Seaweed as a Source of Natural Antioxidants: Therapeutic Activity and Food Applications

Seaweed in the Diet as a Source of Bioactive Metabolites and a Potential Natural Immunity Booster: A Comprehensive Review

Seaweed plays an essential role in the survival of marine life, provides habitats and helps in nutrient recycling. It is rich in valuable nutritious compounds such as pigments, proteins, polysaccharides, minerals, vitamins, omega-rich oils, secondary metabolites, fibers and sterols. Pigments like fucoxanthin and astaxanthin and polysaccharides like laminarin, fucoidan, galactan and ulvan possess immune-modulatory and immune-enhancing properties. Moreover, they show antioxidative, antidiabetic, anticancer, anti-inflammatory, antiproliferative, anti-obesity, antimicrobial, anticoagulation and anti-aging properties and can prevent diseases such as Alzheimer's and Parkinson's and cardiovascular diseases. Though seaweed is frequently consumed by Eastern Asian countries like China, Japan, and Korea and has gained the attention of Western countries in recent years due to its nutritional properties, its consumption on a global scale is very limited because of a lack of awareness. Thus, to incorporate seaweed into the global diet and to make it familiar as a functional food, issues such as large-scale cultivation, processing, consumer acceptance and the development of seaweed-based food products need to be addressed. This review is intended to give a brief overview of the present status of seaweed, its nutritional value and its bioactive metabolites as functional foods for human health and diseases owing to its immunity-boosting potential. Further, seaweed as a source of sustainable food and its prospects along with its issues are discussed in this review.

Chemical Composition, Free Radicals and Pathogenic Microbes in the Extract Derived from Dictyota dichotoma: In Silico and In Vitro Approaches

Marine algae are renowned for their health benefits due to the presence of functional bioactive compounds. In this context, this study aims to valorize the extract of a seaweed, Dictyota dichotoma (D. dichotoma), through phytochemical characterization using liquid chromatography-mass spectrometry (HPLC-MS), as well as in vitro and in silico evaluation of its biological activities (antioxidant and antimicrobial). Phytochemical characterization revealed that the ethanolic extract of Dictyota dichotoma (DdEx) is rich in phenolic compounds, with a total of 22 phycocompounds identified. Antioxidant activity, measured by various methods, showed an IC50 of 120 µg/mL for the DPPH assay, an EC50 of 120.53 µg/mL for the FRAP assay, and a total antioxidant power of 685.26 µg AAE/mg according to the phosphomolybdate (TAC) method. Evaluation of antibacterial activity showed a zone of inhibition diameter ranging from 11.93 to 22.58 mm, with the largest zone observed for the Escherichia coli (E. coli) strain. For antifungal activity, inhibition zone diameters ranged from 22.38 to 23.52 mm, with the largest recorded for the Saccharomyces cerevisiae (S. cerevisiae) strain. The in silico study identified tetragalloyl-glucose, apigenin-7-O-glucoside, and pentagalloyl-glucose as the most active compounds against NADPH oxidase, with docking scores of -7.723, -7.424, and -6.402 kcal/mol, respectively. Regarding antibacterial activity, apigenin-7-O-glucoside, pelargonidin-3-O-glucoside, and secoisolariciresinol demonstrated high affinity for E. coli beta-ketoacyl-[acyl carrier protein] synthase, with docking scores of -7.276, -6.811, and -6.594 kcal/mol, respectively. These in vitro and in silico evaluations showed that D. dichotoma extract possesses antioxidant and antimicrobial properties, due to its richness in bioactive compounds identified by HPLC.

Assessment of chemical risks and benefits connected with macroalgae consumption

Reducing animal-based food production and consumption due to environmental issues and undergoing upcoming changes in food dietary patterns is pushing European society to search for new protein sources. Consuming macroalgae (seaweed) is one of the possible solutions, and it is an exciting alternative for both sustainability and consumers' health. The aim of this work, implemented under the EU-FORA fellowship programme, was to evaluate the current and projected consumption of macroalgae in terms of possible beneficial and detrimental effects on consumers. The risk-benefit assessment methodology was selected as a tool for this task, and a broad range of qualitative analyses of raw material composition (e.g. fatty acids, micro-, macroelements, heavy metals, biogenic amines). The current levels of macroalgae consumption in the EU are deficient; therefore, alternate scenarios using data from other countries and substitution scenarios are needed. Iodine turned out to be the most pivotal constituent - on the one hand; it is an element essential for life, often fortified in foods like milk or salt; on the other, its overdosing leads to serious thyroid complications. A very high variance in iodine levels between algal species was observed; therefore, it was suggested that this valuable knowledge is helpful in dietary recommendations.

Toxicity of Macroalgae Extracts to Larvae of the Northern House Mosquito

The continuous use of synthetic insecticides to suppress mosquito larvae has detrimental impacts on the environment and human health. Finding novel and target-specific bio-insecticides has become crucial. Here, the larvicidal and genotoxic activities of different extracts from Ulva lactuca and Turbinaria ornata toward Culex pipiens larvae were investigated. The macroalgae thalli were subjected to various solvent extractions followed by phytochemical quantification, larvicidal testing on C. pipiens larvae, genotoxic evaluation through comet assays, and compound characterization by gas chromatography-mass spectrometry. The methylene chloride extract from U. lactuca displayed the highest toxicity with LC50 = 30.99 ppm, followed by the acetone extract from T. ornata, with LC50 = 52.09 ppm after 72 h. U. lactuca exhibited the maximum contents of total alkaloids, total flavonoids, total terpenoids, total phenols, and total tannins with the methanol extract, while the acetone extract from T. ornata exhibited the maximum contents of total alkaloids, total flavonoids, total terpenoids, and total phenols. The methylene chloride extract of U. lactuca and the acetone extract of T. ornata caused significant DNA damage in larva body cells. Thus, the methylene chloride extract from U. lactuca and the acetone extract from T. ornata showed promising potential as environmentally friendly larvicides against C. pipiens larvae.

Seaweed Nutritional Value and Bioactive Properties: Insights from Ascophyllum nodosum, Palmaria palmata, and Chondrus crispus

This study investigates the nutritional composition and bioactive properties of Palmaria palmata (dulse), Ascophyllum nodosum (knotted wrack), and Chondrus crispus (Irish moss). Understanding the nutritional values of these seaweeds is very important due to their potential health benefits, especially their antioxidant properties and cytotoxic activities, which point to their ability to inhibit cancer cell proliferation. Comprehensive analyses were conducted to assess protein content, amino acid composition, mineral profile, fatty acids, polyphenols, total carotenoids, antioxidant activity, and cytotoxicity against cervical (HeLa), and colon (HCT-116) cell lines. P. palmata exhibited the highest protein content, while C. crispus was richest in calcium, iron, manganese, and zinc. Amino acid analysis revealed C. crispus as being particularly high in essential and non-essential amino acids, including alanine, glutamic acid, and glycine. A. nodosum and C. crispus were rich in polyunsaturated fatty acids (PUFAs), notably eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). A. nodosum showed the highest total carotenoid content. Polyphenol analysis highlighted the presence of compounds such as p-coumaric acid, gallic acid, and p-hydroxybenzoic acid across the species. Both the ethanolic and hexane A. nodosum extracts demonstrated the strongest antioxidant potential in DPPH• and ABTS+ assays. The cytotoxicity evaluation revealed high anticancer activity of A. nodosum and C. crispus hexane extract against HeLa and HCT-116, though it employed cell cycle arrest and apoptosis. A. nodosum hexane extract exhibited moderate selective anticancer activity against HCT-116. These findings underscore the nutritional diversity and potential health benefits of these macroalgae (seaweed) species, suggesting their suitability as functional foods or supplements, offering diverse nutritional and therapeutic benefits.

A comprehensive review on microbial diversity and anticancer compounds derived from seaweed endophytes: a pharmacokinetic and pharmacodynamic approach

Seaweed endophytes are a rich source of microbial diversity and bioactive compounds. This review provides a comprehensive analysis of the microbial diversity associated with seaweeds and their interaction between them. These diverse bacteria and fungi have distinct metabolic pathways, which result in the synthesis of bioactive compounds with potential applications in a variety of health fields. We examine many types of seaweed-associated microorganisms, their bioactive metabolites, and their potential role in cancer treatment using a comprehensive literature review. By incorporating recent findings, we hope to highlight the importance of seaweed endophytes as a prospective source of novel anticancer drugs and promote additional studies in this area. We also investigate the pharmacokinetic and pharmacodynamic profiles of these bioactive compounds because understanding their absorption, distribution, metabolism, excretion (ADMET), and toxicity profiles is critical for developing bioactive compounds with anticancer potential into effective cancer drugs. This knowledge ensures the safety and efficacy of proposed medications prior to clinical trials. This study not only provides promise for novel and more effective treatments for cancer with fewer side effects, but it also emphasizes the necessity of sustainable harvesting procedures and ethical considerations for protecting the delicate marine ecology during bioprospecting activities.

Atlantic Canadians' Sensory Perception of Couscous Made with Sugar Kelp (Saccharina latissma)

Sugar kelp (Saccharina latissma) has many nutritional benefits and has been identified as a rich source of fibre, vitamins, and antioxidants. However, it is not regularly consumed in the Western world, and the sensory perception of foods containing sugar kelp must be investigated to increase acceptance in North America. This study evaluated consumers' (n = 99) sensory perception of couscous with increasing amounts of sugar kelp (0% (control), 4%, 6%, 8%, and 10% wt/wt). Furthermore, consumers' purchase intent, liking, and emotional response to couscous with added sugar kelp was evaluated with and without nutritional information. Sugar kelp at 6% incorporation did not impact the consumers' liking scores ("Like Slightly" on the hedonic scale), but at 8% the consumers' liking significantly decreased ("Neither Like nor Dislike"). The 8% and 10% levels of sugar kelp addition led to astringency, bitter, hard, brackish, fishy, and chewy attributes being perceived by the consumers. The consumers identified they preferred samples that had soft, savoury, salty, and bland flavours and disliked samples that were brackish and gritty. The nutritional information did not increase overall liking scores, purchase intent, or emotional response. However, the inclusion of sugar kelp in the couscous did lead to an increased selection of positive emotions like happy, joyful, pleasant, and enthusiastic. Overall, the consumers were interested in foods containing seaweed and believed they were nutritious. The results indicated that sugar kelp could be added to couscous up to 6% wt/wt without impacting overall liking.

Macroalgae-derived bioactive compounds for functional food and pharmaceutical applications-a critical review

The rising demand for global food resources, combined with an overreliance on land-based agroecosystems, poses a significant challenge for the sustainable production of food products. Macroalgae cultivation is a promising approach to mitigate impending global food insecurities due to several key factors: independence from terrestrial farming, rapid growth rates, unique biochemical makeup, and carbon capture potential. Furthermore, macroalgae are rich in vitamins, minerals, essential amino acids, polyunsaturated fatty acids and fiber, demonstrating significant potential as sustainable alternatives for enhancing dietary diversity and fulfilling nutritional requirements. This review provides an overview of the nutritional composition and functional properties of commercially cultivated macroalgae species, with emphasis on their viability as value additions to the functional food market. Furthermore, the review discusses the technological aspects of integrating macroalgae into food products, covering both innovative solutions and existing challenges. Macroalgae, beyond being nutritional powerhouses, contain a plethora of bioactive compounds with varied biological activities, including anti-diabetic, anti-cancer, cardioprotective, and neuroprotective properties, making them excellent candidates in developing novel pharmaceuticals. Thus, this review also summarizes the pharmaceutical applications of macroalgae, identifies research gaps and proposes potential strategies for incorporating macroalgae-derived bioactive compounds into therapeutic products.

Understanding Macroalgae: A Comprehensive Exploration of Nutraceutical, Pharmaceutical, and Omics Dimensions

Driven by a surge in global interest in natural products, macroalgae or seaweed, has emerged as a prime source for nutraceuticals and pharmaceutical applications. Characterized by remarkable genetic diversity and a crucial role in marine ecosystems, these organisms offer not only substantial nutritional value in proteins, fibers, vitamins, and minerals, but also a diverse array of bioactive molecules with promising pharmaceutical properties. Furthermore, macroalgae produce approximately 80% of the oxygen in the atmosphere, highlighting their ecological significance. The unique combination of nutritional and bioactive attributes positions macroalgae as an ideal resource for food and medicine in various regions worldwide. This comprehensive review consolidates the latest advancements in the field, elucidating the potential applications of macroalgae in developing nutraceuticals and therapeutics. The review emphasizes the pivotal role of omics approaches in deepening our understanding of macroalgae's physiological and molecular characteristics. By highlighting the importance of omics, this review also advocates for continued exploration and utilization of these extraordinary marine organisms in diverse domains, including drug discovery, functional foods, and other industrial applications. The multifaceted potential of macroalgae warrants further research and development to unlock their full benefits and contribute to advancing global health and sustainable industries.

Natural antioxidants as strategy to minimize the presence of lipid oxidation products in canned fish: Research progress, current trends and future perspectives

Canned fish is one of the most popular forms of fish consumption due to its high nutritional value, availability, and practicality. However, canning may induce lipid oxidation. Thus, this study provides in-depth information on the impact of high temperatures applied during canning on fish lipids. The thermo-oxidation is evidenced, for example, by the high levels of both primary and secondary oxidation products determined in fish after canning, as well as the presence of harmful compounds such as cholesterol oxides. Given the role of lipid oxidation in canned fish, this study also presents a comprehensive review on using natural antioxidants to control it. The antioxidant properties of common liquid mediums (vegetable oils and sauces) are highlighted. Moreover, adding algae extracts, spices, and condiments to the liquid medium to enhance its antioxidant potential has been considered, while the exploitation of by-products and wastes from the food industry also emerges as a suitable strategy. Besides the promising results, these practices may promote positive impacts on other quality parameters (e.g. water and oil holding capacities, texture, microbiological growth). However, further studies are needed, including research on aspects related to safety, effective concentrations and application methods, without ignoring consumers' sensory acceptance.

Diversity and impacts of macroalgae and cyanobacteria on multi-stressed coral reefs in the Gulf of Mannar Marine Biosphere Reserve

In India, intertidal seaweed resources are widely investigated and utilized for various applications, whereas reef-associated seaweed resources and their impacts on corals are lesser known. Thus, the present study investigated the diversity and impacts of macroalgae and cyanobacteria on coral reefs distributed in 21 islands under the Gulf of Mannar Marine Biosphere Reserve (GoMMBR), Tamil Nadu. About 140 macroalgal species representing 53 species of Chlorophyta, 32 species of Ochrophyta (Phaeophyta), and 55 species of Rhodophyta were recorded. Only three cyanobacterial species were documented during this study. All the documented species were categorized as edible, medicinal, smothering, bloom-forming, sediment trapping, and auxiliary. Diversity indices and multivariate analysis indicated latitudinal gradient distribution of macroalgae, where the maximum diversity was observed from the Mandapam group of Islands. The predominant genera observed in all the islands were Caulerpa, Halimeda, Turbinaria, and Sargassum. The updated checklist of seaweeds and cyanobacteria of India revealed 1118 and 258 species, correspondingly, on Indian coasts, including coral reef regions. The use of traditional morphology-based techniques in this study without molecular approaches to identify all of the specimens limits our investigation. Thus, molecular taxonomy is necessary to revalidate and confirm the actual genetic diversity existing in the Indian waters. Results of this study would benefit the scientific community and industries in various aspects, such as molecular taxonomy, biomass utilization, reef conservation, and industrial applications.

Anti-Inflammatory Effects of Bioactive Compounds from Seaweeds, Bryozoans, Jellyfish, Shellfish and Peanut Worms

Inflammation is a defense mechanism of the body in response to harmful stimuli such as pathogens, damaged cells, toxic compounds or radiation. However, chronic inflammation plays an important role in the pathogenesis of a variety of diseases. Multiple anti-inflammatory drugs are currently available for the treatment of inflammation, but all exhibit less efficacy. This drives the search for new anti-inflammatory compounds focusing on natural resources. Marine organisms produce a broad spectrum of bioactive compounds with anti-inflammatory activities. Several are considered as lead compounds for development into drugs. Anti-inflammatory compounds have been extracted from algae, corals, seaweeds and other marine organisms. We previously reviewed anti-inflammatory compounds, as well as crude extracts isolated from echinoderms such as sea cucumbers, sea urchins and starfish. In the present review, we evaluate the anti-inflammatory effects of compounds from other marine organisms, including macroalgae (seaweeds), marine angiosperms (seagrasses), medusozoa (jellyfish), bryozoans (moss animals), mollusks (shellfish) and peanut worms. We also present a review of the molecular mechanisms of the anti-inflammatory activity of these compounds. Our objective in this review is to provide an overview of the current state of research on anti-inflammatory compounds from marine sources and the prospects for their translation into novel anti-inflammatory drugs.

Protective Effect of Sargassum fusiforme Fucoidan against Ethanol-Induced Oxidative Damage in In Vitro and In Vivo Models

Our previous studies have evaluated the bioactivities of a fucoidan isolated from Sargassum fusiforme (SF-F). To further investigate the health benefit of SF-F, in the present study, the protective effect of SF-F against ethanol (EtOH)-induced oxidative damage has been evaluated in in vitro and in vivo models. SF-F effectively improved the viability of EtOH-treated Chang liver cells by suppressing apoptosis. In addition, the in vivo test results indicate that SF-F significantly and dose-dependently increased the survival rate of zebrafish treated with EtOH. Further research results show that this action works through decreasing cell death via reduced lipid peroxidation by scavenging intracellular reactive oxygen species in EtOH-stimulated zebrafish. These results indicate that SF-F effectively protected Chang liver cells and zebrafish against EtOH-induced oxidative damage and suggest the potential of SF-F to be used as an ingredient in the functional food industry.

Edible Seaweeds Extracts: Characterization and Functional Properties for Health Conditions

Seaweeds are popular foods due to claimed beneficial health effects, but for many there is a lack of scientific evidence. In this study, extracts of the edible seaweeds Aramé, Nori, and Fucus are compared. Our approach intends to clarify similarities and differences in the health properties of these seaweeds, thus contributing to target potential applications for each. Additionally, although Aramé and Fucus seaweeds are highly explored, information on Nori composition and bioactivities is scarce. The aqueous extracts of the seaweeds were obtained by decoction, then fractionated and characterized according to their composition and biological activity. It was recognized that fractioning the extracts led to bioactivity reduction, suggesting a loss of bioactive compounds synergies. The Aramé extract showed the highest antioxidant activity and Nori exhibited the highest potential for acetylcholinesterase inhibition. The identification of the bioactive compounds in the extracts allowed to see that these contained a mixture of phloroglucinol polymers, and it was suggested that Nori’s effect on acetylcholinesterase inhibition may be associated with a smaller sized phlorotannins capable of entering the enzyme active site. Overall, these results suggest a promising potential for the use of these seaweed extracts, mainly Aramé and Nori, in health improvement and management of diseases, namely those associated to oxidative stress and neurodegeneration.

Enhancement of cytotoxic and antioxidant activities of Digenea simplex chloroform extract using the nanosuspension technique

Digenea simplex (D. simplex), an Egyptian marine red macroalga, contains a diverse group of phytochemicals with unique bioactivities. At the same time, the synthesis of nanosuspension (NS) has received increasing interest to optimize the technological aspects of drugs. Thence, the main objective of this work was to use the chloroform extract (ChlE) of D. simplex to prepare its nanosuspension (ChlE-NS) formulation to increase its aqueous solubility, thereby improving its bioactivity. By using FTIR, GC/MS analysis, and phytochemical screening assays, the chemical profiling of ChlE was assessed. NS was prepared by the antisolvent precipitation technique using 1.5% w/v polyvinyl alcohol (PVA). A light microscope, FTIR, particle size distribution, polydispersity index (PDI), and zeta potential (ZP) measurements was used to characterize the prepared NS. Four cancer cell lines were used in the MTT experiment to investigate the anticancer potential of ChlE and ChlE-NS. An apoptotic mechanism was established using acridine orange/ethidium bromide (AO/EB) dual staining, DNA fragmentation, and increased caspase activity. ChlE and ChlE-NS were also evaluated as antioxidants using DPPH and ABTS free radical assays. The results showed that, when compared to ChlE, ChlE-NS had greater cytotoxic activity against the four cancer cell lines. However, results of antioxidant activity showed that ChlE-NS had an IC₅₀ of 36.86 ± 0.09 and 63.5 ± 0.47%, while ChlE had values of 39.90 ± 0.08 and 86.5 ± 0.8% in DPPH and ABTS assays, respectively. Based on the results of this research, D. simplex ChlE-NS may be an effective strategy for enhancing ChlE's cytotoxic and antioxidant activities.

Biological Properties and Health-Promoting Functions of Laminarin: A Comprehensive Review of Preclinical and Clinical Studies

Marine algal species comprise of a large portion of polysaccharides which have shown multifunctional properties and health benefits for treating and preventing human diseases. Laminarin, or β-glucan, a storage polysaccharide from brown algae, has been reported to have potential pharmacological properties such as antioxidant, anti-tumor, anti-coagulant, anticancer, immunomodulatory, anti-obesity, anti-diabetic, anti-inflammatory, wound healing, and neuroprotective potential. It has been widely investigated as a functional material in biomedical applications as it is biodegradable, biocompatible, and is low toxic substances. The reported preclinical and clinical studies demonstrate the potential of laminarin as natural alternative agents in biomedical and industrial applications such as nutraceuticals, pharmaceuticals, functional food, drug development/delivery, and cosmeceuticals. This review summarizes the biological activities of laminarin, including mechanisms of action, impacts on human health, and reported health benefits. Additionally, this review also provides an overview of recent advances and identifies gaps and opportunities for further research in this field. It further emphasizes the molecular characteristics and biological activities of laminarin in both preclinical and clinical settings for the prevention of the diseases and as potential therapeutic interventions.

Therapeutic Applications of Fucoidans and their Potential to Act Against COVID-19

In this review article, we present the updated evidence of therapeutic applications of fucoidan (a seaweed polysaccharide) and its novel potential to treat infectious diseases such as coronavirus disease (COVID-19). Because of their many biological activities, seaweeds have been identified as a rich and useful source of bioactive chemicals. Sulfated polysaccharides from the sea are considered a source of physiologically active chemicals that might be used in medication development. Antitumor, antiviral, antioxidant, antibacterial, anticoagulant, and immune-inflammatory properties have all been described for these compounds. By interfering at various phases of viral infection, marine sulfated polysaccharide has a virucidal effect. As a result, it opens the door to the development of antiviral treatments. Virus entry into host cells is an initial process, avoiding this type of entry makes any precautionary measure effective. The inhibitory action of certain marine sulfated polysaccharides against coronavirus was tested, and fucoidan, iota-carrageenan, and sea cucumber sulfated polysaccharides all showed a substantial antiviral impact. Fucoidan is one of the useful sulfated polysaccharides that has been widely studied and explored in various research. There are different sources of fucoidans, which have been used in the treatment of viral infection. Additionally, we highlight the mechanism of action of fuocidan against COVID-19. Hence, we could suggest that COVID-19 might be prevented and treated using these sulfated polysaccharides. This review thus highlights ample evidence to support the hypothesis that a large number of drugs have been developed from powerful compounds isolated from marine seaweeds.

Caulerpa racemosa extract inhibits HeLa cancer cells migration by altering expression of epithelial-mesenchymal transition proteins

Introduction: Cervical cancer is caused by persistent infections of human papillomavirus types 16 and 18. Also, it is classified as a malignancy since it is able to spread itself to other sites and form a metastasis. Lymph nodes metastasis is an important factor related to cervical cancer survival. The previous study reported that Caulerpa racemosa has an anti-cancer effect by inducing apoptosis by inhibiting p53 protein degradation in HeLa cancer cells. In this study, we conducted a follow-up test to determine the anticancer effect of Caulerpa racemosa as an antimetastatic agent on HeLa cancer cells.

Methods: A true experimental study with a post-test-controlled group design was carried out on four groups of HeLa cell cultures by presenting different concentrations of Caulerpa racemosa extract. Moreover, to identify the antimetastatic effect, HeLa cells treated with Caulerpa racemosa extract were subjected to the woud healing scratch test and immunofluorescence staining assays. Data analysis was gained with qualitative and quantitative approaches. Quantitative methods such as One-way analysis of variance, Tukey’s multiple comparison test, and Pearson’s correlation were conducted.

Result: We found that Caulerpa racemosa significantly inhibit HeLa cells wound healing migration. We also demonstrated the effect of Caulerpa racemosa in downregulating Snail and Vimentin protein expression and upregulating E-Cadherin protein expression.

Conclusion:Caulerpa racemosa extract inhibits HeLa cancer cells migration by altering important regulator proteins expressions of epithelial-mesenchymal transition pathways.

Concise review of green algal genus Monostroma Thuret

Monostroma (Ulotrichales, Chlorophyta) is the most intensively cultivated genus among green seaweeds, accounting for over 90% of total green algal cultivation. It is commonly found in the eulittoral zones of marine and estuarine habitats, thus contributing significantly to the ecology of the coastal ecosystem. Morphologically, the frond of Monostroma is blade-like with eponymous one-cell thickness; therefore, it is also known as "Slender sea lettuce". Monostroma nitidum is often used for salad ingredients, boiled tsukudani, soups, etc., due to its health benefits. Monostroma kuroshiense is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. This genus remains one of the well-studied seaweed genera for ecophysiology, habitat-dependent seasonality of its growth pattern, gametangial ontogeny and phylogenetics. Moreover, rhamnan sulfate (RS), a sulfated polysaccharide, is the main component of the fiber extracted from M. nitidum and studied for various biological activities. This review presents the taxonomy, morphology, anatomy, life history, distribution, ecology, physiology, cultivation and harvesting, chemical composition, and biotechnological applications of this genus.

Seaweed-Derived Phenolic Compounds in Growth Promotion and Stress Alleviation in Plants

Abiotic and biotic stress factors negatively influence the growth, yield, and nutritional value of economically important food and feed crops. These climate-change-induced stress factors, together with the ever-growing human population, compromise sustainable food security for all consumers across the world. Agrochemicals are widely used to increase crop yield by improving plant growth and enhancing their tolerance to stress factors; however, there has been a shift towards natural compounds in recent years due to the detrimental effect associated with these agrochemicals on crops and the ecosystem. In view of these, the use of phenolic biostimulants as opposed to artificial fertilizers has gained significant momentum in crop production. Seaweeds are marine organisms and excellent sources of natural phenolic compounds that are useful for downstream agricultural applications such as promoting plant growth and improving resilience against various stress conditions. In this review, we highlight the different phenolic compounds present in seaweed, compare their extraction methods, and describe their downstream applications in agriculture.

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.

Anti-cancer properties of Caulerpa racemosa by altering expression of Bcl-2, BAX, cleaved caspase 3 and apoptosis in HeLa cancer cell culture

The main cause of cervical cancer is infection with Human Papilloma Virus (HPV). Loss of apoptotic control allows cancer cells to survive longer and allows time for mutation accumulation thereby increasing the ability to invade during tumor development. Treatment options for cervical cancer today are surgery, radiotherapy, and chemotherapy. Toxicity to normal cells, adverse side effects, and drug resistance are the main barriers to the use of chemotherapy. Among marine organisms such as bacteria, fungi, actinobacteria, and seaweed have been used for the treatment of cancer. Caulerpa has bioactive metabolites, namely alkaloids, terpenoids, flavonoids, steroids and tannins and its bioactivity has been reported against many diseases including cancer. This study aimed to evaluate the anticancer activity of C. racemosa on HeLa cervical cancer cells. The study used a true experimental post-test only control group design to determine the effect of C. racemosa extract on HeLa cancer cells. C. racemosa extract was given in doses of 50 μg/mL, 100 μg/mL, 200 μg/mL, and 0 μg/mL as controls. Quantitative measurement of apoptosis was measured using flowcytometry and the expression of Bcl-2, BAX, and cleaved-caspase 3 as pro and anti-apoptotic proteins was measured using immunofluorescence. Trypan blue exclusion test was performed to measure cell viability. C. racemosa extract significantly increased the expression of pro-apoptotic proteins BAX and cleaved caspase-3 compared to controls. Annexin V-PI analysis showed the induction of apoptosis in treated cells and decreased HeLa cell viability at 24 hours and 48 hours post-treatment (p-value <0.05). C. racemosa extract has potential as an anti-cancer with pro-apoptotic and anti-proliferative activity on HeLa cancer cells and can be explored further as a cervical cancer therapy.

A Review on Nutrients, Phytochemicals, and Health Benefits of Green Seaweed, Caulerpa lentillifera

Caulerpa lentillifera is a type of green seaweed widely consumed as a fresh vegetable, specifically in Southeast Asia. Interestingly, this green seaweed has recently gained popularity in the food sector. Over the last two decades, many studies have reported that C. lentillifera is rich in polyunsaturated fatty acids, minerals, vitamins, and bioactive compounds that contribute many health benefits. On the other hand, there is currently hardly any article dedicated specifically to C. lentillifera regarding nutritional composition and recent advancements in its potential health benefits. Hence, this study will summarise the findings on the nutritional content of C. lentillifera and compile recently discovered beneficial properties throughout the past decade. From the data compiled in this review paper, it can be concluded that the nutrient and phytochemical profile of C. lentillifera differs from one region to another depending on various external factors. As a result, this paper will offer researchers the groundwork to develop food products based on C. lentillifera. The authors of this paper are hopeful that a more systematic review could be done in the future as currently, existing data is still scarce.

Novel Technologies for Seaweed Polysaccharides Extraction and Their Use in Food with Therapeutically Applications—A Review

The use of seaweed for therapeutic purposes is ancient, but only in the last decade, with advanced technologies, has it been possible to extract seaweed’s bioactive compounds and test their potential properties. Algal metabolites possess nutritional properties, but they also exhibit antioxidant, antimicrobial, and antiviral activities, which allow them to be involved in several pharmaceutical applications. Seaweeds have been incorporated since ancient times into diets as a whole food. With the isolation of particular seaweed compounds, it would be possible to develop new types of food with therapeutically properties. Polysaccharides make up the majority of seaweed biomass, which has triggered an increase in interest in using seaweed for commercial purposes, particularly in the production of agar, carrageenan, and alginate. The bio-properties of polysaccharides are strictly dependent to their chemical characteristics and structure, which varies depending on the species, their life cycles, and other biotic and abiotic factors. Through this review, techniques for seaweed polysaccharides extraction are reported, with studies addressing the advantages for human health from the incorporation of algal compounds as dietary supplements and food additives.

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.

Recent Progress in Antioxidant Active Substances from Marine Biota

BACKGROUND

The well-recognized but not fully explored antioxidant activity of marine-biota-derived, biologically active substances has led to interest in their study as substitutes of antibiotics, antiaging agents, anticancer and antiviral drugs, and others. The aim of this review is to present the current state of the art of marine-biota-derived antioxidants to give some ideas for potential industrial applications.

METHODS

This review is an update for the last 5 years on the marine sources of natural antioxidants, different classes antioxidant compounds, and current derivation biotechnologies.

RESULTS

New marine sources of antioxidants, including byproducts and wastes, are presented, along with new antioxidant substances and derivation approaches.

CONCLUSIONS

The interest in high-value antioxidants from marine biota continues. Natural substances combining antioxidant and antimicrobial action are of particular interest because of the increasing microbial resistance to antibiotic treatments. New antioxidant substances are discovered, along with those extracted from marine biota collected in other locations. Byproducts and wastes provide a valuable source of antioxidant substances. The application of optimized non-conventional derivation approaches is expected to allow the intensification of the production and improvement in the quality of the derived substances. The ability to obtain safe, high-value products is of key importance for potential industrialization.

Sargassum plagiophyllum Extract Enhances Colonic Functions and Modulates Gut Microbiota in Constipated Mice

Constipation is a symptom that is widely found in the world’s population. Various dietary supplementations are used to relieve and prevent constipation. Seaweed is widely used for its health benefits. In this study, we aimed to investigate the effects of Sargassum plagiophyllum extract (SPE) on functions of the gastrointestinal tract and gut microbiota. The results show that SPE pretreatment increased the frequency of gut contraction, leading to reduce gut transit time. SPE pretreatment also significantly increased the secretion of Cl− and reduced Na+ absorption, increasing fecal water content in constipated mice (p < 0.05). In addition, the Bifidobacteria population in cecal contents was significantly higher in constipated mice pretreated with 500 mg/kg SPE for 14 days than in untreated constipated mice (p < 0.05). Our findings suggest that SPE can prevent constipation in loperamide-induced mice. This study may be useful for the development of human food supplements from S. plagiophyllum, which prevent constipation.