Antimicrobial Action of Compounds from Marine Seaweed

Combating the causative agent of amoebic keratitis, Acanthamoeba castellanii, using Padina pavonica alcoholic extract: toxicokinetic and molecular docking approaches

Natural products play a significant role in providing the current demand as antiparasitic agents, which offer an attractive approach for the discovery of novel drugs. The present study aimed to evaluate in vitro the potential impact of seaweed Padina pavonica (P. pavonica) extract in combating Acanthamoeba castellanii (A. castellanii). The phytochemical constituents of the extract were characterized by Gas chromatography-mass spectrometry. Six concentrations of the algal extract were used to evaluate its antiprotozoal activity at various incubation periods. Our results showed that the extract has significant inhibition against trophozoites and cysts viability, with complete inhibition at the high concentrations. The IC50 of P. pavonica extract was 4.56 and 4.89 µg/mL for trophozoites and cysts, respectively, at 24 h. Morphological alterations of A. castellanii trophozoites/cysts treated with the extract were assessed using inverted and scanning electron microscopes and showed severe damage features upon treatment with the extract at different concentrations. Molecular Docking of extracted compounds against Acanthamoeba cytochrome P450 monooxygenase (AcCYP51) was performed using Autodock vina1.5.6. A pharmacokinetic study using SwissADME was also conducted to investigate the potentiality of the identified bioactive compounds from Padina extract to be orally active drug candidates. In conclusion, this study highlights the in vitro amoebicidal activity of P. pavonica extract against A. castellanii adults and cysts and suggests potential AcCYP51 inhibition.

Algae-derived compounds: Bioactivity, allergenicity and technologies enhancing their values

As a rapidly growing source of human nutrients, algae biosynthesize diverse metabolites which have promising bioactivities. However, the potential allergenicity of algal components hinder their widespread adoption. This review provides a comprehensive review of various macro and micronutrients derived from algal biomass, with particular focus on bioactive compounds, including peptides, polyphenols, carotenoids, omega-3 fatty acids and phycocyanins. The approaches used to produce algal bioactive compounds and their health benefits (antioxidant, antidiabetic, cardioprotective, anti-inflammatory and immunomodulatory) are summarised. This review particularly focuses on the state-of-the-art of precision fermentation, encapsulation, cold plasma, high-pressure processing, pulsed electric field, and subcritical water to reduce the allergenicity of algal compounds while increasing their bioactivity and bioavailability. By providing insights into current challenges of algae-derived compounds and opportunities for advancement, this review contributes to the ongoing discourse on maximizing their application potential in the food nutraceuticals, and pharmaceuticals industries.

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

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

Macroalgae farming for sustainable future: Navigating opportunities and driving innovation

Seaweed cultivation has garnered significant interest, driven by its wide range of biomass benefits. However, comprehensive assessments from various perspectives are imperative to ensure the sustainable cultivation of seaweed. Biotic and Abiotic factors can significantly impact seaweed yield in complex commercial farming. Biotic factors include bacteria, fungi, viruses, and other algae, while abiotic factors include environmental conditions such as temperature, salinity, light intensity, and nutrient availability. Additionally, the susceptibility of seaweeds to pests and diseases further compounds the issue, leading to potential crop losses. This study endeavours to shed light on the immense potential of macroalgae cultivation and underscores the pressing need for scientific advancements in this field. The comprehensive review clearly explains the latest developments in seaweed cultivation and highlights significant advances from diverse seaweed research. Moreover, it provides insightful glimpses into possible future developments that could shape the trajectory of this promising industry.

Ingredients in Commercially Available Mouthwashes

OBJECTIVES

Mouthwashes, a cornerstone of oral and dental hygiene, play a pivotal role in combating the formation of dental plaque, a leading cause of periodontal disease and dental caries. This study aimed to review the composition of mouthwashes found on retail shelves in Turkey and evaluate their prevalence and side effects, if any.

METHODS

The mouthwashes examined were sourced from the 5 largest chain stores in each district of Istanbul. A comprehensive list of the constituents was meticulously recorded. The research was supported by an extensive compilation of references from scholarly databases such as Google Scholar, PubMed, and ScienceDirect. Through rigorous analysis, the relative proportions of mouthwash ingredients and components were determined.

RESULTS

A total of 45 distinctive variations of mouthwashes, representing 17 prominent brands, were identified. Amongst the 116 ingredients discovered, 70 were evaluated for potential adverse effects and undesirable side effects. The aroma of the mouthwash (n = 45; 100%), as welll as their sodium fluoride (n = 28; 62.22%), sodium saccharin (n = 29; 64.44%), sorbitol (n = 21; 46.6%), and propylene glycol (n = 28; 62.22%) content were the main undesireable features.

CONCLUSIONS

The limited array of mouthwashes found on store shelves poses a concern for both oral and public health. Furthermore, the intricate composition of these products, consisting of numerous ingredients with the potential for adverse effects, warrants serious attention. Both clinicians and patients should acknowledge the importance and unwarranted side effects of the compnents of the mouthwashes.

Biomimetic ZrO2-modified seaweed residue with excellent fluorine/ bacteria removal and uranium extraction properties for wastewater purification

Exploring and developing promising biomass composite membranes for the water purification and waste resource utilization is of great significance. The modification of biomass has always been a focus of research in its resource utilization. In this study, we successfully prepare a functional composite membrane, activated graphene oxide/seaweed residue-zirconium dioxide (GOSRZ), with fluoride removal, uranium extraction, and antibacterial activity by biomimetic mineralization of zirconium dioxide nanoparticles (ZrO2 NPs) on seaweed residue (SR) grafted with oxidized graphene (GO). The GOSRZ membrane exhibits highly efficient and specific adsorption of fluoride. For the fluoride concentrations in the range of 100-400 mg/L in water, the removal efficiency can reach over 99 %, even in the presence of interfering ions. Satisfactory extraction rates are also achieved for uranium by the GOSRZ membrane. Additionally, the antibacterial performance studies show that this composite membrane efficiently removes Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA). The high adsorption of F- and U(VI) to the composite membrane is ascribed to the ionic exchange and coordination interactions, and its antibacterial activity is caused by the destruction of bacterial cell structure. The sustainability of the biomass composite membranes is further evaluated using the Sustainability Footprint method. This study provides a simple preparation method of biomass composite membrane, expands the water purification treatment technology, and offers valuable guidance for the resource utilization of seaweed waste and the removal of pollutants in wastewater.

Antitumor Activity and Mechanism of Terpenoids in Seaweeds Based on Literature Review and Network Pharmacology

Seaweeds are a treasure trove of natural secondary metabolites. Terpenoids extracted from seaweeds are shown to possess a variety of antitumor cellular activities. However, due to the complex and diverse structures of terpenoids, their therapeutic targets and complex mechanisms of action have not been clarified. The present study summarises the research on terpenoids from seaweeds in oncological diseases over the last 20 years. Terpenoids show different degrees of inhibitory effects on different types of tumor cells, suggesting that terpenoids in seaweeds may have potential antitumor disease potential. Terpenoids with potential antitumor activity and their mechanism of action are investigated using network pharmacology. A total of 125 terpenoids and 286 targets are obtained. Proto-oncogene tyrosine-protein kinase Src(SRC), Signal transducer and activator of transcription 3 (STAT3), Mitogen-activated protein kinase (MAPK3, MAPK1), Heat shock protein HSP 90-alpha (HSP90AA1), Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), and RAC-alpha serine/threonine-protein kinase (AKT1) are defined as core targets. According to GO function and Kyoto encyclopedia of genes and genomes(KEGG) enrichment analysis, terpenoids may affect the Phoshatidylinositol 3'-kinase (PI3K)-Akt signaling pathway, Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor resistance, Prostate cancer, MAPK signaling pathway, and Proteoglycans in cancer. In addition, the molecular docking results show that the selected terpenoids are all able to bind strongly to the active protein. Terpenoids may slow down the progression of cancer by controlling apoptosis, proliferation, and protein and enzyme binding.

Evaluation of the potential of extract of seaweed Eucheuma denticulatum as an alternative to antibiotic growth promoter in broiler chickens

The seaweeds are in focus for their immunity and gut health-stimulating potentials in humans and farm animals, but their potential as a gut health-promoting agent and performance booster to replace antibiotic growth promoters (AGP) in broiler chicken-feed remains to be evaluated. In vivo feeding experiments were conducted on commercial broiler chickens (1-42 days post-hatch) to evaluate dried aqueous exact of red seaweed Eucheuma denticulatum (referred to as PBD 5). Each of the three test diets (basal diet with three dosing regimens of PBD5, 0.25 g kg -1 for 0-6 weeks, 0.25 g kg -1 for 0-4 weeks or 1.0 g kg -1 for 0-2 weeks), along with an AGP supplemented diet (Virginiamycin (V), 20 ppm in basal diet), and a control diet was fed to 13 pen replicates of five chicks in each. PBD5 at 1.0 g kg -1 diet for 0-2 weeks improved (P < 0.05) cumulative feed efficiency (4.65 % improvement at 28 d, and 3.74 % at 35 d) than the control and comparable to the V group and the trend in improvement persisted up to 42 d. The group fed with PBD5 @ 1.0 g kg -1 for 0-2 weeks had significantly (P < 0.05) higher serum IgG level, glutathione peroxidase levels, fat digestibility, and expression of occludin and avian beta-defensin 4 gene in the gut and a trend of increased expression of growth hormone receptor gene in the liver as compared to the control with no significant effect on body weight, phytohemagglutinin response or haemagglutination inhibition titer. At d 25 of age, fecal E. coli count was significantly (P < 0.01) lower in the seaweed extract groups and the V group as compared to the control. It can be concluded that dried aqueous extract of E. denticulatum at 1 g kg -1 diet for 0-2 weeks can be used as an alternative to antibiotic growth promoter in broiler chickens to improve feed efficiency and reduce gut pathogen load, and the improved performance was associated with increased expression of gut immunity and growth hormone receptor genes.

In Vitro Viability Tests of New Ecofriendly Nanosystems Incorporating Essential Oils for Long-Lasting Conservation of Stone Artworks

The study explores the application of natural biocides (oregano essential oil and eugenol, directly applied in solutions or encapsulated within silica nanocapsules) for safeguarding stone cultural heritage from biodeterioration, using green algae (Chlorococcum sp.) and cyanobacteria (Leptolyngbya sp.) as common pioneer biodeteriogens. Core-shell nanocontainers were built for a controlled release of microbicidal agents, a safe application of chemicals and a prolonged efficacy. The qualitative and quantitative evaluations of biocide efficiency at different doses were periodically performed in vitro, after six scheduled intervals of time (until 100 days). The release kinetics of composite biocide-embedding silica nanocapsules were characterized by the UV-Vis spectroscopy technique. Data showed both promising potential and some limitations. The comparative tests of different biocidal systems shed light on their variable efficacy against microorganisms, highlighting how encapsulation influences the release dynamics and the overall effectiveness. Both the essential oils showed a potential efficacy in protective antifouling coatings for stone artifacts. Ensuring compatibility with materials, understanding their differences in biocidal activity and their release rates becomes essential in tailoring gel, microemulsion or coating products for direct on-site application.

Scope and challenges of seaweed utilization in food and nutraceutical industry in India: a review

Seaweeds are an excellent source of unique antioxidant phytochemicals, dietary fibres, essential amino acids, vitamins, polyunsaturated fatty acids and minerals. The presence of such structurally diverse and high value bioactive compounds has led to popularization of seaweed as functional food ingredient in global health supplement market. India, with a long coastline of 8100 km and exclusive economic zone of 2.17 million km2, is rich in diverse seaweed resources belonging to almost 700 species. However, food and nutraceutical application of Indian seaweed is highly constrained. Apart from Kappaphycus alvarezii, there is no systematic commercial cultivation of seaweed in India. The regulatory framework for use of seaweed as food is still developing and consumer acceptance is still low. However, there is a timely and renewed interest from different government agencies and research organisations to develop a thriving food and nutraceutical industry using India's vast seaweed resources. The review briefly describes the nutritional and functional food potential of the seaweed and goes on to discuss the scope of seaweed utilization in food and nutraceutical industry in India. Further, the review has identified the regulatory challenges and quality control requirements for use of seaweeds in food and nutraceuticals.

Antibacterial properties of marine algae incorporated polylactide acid membranes as an alternative to clinically applied different collagen membranes

The reconstruction of bony defects in the alveolar crest poses challenges in dental practice. Guided tissue regeneration (GTR) and guided bone regeneration (GBR) procedures utilize barriers to promote bone regeneration and prevent epithelial growth. This study focuses on evaluating the antibacterial properties of marine algae-polylactic acid (PLA) composite membranes compared to commercially available collagen membranes. Marine algae (Corallina elongata, Galaxaura oblongata, Cystoseira compressa, Saragassum vulgare, and Stypopodium schimperi) were processed into powders and blended with PLA to fabricate composite membranes. Cytocompatibility assays using human periodontal ligament fibroblasts (n = 3) were performed to evaluate biocompatibility. Antibacterial effects were assessed through colony-forming units (CFU) and scanning electron microscopy (SEM) analysis of bacterial colonization on the membranes. The cytocompatibility assays demonstrated suitable biocompatibility of all marine algae-PLA composite membranes with human periodontal ligament fibroblasts. Antibacterial assessment revealed that Sargassum vulgare-PLA membranes exhibited the highest resistance to bacterial colonization, followed by Galaxaura oblongata-PLA and Cystoseira compressa-PLA membranes. SEM analysis confirmed these findings and revealed smooth surface textures for the marine algae-PLA membranes compared to the fibrous and porous structures of collagen membranes. Marine algae-PLA composite membranes show promising antibacterial properties and cytocompatibility for guided bone and tissue regeneration applications. Sargassum vulgare-PLA membranes demonstrated the highest resistance against bacterial colonization. These findings suggest that marine algae-PLA composite membranes could serve as effective biomaterials for infection control and tissue regeneration. Further in vivo validation and investigation of biodegradation properties are necessary to explore their clinical potential.

Characterization and biological applications of gonadal extract of Paracentrotus lividus collected along the Mediterranean coast of Alexandria, Egypt

Marine invertebrates represent a valuable reservoir of pharmaceutical bioactive compounds with potential relevance to various medical applications. These compounds exhibit notable advantages when compared to their terrestrial counterparts, in terms of their potency, activity, and mechanism of action. Within this context, the present work aimed to extract, chemically characterize, and investigate the bioactivity of the gonadal extract of the sea urchin Paracentrotus lividus (P. lividus) collected along the Mediterranean coast of Alexandria, Egypt. Fractions of the gonadal extract were characterized by Spectrophotometry and gas chromatography-mass spectrometry (GC-MS), and their bioactivities were investigated in vitro. The analysis supported the extract richness of carotenoids and bioactive compounds. The extract showed promising anticancer activity against three different breast cancer cell lines with different levels of aggressiveness and causative factors, namely MDA-MB-231, MDA-MB-453, and HCC-1954. Gene expression analysis using RT-qPCR showed that P. lividus extract inhibited the expression of crucial factors involved in cell cycle regulation and apoptosis. In addition, the extract significantly inhibited the lipo-polysaccharides (LPS) induced inflammation in the RAW264.7 macrophage cell line and exerted anti-bacterial activity against the Gram-negative bacteria Klebsiella pneumoniae and Pseudomonas aeruginosa. Collectively, these results demonstrated the chemical richness and the wide-scale applicability of P. lividus gonadal extract as an anti-cancer, anti-bacterial, and anti-inflammatory natural extract.

Evaluation of Cladophora and Chlamydomonas microalgae for environmental sustainability: A comparative study of antimicrobial and photocatalytic dye degradation

The present study emphasizes exploring the potential of bioactive compounds such as polysaccharides, protein, pigments, antioxidants, and vitamins extracted from two microalgae species, Cladophora and Chlamydomonas. The extraction process was optimized for different periods, and the extracted bioactive compounds were characterized. These bioactive compounds showed significant antibacterial activity against gram-positive and gram-negative bacteria. Notably, Cladophora species exhibited a higher zone of inhibition than Chlamydomonas species against both gram-positive and gram-negative bacterial strains. Moreover, the photocatalytic activity of these bioactive compounds was investigated for the degradation of methylene blue and crystal violet dyes under different light conditions. The results demonstrated that Cladophora species exhibited superior photocatalytic activity under natural sunlight, UV light, and visible light sources compared to Chlamydomonas species. Moreover, Cladophora species achieved the highest dye degradation efficiencies of 78% and 72% for methylene blue and crystal violet, respectively, within 150 min compared to UV light and visible light sources.

Ulva fasciata, a green alga, attenuates the kidney and liver dysfunctions in rats induced by acetaminophen

Acetaminophen (AAP) is an analgesic-antipyretic drug which is considered safe at recommended dose, but its overuse may induce renal and hepatic injuries. Marine macro algae have great potential against drug-induced renal and hepatic dysfunctions. The present study described the reno-protective and hepato-protective effects of the ethanol extract of an edible green alga Ulva fasciata and its fractions (n-hexane, chloroform and methanol) against AAP toxicity. In the 1st set of experiment, rats were divided into five groups. Of which two were treatment groups beside three controls, the first treatment group was given ethanol extract of U. fasciata alone and the second group was given the same extract with AAP. In the 2nd set of experiment, rats were divided into nine groups, of which three treatment groups administered n-hexane, chloroform and methanol fractions of ethanol extract of U. fasciata respectively while other three treatment groups received the same fractions individually with AAP. On the 11th day, rats were decapitated after 12 h of fasting from both sets, blood samples were collected for assessment of biochemical parameters and kidney tissues were used for determination of oxidants and antioxidants. Histopathological assessment was also done in kidney tissues. A single dose of AAP (600 mg/kg) affected kidney markers including creatinine, urea and blood urea nitrogen (BUN) and hepatic enzymes. Ethanolic extract of U. fasciata normalized kidney and liver markers in AAP intoxicated rats. AAP also reduced glutathione (GSH) in kidney tissues and altered kidney architecture, which were improved by ethanolic extract and chloroform soluble fraction of U. fasciata. A total of 14 polyunsaturated fatty acids were identified from chloroform soluble fraction of U. fasciata by GC-MS and assumed these may be involved in protective activities of U. fasciata.

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.

Anti-methanogenic potential of seaweeds and seaweed-derived compounds in ruminant feed: current perspectives, risks and future prospects

With methane emissions from ruminant agriculture contributing 17% of total methane emissions worldwide, there is increasing urgency to develop strategies to reduce greenhouse gas emissions in this sector. One of the proposed strategies is ruminant feed intervention studies focused on the inclusion of anti-methanogenic compounds which are those capable of interacting with the rumen microbiome, reducing the capacity of ruminal microorganisms to produce methane. Recently, seaweeds have been investigated for their ability to reduce methane in ruminants in vitro and in vivo, with the greatest methane abatement reported when using the red seaweed Asparagopsis taxiformis (attributed to the bromoform content of this species). From the literature analysis in this study, levels of up to 99% reduction in ruminant methane emissions have been reported from inclusion of this seaweed in animal feed, although further in vivo and microbiome studies are required to confirm these results as other reports showed no effect on methane emission resulting from the inclusion of seaweed to basal feed. This review explores the current state of research aiming to integrate seaweeds as anti-methanogenic feed additives, as well as examining the specific bioactive compounds within seaweeds that are likely to be related to these effects. The effects of the inclusion of seaweeds on the ruminal microbiome are also reviewed, as well as the future challenges when considering the large-scale inclusion of seaweeds into ruminant diets as anti-methanogenic agents.

Annotation of GC-MS Data of Antimicrobial Constituents in the Antarctic Seaweed Phaeurus antarcticus by Molecular Networking

Phaeurus antarcticus is a member of the Desmarestiaceae family endemic to the Antarctic Peninsula. Reports addressing its chemical composition and biological activities are scarce. Herein, bioactive non-polar compounds of P. antarcticus against pathogenic bacteria, Leishmania amazonensis and Neospora caninum parasites were targeted through GC-MS Molecular Networking and multivariate analysis (OPLS-DA). The effects on horseradish peroxidase (HRP) were also evaluated. P. antarcticus exhibited selective bacteriostatic and bactericidal activities against Staphylococcus aureus with MIC and MBC values from 6.25-100 μg mL-1 . Fractions HX-FC and HX-FD were the most active against L. amazonensis with EC50 ranging from 18.5-62.3 μg mL-1 . Additionally, fractions HX-FC and HX-FD showed potent inhibition of N. caninum at EC50 values of 2.8 and 6.3 μg mL-1 , respectively. All fractions inhibited HRP activity, indicating possible interactions with Heme proteins. It was possible to annotate compounds from tree mains clusters, containing terpenoids, steroids, fatty acids, and alcohols by correlating the spectral data of the GC-MS analysis with Molecular Networking and the OPLS-DA results.

Gracilaria salicornia as potential substratum for green synthesis of Cerium Oxide Nanoparticles coupled hydrogel: An effective antimicrobial thin film

Sodium alginate based (SA) hydrogel supplemented Cerium Oxide nanoparticles (CeO2NPs) was produced to fabricate an antimicrobial thin film using an aqueous extract of G. salicornia (Gs). The Gs-CeO2NPs were characterized via SEM, FT-IR, EDX, XRD and DLS, the particle size was 200 nm, agreed with XRD. Gs-SA powder was extracted and incorporated with CeO2NPs. The Gs-SA and its composite thin film (Gs-CeO2NPs-SATF) were characterized including viscosity, FT-IR, TGA, and SEM. The adhesion of Gs-SA coating around Gs-CeO2NPs confirmed via FTIR. The antimicrobial properties of Gs-CeO2NPs and CeO2NPs-SATF were proved in MICs for E. coli and Candida albicans at 62.5 and 250.0 μg/mL. The biofilm inhibition efficiency of CeO2NPs-SATF was 74.67 ± 0.98% and 65.45 ± 0.40% for E. coli and Candida albicans. The CeO2NPs-SATF was polydisperse in nature and film structure gets fluctuated with NPs concentration. Increased NPs into SATF enhances pore size of gel and corroborated with viscous behaviour. The cytotoxicity of Gs-CeO2NP-SA in Artemia salina at higher concentration 100 μg/mL provides less lethal effect into the adult. The antioxidant activity of Gs-CeO2NP-SA in DPPH assay was noticed at 0.6 mg ml-1 with radical scavenging activity at 65.85 ± 0.81%. Thus the Gs-CeO2NP-SATF would be suitable in antimicrobial applications.

Exploring the hidden treasures of Nitella hyalina: a comprehensive study on its biological compounds, nutritional profile, and unveiling its antimicrobial, antioxidative, and hypoglycemic properties

Macroalgae has the potential to be a precious resource in food, pharmaceutical, and nutraceutical industries. Therefore, the present study was carried out to identify and quantify the phyco-chemicals and to assess the nutritional profile, antimicrobial, antioxidant, and anti-diabetic properties of Nitella hyalina extracts. Nutritional composition revealed0.05 ± 2.40% ash content, followed by crude protein (24.66 ± 0.95%), crude fat (17.66 ± 1.42%), crude fiber (2.17 ± 0.91%), moisture content (15.46 ± 0.48%) and calculated energy value (173.50 ± 2.90 Kcal/100 g). 23 compounds were identified through GC-MS analysis in ethyl acetate extract, with primary compounds being Palmitic acid, methyl ester, (Z)-9-Hexadecenoic acid, methyl ester, and Methyl tetra decanoate. Whereas 15 compounds were identified in n-butanol extract, with the major compounds being Tetra decanoic acid, 9-hexadecanoic acid, Methyl pentopyranoside, and undecane. FT-IR spectroscopy confirmed the presence of alcoholic phenol, saturated aliphatic compounds, lipids, carboxylic acid, carbonyl, aromatic components, amine, alkyl halides, alkene, and halogen compounds. Moreover, n-butanol contains 1.663 ± 0.768 mg GAE/g, of total phenolic contents (TPC,) and 2.050 ± 0.143 QE/g of total flavonoid contents (TFC), followed by ethyl acetate extract, i.e. 1.043 ± 0.961 mg GAE/g and 1.730 ± 0.311 mg QE/g respectively. Anti-radical scavenging effect in a range of 34.55-46.35% and 35.39-41.79% was measured for n-butanol and ethyl acetate extracts, respectively. Antimicrobial results declared that n-butanol extract had the highest growth inhibitory effect, followed by ethyl acetate extract. Pseudomonas aeruginosa was reported to be the most susceptible strain, followed by Staphylococcus aureus and Escherichia coli, while Candida albicans showed the least inhibition at all concentrations. In-vivo hypoglycemic study revealed that both extracts exhibited dose-dependent activity. Significant hypoglycemic activity was observed at a dose of 300 mg/kg- 1 after 6 h i.e. 241.50 ± 2.88, followed by doses of 200 and 100 mg/kg- 1 (245.17 ± 3.43 and 250.67 ± 7.45, respectively) for n-butanol extract. In conclusion, the macroalgae demonstrated potency concerning antioxidant, antimicrobial, and hypoglycemic properties.

Rehashing Our Insight of Seaweeds as a Potential Source of Foods, Nutraceuticals, and Pharmaceuticals

In a few Southeast Asian nations, seaweeds have been a staple of the cuisine since prehistoric times. Seaweeds are currently becoming more and more popular around the world due to their superior nutritional value and medicinal properties. This is because of rising seaweed production on a global scale and substantial research on their composition and bioactivities over the past 20 years. By reviewing several articles in the literature, this review aimed to provide comprehensive information about the primary and secondary metabolites and various classes of bioactive compounds, such as polysaccharides, polyphenols, proteins, and essential fatty acids, along with their bioactivities, in a single article. This review also highlights the potential of seaweeds in the development of nutraceuticals, with a particular focus on their ability to enhance human health and overall well-being. In addition, we discuss the challenges and potential opportunities associated with the advancement of pharmaceuticals and nutraceuticals derived from seaweeds, as well as their incorporation into different industrial sectors. Furthermore, we find that many bioactive constituents found in seaweeds have demonstrated potential in terms of different therapeutic attributes, including antioxidative, anti-inflammatory, anticancer, and other properties. In conclusion, seaweed-based bioactive compounds have a huge potential to play an important role in the food, nutraceutical, and pharmaceutical sectors. However, future research should pay more attention to developing efficient techniques for the extraction and purification of compounds as well as their toxicity analysis, clinical efficacy, mode of action, and interactions with regular diets.

Algae as a potential source of protein meat alternatives

With the rise of plant-based meat alternatives, there is a growing need for sustainable and nutritious sources of protein. Alga is a rich protein source, and initial studies show that it can be a good component in developing protein meat alternatives. However, there are certain limitations in their use as the need for efficient and optimal technical process in large-scale protein extraction and purification, as well as overcoming certain negative effects such as potentially harmful compounds, allergenicity issues, or sensorial affections, especially in color but also in textural and flavor characteristics. This review offers a vision of the fledgling research about using alga protein in the development of meat alternatives or supplementing meat products.

Marine-Derived Components: Can They Be a Potential Therapeutic Approach to Parkinson's Disease?

The increase in the life expectancy average has led to a growing elderly population, thus leading to a prevalence of neurodegenerative disorders, such as Parkinson's disease (PD). PD is the second most common neurodegenerative disorder and is characterized by a progressive degeneration of the dopaminergic neurons in the substantia nigra pars compacta (SNpc). The marine environment has proven to be a source of unique and diverse chemical structures with great therapeutic potential to be used in the treatment of several pathologies, including neurodegenerative impairments. This review is focused on compounds isolated from marine organisms with neuroprotective activities on in vitro and in vivo models based on their chemical structures, taxonomy, neuroprotective effects, and their possible mechanism of action in PD. About 60 compounds isolated from marine bacteria, fungi, mollusk, sea cucumber, seaweed, soft coral, sponge, and starfish with neuroprotective potential on PD therapy are reported. Peptides, alkaloids, quinones, terpenes, polysaccharides, polyphenols, lipids, pigments, and mycotoxins were isolated from those marine organisms. They can act in several PD hallmarks, reducing oxidative stress, preventing mitochondrial dysfunction, α-synuclein aggregation, and blocking inflammatory pathways through the inhibition translocation of NF-kB factor, reduction of human tumor necrosis factor α (TNF-α), and interleukin-6 (IL-6). This review gathers the marine natural products that have shown pharmacological activities acting on targets belonging to different intracellular signaling pathways related to PD development, which should be considered for future pre-clinical studies.

Novel Fucoidan Pharmaceutical Formulations and Their Potential Application in Oncology-A Review

Fucoidan belongs to the family of marine sulfated, L-fucose-rich polysaccharides found in the cell wall matrix of various brown algae species. In the last few years, sulfated polysaccharides have attracted the attention of researchers due to their broad biological activities such as anticoagulant, antithrombotic, antidiabetic, immunomodulatory, anticancer and antiproliferative effects. Recently the application of fucoidan in the field of pharmaceutical technology has been widely investigated. Due to its low toxicity, biocompatibility and biodegradability, fucoidan plays an important role as a drug carrier for the formulation of various drug delivery systems, especially as a biopolymer with anticancer activity, used for targeted delivery of chemotherapeutics in oncology. Furthermore, the presence of sulfate residues with negative charge in its structure enables fucoidan to form ionic complexes with oppositely charged molecules, providing relatively easy structure-forming properties in combination with other polymers. The aim of the present study was to overview essential fucoidan characteristics, related to its application in the development of pharmaceutical formulations as a single drug carrier or in combinations with other polymers. Special focus was placed on micro- and nanosized drug delivery systems with polysaccharides and their application in the field of oncology.

Keep It Simple: Improving the Ex Situ Culture of Cystoseira s.l. to Restore Macroalgal Forests

Brown algae from genus Cystoseira s.l. form dense underwater forests that represent the most productive areas in the Mediterranean Sea. Due to the combined effects of global and local stressors such as climate change, urbanization, and herbivore outbreaks, there has been a severe decline in brown algal forests in the Mediterranean Sea. Natural recovery of depleted sites is unlikely due to the low dispersal capacity of these species, and efficient techniques to restore such habitats are needed. In this context, the aims of our study were (1) to improve and simplify the current ex situ laboratory protocol for the cultivation of Gongolaria barbata by testing the feasibility of some cost-effective and time-efficient techniques on two donor sites of G. barbata and (2) to evaluate the survival and growth of young thalli during the laboratory phase and during the most critical five months after out-planting. Specifically, the following ex situ cultivation methods were tested: (A) cultivation on clay tiles in mesocosms with culture water prepared by three different procedures (a) filtered seawater with a 0.22 μm filter membrane, (b) filtered seawater with a 0.7 μm filter membrane (GF), and (c) UV-sterilized water, and (B) cultivation on clay tiles in open laboratory systems. After two weeks, all thalli were fixed to plastic lantern net baskets suspended at a depth of 2 m in the coastal sea (hybrid method), and the algal success was monitored in relation to the different donor sites and cultivation protocol. The satisfactory results of this study indicate that UV-sterilized water is suitable for the cultivation of G. barbata in mesocosm, which significantly reduces the cost of the laboratory phase. This opens the possibility of numerous and frequent algal cultures during the reproductive period of the species. Additionally, if the young thalli remain in the lantern net baskets for an extended period of several months, they can grow significantly in the marine environment without being exposed to pressure from herbivorous fish.

Screening macroalgae for mitigation of enteric methane in vitro

This study investigated the effects of 67 species of macroalgae on methanogenesis and rumen fermentation in vitro. Specimens were analyzed for their effect on ruminal fermentation and microbial community profiles. Incubations were carried out in an automated gas production system for 24-h and macroalgae were tested at 2% (feed dry matter basis) inclusion rate. Methane yield was decreased 99% by Asparagopsis taxiformis (AT) when compared with the control. Colpomenia peregrina also decreased methane yield 14% compared with control; no other species influenced methane yield. Total gas production was decreased 14 and 10% by AT and Sargassum horneri compared with control, respectively. Total volatile fatty acid (VFA) concentration was decreased between 5 and 8% by 3 macroalgae, whereas AT reduced it by 10%. Molar proportion of acetate was decreased 9% by AT, along with an increase in propionate by 14%. Asparagopsis taxiformis also increased butyrate and valerate molar proportions by 7 and 24%, respectively, whereas 3 macroalgae species decreased molar proportion of butyrate 3 to 5%. Vertebrata lanosa increased ammonia concentration, whereas 3 other species decreased it. Inclusion of AT decreased relative abundance of Prevotella, Bacteroidales, Firmicutes and Methanobacteriaceae, whereas Clostridium, Anaerovibrio and Methanobrevibacter were increased. Specific gene activities for Methanosphaera stadtmane and Methanobrevibacter ruminantium were decreased by AT inclusion. In this in vitro study, Asparagopsis taxiformis was most effective in decreasing methane concentration and yield, but also decreased total gas production and VFA concentration which indicates overall inhibition of ruminal fermentation. No other macroalgae were identified as potential mitigants of enteric methane.

Biocompatible polysaccharide fabricated graphene oxide nanoparticles: A versatile nanodrug carrier to deliver κ- carrageenan against cancer cells

A graphene oxide mediated hybrid nano system for pH stimuli-responsive and in vitro drug delivery targeted for cancer was described in this study. Graphene oxide (GO) functionalized Chitosan (CS) mediated nanocarrier capped with xyloglucan (XG) was fabricated with and without Kappa carrageenan (κ-C) from red seaweed, Kappaphycus alverzii, as an active drug. FTIR, EDAX, XPS, XRD, SEM and HR-TEM studies were carried out for GO-CS-XG nanocarrier loaded with and without active drugs to understand the physicochemical properties. XPS (C1s, N1s and O1s) confirmed the fabrications of XG and functionalization of GO by CS via the binding energies at 284.2 eV, 399.4 eV and 531.3 eV, respectively. The amount of drug loaded in vitro was 0.422 mg/mL. The GO-CS-XG nanocarrier showed a cumulative drug release of 77 % at acidic pH 5.3. In contrast to physiological conditions, the release rate of κ-C from the GO-CS-XG nanocarrier was considerably higher in the acidic condition. Thus, a pH stimuli-responsive anticancer drug release was successfully achieved with the GO-CS-XG-κ-C nanocarrier system for the first time. The drug release mechanism was carried out using various kinetic models that showed a mixed release behavior depending on concentration and diffusion/swelling mechanism. The best-fitting model which supports our release mechanism are zero order, first order and Higuchi models. GO-CS-XG and κ-C loaded nanocarrier biocompatibility were determined by in vitro hemolysis and membrane stabilization studies. MCF-7 and U937 cancer cell lines were used to study the cytotoxicity of the nanocarrier by MTT assay, which indicates excellent cytocompatibility. These findings support the versatile use of a green renewable biocompatible GO-CS-XG nanocarrier as targeted drug delivery and potential anticancer agent for therapeutic purposes.

New Insight on In Vitro Biological Activities of Sulfated Polysaccharides from Ulvophyte Green Algae

Green algae are natural bioresources that have excellent bioactive potential, partly due to sulfated polysaccharides (SPs) which are still rarely explored for their biological activities. There is currently an urgent need for studies exploring the anticancer biological activity of SPs extracted from two Indonesian ulvophyte green algae: the sulfated polysaccharide of Caulerpa racemosa (SPCr) and the sulfated polysaccharide of Caulerpa lentillifera (SPCl). The method of isolating SPs and their assessment of biological activities in this study were based on previous and similar studies. The highest yield sulfate/total sugar ratio was presented by SPCr than that of SPCl. Overall, SPCr exhibits a strong antioxidant activity, as indicated by smaller EC₅₀ values obtained from a series of antioxidant activity assays compared to the EC₅₀ values of Trolox (control). As an anti-obesity and antidiabetic, the overall EC₅₀ value of both SPs was close to the EC₅₀ of the positive control (orlistat and acarbose). Even more interesting was that SPCl displayed wide-ranging anticancer effects on colorectal, hepatoma, breast cancer cell lines, and leukemia. Finally, this study reveals new insights in that SPs from two Indonesian green algae have the potential to be promising nutraceuticals as novel antioxidative actors, and to be able to fight obesity, diabetes, and even cancer.

Utilization of Marine Seaweeds as a Promising Defense Against COVID-19: a Mini-review

COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which mainly affects the respiratory system. It has been declared as a "pandemic" in March 2020 by the World Health Organization due to the high spreading rate. SARS-CoV-2 binds with the angiotensin-converting enzyme 2 (ACE2) receptors on the cell surface which leads to the downregulation of ACE2 and upregulation of angiotensin-converting enzyme (ACE) receptors. The elevated level of cytokines and ACE receptors leads to the severity of SARS-CoV-2 infection. Due to the limited availability of vaccines and recurrent attacks of COVID-19 mainly in low-income countries, it is important to search for natural remedies to prevent or treat COVID-19 infection. Marine seaweeds are a rich source of bioactive compounds such as phlorotannins; fucoidan; carotenoids; omega-3 and omega-6 fatty acids; vitamins B₁₂, D, and C; and minerals including zinc and selenium that exhibit antioxidant, antiviral, and anti-inflammatory activities. Furthermore, bioactive compounds present in marine seaweeds have the ability to inhibit ACEs by inducing ACE2 which exhibits anti-inflammatory effects in COVID-19. Correspondingly, soluble dietary fibers present in seaweeds are served as prebiotics by generating short-chain fatty acids through fermentation. Hence, seaweeds can be utilized to reduce the gastrointestinal infections associated with SARS-CoV-2 infection.

The Potential of Algae in the Nutricosmetic Sector

Seaweeds or algae are marine autotrophic organisms. They produce nutrients (e.g., proteins, carbohydrates, etc.) essential for the survival of living organisms as they participate in biochemical processes and non-nutritive molecules (such as dietary fibers and secondary metabolites), which can improve their physiological functions. Seaweed polysaccharides, fatty acids, peptides, terpenoids, pigments, and polyphenols have biological properties that can be used to develop food supplements and nutricosmetic products as they can act as antibacterial, antiviral, antioxidant, and anti-inflammatory compounds. This review examines the (primary and secondary) metabolites produced by algae, the most recent evidence of their effect on human health conditions, with particular attention to what concerns the skin and hair's well-being. It also evaluates the industrial potential of recovering these metabolites from biomass produced by algae used to clean wastewater. The results demonstrate that algae can be considered a natural source of bioactive molecules for well-being formulations. The primary and secondary metabolites' upcycling can be an exciting opportunity to safeguard the planet (promoting a circular economy) and, at the same time, obtain low-cost bioactive molecules for the food, cosmetic, and pharmaceutical industries from low-cost, raw, and renewable materials. Today's lack of methodologies for recovering bioactive molecules in large-scale processes limits practical realization.

Marine Algal Polyphenols as Skin Protective Agents: Current Status and Future Prospectives

The skin is the outermost anatomical barrier, which plays a vital role in the maintenance of internal homeostasis and protection against physical, chemical, and biological detractors. Direct contact with various stimuli leads to several physiological changes that are ultimately important for the growth of the cosmetic industry. Due to the consequences of using synthetic compounds in skincare and cosmeceutical-related industries, the pharmaceutical and scientific communities have recently shifted their focus to natural ingredients. The nutrient-rich value of algae, which are some of the most interesting organisms in marine ecosystems, has attracted attention. Secondary metabolites isolated from seaweeds are potential candidates for a wide range of economic applications, including food, pharmaceuticals, and cosmetics. An increasing number of studies have focused on polyphenol compounds owing to their promising biological activities against oxidation, inflammation, allergies, cancers, melanogenesis, aging, and wrinkles. This review summarizes the potential evidence of the beneficial properties and future perspectives of using marine macroalgae-derived polyphenolic compounds for advancing the cosmetic industry.

Biopharmaceutical applications of microbial polysaccharides as materials: A review

Biological characteristics of natural polymers make microbial polysaccharides an excellent choice for biopharmaceuticals. Due to its easy purifying procedure and high production efficiency, it is capable of resolving the existing application issues associated with some plant and animal polysaccharides. Furthermore, microbial polysaccharides are recognized as prospective substitutes for these polysaccharides based on the search for eco-friendly chemicals. In this review, the microstructure and properties of microbial polysaccharides are utilized to highlight their characteristics and potential medical applications. From the standpoint of pathogenic processes, in-depth explanations are provided on the effects of microbial polysaccharides as active ingredients in the treatment of human diseases, anti-aging, and drug delivery. In addition, the scholarly developments and commercial applications of microbial polysaccharides as medical raw materials are also discussed. The conclusion is that understanding the use of microbial polysaccharides in biopharmaceuticals is essential for the future development of pharmacology and therapeutic medicine.

Seasonal Changes in the Biochemical Composition of Dominant Macroalgal Species along the Egyptian Red Sea Shore

Macroalgae are significant biological resources in coastal marine ecosystems. Seasonality influences macroalgae biochemical characteristics, which consequentially affect their ecological and economic values. Here, macroalgae were surveyed from summer 2017 to spring 2018 at three sites at 7 km (south) from El Qusier, 52 km (north) from Marsa Alam and 70 km (south) from Safaga along the Red Sea coast, Egypt. Across all the macroalgae collected, Caulerpa prolifera (green macroalgae), Acanthophora spicifera (red macroalgae) and Cystoseira myrica, Cystoseira trinodis and Turbinaria ornata (brown macroalgae) were the most dominant macroalgal species. These macroalgae were identified at morphological and molecular (18s rRNA) levels. Then, the seasonal variations in macroalgal minerals and biochemical composition were quantified to determine the apt period for harvesting based on the nutritional requirements for commercial utilizations. The chemical composition of macroalgae proved the species and seasonal variation. For instance, minerals were more accumulated in macroalgae C. prolifera, A. spicifera and T. ornata in the winter season, but they were accumulated in both C. myrica and C. trinodis in the summer season. Total sugars, amino acids, fatty acids and phenolic contents were higher in the summer season. Accordingly, macroalgae collected during the summer can be used as food and animal feed. Overall, we suggest the harvesting of macroalgae for different nutrients and metabolites in the respective seasons.

Antifungal activity of Gracilaria corticata methanol extract against Trichophyton mentagrophytes, Microsporum canis, and Microsporum gypseum on rat dermatophytosis models

Background and Purpose

Dermatophytosis is one of the most prevalent zoonotic diseases. Increased resistance of dermatophytosis-causing pathogens against antidermatophytic agents highlights the need for alternative medicine with higher efficiency and lower side effects. In the present study, the in vitro antifungal activities of different concentrations of Gracilaria corticata methanol extract against Trichophyton mentagrophytes, Microsporum canis, and Microsporum gypseum were assessed and their efficacy was evaluated in rat dermatophytosis models.

Materials and Methods

The broth microdilution and well diffusion methods were used to determine the in vitro antidermatophytic activity. The in vivo study was carried out using 40 dermatophytosis-infected adults male Wistar rats. The animals were divided into 4 groups (5% and 10% G. corticata ointment, terbinafine, and Vaseline) and treated with ointment until complete recovery. The percentage of wound closure was calculated for each group.

Results

The results revealed that G. corticata methanol extract was effective to varying extents against the tested dermatophytes. The highest inhibitory activity of G. corticata was found against T. mentagrophytes with minimum inhibitory concentration and minimum fungicidal concentration values of 4 and 9 µg mL-1, respectively. The in vivo experiment revealed that 10% G. corticata ointment significantly accelerated skin lesions reduction and completely cured M. gypseum, T. mentagrophytes, and M. canis infections after 19, 25, and 38 days, respectively.

Conclusion

The methanol extract of G. corticata exhibited significant antifungal activity in vitro and in vivo, suggesting that it could be used as an alternative to antidermatophytic therapy in a dose-dependent manner.

In Vitro Evaluation of Brown Seaweed Laminaria spp. as a Source of Antibacterial and Prebiotic Extracts That Could Modulate the Gastrointestinal Microbiota of Weaned Pigs

Laminaria spp. and their extracts have preventative potential as dietary supplements during weaning in pigs. The first objective of this study was to evaluate increasing concentrations of four whole seaweed biomass samples from two different Laminaria species harvested in two different months in a weaned pig faecal batch fermentation assay. Particularly, February and November whole seaweed biomass samples of L. hyperborea (LHWB-F and LHWB-N) and L. digitata (LDWB-F and LDWB-N) were used. In the next part of the study, the increasing concentrations of four extracts produced from L. hyperborea (LHE1-4) and L. digitata (LDE1-4) were evaluated in individual pure-culture growth assays using a panel of beneficial and pathogenic bacterial strains (second objective). The LHE1-4 and LDE1-4 were obtained using different combinations of temperature, incubation time and volume of solvent within a hydrothermal-assisted extraction methodology (E1-4). In the batch fermentation assay, the L. hyperborea biomass samples, LHWB-F and LHWB-N, lowered Bifidobacterium spp. counts compared to the L. digitata biomass samples, LDWB-F and LDWB-N (p < 0.05). LHWB-F and LDWB-N reduced Enterobacteriaceae counts (p < 0.05). LHWB-F and LDWB-F were selected as the most and least promising sources of antibacterial extracts from which to produce LHE1-4 and LDE1-4. In the pure-culture growth assays, E1- and E4-produced extracts were predominantly associated with antibacterial and bifidogenic activities, respectively. LHE1 reduced both Salmonella Typhimurium and Enterotoxigenic Escherichia coli with LDE1 having a similar effect on both of these pathogenic strains, albeit to a lesser extent (p < 0.05). Both LHE1 and LDE1 reduced B. thermophilum counts (p < 0.05). LDE4 exhibited strong bifidogenic activity (p < 0.05), whereas LHE4 increased Bifidobacterium thermophilum and Lactiplantibacillus plantarum counts (p < 0.05). In conclusion, antibacterial and bifidogenic extracts of Laminaria spp. were identified in vitro with the potential to alleviate gastrointestinal dysbiosis in newly weaned pigs.

Seaweed for climate mitigation, wastewater treatment, bioenergy, bioplastic, biochar, food, pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

Antimicrobial therapeutics isolated from algal source: retrospect and prospect

In the last few decades, attention on new natural antimicrobial compounds has arisen due to a change in consumer preferences and the increase in the number of resistant microorganisms. Algae are defined as photosynthetic organisms that demonstrate a wide range of adaptability to adverse environmental conditions like temperature extremes, photo-oxidation, high or low salinity, and osmotic stress. Algae are primarily known to produce large amounts of secondary metabolite against various kinds of pathogenic microbes. Among these algae, micro and microalgae of river, lake, and algae of oceanic origin have been reported to have antimicrobial activity against the bacteria and fungi of pathogenic nature. Various polar and non- polar extracts of micro- and macro algae have been used for the suppression of these pathogenic fungi. Apart from these, certain algal derivatives have also been isolated from these having antibacterial and antifungal potential. Among the bioactive molecules of algae, polysaccharides, sulphated polysaccharides, phyco-cyanobilins polyphenols, lectins, proteins lutein, vitamin E, B₁₂ and K₁, peptides, polyunsaturated fatty acids and pigments can be highlighted. In the present review, we will discuss the biological activity of these derived compounds as antifungal/ antibacterial agents and their most promising applications. A brief outline is also given for the prospects of these isolated phytochemicals and using algae as therapeutic in the dietary form. We have also tried to answer whether alga-derived metabolites can serve as potential therapeutics for the treatment of SARS-CoV-2 like viral infections too.

The Therapeutic Potential of Algal Nanoparticles: A Brief Review

Recently, the green synthesis of metallic nanoparticles (NPs) has received tremendous attention as a simple approach. The green pathway of biogenic synthesis of metallic NPs through microbes may provide a sustainable and environmentally friendly protocol. Green technology is the most innovative technology for various biological activities and lacks toxic effects. Reports have shown the algae-mediated synthesis of metal NPs. Algae are widely used for biosynthesis as they grow fast; they produce biomass on average ten times that of plants and are easily utilized experimentally. In the future, the production of metal NPs by different microalgae and their biological activity can be explored in diverse areas such as catalysis, medical diagnosis, and anti-biofilm applications.

Mechanical, Barrier, Antioxidant and Antimicrobial Properties of Alginate Films: Effect of Seaweed Powder and Plasma-Activated Water

The incorporation of natural fillers such as seaweed may potentially enhance the properties of biopolymer films. In this study, we investigated the effect of seaweed powder as a bio-filler in alginate-based films at different concentrations (10, 30, and 50%, w/w alginate) and particle sizes (100 and 200 μm) on the mechanical, barrier, antioxidant, and antimicrobial properties of alginate which are essential for food packaging applications. Initially, mechanical properties of the alginate films prepared at different temperatures were evaluated to find the optimal temperature for preparing alginate solution. The addition of seaweed powder did not have any positive effect on the mechanical properties of the alginate films. However, the barrier (water vapor transmission rate) and antioxidant properties were improved with the addition of seaweed filler regardless of concentration. In addition, selected films were prepared in plasma-activated water (PAW). The mechanical properties (tensile strength, but not elongation at break) of the films prepared with PAW improved compared to the films prepared in distilled water, while a significant decrease was observed when incorporated with the seaweed filler. The films prepared in PAW also showed improved barrier properties compared to those prepared in distilled water. The antimicrobial activity of the alginate-seaweed film-forming solution was in general more pronounced when prepared with PAW and stored at 10 °C, particularly at the highest concentration of the film-forming solution (83.3% v/v). A more pronounced inhibitory effect was observed on the Gram-positive S. aureus than on the Gram-negative E. coli, which has been attributed to the different composition and structure of the respective cell walls. This study has demonstrated the potential of seaweed filler in combination with PAW towards enhanced functionality and bioactivity of alginate films for potential food packaging applications.

Seasonal Changes in Chemical Profile and Antioxidant Activity of Padina pavonica Extracts and Their Application in the Development of Bioactive Chitosan/PLA Bilayer Film

Seaweeds are a potentially sustainable source of natural antioxidants that can be used in the food industry and possibly for the development of new sustainable packaging materials with the ability to extend the shelf-life of foods and reduce oxidation. With this in mind, the seasonal variations in the chemical composition and antioxidant activity of brown seaweed (Padina pavonica) extracts were investigated. The highest total phenolic content (TPC) and antioxidant activity (measured by ferric reducing/antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and oxygen radical absorbance capacity (ORAC)) were found for P. pavonica June extract. The TPC of 26.69 ± 1.86 mg gallic acid equivalent/g, FRAP of 352.82 ± 15.41 µmole Trolox equivalent (TE)/L, DPPH of 52.51 ± 2.81% inhibition, and ORAC of 76.45 ± 1.47 µmole TE/L were detected. Therefore, this extract was chosen for the development of bioactive PLA bilayer film, along with chitosan. Primary or quaternary chitosan was used as the first layer on polylactic acid (PLA) films. A suspension of chitosan particles with entrapped P. pavonica extract was used as the second layer. X-ray photoelectron spectroscopy confirmed the presence of layers on the material surface. The highest recorded antioxidant activity of the newly developed films was 63.82% inhibition. The developed functional films exhibited antifogging and antioxidant properties, showing the potential for application in the food industry.

Global seaweed farming and processing in the past 20 years

Seaweed has emerged as one of the most promising resources due to its remarkable adaptability, short development period, and resource sustainability. It is an effective breakthrough to alleviate future resource crises. Algal resources have reached a high stage of growth in the past years due to the increased output and demand for seaweed worldwide. Several aspects global seaweed farming production and processing over the last 20 years are reviewed, such as the latest situation and approaches of seaweed farming. Research progress and production trend of various seaweed application are discussed. Besides, the challenges faced by seaweed farming and processing are also analyzed, and the related countermeasures are proposed, which can provide advice for seaweed farming and processing. The primary products, extraction and application, or waste utilization of seaweed would bring greater benefits with the continuous development and improvement of applications in various fields.

Graphical Abstract

Fucoidan from Marine Macroalgae: Biological Actions and Applications in Regenerative Medicine, Drug Delivery Systems and Food Industry

The marine macroalgae produce a collection of bioactive polysaccharides, of which the sulfated heteropolysaccharide fucoidan produced by brown algae of the class Phaeophyceae has received worldwide attention because of its particular biological actions that confer nutritional and health benefits to humans and animals. The biological actions of fucoidan are determined by their structure and chemical composition, which are largely influenced by the geographical location, harvest season, extraction process, etc. This review discusses the structure, chemical composition and physicochemical properties of fucoidan. The biological action of fucoidan and its applications for human health, tissue engineering, regenerative medicine and drug delivery are also addressed. The industrial scenario and prospects of research depicted would give an insight into developing fucoidan as a commercially viable and sustainable bioactive material in the nutritional and pharmacological sectors.

Anti-colorectal cancer effects of seaweed-derived bioactive compounds

Seaweeds are classified as Chlorophyta, Rhodophyta, and Phaeophyta. They constitute a number of the most significant repositories of new therapeutic compounds for human use. Seaweed has been proven to possess diverse bioactive properties, which include anticancer properties. The present review focuses on colorectal cancer, which is a primary cause of cancer-related mortality in humans. In addition, it discusses various compounds derived from a series of seaweeds that have been shown to eradicate or slow the progression of cancer. Therapeutic compounds extracted from seaweed have shown activity against colorectal cancer. Furthermore, the mechanisms through which these compounds can induce apoptosis in vitro and in vivo were reviewed. This review emphasizes the potential utility of seaweeds as anticancer agents through the consideration of the capability of compounds present in seaweeds to fight against colorectal cancer.

Fucoxanthin: A Promising Phytochemical on Diverse Pharmacological Targets

Fucoxanthin (FX) is a special carotenoid having an allenic bond in its structure. FX is extracted from a variety of algae and edible seaweeds. It has been proved to contain numerous health benefits and preventive effects against diseases like diabetes, obesity, liver cirrhosis, malignant cancer, etc. Thus, FX can be used as a potent source of both pharmacological and nutritional ingredient to prevent infectious diseases. In this review, we gathered the information regarding the current findings on antimicrobial, antioxidant, anti-inflammatory, skin protective, anti-obesity, antidiabetic, hepatoprotective, and other properties of FX including its bioavailability and stability characteristics. This review aims to assist further biochemical studies in order to develop further pharmaceutical assets and nutritional products in combination with FX and its various metabolites.

Sarcodia suae modulates the immunity and disease resistance of white shrimp Litopenaeus vannamei against Vibrio alginolyticus via the purine metabolism and phenylalanine metabolism

Red seaweeds have several biofunctional properties, including immunomodulatory, antitumor, antioxidant, and antibacterial activities. In this study, we examined the effects of diets containing Sarcodia suae on the immune response, immune-related gene expressions, and disease resistance against Vibrio alginolyticus in white shrimp Litopenaeus vannamei. In addition, ¹H NMR metabolomics was applied to analyze the metabolites extracted from shrimp fed with S. suae and their functions in regulating immunity. A diet containing only fish meal was used as the control diet (S₀), and three diets containing different concentrations of S. suae powder, 2.5% (S2.5), 5% (S5), and 7.5% (S7.5) were used as experimental diets. Shrimp were fed diets for 20 days. Compared to the control group (S0), results showed that (1) shrimp fed diets supplemented with 5-7.5% of S. suae powder significantly increased anti-V. alginolyticus activity; (2) phagocytic activity (PA) increased in all shrimp fed with S. suae, but total haemocyte count (THC) only increased in S7.5 group; and (3) the expression of glutathione peroxidase (GPx) in haemocyte were significantly higher in S7.5 groups. Results from the ¹H NMR analysis revealed that 19 heapatopancreatic metabolites were matched and identified among groups. Based on the KEGG enrichment analysis, the up-regulated metabolites in the shrimp fed S5 and S7.5 diets were primarily due to the metabolism of purine and phenylalanine and their respective pathways. Results from these trials reveal that diets containing S. suae can increase immune response, thereby increasing shrimp resistance to V. alginolyticus. The purine and phenylalanine metabolic pathways may be considered as the relevant pathways for optimizing immunomodulatory responses.