Antioxidant and Antibacterial Properties of Essential Oil Extracted from an Edible SeaweedUndaria Pinnatifida

Harnessing marine resources for Alzheimer's therapy: A review integrating bioactivity and molecular docking

Alzheimer's disease (AD) is a neurodegenerative condition resulting in cognitive impairment and the formation of neurofibrillary tangles and plaques in the brain. The drivers of AD's molecular progression and pathology include the accumulation of amyloid β protein (Aβ); thus, Aβ is an intervention target. However, the limitations in clinical trials of Aβ-targeted medicine and the failure to intervene in disease progression have raised concerns about the use of this drug and its veracious route. In particular, we comprehensively reviewed the potential effect of marine compounds and the mechanism of isolation and extraction from marine organisms resulting in the optimization of AD treatment. Furthermore, the hub compounds were docked with Beta-secretase receptors to strengthen the extrapolation of mechanistic interactions thus inhibiting the activity of an enzyme. An extensive review revealed that marine aquaculture and its byproducts are a promising source and isolated with green methods or less investment, ensuring their sustainability. MNPs harbor specific pharmacological features that enable them to exert neuroprotective effects by minimizing events such as Aβ peptide formation and reactive oxygen species (ROS) generation.

Exploring the effect of different diet types on ageing and age-related diseases

In recent times, there has been growing interest in understanding the factors contributing to prolonged and healthy lifespans observed in specific populations, tribes, or countries. Factors such as environmental and dietary play significant roles in shaping the ageing process and are often the focus of inquiries seeking to unravel the secrets behind longevity. Among these factors, diet emerges as a primary determinant, capable of either promoting or mitigating the onset of age-related diseases that impact the ageing trajectory. This review examines the impact of various diet types on ageing and age-related conditions, including cardiovascular disease, cancer, neurodegenerative disorders, and metabolic syndrome. Different dietary patterns, such as the Mediterranean diet, the Japanese diet, vegetarian and vegan diets, as well as low-carbohydrate and ketogenic diets, are evaluated for their potential effects on longevity and health span. Each diet type is characterized by distinct nutritional profiles, emphasizing specific food groups, macronutrient compositions, and bioactive components, which may exert diverse effects on ageing processes and disease risk. Additionally, dietary factors such as calorie restriction, intermittent fasting, and dietary supplementation are explored for their potential anti-ageing and disease-modifying effects. Understanding the influence of various diet types on ageing and age-related diseases can inform personalized dietary recommendations and lifestyle interventions aimed at promoting healthy aging and mitigating age-associated morbidities.

Valorisation of the Invasive Macroalgae Undaria pinnatifida (Harvey) Suringar for the Green Synthesis of Gold and Silver Nanoparticles with Antimicrobial and Antioxidant Potential

Bacterial and fungal infections are a challenging global problem due to the reported increasing resistance of pathogenic microorganisms to conventional antimicrobials. Nanomaterials are a promising strategy to fight infections caused by multidrug-resistant microbes. In this work, gold (Au@UP) and silver (Ag@UP) nanoparticles were produced for the first time by green synthesis using an aqueous extract of the invasive macroalgae Undaria pinnatifida (UP). The nanoparticles were characterized by a wide range of physicochemical techniques. Au@UP and Ag@UP demonstrated to be spherical and crystalline with an average size of 6.8 ± 1.0 nm and 14.1 ± 2.8 nm, respectively. Carbohydrates and proteins of the UP extract may participate in the synthesis and capping of the nanoparticles. The UP extract, Ag@UP, and Au@UP were assessed for their antimicrobial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Candida auris. Ag@UP showed the highest antimicrobial activity with very low MIC and MBC values for all the tested bacteria, and Au@UP demonstrated to be very effective against biofilm-producing bacteria. The antifungal properties of both Ag@UP and Au@UP were remarkable, inhibiting hyphae formation. This study points towards a very promising biomedical exploitation of this invasive brown algae.

Pro-Apoptotic Activity and Cell Cycle Arrest of Caulerpa sertularioides against SKLU-1 Cancer Cell in 2D and 3D Cultures

Cancer is a disease with the highest mortality and morbidity rate worldwide. First-line drugs induce several side effects that drastically reduce the quality of life of people with this disease. Finding molecules to prevent it or generate less aggressiveness or no side effects is significant to counteract this problem. Therefore, this work searched for bioactive compounds of marine macroalgae as an alternative treatment. An 80% ethanol extract of dried Caulerpa sertularioides (CSE) was analyzed by HPLS-MS to identify the chemical components. CSE was utilized through a comparative 2D versus 3D culture model. Cisplatin (Cis) was used as a standard drug. The effects on cell viability, apoptosis, cell cycle, and tumor invasion were evaluated. The IC₅₀ of CSE for the 2D model was 80.28 μg/mL versus 530 μg/mL for the 3D model after 24 h of treatment exposure. These results confirmed that the 3D model is more resistant to treatments and complex than the 2D model. CSE generated a loss of mitochondrial membrane potential, induced apoptosis by extrinsic and intrinsic pathways, upregulated caspases-3 and -7, and significantly decreased tumor invasion of a 3D SKLU-1 lung adenocarcinoma cell line. CSE generates biochemical and morphological changes in the plasma membrane and causes cell cycle arrest at the S and G2/M phases. These findings conclude that C. sertularioides is a potential candidate for alternative treatment against lung cancer. This work reinforced the use of complex models for drug screening and suggested using CSE's primary component, caulerpin, to determine its effect and mechanism of action on SKLU-1 in the future. A multi-approach with molecular and histological analysis and combination with first-line drugs must be included.

Effect of Refining and Fractionation Processes on Minor Components, Fatty Acids, Antioxidant and Antimicrobial Activities of Shea Butter

Shea butter is becoming increasingly popular in foods, cosmetics and pharmaceutical products. This work aims to study the effect of the refining process on the quality and stability of fractionated and mixed shea butters. Crude shea butter, refined shea stearin, olein and their mixture (1:1 w/w) were analyzed for fatty acids, triacylglycerol composition, peroxide value (PV), free fatty acids (FFA), phenolic (TPC), flavonoid (TFC), unsaponifiable matter (USM), tocopherol and phytosterol content. Additionally, the oxidative stability, radical scavenging activity (RSA), antibacterial and antifungal activities were evaluated. The two main fatty acids in the shea butter samples were stearic and oleic. The refined shea stearin showed lower PV, FFA, USM, TPC, TFC, RSA, tocopherol and sterol content than crude shea butter. A higher EC50 was observed, but antibacterial activity was much lower. The refined olein fraction was characterized by lower PV, FFA and TFC in comparison with crude shea butter, but USM, TPC, RSA, EC50, tocopherol and sterol content was unchanged. The antibacterial activity was higher, but the antifungal activity was lower than those of crude shea butter. When both fractions were mixed, their fatty acid and triacylglycerol composition were similar to those of crude shea butter, but other parameters were different.

An Overview on Antimicrobial Potential of Edible Terrestrial Plants and Marine Macroalgae Rhodophyta and Chlorophyta Extracts

Antibiotics are used to prevent and treat bacterial infections. After a prolonged use of antibiotics, it may happen that bacteria adapt to their presence, developing antibiotic resistance and bringing up health complications. Nowadays, antibiotic resistance is one of the biggest threats to global health and food security; therefore, scientists have been searching for new classes of antibiotic compounds which naturally express antimicrobial activity. In recent decades, research has been focused on the extraction of plant compounds to treat microbial infections. Plants are potential sources of biological compounds that express several biological functions beneficial for our organism, including antimicrobial activity. The high variety of compounds of natural origin makes it possible to have a great bioavailability of antibacterial molecules to prevent different infections. The antimicrobial activity of marine plants, also called seaweeds or macroalgae, for both Gram-positive and Gram-negative, and several other strains infective for humans, has been proven. The present review presents research focused on the extraction of antimicrobial compounds from red and green macroalgae (domain Eukarya, kingdom Plantae). Nevertheless, further research is needed to verify the action of macroalgae compounds against bacteria in vitro and in vivo, to be involved in the production of safe and novel antibiotics.

Determination of Antioxidant, Antimicrobial Activity, Heavy Metals and Elements Content of Seaweed Extracts

The aim of the research was to determine the antioxidant and antimicrobial activity, determination of chemical elements and heavy metals in seaweed extracts of wakame, arame, dulse, laminaria, kombu, and hijiki. Antioxidant activity was determined by DPPH method and the activity ranged from 0.00 to 2641.34 TEAC. The highest antioxidant activity was observed in kombu (2641.34 TEAC) and arame (2457.5 TEAC). Antimicrobial activity was analyzed by disk diffusion method and MIC method. Three G+ bacteria (Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis), three G- bacteria (Salmonella enterica, Pseudomonas aeruginosa, Yersinia enterocolitica), and four yeasts (Candida tropicalis, C. krusei, C. glabrata, C. albicans) were used as model organisms. The size of inhibition zones ranged from 0.00 to 8.67 mm. The minimum inhibitory concentrations of the selected seaweeds ranged from MIC50 98.46 (MIC90 100.25) to MIC50 3.43 µL/mL (MIC90 5.26 µL/mL). The content of selected elements was determined in seaweed samples by ICP-OES. The chemical composition of the algae showed differences between species and the presence of heavy metals. Arsenic, cadmium, and aluminum were confirmed. All seaweed samples contained arsenic ranging from 6.6546 to 76.48 mg/kg. Further investigation of seaweeds is needed to identify the active substances present in the algae that are responsible for antioxidant and antimicrobial activity. This study was carried out to evaluate the antimicrobial and antioxidant activity of extracts from five commonly consumed seaweeds for their ability to inhibit selected microorganisms and to determine the health risk due to heavy metals content. Our study contributes to the evidence that seaweeds have antimicrobial and antioxidant activity and seaweed extracts have for pharmacological applications.

Seaweed Polysaccharide in Food Contact Materials (Active Packaging, Intelligent Packaging, Edible Films, and Coatings)

Food contact materials (FCMs) are materials that come in contact with food products such as food packaging which play a significant role in the food quality and safety. Plastic, which is a major food packaging material, harms the eco-system, wildlife, and the environment. As a result, numerous researches have been in progress on alternative polymers, which has similar properties as plastic but is also environmentally friendly (biodegradable). In recent years, the utilization of seaweed polysaccharides has piqued interest due to its biodegradability, non-toxicity, antioxidant capabilities, and excellent film formation ability. However, it has a number of drawbacks such as low tensile strength, water solubility, and moderate antibacterial characteristics, among others. The addition of other biopolymers, nanoparticles, or natural active agents improves these features. In this review article, we have summarized the current state of seaweed polysaccharide research in active packaging, intelligent packaging, edible films, and coatings. It also highlights the physical, thermal, antioxidant, and other properties of these materials. Finally, the article discusses the relevant legislation as well as the field’s future prospects. Research shows that seaweeds polysaccharide looks promising as a sustainable food contact material, but there is always a potential for development to make it market feasible.

Seaweed Supplementation Failed to Affect Fecal Microbiota and Metabolome as Well as Fecal IgA and Apparent Nutrient Digestibility in Adult Dogs

The present study investigated in dogs the dietary effects of intact seaweeds on some fecal bacterial populations and metabolites, fecal IgA and apparent total tract digestibility (ATTD). Ten healthy adult dogs were enrolled in a 5 × 5 replicated Latin square design to evaluate five dietary treatments: control diet (CD); CD + Ascophyllum nodosum; CD + Undaria pinnatifida; CD + Saccharina japonica; CD + Palmaria palmata (n replicates per treatment = 10). Seaweeds were added to food at a daily dose of 15 g/kg. The CD contained silica as a digestion marker. Each feeding period lasted 28 d, with a 7 d wash-out in between. Feces were collected at days 21 and 28 of each period for chemical and microbiological analyses. Fecal samples were collected during the last five days of each period for ATTD assessment. Dogs showed good health conditions throughout the study. The fecal chemical parameters, fecal IgA and nutrient ATTD were not influenced by algal supplementation. Similarly, microbiological analyses did not reveal any effect by seaweed ingestion. In conclusion, algal supplementation at a dose of 15 g/kg of diet failed to exert noticeable effects on the canine fecal parameters evaluated in the present study.

Microbiological Contamination of Ready-to-Eat Algae and Evaluation of Bacillus cereus Behavior by Microbiological Challenge Test

ABSTRACT

Consumption of seaweeds (forms of algae), often categorized as a superfood, is becoming popular in western countries. Algae can be marketed fresh, but are usually sold dehydrated to ensure longer shelf life. Their consumption, often as ready-to-eat, opens up possible risks for public health because of foodborne pathogens that can contaminate the raw material during harvesting or manipulation. In this study, 14 ready-to-eat foods based on dehydrated algae, representative of the most consumed species, were considered. The microbial content, with a focus on Listeria monocytogenes and Bacillus cereus, was investigated by plate counts, and B. cereus strains were isolated and identified by 16S rRNA gene sequencing. The microbiological quality was heterogeneous among the samples and, in particular, marine bacteria, Listeria spp., B. cereus, and coliforms were detected. To contribute to related risk assessment, the ability of B. cereus to grow during refrigerated storage was evaluated, to our knowledge for the first time, by a microbiological challenge test on two ready-to-eat foods based on Undaria pinnatifida and Palmaria palmata. Despite this study demonstrating the inability of B. cereus to proliferate in seaweed-based food, its presence in dehydrated foodstuffs cannot rule out replication after rehydration before consumption, making it necessary to elucidate the possible risks for consumers.

HIGHLIGHTS

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.

Antimicrobials from Seaweeds for Food Applications

The exponential growth of emerging multidrug-resistant microorganisms, including foodborne pathogens affecting the shelf-life and quality of foods, has recently increased the needs of the food industry to search for novel, natural and eco-friendly antimicrobial agents. Macroalgae are a bio-diverse group distributed worldwide, known to produce multiple compounds of diverse chemical nature, different to those produced by terrestrial plants. These novel compounds have shown promising health benefits when incorporated into foods, including antimicrobial properties. This review aims to provide an overview of the general methods and novel compounds with antimicrobial properties recently isolated and characterized from macroalgae, emphasizing the molecular pathways of their antimicrobial mechanisms of action. The current scientific evidence on the use of macroalgae or macroalgal extracts to increase the shelf-life of foods and prevent the development of foodborne pathogens in real food products and their influence on the sensory attributes of multiple foods (i.e., meat, dairy, beverages, fish and bakery products) will also be discussed, together with the main challenges and future trends of the use of marine natural products as antimicrobials.

A Biorefinery Approach to the Biomass of the Seaweed Undaria pinnatifida (Harvey Suringar, 1873): Obtaining Phlorotannins-Enriched Extracts for Wound Healing

Brown seaweeds are recognized sources of compounds with a wide range of properties and applications. Within these compounds, phlorotannins are known to possess several bioactivities (e.g., antioxidant, anti-inflammatory, and antimicrobial) with potential to improve wound healing. To obtain phlorotannins enriched extracts from Undaria pinnatifida, a biorefinery was set using low-cost industry-friendly methodologies, such as sequential solid-liquid extraction and liquid-liquid extraction. The obtained extracts were screened for their antioxidant and antimicrobial activity against five common wound pathogens and for their anti-inflammatory potential. The ethanolic wash fraction (wE100) had the highest antioxidant activity (114.61 ± 10.04 mmol·mg-1 extract by Diphenyl-1-picrylhydrazyl (DPPH) and 6.56 ± 1.13 mM eq. Fe II·mg-1 extract by and Ferric Reducing Antioxidant Power (FRAP)), acting efficiently against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria, and showing a nitric oxide production inhibition over 47% when used at 0.01 µg·mL-1. NMR and FTIR chemical characterization suggested that phlorotannins are present. Obtained fraction wE100 proved to be a promising candidate for further inclusion as wound healing agents, while the remaining fractions analyzed are potential sources for other biotechnological applications, giving emphasis to a biorefinery and circular economy framework to add value to this seaweed and the industry.

Invasive Seaweeds in the Iberian Peninsula: A Contribution for Food Supply

The introduction of exotic organisms in marine ecosystems can lead to economic and ecological losses. Globally, seaweeds represent a significant part of these non-indigenous species (NIS), with 407 introduced algal species. Furthermore, the presence of NIS seaweeds has been reported as a major concern worldwide since the patterns of their potential invasion mechanisms and vectors are not yet fully understood. Currently, in the Iberian Peninsula, around 50 NIS seaweeds have been recorded. Some of these are also considered invasive due to their overgrowth characteristic and competition with other species. However, invasive seaweeds are suitable for industrial applications due to their high feedstock. Hence, seaweeds' historical use in daily food diet, allied to research findings, showed that macroalgae are a source of nutrients and bioactive compounds with nutraceutical properties. The main goal of this review is to evaluate the records of NIS seaweeds in the Iberian Peninsula and critically analyze the potential of invasive seaweeds application in the food industry.

Edible Seaweeds and Spirulina Extracts for Food Application: In Vitro and In Situ Evaluation of Antimicrobial Activity towards Foodborne Pathogenic Bacteria

Research is more and more focused on studying and selecting food preservatives of natural origin. In this scenario, algae are an excellent source of bioactive compounds, among which are antimicrobials, whose presence is variable depending on the algal species and environmental conditions. The aim of the present study was to obtain, by a food grade approach, antimicrobial extracts from five species already approved as foods and to test their efficacy in vitro (agar well diffusion assay) and in situ (microbial challenge test) towards foodborne pathogenic bacteria. Moreover, the total phenolic compounds of the extracts were determined in order to evaluate possible correlations with the antimicrobial activity. Strains belonging to Salmonella spp., Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Bacillus cereus were considered. Overall, the extracts showed a good antimicrobial activity in vitro towards all the tested microorganisms, especially L. monocytogenes (15 mm of inhibition diameter). The effect of inhibition was monitored during 24, 48 and 120 h showing a good persistence in time. Arthrospira platensis exerted the highest efficacy, further revealed towards L. monocytogenes on salmon tartare as bacteriostatic using 0.45% of the extract and bactericidal using 0.90%. The presence of phenolic compounds could be related to the antimicrobial activity but was not revealed as the main component of this activity. The extract with the highest phenolic content (18.79 ± 1.90 mg GAE/g) was obtained from Himanthalia elongata. The efficacy, confirmed also in a food matrix, might open perspectives for their application as food preservative.

Seaweed Essential Oils as a New Source of Bioactive Compounds for Cyanobacteria Growth Control: Innovative Ecological Biocontrol Approach

The application of natural compounds extracted from seaweeds is a promising eco-friendly alternative solution for harmful algae control in aquatic ecosystems. In the present study, the anti-cyanobacterial activity of three Moroccan marine macroalgae essential oils (EOs) was tested and evaluated on unicellular Microcystis aeruginosa cyanobacterium. Additionally, the possible anti-cyanobacterial response mechanisms were investigated by analyzing the antioxidant enzyme activities of M. aeruginosa cells. The results of EOs GC-MS analyses revealed a complex chemical composition, allowing the identification of 91 constituents. Palmitic acid, palmitoleic acid, and eicosapentaenoic acid were the most predominant compounds in Cystoseira tamariscifolia, Sargassum muticum, and Ulva lactuca EOs, respectively. The highest anti-cyanobacterial activity was recorded for Cystoseira tamariscifolia EO (ZI = 46.33 mm, MIC = 7.81 μg mL-1, and MBC = 15.62 μg mL-1). The growth, chlorophyll-a and protein content of the tested cyanobacteria were significantly reduced by C. tamariscifolia EO at both used concentrations (inhibition rate >67% during the 6 days test period in liquid media). Furthermore, oxidative stress caused by C. tamariscifolia EO on cyanobacterium cells showed an increase of the activities of superoxide dismutase (SOD) and catalase (CAT), and malondialdehyde (MDA) concentration was significantly elevated after 2 days of exposure. Overall, these experimental findings can open a promising new natural pathway based on the use of seaweed essential oils to the fight against potent toxic harmful cyanobacterial blooms (HCBs).

Metabolites from Marine Microorganisms, Micro, and Macroalgae: Immense Scope for Pharmacology

Marine organisms produce a large array of natural products with relevance in drug discovery. These compounds have biological activities such as antioxidant, antibacterial, antitumor, antivirus, anticoagulant, anti-inflammatory, antihypertensive, antidiabetic, and so forth. Consequently, several of the metabolites have made it to the advanced stages of clinical trials, and a few of them are commercially available. In this review, novel information on natural products isolated from marine microorganisms, microalgae, and macroalgae are presented. Given due research impetus, these marine metabolites might emerge as a new wave of promising drugs.

A sustainable process for the recovery of volatile constituents from Gracilaria lemaneiformis in agar production and evaluation of their antioxidant activities

Background

Gracilaria lemaneiformis is a common red alga used as a raw material source for the agar industry. Its extract is rich in natural volatile constituents (VCs) having antioxidant activities. Herein, a sustainable method was used to recover VCs from the alga. The chemical composition of VCs present in the n-hexane fraction was analyzed by gas chromatography-mass spectroscopy (GC-MS) and the antioxidant potential was measured using a series of in vitro biochemical assays, including DPPH, hydroxyl, and superoxide radical scavenging assays.

Results

The recovery yield of the VCs was 0.823 wt% of the dry mass of G. lemaneiformis. A total of 25 VCs were successfully identified, comprising approximately 99.94% of the total volume. The major component was n-hexadecanoic acid (38.57%), followed by oleic acid (25.48%), arachidonic acid (12.84%), and tetradecanoic acid (2.52%). In addition, The VCs displayed strong free radical scavenging activity in the DPPH (IC₅₀ = 21.56 mg/L), hydroxyl (IC₅₀ = 18.34 mg/L), and superoxide (IC₅₀ = 391.12 mg/L) radical scavenging assays. The antioxidant activities of the VCs exhibited a dose-dependence at concentrations ranging from 5 to 200 mg/L.

Conclusion

The results indicated that the sustainable process improved the agar quality and that the extract contained many natural VCs with antioxidant activities, which have the potential to be used in functional food and cosmetics instead of as a discarded byproduct of the agar industry.

Chemical composition and antioxidant potential of essential oil and methanol extract from Tunisian and French fennel (Foeniculum vulgare Mill.) seeds

This study was designed to examine the effect of provenance on the phytochemical and antioxidant properties of essential oil and methanolic extract from Tunisian and French fennel seeds (FFS). Analysis of the essential oil showed that although the same main compounds were found in Tunisian and FFS cultivars, some differences were present in their proportions allowing to classify them in two chemotypes. The first class was composed by trans-anethole (63.41%-78.26%) for Tunisian cultivars and the second one by estragole (44.72%-88.92%) for French cultivars. The phenolic composition of all fennel seed extracts was characterized by its richness in quinic acid, 4-O-caffeoylquinic acid, p-coumaric acid, and 4-O-caffeoylquinic acid. All fennel seed extracts showed a better antioxidant potential than their essential oils depending on the origin. Principal component analysis showed a dispersion of the cultivars on three groups depending on the chemotype diversity. PRACTICAL APPLICATIONS: Recently, much attention has been focused on fennel due to the nutritional and health-protective value of their seeds. Several studies have highlighted the importance of fennel seed extracts and essential oils as key ingredients rich in bioactive compounds serving in formulation of new functional food products. This investigation designed to examine the effect of provenance on phytochemical and antioxidant potentials of Tunisian and French fennel seed extracts and essential oils.