Emerging Technologies for the Extraction of Marine Phenolics: Opportunities and Challenges

Optimizing a biorefinery design for the valorization of Rugulopteryx okamurae by extracting bioactive compounds and enhancing methane production

The Mediterranean Sea has suffered recently from the unprecedent invasion of the alien macroalga Rugulopteryx okamurae due to global warming and climate change putting at risk the natural local ecosystem. Since 2015 this alga has colonized a great area on the western coast of the Mediterranean Sea and it has been also spotted in other areas such as the Azores Islands or the south of France. The arrival of alga tides into the coasts also provokes collateral environmental problems that need to be addressed. Seaweed-based biorefineries are considered a promising alternative within a circular economy model. This study aims to assess the potential of R. okamurae as raw material for the extraction of reducing sugars (RS) and total polyphenolic compounds (TPC) with antioxidant capacities, the subsequent production of methane from the extracted residue, and the final use of the anaerobic digestate as fertilizer. However, the presence of bioactive compounds greatly varies due to seasonality, location or even natural degradation. In order to provide some insights about these issues, two different batches were assessed: i.e. natural and ashore R. okamurae. As brown algae are characterised by a cell wall composed of crystalline cellulose and lignin, the biomasses studied were mechanically pretreated (dried at 100 °C and milled during 60 s) before the single and sequential extraction processes. Results showed that the extraction of the targeted compounds increased by 30-80 % when the biomasses were extracted sequentially. Similarly, the biochemical methane potential of the extracted solid residues increased as the RS and TPC content was reduced (120-150 NLCH4 kg-1VS), with no significant impact regarding the biomass origin (natural or ashore) or the extraction process order. An increase in the kinetic constant k (first-order model) of 150% and 75% was observed when the fresh biomass was extracted with water and ethanol, respectively, compared to the value obtained for the unextracted biomass. Finally, the physicochemical characteristics of the different anaerobic digestates generated were assessed for their potential use as biofertilizer. In this study, most of the digestate' liquid fractions (7 out of 10) comply with European regulations for organic fertilizers and could be used directly.

Integrative metabolomics and chemometrics depict the metabolic alterations of differently processed red kidney beans (Phaseolus vulgaris L.) and in relation to in-vitro anti-diabetic efficacy

Red kidney beans (RKB) serve as a powerhouse packed with a plethora of largely unexplored extraordinary chemical entities with potential significance. However, their nutraceutical applications as a functional hypoglycemic food still lag behind and warrant further investigation. With a scope to optimize chemical and biological traits of RKB, green modification approaches (processing methods) seem inevitable. Accordingly, the current study offered the first integrative workflow to scrutinize dynamic changes in chemical profiles of differently processed RKB and their potential entanglements on diabetes mitigation using Ultra Performance Liquid Chromatography-mass spectrometry (UPLC-MS/MS) coupled with chemometrics. Different physical and biological processing treatments namely germination, fermentation, cooking and dehulling were preliminarily implemented on RKB. Complementarily, the concomitant metabolite alterations among differently processed RKB were monitored and interpreted. Next, an in-vitro α-amylase and α-glycosidase inhibitory testing of the differently processed samples was conducted and integrated with orthogonal projection to latent structures (OPLS) analysis to pinpoint the possible efficacy compounds. A total of 72 compounds spanning fatty acids and their glycerides, flavonoids, phenolic acids, amino acids, dipeptides, phytosterols and betaxanthins were profiled. Given this analysis and compared with raw unprocessed samples, it was found that flavonoids experienced notable accumulation during germination while both fermentation and dehulling approaches sharply intensified the content of amino acids and dipeptides. Comparably, Fatty acids, phytosterols and betaxanthins were unevenly distributed among the comparable samples. Admittedly, OPLS-DA revealed an evident discrimination among the processed samples assuring their quite compositional discrepancies. In a more targeted approach, kaempferol-O-sophoroside, quercetin, carlinoside and betavulgarin emerged as focal discriminators of sprouted samples while citrulline, linoleic acid, linolenoyl-glycerol and stigmasterol were the determining metabolites in cooked samples. Our efficacy experimental findings emphasized that the different RKB samples exerted profound inhibitory actions against both α-amylase and α-glycosidase enzymes with the most promising observations in the case of sprouted and cooked samples. Coincidently, OPLS analysis revealed selective enhancement of possible efficacy constituents primarily citrulline, formononetin, gamabufotalin, kaempferol-O-sophoroside, carlinoside, oleic acid and ergosterol in sprouted and cooked samples rationalizing their noteworthy α-amylase and α-glucosidase inhibitory activities. Taken together, this integrated work provides insightful perspectives beyond the positive impact of different processing protocols on bioactives accumulation and pharmacological traits of RKB expanding their utilization as functional hypoglycemic food to rectify diabetes.

Marine Polyphenols in Cardiovascular Health: Unraveling Structure-Activity Relationships, Mechanisms, and Therapeutic Implications

Cardiovascular diseases (CVDs) are responsible for significant mortality rates globally that have been raised due to the limitation of the available treatments and prevalence of CVDs. The innovative research and identification of potential preventives for CVDs are essential to alleviate global deaths and complications. The marine environment is a rich source of bioactive substances and provides a unique chemical arsenal against numerous ailments due to its unrivaled biodiversity. Marine polyphenolic compounds (MPCs) are unique because of their structural variety and biologically significant activity. Further, MPCs are well-reported for their valuable biological activities, such as anti-inflammatory, cardioprotective, and antioxidant, demonstrating encouraging results in preventing and treating CVDs. Therefore, investigation of the structure-activity relationship (SAR) between MPCs and CVDs provides insights that reveal how the structural components of these compounds affect their effectiveness. Further, comprehending this correlation is essential for advancing medications and nutraceuticals sourced from marine sources, which could transform the strategy for treating and preventing cardiovascular diseases. Therefore, this study provides a comprehensive analysis of existing research by emphasizing the role of MPCs in CVD treatments and evaluating the SAR between MPCs and CVDs with challenges and future directions.

Deep eutectic solvents for the extraction of polyphenols from food plants

Deep Eutectic Solvents (DESs) offer a promising, sustainable alternative for extracting polyphenols from food plants, known for their health benefits. Traditional extraction methods are often costly and involve toxic solvents. This review discusses the basic concepts, preparation techniques, and factors influencing the effective and safe use of DESs in polyphenol extraction. DESs' adaptability allows integration with other green extraction technologies, such as microwave- and ultrasound-assisted extractions, enhancing their efficiency. This adaptability demonstrates the potential of DESs in the sustainable extraction of bioactive compounds. Current research indicates that DESs could play a significant role in the sustainable procurement of these compounds, marking an important advancement in food science research and development. The review underscores DESs as a realistic, eco-friendly alternative in the realm of natural extraction technologies, offering a significant contribution to sustainable practices in food science.

Seaweed-derived phenolic compounds as diverse bioactive molecules: A review on identification, application, extraction and purification strategies

Seaweed, a diverse group of marine macroalgae, has emerged as a rich source of bioactive compounds with numerous health-promoting properties. Among these, phenolic compounds have garnered significant attention for their diverse therapeutic applications. This review examines the methodologies employed in the extraction and purification of phenolic compounds from seaweed, emphasizing their importance in unlocking the full potential of these oceanic treasures. The article provides a comprehensive overview of the structural diversity and biological activities of seaweed-derived phenolics, elucidating their antioxidant, anti-inflammatory, and anticancer properties. Furthermore, it explores the impact of extraction techniques, including conventional methods and modern green technologies, on the yield and quality of phenolic extracts. The purification strategies for isolating specific phenolic compounds are also discussed, shedding light on the challenges and advancements in this field. Additionally, the review highlights the potential applications of seaweed-derived phenolics in various industries, such as pharmaceuticals, cosmetics, and functional foods, underscoring the economic value of these compounds. Finally, future perspectives and research directions are proposed to encourage continued exploration of seaweed phenolics, fostering a deeper understanding of their therapeutic potential and promoting sustainable practices in the extraction and purification processes. This comprehensive review serves as a valuable resource for researchers, industry professionals, and policymakers interested in harnessing the untapped potential of phenolic compounds from seaweed for the betterment of human health and environmental sustainability.

Production of secondary metabolites using tissue culture-based biotechnological applications

Plants are the sources of many bioactive secondary metabolites which are present in plant organs including leaves, stems, roots, and flowers. Although they provide advantages to the plants in many cases, they are not necessary for metabolisms related to growth, development, and reproduction. They are specific to plant species and are precursor substances, which can be modified for generations of various compounds in different plant species. Secondary metabolites are used in many industries, including dye, food processing and cosmetic industries, and in agricultural control as well as being used as pharmaceutical raw materials by humans. For this reason, the demand is high; therefore, they are needed to be obtained in large volumes and the large productions can be achieved using biotechnological methods in addition to production, being done with classical methods. For this, plant biotechnology can be put in action through using different methods. The most important of these methods include tissue culture and gene transfer. The genetically modified plants are agriculturally more productive and are commercially more effective and are valuable tools for industrial and medical purposes as well as being the sources of many secondary metabolites of therapeutic importance. With plant tissue culture applications, which are also the first step in obtaining transgenic plants with having desirable characteristics, it is possible to produce specific secondary metabolites in large-scale through using whole plants or using specific tissues of these plants in laboratory conditions. Currently, many studies are going on this subject, and some of them receiving attention are found to be taken place in plant biotechnology and having promising applications. In this work, particularly benefits of secondary metabolites, and their productions through tissue culture-based biotechnological applications are discussed using literature with presence of current studies.

Estudio de la variabilidad en el tiempo y espacio de la actividad antioxidante y composición bioquímica de Kappaphycus alvarezii en diferentes densidades de siembra

Kappaphycus alvarezii es una de las especies de algas más cultivadas en el mundo, debido a su alto contenido de compuestos bioactivos con reportes antioxidantes y bioestimulantes. El presente estudio evaluó el efecto de las densidades de plantación sobre la composición bioquímica y antioxidante de K. alvarezii cultivada en un sistema de línea larga durante las estaciones seca y húmeda, con el fin de proporcionar una base científica para una cosecha óptima. Se midieron el contenido de humedad, cenizas, grasa, fibra, auxinas, fenoles, flavonoides, DPPH y ABTS. Los datos se analizaron mediante pruebas t, Wilcoxon, Kruskal-Wallis y ANOVA unidireccional. Los resultados mostraron un mayor contenido de grasa (2,01 % P.s), fibra bruta (5,21% P.s), contenido total de fenoles (324,09 μg GAE/g P.s) y ABTS (9,32 μg GAE/g P.s) durante la estación seca. Con respecto a la densidad de plantación, se produjo un aumento significativo del contenido en cenizas, fenoles totales y ABTS con una densidad de 10 líneas.célula-1 al mismo tiempo. Los contenidos de flavonoides, DPPH y auxina mostraron una tendencia estacional opuesta, alcanzando los niveles máximos en la estación húmeda. Este estudio aporta nueva información sobre las condiciones ambientales que pueden provocar cambios en la actividad antioxidante y la composición bioquímica de esta especie con vistas al desarrollo de bioproductos para diferentes sectores industriales como el alimentario, el farmacéutico y el de los fertilizantes en Ecuador. Palabras claves: Alga roja; Fenoles; Flavonoides; Antioxidante; Composición bioquímica; Variación estacional; densidad de siembra.

Succession dynamics of microbial communities responding to the exogenous microalgae ZM-5 and analysis of the environmental sustainability of a constructed wetland system

Constructed wetlands (CWs) are economical and effective swine tailwater treatment systems. However, nitrogen removal in CWs is limited by the lack of carbon source for denitrification. In this study, we studied the feasibility of dosing the microalgae ZM-5 to improve the nitrogen removal ability in CWs. Compared to the control CW, a 20 % higher removal capacity of COD and TN was observed for the coupled system (EG). The microalgae ZM-5 could interact with denitrifying bacteria to compensate for the deficiency of denitrifying stage in CWs. HT-qPCR chip analysis also provided evidence that denitrification genes significantly increased (p < 0.05). According to the life cycle assessment (LCA), ultrasonic extraction had the best environmental sustainability among four lipid extraction processes. As an improvement strategy, clean energy could be utilized to optimize the electricity source to reduce environmental load (45 %-60 %). These findings offer new insights into the feasibility of EG for environmentally sustainable wastewater treatment.

Marine enzymes: Classification and application in various industries

Oceans are regarded as a plentiful and sustainable source of biological compounds. Enzymes are a group of marine biomaterials that have recently drawn more attention because they are produced in harsh environmental conditions such as high salinity, extensive pH, a wide temperature range, and high pressure. Hence, marine-derived enzymes are capable of exhibiting remarkable properties due to their unique composition. In this review, we overviewed and discussed characteristics of marine enzymes as well as the sources of marine enzymes, ranging from primitive organisms to vertebrates, and presented the importance, advantages, and challenges of using marine enzymes with a summary of their applications in a variety of industries. Current biotechnological advancements need the study of novel marine enzymes that could be applied in a variety of ways. Resources of marine enzyme can benefit greatly for biotechnological applications duo to their biocompatible, ecofriendly and high effectiveness. It is beneficial to use the unique characteristics offered by marine enzymes to either develop new processes and products or improve existing ones. As a result, marine-derived enzymes have promising potential and are an excellent candidate for a variety of biotechnology applications and a future rise in the use of marine enzymes is to be anticipated.

A macroporous resin purification process to obtain food-grade phlorotannin-rich extracts with α-glucosidase inhibitory activity from Chilean brown seaweeds: An UHPLC-MSn profiling

An efficient macroporous resin purification process was designed to obtain food-grade phlorotannin-rich extracts from the seaweeds Durvillaea incurvata and Lessonia spicata. Phlorotannins were profiled to relate structures with the α-glucosidase inhibitory activity of the extracts. Liquid chromatography-mass spectrometry was applied for tentative identification. The best phlorotannin purification performance was achieved with HP-20 resin and elution with 80% v/v ethanol. This is the first study that demonstrates the effectivity of HP-20 resin for removing potentially toxic elements (As, Cd) from seaweed extracts. Fucols/phlorethols/fucophlorethols isomers up to 4 phloroglucinol units (PGU) were the most representative phlorotannins. High molecular weight species (11-21 PGU), although in low abundances, were detected in D. incurvata for the first time. Eckols, carmalols, fuhalols, phenolic acids, and flavonoids were also detected. Some extracts' potent α-glucosidase inhibitory activities were related to their high phlorotannin abundances, the presence of phlorotannins of a high degree of polymerization, and the phlorotannins class.

Isolation of Cherry Seed Oil Using Conventional Techniques and Supercritical Fluid Extraction

This study aims to compare the suitability of three extraction techniques (cold pressing, Soxhlet and supercritical fluid extraction (SFE)) to isolate oil from cherry seeds. Oils were examined in terms of extraction yield, fatty acids profile, tocopherols yield and antioxidant activity. Additionally, influence of SFE parameters was evaluated using one-factor-at-a-time design with pressure (200−350 bar), temperature (40−70 °C), flow rate (0.2−0.4 kg/h) and particle size (<800 µm and >800 µm). Oil yields ranged from 2.50% to 13.02%, whereas the highest yield was achieved with SFE. Samples were rich in polyunsaturated fatty acids, regardless of the applied extraction technique. The main fatty acids were linoleic (46.32−47.29%), oleic (40.89−41.65%), palmitic (6.56−8.00%) and stearic (2.21−2.30%) acid. Total tocopherols yield was between 16.63 mg/100 g oil and 60.61 mg/100 g oil, and highest yield was achieved with SFE. Among the tocopherols, γ-tocopherol was the most abundant, followed by α-, δ- and β-tocopherol. Antioxidant activity was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic) cation (ABTS) assays, and the results indicated that SFE extracts exhibited better or comparable antioxidant potential compared to traditional techniques. The comparison between modern and conventional extractions for oil recovery demonstrates pros and cons for the possibility of industrial application.

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.

Bio-accumulation and health risk assessment of heavy metals in different edible fish species from Hurghada City, Red Sea, Egypt

BACKGROUND

Heavy metal contamination has become a serious issue in this century especially detected in fish organs. Due to the presence of radioactive compounds in agricultural and sewage effluent, which destroys aquatic ecosystems, threatening human livelihoods. Health hazards associated with low and high consumption consumers assessed in five commercial fish species collected from Hurghada City, Egypt, during winter and summer, 2020. Atomic absorption spectrophotometer technique used for determination heavy meals in different organs and expressed as μg/g wet weight.

RESULTS

Heavy metal concentrations in muscle ranged between:(0.054-0.109), (0.260-1.043), (0.264-0.897), (5.895-11.898), (0.381-0.970), (13.582-29.133) and (0.332-0.589) µg/g for Cd, Pb, Mn, Zn, Cu, Fe and Ni respectively, which were lower than those of gills and liver. These concentrations were within WHO, FAO/WHO, and EU standards. Consumption of edible species was lower than the (TDIs) established by the (JECFA) and Egyptian Standards. Even though THQ and TTHQ values were < 1 while, in children with highly consumer were> 1.

CONCLUSION

This study concluded that intake of Red Sea fish is safe for human health. It is critical for consumers to be aware of the consequences of excessive fish consumption, particularly children with highly consumer, which represent possible health risks.

Recent insights into polysaccharide-based hydrogels and their potential applications in food sector: A review

Hydrogels are ideal for various food applications because of their softness, elasticity, absorbent nature, flexibility, and hygroscopic nature. Polysaccharide hydrogels are particularly suitable because of the hydrophilic nature, their food compatibility, and their non-immunogenic character. Such hydrogels offer a wide range of successful applications such as food preservation, pharmaceuticals, agriculture, and food packaging. Additionally, polysaccharide hydrogels have proven to play a significant role in the formulation of food flavor carrier systems, thus diversifying the horizons of newer developments in food processing sector. Polysaccharide hydrogels are comprised of natural polymers such as alginate, chitosan, starch, pectin and hyaluronic acid when crosslinked physically or chemically. Hydrogels with interchangeable, antimicrobial and barrier properties are referred to as smart hydrogels. This review brings together the recent and relevant polysaccharide research in these polysaccharide hydrogel applications areas and seeks to point the way forward for future research and interventions. Applications in carrying out the process of flavor carrier system directly through their incorporation in food matrices, broadening the domain for food application innovations. The classification and important features of polysaccharide-based hydrogels in food processing are the topics of the current review study.

Angiotensin-I-Converting Enzyme Inhibitory Activity of Protein Hydrolysates Generated from the Macroalga Laminaria digitata (Hudson) JV Lamouroux 1813

Seaweeds have a long history of use as both food and medicine, especially in Asian cultures. Moreover, there is growing interest in the use of seaweed ingredients and bioactive compounds in pharmaceutical and nutraceutical products. One ailment that seaweed bioactive compounds may impact is hypertension caused by the enzyme Angiotensin Converting Enzyme 1 (ACE-1; EC 3.4.15.1), found within the Renin-Angiotensin Aldosterone System (RAAS), which causes vasoconstriction of blood vessels, including veins and arteries. The aim of this paper is to generate bioactive peptide containing protein hydrolysates from the brown seaweed Laminaria digitata (Hudson) JV Lamouroux 1813. Proteins were extracted from this seaweed by disrupting the seaweed cell wall using a combination of carbohydrases and proteolytic enzymes. Bioactive peptide containing permeates were generated from L. digitata protein hydrolysates, and both hydrolysates and permeates were screened for their ability to inhibit the enzyme ACE-1. The protein content of the permeate fractions was found to be 23.87% compared to the untreated seaweed, which contained 15.08% protein using LECO analysis. Hydrolysis and filtration resulted in a "white" protein powder, and the protein content of this powder increased by 9% compared to the whole seaweed. The total amino acid (TAA) content of the L. digitata protein permeate was 53.65 g/100 g of the sample, and contains over 32% essential amino acids (EAA). Furthermore, the L. digitata permeate was found to inhibit the ACE-1 enzyme by 75% when compared to the commercial drug Captopril© when assayed at a concentration of 1 mg/mL. The inhibition of ACE-1 (the IC50 value) of 590 µg/mL for the L. digitata permeate compares well with Captopril©, which had 100% inhibition of ACE-1, with an IC50 value of 500 µg/mL. This study indicates that there is potential to develop protein powders with ACE-1 inhibitory bioactivities from the brown seaweed L. digitata using enzymatic hydrolysis as a cell disruption and protein extraction/hydrolysate generation procedure.

Comprehensive metabolomics unveil the discriminatory metabolites of some Mediterranean Sea marine algae in relation to their cytotoxic activities

Marine algae have served as a treasure trove of structurally variable and biologically active metabolites. The present study emphasizes on UPLC–MS metabolites fingerprinting for the first systematic broad scale metabolites characterization of three different phyla of marine seaweeds; Ulva fasciata, Pterocladia capillacea and Sargassum hornschuchii along with Spirulina platensis harvested from the Mediterranean Sea. A total of 85 metabolites belonging to various classes including mostly fatty acids and their derivatives, terpenoids, amino acids and dipeptides with considerable amounts of polyphenolic compounds. OPLS-DA model offered a better overview of phylum-based discrimination rapidly uncovering the compositional heterogeneity in metabolite profiles of algae extracts. An OPLS model was constructed using the cytotoxic activities against PC3 and MDA-MB-231 tumor cells to succinctly screen cytotoxic discriminatory metabolites among the tested algae species. The coefficient plot revealed that unsaturated fatty acids as stearidonic acid and linolenic acid, terpenoids namely as rosmanol, campestanol, dipeptides primarily glutamylglycine, glycyltyrosine along with polyphenolic compounds being abundantly present in S. platensis and U. fasciata samples with relatively marked cytotoxic potential might be the significant contributors synergistically meditating their anti-proliferative activity against PC3 and MDA-MB-231 tumor cells. Such results serve as baseline for understanding the chemistry of these species and performing strict correlation between metabolite and activity where a lack of information in this regard is observed.

Effect of Extraction Temperature on Pressurized Liquid Extraction of Bioactive Compounds from Fucus vesiculosus

This study was aimed at investigating the effect of low polarity water (LPW) on the extraction of bioactive compounds from Fucus vesiculosus and to examine the influence of temperature on the extraction yield, total phenolic content, crude alginate, fucoidan content, and antioxidant activity. The extractions were performed at the temperature range of 120-200 °C with 10 °C increments, and the extraction yield increased linearly with the increasing extraction temperature, with the highest yields at 170-200 °C and with the maximum extraction yield (25.99 ± 2.22%) at 190 °C. The total phenolic content also increased with increasing temperature. The extracts showed a high antioxidant activity, measured with DPPH (2,2-Diphenyl-1-picrylhydrazyl) radicals scavenging and metal-chelating activities of 0.14 mg/mL and 1.39 mg/mL, respectively. The highest yield of alginate and crude fucoidan were found at 140 °C and 160 °C, respectively. The alginate and crude fucoidan contents of the extract were 2.13% and 22.3%, respectively. This study showed that the extraction of bioactive compounds from seaweed could be selectively maximized by controlling the polarity of an environmentally friendly solvent.

Phytocompounds as an Alternative Antimicrobial Approach in Aquaculture

Despite culturing the fastest-growing animal in animal husbandry, fish farmers are often adversely economically affected by pathogenic disease outbreaks across the world. Although there are available solutions such as the application of antibiotics to mitigate this phenomenon, the excessive and injudicious use of antibiotics has brought with it major concerns to the community at large, mainly due to the rapid development of resistant bacteria. At present, the use of natural compounds such as phytocompounds that can be an alternative to antibiotics is being explored to address the issue of antimicrobial resistance (AMR). These phytocompounds are bioactive agents that can be found in many species of plants and hold much potential. In this review, we will discuss phytocompounds extracted from plants that have been evidenced to contain antimicrobial, antifungal, antiviral and antiparasitic activities. Further, it has also been found that compounds such as terpenes, phenolics, saponins and alkaloids can be beneficial to the aquaculture industry when applied. This review will focus mainly on compounds that have been identified between 2000 and 2021. It is hoped this review will shed light on promising phytocompounds that can potentially and effectively mitigate AMR.

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.

Anticancer Activities of Marine-Derived Phenolic Compounds and Their Derivatives

Since the middle of the last century, marine organisms have been identified as producers of chemically and biologically diverse secondary metabolites which have exerted various biological activities including anticancer, anti-inflammatory, antioxidant, antimicrobial, antifouling and others. This review primarily focuses on the marine phenolic compounds and their derivatives with potent anticancer activity, isolated and/or modified in the last decade. Reports on the elucidation of their structures as well as biosynthetic studies and total synthesis are also covered. Presented phenolic compounds inhibited cancer cells proliferation or migration, at sub-micromolar or nanomolar concentrations (lamellarins D (37), M (38), K (39), aspergiolide B (41), fradimycin B (62), makulavamine J (66), mayamycin (69), N-acetyl-N-demethylmayamycin (70) or norhierridin B (75)). In addition, they exhibited anticancer properties by a diverse biological mechanism including induction of apoptosis or inhibition of cell migration and invasive potential. Finally, phlorotannins 1–7 and bromophenols 12–29 represent the most researched phenolic compounds, of which the former are recognized as protective agents against UVB or gamma radiation-induced skin damages. Finally, phenolic metabolites were assorted into six main classes: phlorotannins, bromophenols, flavonoids, coumarins, terpenophenolics, quinones and hydroquinones. The derivatives that could not be attributed to any of the above-mentioned classes were grouped in a separate class named miscellaneous compounds.

Sustainable Drying and Green Deep Eutectic Extraction of Carotenoids from Tomato Pomace

The extraction of molecules with high added value plays an important role in the recovery of food waste. This work aimed to valorize tomato pomace, a by-product composed of skin and seeds, through extraction of carotenoids, especially lycopene and β-carotene. The tomato pomace was dried using three different methods (freeze-drying, heat drying, and non-thermal air-drying) to reduce its weight, volume, and water activity and to concentrate the carotenoid fraction. These drying approaches were compared considering the extractive potential. Three solvent mixtures were compared, a traditional one (n-hexane:acetone) and two green deep eutectic solvent mixtures (ethyl acetate:ethyl lactate and menthol:lactic acid) in combination with different drying procedures. The extract obtained using ethyl acetate:ethyl lactate with non-thermal air-drying showed the highest contents of lycopene and β-carotene (75.86 and 3950.08 µg/g of dried sample, respectively) compared with the other procedures.

Microalgal secondary metabolite productions as a component of biorefinery: A review

The interest in developing microalgae for industrial use has been increasing because of concerns about the depletion of petroleum resources and securing sustainable energy sources. Microalgae have high biomass productivity and short culture periods. However, despite these advantages, various barriers need to be overcome for industrial applications. Microalgal cultivation has a high unit price, thus rendering industrial application difficult. It is indispensably necessary to co-produce their primary and secondary metabolites to compensate for these shortcomings. In this regard, this article reviews the following aspects, (1) co-production of primary and secondary metabolites in microalgae, (2) induction methods for the promotion of the biosynthesis of secondary metabolites, and (3) perspectives on the co-production and co-extraction of primary and secondary metabolites. This paper presents various approaches for producing useful metabolites from microalgae and suggests strategies that can be utilized for the co-production of primary and secondary metabolites.

Seasonal characterization and quantification of biomolecules from sargassum collected from Mexican Caribbean coast - A preliminary study as a step forward to blue economy

Since 2014, Mexican Caribbean coasts have experienced an atypical massive arrival of pelagic Sargassum accumulated on the shores triggers economic losses, public health problems, and ecosystem damaging near the coastline. Mechanical harvesting has been implemented ending in landfills. Since Sargassum algae represent abundant biomass in tropical regions of the world, it has shown potential as a feedstock to supply bioprocesses focused on obtaining high-value compounds and bioproducts. Nevertheless, there is a lack of data on the biochemical composition of Sargassum biomass from Mexican Caribbean coasts to propose valorization pathways. This study conducted a biochemical and elemental characterization of Sargassum biomass and compared, through statistical analysis, the effect of the season (dry and wet), place of collection (from the beach and shallow water), and method of extraction (Microwave-Assisted Extraction and Enzyme Assisted Extraction) on biomass composition. The biomass composition, expressed in dry weight basis, revealed 5-7% moisture content, 24-31 % ash, 2.6-3.8 % lipids, 1.8-7.0 %, total carbohydrates, 3-11 % total proteins, 1.5-2.31 mgGAg-1 total phenolic compounds (TPC), 2.7-2.9 kcal g-1 calorific power, and metals such as As (30-146.3 ppm), Fe (16.5-45 ppm), P (197-472 ppm). The most influential factor on the compositional content of Sargassum biomass was the season of the year, followed by the extraction method and the place of collection of Sargassum. These results will elucidate information on the biotechnological potential of Sargassum biomass from the Mexican Caribbean, contributing to sustainability challenges of the region, minimizing waste, and making the most of resources.

Extraction and characterization of microalgae-derived phenolics for pharmaceutical applications: A systematic review

Microalgae are regarded as a rich trove of diverse secondary metabolites that exert remarkable biological activities. In particular, microalgae-derived bioactive phenolic compounds (MBPCs) are a boon to biopharmaceutical and nutraceutical industries due to their diverse bioactivities, including antimicrobial, anticancer, antiviral, and immunomodulatory activities. The state-of-the-art green technologies for extraction and purification of MBPCs, along with the modern progress in the identification and characterization of MBPCs, have accelerated the discovery of novel active pharmaceutical compounds. However, several factors regulate the production of these bioactive phenolic compounds in microalgae. Furthermore, some microalgae species produce toxic phenolic compounds that negatively impact the aquatic ecosystem, animal, and human life. Therefore, the focus of this review paper is to bring into light the current innovations in bioprospection, extraction, purification, and characterization of MBPCs. This review is also aimed at a better understanding of the physicochemical factors regulating the production of MBPCs at an industrial scale. Finally, the present review covers the recent advances in toxicological evaluation, diverse applications, and future prospects of MBPCs in biopharmaceutical industries.

Valorization of the Red Algae Gelidium sesquipedale by Extracting a Broad Spectrum of Minor Compounds Using Green Approaches

Until now, the red algae Gelidium sesquipedale has been primarily exploited for agar production, leaving an undervalued biomass. In this work, the use of eco-friendly approaches employing ultrasound-assisted extraction (UAE) and green solvents was investigated to valorize the algal minor compounds. The green methods used herein showed an attractive alternative to efficiently extract a broad spectrum of bioactive compounds in short extraction times (15 to 30 min vs. 8 h of the conventional method). Using the best UAE conditions, red seaweed extracts were characterized in terms of total phenolics (189.3 ± 11.7 mg GAE/100 g dw), flavonoids (310.7 ± 9.7 mg QE/100 g dw), mycosporine-like amino acids (MAAs) (Σ MAAs = 1271 mg/100 g dw), and phycobiliproteins (72.4 ± 0.5 mg/100 g dw). Additionally, produced algal extracts exhibited interesting antioxidant and anti-enzymatic activities for potential applications in medical and/or cosmetic products. Thus, this study provides the basis to reach a superior valorization of algal biomass by using alternative methods to extract biologically active compounds following eco-friendly approaches. Moreover, the strategies developed not only open new possibilities for the commercial use of Gelidium sesquipedale, but also for the valorization of different algae species since the techniques established can be easily adapted.

Benefits and Drawbacks of Ultrasound-Assisted Extraction for the Recovery of Bioactive Compounds from Marine Algae

The increase in life expectancy has led to the appearance of chronic diseases and interest in healthy aging, in turn promoting a growing interest in bioactive compounds (BCs) and functional ingredients. There are certain foods or products rich in functional ingredients, and algae are one of them. Algae consumption has been nominal in Europe until now. However, in recent years, it has grown significantly, partly due to globalization and the adoption of new food trends. With the aim of obtaining BCs from foods, multiple methods have been proposed, ranging from conventional ones, such as maceration or Soxhlet extraction, to more innovative methods, e.g., ultrasound-assisted extraction (UAE). UAE constitutes a novel method, belonging to so-called green chemistry, that enables the extraction of BCs requiring lower amounts of solvent and energy costs, preserving the integrity of such molecules. In recent years, this method has been often used for the extraction of different BCs from a wide range of algae, especially polysaccharides, such as carrageenans and alginate; pigments, including fucoxanthin, chlorophylls, or β-carotene; and phenolic compounds, among others. In this way, the application of UAE to marine algae is an efficient and sustainable strategy to pursue their deep characterization as a new source of BCs, especially suitable for vegetarian and vegan diets.

Pressurized Hot Liquid Extraction with 15% v/v Glycerol-Water as An Effective Environment-Friendly Process to Obtain Durvillaea incurvata and Lessonia spicata Phlorotannin Extracts with Antioxidant and Antihyperglycemic Potential

Brown seaweed phlorotannins have shown the potential to promote several health benefits. Durvillaea incurvata and Lessonia spicata-species that are widely distributed in central and southern Chile-were investigated to obtain phlorotannin extracts with antioxidant and antihyperglycemic potential. The use of an environmentally friendly and food-grade glycerol-based pressurized hot liquid extraction (PHLE) process (15% v/v glycerol water) was assessed for the first time to obtain phlorotannins. Multiple effects were analyzed, including the effect of the species, harvesting area (Las Cruces and Niebla), and anatomical part (holdfast, stipe, and frond) on the extracts' polyphenol content (TPC), antioxidant capacity (AC), and carbohydrate-hydrolyzing enzyme-α-glucosidase and α-amylase-inhibitory activity. Contaminants, such as mannitol, heavy metals (As, Cd, Pb, Hg, and Sn), and 5-hydroxymethylfurfural (HMF), were also determined. The anatomical part used demonstrated a significant impact on the extracts' TPC and AC, with holdfasts showing the highest values (TPC: 95 ± 24 mg phloroglucinol equivalents/g dry extract; DPPH: 400 ± 140 μmol Trolox equivalents/g dry extract; ORAC: 560 ± 130 μmol TE/g dry extract). Accordingly, holdfast extracts presented the most potent α-glucosidase inhibition, with D. incurvata from Niebla showing an activity equivalent to fifteen times that of acarbose. Only one frond and stipe extract showed significant α-glucosidase inhibitory capacity. No α-amylase inhibition was found in any extract. Although no HMF was detected, potentially hazardous cadmium levels (over the French limit) and substantial mannitol concentrations-reaching up to 50% of the extract dry weight-were found in most seaweed samples and extracts. Therefore, further purification steps are suggested if food or pharmaceutical applications are intended for the seaweed PHLE extracts obtained in this study.

Supercritical Fluid Extraction Kinetics of Cherry Seed Oil: Kinetics Modeling and ANN Optimization

This study was primarily focused on the supercritical fluid extraction (SFE) of cherry seed oil and the optimization of the process using sequential extraction kinetics modeling and artificial neural networks (ANN). The SFE study was organized according to Box-Behnken design of experiment, with additional runs. Pressure, temperature and flow rate were chosen as independent variables. Five well known empirical kinetic models and three mass-transfer kinetics models based on the Sovová’s solution of SFE equations were successfully applied for kinetics modeling. The developed mass-transfer models exhibited better fit of experimental data, according to the calculated statistical tests (R², SSE and AARD). The initial slope of the SFE curve was evaluated as an output variable in the ANN optimization. The obtained results suggested that it is advisable to lead SFE process at an increased pressure and CO₂ flow rate with lower temperature and particle size values to reach a maximal initial slope.

Exploitation of Marine Molecules to Manage Alzheimer's Disease

Neurodegenerative diseases are sociosanitary challenges of today, as a result of increased average life expectancy, with Alzheimer’s disease being one of the most prevalent. This pathology is characterized by brain impairment linked to a neurodegenerative process culminating in cognitive decline and behavioral disorders. Though the etiology of this pathology is still unknown, it is usually associated with the appearance of senile plaques and neurofibrillary tangles. The most used prophylaxis relies on anticholinesterase drugs and NMDA receptor antagonists, whose main action is to relieve symptoms and not to treat or prevent the disease. Currently, the scientific community is gathering efforts to disclose new natural compounds effective against Alzheimer’s disease and other neurodegenerative pathologies. Marine natural products have been shown to be promising candidates, and some have been proven to exert a high neuroprotection effect, constituting a large reservoir of potential drugs and nutraceutical agents. The present article attempts to describe the processes of extraction and isolation of bioactive compounds derived from sponges, algae, marine bacteria, invertebrates, crustaceans, and tunicates as drug candidates against AD, with a focus on the success of pharmacological activity in the process of finding new and effective drug compounds.

Evaluation of Ultrasound, Microwave, Ultrasound-Microwave, Hydrothermal and High Pressure Assisted Extraction Technologies for the Recovery of Phytochemicals and Antioxidants from Brown Macroalgae

This study aims to explore novel extraction technologies (ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), ultrasound-microwave-assisted extraction (UMAE), hydrothermal-assisted extraction (HAE) and high-pressure-assisted extraction (HPAE)) and extraction time post-treatment (0 and 24 h) for the recovery of phytochemicals and associated antioxidant properties from Fucus vesiculosus and Pelvetia canaliculata. When using fixed extraction conditions (solvent: 50% ethanol; extraction time: 10 min; algae/solvent ratio: 1/10) for all the novel technologies, UAE generated extracts with the highest phytochemical contents from both macroalgae. The highest yields of compounds extracted from F. vesiculosus using UAE were: total phenolic content (445.0 ± 4.6 mg gallic acid equivalents/g), total phlorotannin content (362.9 ± 3.7 mg phloroglucinol equivalents/g), total flavonoid content (286.3 ± 7.8 mg quercetin equivalents/g) and total tannin content (189.1 ± 4.4 mg catechin equivalents/g). In the case of the antioxidant activities, the highest DPPH activities were achieved by UAE and UMAE from both macroalgae, while no clear pattern was recorded in the case of FRAP activities. The highest DPPH scavenging activities (112.5 ± 0.7 mg trolox equivalents/g) and FRAP activities (284.8 ± 2.2 mg trolox equivalents/g) were achieved from F. vesiculosus. Following the extraction treatment, an additional storage post-extraction (24 h) did not improve the yields of phytochemicals or antioxidant properties of the extracts.

Bioactive Compounds from Marine Sponges: Fundamentals and Applications

Marine sponges are sessile invertebrates that can be found in temperate, polar and tropical regions. They are known to be major contributors of bioactive compounds, which are discovered in and extracted from the marine environment. The compounds extracted from these sponges are known to exhibit various bioactivities, such as antimicrobial, antitumor and general cytotoxicity. For example, various compounds isolated from Theonella swinhoei have showcased various bioactivities, such as those that are antibacterial, antiviral and antifungal. In this review, we discuss bioactive compounds that have been identified from marine sponges that showcase the ability to act as antibacterial, antiviral, anti-malarial and antifungal agents against human pathogens and fish pathogens in the aquaculture industry. Moreover, the application of such compounds as antimicrobial agents in other veterinary commodities, such as poultry, cattle farming and domesticated cats, is discussed, along with a brief discussion regarding the mode of action of these compounds on the targeted sites in various pathogens. The bioactivity of the compounds discussed in this review is focused mainly on compounds that have been identified between 2000 and 2020 and includes the novel compounds discovered from 2018 to 2021.

Alginate: From Food Industry to Biomedical Applications and Management of Metabolic Disorders

Initially used extensively as an additive and ingredient in the food industry, alginate has become an important compound for a wide range of industries and applications, such as the medical, pharmaceutical and cosmetics sectors. In the food industry, alginate has been used to coat fruits and vegetables, as a microbial and viral protection product, and as a gelling, thickening, stabilizing or emulsifying agent. Its biocompatibility, biodegradability, nontoxicity and the possibility of it being used in quantum satis doses prompted scientists to explore new properties for alginate usage. Thus, the use of alginate has been expanded so as to be directed towards the pharmaceutical and biomedical industries, where studies have shown that it can be used successfully as biomaterial for wound, hydrogel, and aerogel dressings, among others. Furthermore, the ability to encapsulate natural substances has led to the possibility of using alginate as a drug coating and drug delivery agent, including the encapsulation of probiotics. This is important considering the fact that, until recently, encapsulation and coating agents used in the pharmaceutical industry were limited to the use of lactose, a potentially allergenic agent or gelatin. Obtained at a relatively low cost from marine brown algae, this hydrocolloid can also be used as a potential tool in the management of diabetes, not only as an insulin delivery agent but also due to its ability to improve insulin resistance, attenuate chronic inflammation and decrease oxidative stress. In addition, alginate has been recognized as a potential weight loss treatment, as alginate supplementation has been used as an adjunct treatment to energy restriction, to enhance satiety and improve weight loss in obese individuals. Thus, alginate holds the promise of an effective product used in the food industry as well as in the management of metabolic disorders such as diabetes and obesity. This review highlights recent research advances on the characteristics of alginate and brings to the forefront the beneficial aspects of using alginate, from the food industry to the biomedical field.