relative to the control. Both ASC and ASP1 tended to increase TGP (P&lt;0.1) relative to the control. In addition to this, the inclusion of seaweed in experiment 1 reduced the production of NH3-N (P&lt;.0001) compared to the control. In experiment 2, seaweed treatment had no effect on diet digestibility or TGP. Both ASP2 and FUV reduced CH4% (P&lt;0.01) but only ASP2 significantly reduced CH4 mmol/d, CH4 L/d and CH4 mmol/g DOM (P&lt;0.05). Daily mMol butyrate was reduced by ASP2 relative to the control and most other seaweeds (P&lt;.0001). In both experiment 1 and 2, seaweed inclusion had no effect on daily total VFA, acetate or propionate production or the acetate:propionate ratio relative to the control. To conclude, including the bromoform-free brown and green seaweeds at 10g/kg DM has no negative effects on diet digestibility or fermentation patterns but also failed to reduce the production of enteric CH4in vitro.

Phlorotannin and its Derivatives, a Potential Antiviral Molecule from Brown Seaweeds, an Overview

Research on seaweeds provides a continual discovery of natural bioactive compounds. The review presents new information on studies of the potential and specific antiviral action of phlorotannin and their derivatives from marine brown algae. Phlorotannin is a polyphenolic derivative and a secondary metabolite from marine brown algae which exhibits a high quality of biological properties. Phlorotannin has a variety of biological activities that include antioxidant, anticancer, antiviral, anti-diabetic, anti-allergic, antibacterial, antihypertensive and immune modulating activities. These phlorotannin properties were revealed by various biochemical and cell-based assays in vitro. This distinctive polyphenol from the marine brown algae may be a potential pharmaceutical and nutraceutical compound. In this review, the extraction, quantification, characterization, purification, and biological applications of phlorotannin are discussed, and antiviral potential is described in detail.

Prospects of dietary seaweeds and their bioactive compounds in sustainable poultry production systems: A symphony of good things?

Modern poultry production systems face numerous economic, environmental, and social sustainability challenges that threaten their viability and acceptability as a major source of animal protein. As scientists and producers scramble to find cost-effective and socially acceptable solutions to these challenges, the dietary use of marine macroalgae (seaweeds) could be an ingenious option. Indeed, the incredible array of nutritive and bioactive compounds present in these macroscopic marine organisms can be exploited as part of sustainable poultry production systems of the future. Incorporating seaweeds in poultry diets could enhance feed utilization efficiency, growth performance, bird health, meat stability and quality, and consumer and environmental health. Theoretically, these benefits are mediated through the putative antiviral, antibacterial, antifungal, antioxidant, anticarcinogenic, anti-inflammatory, anti-allergic, antithrombotic, neuroprotective, hypocholesterolemic, and hypoglycemic properties of seaweed bioactive compounds. Despite this huge potential, exploitation of seaweed for poultry production appears to be constrained by a variety of factors such as high fibre, phenolics, and ash content. In addition, conflicting findings are often reported when seaweeds or their extracts are used in poultry feeding trials. Therefore, the purpose of this review paper is to collate information on the production, phytochemical components, and nutritive value of different seaweed species. It provides an overview ofin vivoeffects of dietary seaweeds as measured by nutrient utilization efficiency, growth performance, and product quality and stability in poultry. The utility of dietary seaweeds in sustainable poultry production systems is explored, while gaps that require further research are highlighted. Finally, opportunities that exist for enhancing the utility of seaweeds as a vehicle for sustainable production of functional poultry products for better global food and nutrition security are presented.

Seaweed-Derived Phlorotannins: A Review of Multiple Biological Roles and Action Mechanisms

Phlorotannins are a group of phenolic secondary metabolites isolated from a variety of brown algal species belonging to the Fucaceae, Sargassaceae, and Alariaceae families. The isolation of phlorotannins from various algal species has received a lot of interest owing to the fact that they have a range of biological features and are very biocompatible in their applications. Phlorotannins have a wide range of therapeutic biological actions, including antimicrobial, antidiabetic, antioxidant, anticancer, anti-inflammatory, anti-adipogenesis, and numerous other biomedical applications. The current review has extensively addressed the application of phlorotannins, which have been extensively investigated for the above-mentioned biological action and the underlying mechanism of action. Furthermore, the current review offers many ways to use phlorotannins to avoid certain downsides, such as low stability. This review article will assist the scientific community in investigating the greater biological significance of phlorotannins and developing innovative techniques for treating both infectious and non-infectious diseases in humans.

Encapsulation of phlorotannins from edible brown seaweed in chitosan: Effect of fortification on bioactivity and stability in functional foods

Phlorotannins are a family of proven therapeutic agents. However, low stability disturbs their full bioactivity expression in the human body. Hence, this study focused on preserving their vitality through encapsulation. Phlorotannins isolated from Sargassum ilicifolium were encapsulated in the chitosan-tripolyphosphate carrier. Their storage stability, processing stability, and bioactivity retention upon in vitro digestion were determined. Results revealed the highest total phlorotannin content (TPC) of 854.38 ± 48 mg Phloroglucinol Equivalence/g in the semi-purified ethyl acetate fraction while the NMR spectrum and the LCMS profile revealed the isolation of phlorotannins in it. Storage at -18℃ and 4℃ temperatures preserved thrice both the encapsulated and non-encapsulated phlorotannins than ambient conditions. Encapsulated compound reported 56.4% of TPC retention at 175 ℃ processing temperature. Fermented fraction of encapsulated form showed significantly higher (p < 0.05) antioxidant activities and TPC (0.23 ± 0.03 mg/mL) suggesting the potential for targeted delivery of phlorotannins to their absorption sites through encapsulation.

Polyphenols of Edible Macroalgae: Estimation of In Vitro Bio-Accessibility and Cytotoxicity, Quantification by LC-MS/MS and Potential Utilization as an Antimicrobial and Functional Food Ingredient

Macroalgae are a rich source of polyphenols, and their ingestion promotes various health benefits. However, information on factors contributing to health benefits such as antioxidants, antimicrobial properties, bioaccessibility, and cytotoxicity is less explored and often unavailable. Therefore, this study aims to investigate the above-mentioned parameters for the brown and green macroalgae Sargassum wightii and Ulva rigida, respectively, collected from the southeast coast of India. S. wightii exhibited higher antioxidant activity and moderate antimicrobial activity against major food pathogens in an agar well diffusion assay and in the broth microdilution method (MIC50 being <0.5 mg/mL for all microorganisms tested). Both macroalgae extracts exhibited significantly high bioaccessibility of polyphenols. To evaluate the safety of the extracts, in vitro cytotoxicity by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was carried out on the primary cells: mouse splenic lymphocytes. An almost complete decline in the cell viability was seen at considerably high concentration (50 mg/mL), expressing the reasonably high safety of the extracts. The extracts of both macroalgae were quantified for polyphenols, wherein fucoxanthin (9.27 ± 2.28 mg/kg DW) and phloroglucinol (17.96 ± 2.80 mg/kg DW) were found to be greater in the S. wightii apart from other phenolics, like gallic acid, quercetin, vanillin, and ferulic acid. The results signify the tremendous scope for the value addition of S. wightii through extraction and purification of polyphenols for its potential exploitation in functional foods and nutraceuticals or as an antimicrobial ingredient in active or smart packaging.

Thermochemical Characterization of Eight Seaweed Species and Evaluation of Their Potential Use as an Alternative for Biofuel Production and Source of Bioactive Compounds

Algae are underexplored resources in Western countries and novel approaches are needed to boost their industrial exploitation. In this work, eight edible seaweeds were subjected to their valorization in terms of nutritional characterization, thermochemical properties, and bioactive profile. Our results suggest that seaweeds present a rich nutritional profile, in which carbohydrates are present in high proportions, followed by a moderate protein composition and a valuable content of ω-3 polyunsaturated fatty acids. The thermochemical characterization of seaweeds showed that some macroalgae present a low ash content and high volatile matter and carbon fixation rates, being promising sources for alternative biofuel production. The bioactive profile of seaweeds was obtained from their phenolic and carotenoid content, together with the evaluation of their associated bioactivities. Among all the species analyzed, Porphyra purpurea presented a balanced composition in terms of carbohydrates and proteins and the best thermochemical profile. This species also showed moderate anti-inflammatory activity. Additionally, Himanthalia elongata extracts showed the highest contents of total phenolics and a moderate carotenoid content, which led to the highest rates of antioxidant activity. Overall, these results suggest that seaweeds can be used as food or functional ingredient to increase the nutritional quality of food formulations.

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

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

In vivo Assessment of Cold Atmospheric Pressure Plasma Technology on the Bioactivity of Spirulina

The present study challenges the in vivo assessment of cold atmospheric pressure plasma (CAPP) technology on the bioactive activity (antioxidant/antiaging and antimicrobial potential) of Spirulina powder, using Caenorhabditis elegans as an animal model. Surface microdischarge cold atmospheric pressure plasma (SMD-CAPP) treatment was 3.3 W discharge power for 7 min. C. elegans lifespan and egg laying were used as indicators of antioxidant/antiaging potential of Spirulina (1 mg/mL), when grown with Spirulina CP-treated [E_SCP] and untreated [E_S], compared with a control [E_0] (non-supplemented with Spirulina). According to our results, under both Spirulina supplemented media [E_SCP and E_S] and for the first 17 days, nematodes experienced an increase in lifespan but without significant differences (p > 0.05) between control and Spirulina CP-treated. Regarding the in vivo assay of the antimicrobial potential of Spirulina against Salmonella enterica serovar Typhimurium (infected worms), no significant differences (p > 0.05) were found between the three exposure scenarios (control [S_0]; Spirulina supplemented media [S_S]; CP-treated Spirulina supplemented media [S_SCP]). According to present results, CAPP-treatment do not influence negatively the lifespan of C. elegans but a reduction in the Spirulina antiaging potential was found. No in vivo modifications in antimicrobial activity seem to be linked to CAPP-processed Spirulina.

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.

Aquatic Phlorotannins and Human Health: Bioavailability, Toxicity, and Future Prospects

Medicinal chemists and pharmacognosists have relied on terrestrial sources for bioactive phytochemicals to manage and treat disease conditions. However, minimal interest is given to sea life, especially macroalgae and their inherent phytochemical reserves. Phlorotannins are a special class of phytochemicals mainly predominant in brown algae of marine and estuarine habitats. Phlorotannins are formed through the polymerization of phloroglucinol residues and derivatives via the polyketide (acetate–malonate) pathway. Studies over the past decades have implicated phlorotannins with several bioactivities, including anti-herbivory, antioxidants, anti-inflammatory, anti-microbial, anti-proliferative, anti-diabetic, radio-protective, adipogenic, anti-allergic, and anti-human immunodeficiency virus (anti-HIV) properties. All these activities are reflected in their applications as nutraceuticals and cosmeceutical agents. This article reviews the chemical composition of phlorotannins, their biological roles, and their applications. Moreover, very few studies on phlorotannin bioavailability, safety, and toxicity have been thoroughly reviewed. The paper concludes by suggesting exciting research questions for further studies.

Extraction and Nano-Sized Delivery Systems for Phlorotannins to Improve Its Bioavailability and Bioactivity

This review aims to provide an informative summary of studies on extraction and nanoencapsulation of phlorotannins to improve their bioavailability and bioactivity. The origin, structure, and different types of phlorotannins were briefly discussed, and the extraction/purification/characterization methods for phlorotannins were reviewed, with a focus on techniques to improve the bioactivities and bioavailability of phlorotannins via nano-sized delivery systems. Phlorotannins are promising natural polyphenol compounds that have displayed high bioactivities in several areas: anticancer, anti-inflammation, anti-HIV, antidiabetic, and antioxidant. This review aims to provide a useful reference for researchers working on developing better utilization strategies for phlorotannins as pharmaceuticals, therapeuticals, and functional food supplements.

Seaweed bioactive compounds: Promising and safe inputs for the green synthesis of metal nanoparticles in the food industry

Scientific research on developing and characterizing eco-friendly metal nanoparticles (NPs) is an active area experiencing currently a systematic and continuous growth. A variety of physical, chemical and more recently biological methods can be used for the synthesis of metal nanoparticles. Among them, reports supporting the potential use of algae in the NPs green synthesis, contribute with only a minor proportion, although seaweed was demonstrated to perform as a successful reducing and stabilizing agent. Thus, the first part of the present review depicts the up-to-date information on the use of algae extracts for the synthesis of metal nanoparticles, including a deep discussion of the certain advantages as well as some limitations of this synthesis route. In the second part, the available characterization techniques to unravel their inherent properties such as specific size, shape, composition, morphology and dispersibility are comprehensively described, to finally focus on the factors affecting their applications, bioactivity, potential toxic impact on living organisms and incorporation into food matrices or food packaging, as well as future prospects. The present article identifies the key knowledge gap in a systematic way highlighting the critical next steps in the green synthesis of metal NPs mediated by algae.

Seasonal Evaluation of Phlorotannin-Enriched Extracts from Brown Macroalgae Fucus spiralis

Fucus spiralis that was collected in the four seasons was submitted to an extraction with ethanol:water (crude extracts Et80), followed by a liquid-liquid fractionation with organic solvents (fraction He from n-hexane; aqueous fractions AQ1, AQ2, AQ3 and AQ4; ethyl acetate fraction EA), with the aim of obtaining phlorotannin-enriched extracts. All the extracts (Et80, He, AQ1, AQ2, AQ3, AQ4 and EA) that were obtained for the F. spiralis of the four seasons were evaluated for their antioxidant capacity and total phenolic compounds. The summer extracts presented the highest contents in polyphenols (TPC), as well as the highest ferric reducing antioxidant power (FRAP), when compared to the samples from the other seasons. The reductive percentage of the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) compound was similar between the seasons. For all the seasons, the EA extract showed the highest polyphenol content (TPC), and the highest antioxidant capacity (highest ferric reducing power (FRAP) and lowest concentration needed to reduce 50% of the DPPH compound), which is in agreement with a phlorotannin-enriched fraction. This study revealed that the polyphenol content and antioxidant power of the F. spiralis extracts are influenced by the time of harvest, as well as by the solvents used for their extraction.

Traditional Applications of Tannin Rich Extracts Supported by Scientific Data: Chemical Composition, Bioavailability and Bioaccessibility

Tannins are polyphenolic compounds historically utilized in textile and adhesive industries, but also in traditional human and animal medicines or foodstuffs. Since 20th-century, advances in analytical chemistry have allowed disclosure of the chemical nature of these molecules. The chemical profile of extracts obtained from previously selected species was investigated to try to establish a bridge between traditional background and scientific data. The study of the chemical composition of these extracts has permitted us to correlate the presence of tannins and other related molecules with the effectiveness of their apparent uses. The revision of traditional knowledge paired with scientific evidence may provide a supporting background on their use and the basis for developing innovative pharmacology and food applications based on formulations using natural sources of tannins. This traditional-scientific approach can result useful due to the raising consumers' demand for natural products in markets, to which tannin-rich extracts may pose an attractive alternative. Therefore, it is of interest to back traditional applications with accurate data while meeting consumer's acceptance. In this review, several species known to contain high amounts of tannins have been selected as a starting point to establish a correlation between their alleged traditional use, tannins content and composition and potential bioaccessibility.

By-Products of Agri-Food Industry as Tannin-Rich Sources: A Review of Tannins' Biological Activities and Their Potential for Valorization

During recent decades, consumers have been continuously moving towards the substitution of synthetic ingredients of the food industry by natural products, obtained from vegetal, animal or microbial sources. Additionally, a circular economy has been proposed as the most efficient production system since it allows for reducing and reutilizing different wastes. Current agriculture is responsible for producing high quantities of organic agricultural waste (e.g., discarded fruits and vegetables, peels, leaves, seeds or forestall residues), that usually ends up underutilized and accumulated, causing environmental problems. Interestingly, these agri-food by-products are potential sources of valuable bioactive molecules such as tannins. Tannins are phenolic compounds, secondary metabolites of plants widespread in terrestrial and aquatic natural environments. As they can be found in plenty of plants and herbs, they have been traditionally used for medicinal and other purposes, such as the leather industry. This fact is explained by the fact that they exert plenty of different biological activities and, thus, they entail a great potential to be used in the food, nutraceutical and pharmaceutical industry. Consequently, this review article is directed towards the description of the biological activities exerted by tannins as they could be further extracted from by-products of the agri-food industry to produce high-added-value products.

Macroalgae as a Source of Valuable Antimicrobial Compounds: Extraction and Applications

In the last few decades, attention on new natural antimicrobial compounds has arisen due to a change in consumer preferences and the increase in the number of resistant microorganisms. Macroalgae play a special role in the pursuit of new active molecules as they have been traditionally consumed and are known for their chemical and nutritional composition and their biological properties, including antimicrobial activity. Among the bioactive molecules of algae, proteins and peptides, polysaccharides, polyphenols, polyunsaturated fatty acids and pigments can be highlighted. However, for the complete obtaining and incorporation of these molecules, it is essential to achieve easy, profitable and sustainable recovery of these compounds. For this purpose, novel liquid-liquid and solid-liquid extraction techniques have been studied, such as supercritical, ultrasound, microwave, enzymatic, high pressure, accelerated solvent and intensity pulsed electric fields extraction techniques. Moreover, different applications have been proposed for these compounds, such as preservatives in the food or cosmetic industries, as antibiotics in the pharmaceutical industry, as antibiofilm, antifouling, coating in active packaging, prebiotics or in nanoparticles. This review presents the main antimicrobial potential of macroalgae, their specific bioactive compounds and novel green extraction technologies to efficiently extract them, with emphasis on the antibacterial and antifungal data and their applications.