Marine Seaweeds Research Articles

MARINE MACROALGAE: PLANT GROWTH STIMULATORS

The modern agricultural sector is mainly dependent on synthetic fertilizer for enhancing the growth of crop improvements but a burden of inorganic and chemical-based fertilizer currently created a serious threat to human health as well as the soil environment. Fertilizer research is therefore focusing on an alternative to chemical fertilizer by exploiting natural sources such as marine macroalgae or seaweed. The use of seaweed will be an eco-friendlier approach to sustainable agriculture. Marine macroalgae or seaweed widely applicable in plant growth enhancements due to the presence of biological active phycocompounds such as proteins, phenolic compounds, amino acids, polysaccharides, plant-growth-promoting hormones, and some growth factors, etc. Several research studies have been carried out on the applicability of seaweed or the effect of marine algae or its components on plants and its quality. These types of constituents play their role in improving the morphological as well as biochemical characteristics of plants. The present review study focuses on the applicability of marine macroalgae as a biofertilizer or plant growth stimulator in agricultural applications. This study further helps to improve the nutritional quality of crops which prove to be useful in further investigations and applications. KEYWORDS: Seaweed, Marine Macroalgae, Biofertilizer, Growth stimulator, Agriculture

Updated Checklist of the Benthic Marine Macroalgae of the Philippines

Records of taxa of benthic marine macroalgae in the Philippines continue to increase as molecularbased biodiversity and systematics research involving seaweed specimens collected from various localities in the country continue to grow. Several molecular systematics studies on seaweeds within the last decade also resulted in taxonomic, nomenclatural, and classification changes, consequently affecting our knowledge and understanding of the biodiversity of the Philippine seaweed flora. Moreover, global efforts to make biodiversity resources that are deposited in various herbaria openly available through online databases provide a good opportunity to reassess our current foundational biodiversity knowledge on these ecologically and economically important marine resources. Herein, we provide an updated checklist of Philippine seaweeds by integrating results of recent biodiversity and systematics studies and by perusing open-access records of seaweeds collected from the Philippines that are deposited in foreign herbaria and/or found in online databases. We report a total of 1,065 seaweed taxa in the Philippines; this is composed primarily of 600 red seaweed taxa (Florideophyceae and Bangiophyceae, Rhodophyta), followed by 272 green seaweed taxa (Ulvophyceae, Chlorophyta), and by 193 brown seaweed taxa (Phaeophyceae, Ochrophyta). We added a total of 104 new records (including recently described species) to the latest checklist on Philippine seaweeds in 2013, more than half of which were derived from records of the collections deposited in foreign herbaria. The latter highlights the need to make herbarium collection records accessible and underscores the important role of herbaria (and museums in general) in documenting and preserving biodiversity resources of biodiversity hotspot areas such as the Philippines. We also reiterate here the call to increase support in building local expertise and funding on marine (seaweed) biodiversity and systematics research as these are crucial not only in documenting and conserving our marine biodiversity resources but also in developing them for their socio-economic values.

Bioassay-Guided Fractionation and Antimicrobial Activities of Padina australis Extracts

Background: Marine seaweeds synthesize different metabolites with various biological activities, including antimicrobial effects. Objectives: The main object of this study was to fractionate the seaweed Padina australis and analyze the antimicrobial activities of these fractions to isolate the bioactive compounds. Methods: Padina australis was collected from the Persian Gulf and extracted by maceration with methanol-ethyl acetate solvent. The extract was evaporated and partitioned by the Kupchan method to yield hexane, dichloromethane, water, and butanol partitions. Dichloromethane partition was further fractionated by MPLC, and antimicrobial activity of the crude extracts and all fractions were investigated using disc diffusion and agar plate count methods. The MIC values of hexane, dichloromethane, chloroform, and butanol partitions and all fractions were calculated. Results: Fraction numbers 11, 4, and 7 showed the highest inhibitory effect with MIC value of 87 µg/mL, 156 µg/mL, and 156 µg/mL against E. coli, P. aeruginosa, and S. aureus, respectively. Conclusions: This study reveals that different fractions of P. australis have antimicrobial activities against various microorganisms.

Retracted] Optimization of Remazol Black B Removal Using Biochar Produced from Caulerpa scalpelliformis Using Response Surface Methodology

Optimization of process conditions for the removal of Remazol Black B was investigated using response surface methodology (Box–Behnken design). The biodecolorization of dye was studied using biochar produced from waste biomass of Caulerpa scalpelliformis (marine seaweeds). The reactions were optimized by varying sorbent dosage, solution pH, temperature, and initial dye concentration. The results indicated that dye removal efficiency of 80.30% was attained at an operating condition of 4 g/L (sorbent dosage), 2.0 (solution pH), 35°C (temperature), and 0.25 mmol/L (initial dye concentration). The regression coefficient of the developed model was calculated to be 97% which shows good fit of the model.

Bioactive Components of Three Seaweed Species from Hadji Panglima Tahil, Sulu Philippines

This study aimed to determine the bioactive composition and properties of three selected marine seaweeds: <i>Ulva reticulata, Halymenia durvillei </i>and <i>Sargassum cristaefolium </i>from Hadji Panglima Tahil, Sulu Philippines. The proximate and heavy metal composition of the seaweeds were determined. Heavy metal analysis in seaweeds showed that zinc registered highest concentration (328.74 mg/kg) in <i>U. reticulata</i>. Other evaluated seaweed species registered lower concentrations of copper (Cu), mercury, and lead indicating that they could be eaten as source of Cu. The concentration reveals that these seaweeds could be source of the micronutrient, and copper. All other seaweeds are safe for human consumption. Nutritional proximate composition of seaweeds in this study revealed that the brown seaweed (i.e. <i>S. cristaefolium</i>) collected from Hadji Panglima Tahil, Sulu Philippines had highest average composition in terms of moisture, lipids, and total soluble solids. Results on nutritional proximate composition of seaweed varies due to the effect of geographical location, time of collection and the weather condition. Dried samples of <i>U. reticulata </i>showed best antioxidant activity while <i>S. cristaefolium</i> had least antioxidant activity. Sulu Philippines is one of the seaweeds suppliers in western Mindanao. Decades ago, seaweeds are known as food delicacy like <i>Caulerpa</i>, <i>Eucheuma</i> and <i>Gracilaria </i>spp. They are eaten raw while the industrial and medicinal uses of extracts from seaweeds were known later by inhabitants. There have been several feeding trials conducted to have the potential as source of aqua feed. Feeding the fishes with seaweed helps to prevent the occurrence of disease to certain extent. Seaweeds contain plenty of protein, vitamin and minerals. Moreover, seaweeds also contain potential bioactive compounds which exhibit antibacterial, antiviral and antifungal properties. The phytochemicals responsible for the bioactivities could be present in the seaweeds which based on literature. In addition to “positive” roles, seaweeds also play critical roles in reef degradation, particularly in ecological “phase shifts” where abundant reef-building corals are replaced by abundant fleshy seaweed. Indeed, the seaweeds screened in this study possess bioactive components and antioxidant which may be considered for future applications in medicine, cosmetics, and some heavy metals composition which may be considered for future applications in food industry.

Remazol Effluent Treatment in Batch and Packed Bed Column Using Biochar Derived from Marine Seaweeds

Remazol Effluent Treatment in Batch and Packed Bed Column Using Biochar Derived from Marine Seaweeds

The Remarkable Antioxidant and Anti-Inflammatory Potential of the Extracts of the Brown Alga Cystoseira amentacea var. stricta.

Inflammation and oxidative stress are part of the complex biological responses of body tissues to harmful stimuli. In recent years, due to the increased understanding that oxidative stress is implicated in several diseases, pharmaceutical industries have invested in the research and development of new antioxidant compounds, especially from marine environment sources. Marine seaweeds have shown the presence of many bioactive secondary metabolites, with great potentialities from both the nutraceutical and the biomedical point of view. In this study, 50%-ethanolic and DMSO extracts from the species C. amentacea var. stricta were obtained for the first time from seaweeds collected in the Ligurian Sea (north-western Mediterranean). The bioactive properties of these extracts were then investigated, in terms of quantification of specific antioxidant activities by relevant ROS scavenging spectrophotometric tests, and of anti-inflammatory properties in LPS-stimulated macrophages by evaluation of inhibition of inflammatory cytokines and mediators. The data obtained in this study demonstrate a strong anti-inflammatory effect of both C. amentacea extracts (DMSO and ethanolic). The extracts showed a very low grade of toxicity on RAW 264.7 macrophages and L929 fibroblasts and a plethora of antioxidant and anti-inflammatory effects that were for the first time thoroughly investigated. The two extracts were able to scavenge OH and NO radicals (OH EC50 between 392 and 454 μg/mL; NO EC50 between 546 and 1293 μg/mL), to partially rescue H2O2-induced RAW 264.7 macrophages cell death, to abate intracellular ROS production in H2O2-stimulated macrophages and fibroblasts and to strongly inhibit LPS-induced inflammatory mediators, such as NO production and IL-1α, IL-6, cyclooxygenase-2 and inducible NO synthase gene expression in RAW 264.7 macrophages. These results pave the way, for the future use of C. amentacea metabolites, as an example, as antioxidant food additives in antiaging formulations as well as in cosmetic lenitive lotions for inflamed and/or damaged skin.

Bioactive Metabolites from Marine Algae as Potent Pharmacophores against Oxidative Stress-Associated Human Diseases: A Comprehensive Review.

In addition to cancer and diabetes, inflammatory and ROS-related diseases represent one of the major health problems worldwide. Currently, several synthetic drugs are used to reduce oxidative stress; nevertheless, these approaches often have side effects. Therefore, to overcome these issues, the search for alternative therapies has gained importance in recent times. Natural bioactive compounds have represented, and they still do, an important source of drugs with high therapeutic efficacy. In the “synthetic” era, terrestrial and aquatic photosynthetic organisms have been shown to be an essential source of natural compounds, some of which might play a leading role in pharmaceutical drug development. Marine organisms constitute nearly half of the worldwide biodiversity. In the marine environment, algae, seaweeds, and seagrasses are the first reported sources of marine natural products for discovering novel pharmacophores. The algal bioactive compounds are a potential source of novel antioxidant and anticancer (through modulation of the cell cycle, metastasis, and apoptosis) compounds. Secondary metabolites in marine Algae, such as phenolic acids, flavonoids, and tannins, could have great therapeutic implications against several diseases. In this context, this review focuses on the diversity of functional compounds extracted from algae and their potential beneficial effects in fighting cancer, diabetes, and inflammatory diseases.

Fucoxanthin attenuates LPS-induced acute lung injury via inhibition of the TLR4/MyD88 signaling axis.

Acute lung injury (ALI) is a critical clinical condition with a high mortality rate. It is believed that the inflammatory storm is a critical contributor to the occurrence of ALI. Fucoxanthin is a natural extract from marine seaweed with remarkable biological properties, including antioxidant, anti-tumor, and anti-obesity. However, the anti-inflammatory activity of Fucoxanthin has not been extensively studied. The current study aimed to elucidate the effects and the molecular mechanism of Fucoxanthin on lipopolysaccharide-induced acute lung injury. In this study, Fucoxanthin efficiently reduced the mRNA expression of pro-inflammatory factors, including IL-10, IL-6, iNOS, and Cox-2, and down-regulated the NF-κB signaling pathway in Raw264.7 macrophages. Furthermore, based on the network pharmacological analysis, our results showed that anti-inflammation signaling pathways were screened as fundamental action mechanisms of Fucoxanthin on ALI. Fucoxanthin also significantly ameliorated the inflammatory responses in LPS-induced ALI mice. Interestingly, our results revealed that Fucoxanthin prevented the expression of TLR4/MyD88 in Raw264.7 macrophages. We further validated Fucoxanthin binds to the TLR4 pocket using molecular docking simulations. Altogether, these results suggest that Fucoxanthin suppresses the TLR4/MyD88 signaling axis by targeting TLR4, which inhibits LPS-induced ALI, and fucoxanthin inhibition may provide a novel strategy for controlling the initiation and progression of ALI.

Biochar derived from Caulerpa scalpelliformis for the removal of Reactive Yellow 81 in batch and packed bed column

The present study investigated the potential of biochar synthesized from Caulerpa scalpelliofrmis, a marine seaweed in the decolorization of Reactive Yellow 81 (RY81). The decolorization study was conducted in batch experiments and also in a packed bed column for continuous study. Maximum uptake of 151.5 mg/g was reported in a batch study under optimum conditions. Biosorption isotherm studies were conducted to understand the biosorption mechanism. A correlation coefficient of 0.9998 was obtained for a four-parameter model Fritz-Schlunder – IV. The kinetic study concluded that pseudo-first-order kinetics predicted the experimental data with a correlation coefficient always greater than 0.984. Desorption studies were carried out to find the best elutant, solid to liquid ratio and regeneration cycles. The maximum uptake of 122.48 mg/g was reported in a column study at optimum conditions. Yoon Nelson model predicted the experimental uptake with a correlation coefficient always greater than 0.99 and the % error was always less than 0.11.

Effects of dietary plant polyphenols and seaweed extract mixture on male-rabbit semen: Quality traits and antioxidant markers.

Feed additive consisting of polysaccharides from brown seaweeds plus phenolic acid, hydroxycinnamic acids, tannins, and flavonoids from plant extracts, was used as rabbit food supplement. Main aim of the study was to determine the effect of natural mix of marine and freshwater seaweed polyphenols on selected reproductive characteristics of male rabbits during the 90-days experiment. Natural mix was incorporated in feed-pellets for rabbits in two different concentrations – 0.3% (T1 group) and 0.6% (T2 group), compared with a control group (C group). In experimental groups a significant increase of concentration of calcium during first 30 days of supplementation was found. An increase of alanine aminotransferase, glutathione peroxidase and ferric reducing ability of plasma and a decrease in aspartate aminotransferase after 90 days were recorded in the same groups. Except for that we noticed decrease of semen distance of curved line and velocity of curved line after 30 days though only while being supplemented with 0.6% proportion of seaweed polyphenols in feed mixture. Based on the results it can be stated that the natural mix in the tested levels do not show adverse effect on male rabbit reproductive parameters, and an improvement of antioxidant status was observed. The feed additives can have a very important effect on growth, health and development of animals in general as it supplies the with the much-needed minerals, nutritional substances and antioxidants, on which we focused in our study.

Cardiovascular Active Peptides of Marine Origin with ACE Inhibitory Activities: Potential Role as Anti-Hypertensive Drugs and in Prevention of SARS-CoV-2 Infection.

Growing interest in hypertension—one of the main factors characterizing the cardiometabolic syndrome (CMS)—and anti-hypertensive drugs raised from the emergence of a new coronavirus, SARS-CoV-2, responsible for the COVID19 pandemic. The virus SARS-CoV-2 employs the Angiotensin-converting enzyme 2 (ACE2), a component of the RAAS (Renin-Angiotensin-Aldosterone System) system, as a receptor for entry into the cells. Several classes of synthetic drugs are available for hypertension, rarely associated with severe or mild adverse effects. New natural compounds, such as peptides, might be useful to treat some hypertensive patients. The main feature of ACE inhibitory peptides is the location of the hydrophobic residue, usually Proline, at the C-terminus. Some already known bioactive peptides derived from marine resources have potential ACE inhibitory activity and can be considered therapeutic agents to treat hypertension. Peptides isolated from marine vertebrates, invertebrates, seaweeds, or sea microorganisms displayed important biological activities to treat hypertensive patients. Here, we reviewed the anti-hypertensive activities of bioactive molecules isolated/extracted from marine organisms and discussed the associated molecular mechanisms involved. We also examined ACE2 modulation in sight of SARS2-Cov infection prevention.

Bioactivity of Ellagic Acid and Velutin: Two Phenolic Compounds Isolated from Marine Algae

MARINE macroalgae are considered as a promising source of chemical compounds with a broad array of biological activities. The bioactive compounds of five marine seaweeds (Ulva lactuca, Padina boryana, Cystoseira myrica, Liagora farinosa and Acanthophora spicifera) were extracted by chloroform, dichloromethane and ethanol. We managed to extract two polyphenolic compounds (ellagic acid and velutin) from the dichloromethane extract of P. boryana and ethanol extract of A. spicifera, respectively. The biological activities of the two isolated compounds as well as the crude extracts were screened. All tested algal extracts showed high antimicrobial activity against target bacteria and fungi except for Pseudomonas aeruginosa was resistant to U. lactuca and C. myrica extracts. Chloroform and ethanol extracts of A. spicifera, and dichloromethane extract of C. myrica showed the highest antimicrobial activity against Bacillus subtilis and Staphylococcus aureus. Dichloromethane extract of P. boryana had the highest antiprotozoal activity against Trypanosoma cruzi and Leishmania donovani (IC50 values, 3.5 and 4.8 μg/mL, respectively), and potent antioxidant activity up to 60 %. Overall, marine macroalgae with high polyphenols and flavonoids content exhibited excellent antimicrobial, antiprotozoal and antioxidant properties. Purified velutin recorded high antimicrobial activities as compared to the tested antibiotics and both ellagic acid and velutin also possessed considerable antiprotozoal activities. This study suggests that, ellagic acid and velutin comprise the key players for the antimicrobial and antiprotozoal activities of P. boryana and A. spicifera extracts, respectively. Thus, these two compounds could be used as pharmaceutically bioactive natural compounds.

Pseudoalteropeptide A, a novel lipopeptide from the marine bacterium Pseudoalteromonas piscicida SWA4_PA4 isolated from marine seaweed.

A new lipopeptide, pseudoalteropeptide A (1) was isolated from the marine bacterium Pseudoalteromonas piscicida SWA4_PA4. The structure was elucidated by spectroscopic analyses including NMR and MSMS spectra. It showed moderate iron chelating activity as well as cytotoxic activity against Jurkat human T lymphocyte cells. isolation/marine bacterium/natural product/structure elucidation.

Sulfated polysaccharides and its commercial applications in food industries-A review.

Polysaccharides a large chain of simple sugars covalently linked by glycosidic bonds which are obtained from living organisms and microbes commercially used in food and pharmaceutical industries. Marine macroalgae or seaweed is an unexploited natural source of polysaccharides, which contains many variant phytonutrients whose cells are enriched with sulfated polysaccharides which have been progressively read these days for their potential value in food and pharmaceutical applications. This review aims the exploration of these polysaccharides in food applications, with a focus on its types and biological properties in the view of food application.

Biological and therapeutic potential of the edible brown marine seaweed Padina australis and their pharmacological mechanisms

Seaweeds have an important place in the ancient systems of medicine. In addition, they also find significant mention in farming and in nutritional diet due to their benefits such as, availability, cheaper price, renewable potential and the advantage of being easily accessible. There are over 10,000 species of seaweeds that reflect their immense diversity. They are further used for both, their flavour and nutritional properties. Edible seaweeds are rich sources of bioactive compounds. In the last three decades, the discovery of metabolites with biological activities from macroalgae has increased significantly. Padina australis has been reported to possess several therapeutic activities including, antioxidant, anti-inflammatory, antibacterial and larvicidal effects. In addition, studies have also reported on the antidiabetic and antihypertensive potential of Padina australis. Till date, there are limited or no scientific reviews that have been published on the pharmacological and therapeutical activities of Padina australis in specific. Thus, there is a need for such a review to appreciate the various biological actions of this potent seaweed.&#x0D; &#x0D; This review, in this direction, attempts to explore the various therapeutic activities of the brown marine seaweed Padina australis, from the current published literature along with their pharmacological and molecular mechanisms, underlying its therapeutic activities. The main limitation of this review is that ancient texts, leisure magazines and traditional manuscripts were not searched.

First report of Evelineus mcintoshii (Langerhans, 1880) (Heteronemertea, Lineidae) from the Mediterranean Sea

The ribbon worm Evelineus mcintoshii is reported for the first time from the Mediterranean Sea. Observations that took place, during two algal surveys, on the intertidal abrasion platforms at the middle of the Levantine Sea of Israel indicated that this species is hiding inside a mixture of local and non-indigenous marine seaweeds. It is probably another alien species, one of many, that adopted the Levantine basin of the Eastern Mediterranean due to tropical environmental conditions that characterize this sea. We discuss the first record of this species and its possible origins as well as the first report of Notospermus geniculatus, the other marine nemertean species recently reported from Israel.

Species composition and distribution of marine macro algae at Co To and Thanh Lan archipelago

This paper exhibites species composition and distribution of marine seaweed at 10 sites of Co To and Thanh Lan islands in May 2019. The studies record 76 species of marine algae in the area, belonging to four divisions: Cyanophytes, Rhodophytes, Ochrophytes and Chlorophytes. Among them, five species are classified into Cyanophytes (comprising 6.6% of total species); thirty-four species into Rhodophytes (44.7%); twenty-one species into Ochrophytes/Phaeophytes (27.6%) and sixteen species into Chlorophytes (21.1%). The species composition of marine seaweeds in Co To and Thanh Lan shows significant differences as follows: 22 species (sites number 4 and 10) to 58 species (site number 2) and the average value is 38.7 species per site. Sørensen similarity coefficient fluctuates from 0.33 (sites number 5 and 10) to 0.84 (sites number 1 and 3) and the average value is 0.53. The current investigations show that four species of twenty-one species are collected in the littoral zone and forty-two species in the sub-littoral zone (in which there are thirteen species distributed in both littoral zone and sub-littoral zone). The algal flora in Co To and Thanh Lan is characterized by subtropics.

Biorefinery for the co-production of protein, hydrochar and additional co-products from a green seaweed Ulva sp. with subcritical water hydrolysis

Marine seaweeds are promising biomass feedstock for the co-production of food, energy and chemicals in a biorefinery. In this study, subcritical water hydrolysis (SWH) was applied to the biomass of green seaweed Ulva sp., fast-growing cosmopolitan seaweed. The SWH was done with seawater at 180 °C and 10.5 bar during 40 min with 8% w/w solid load. This treatment resulted in 211 ± 7 mg of hydrochar g−1 dry weight (DW) of Ulva sp. with higher heating value (HHV) double that of the initial biomass. The liquid fraction content per gram of Ulva DW included 5.2 ± 1.15 mg of 5-HMF; 24.1 ± 2.84 mg total monosaccharides (composed of 14.3 ± 1.78 mg glucose, 5.1 ± 0.41 mg rhamnose, 2.3 ± 0.41 mg fructose, 1 ± 0.06 mg xylose, 0.9 ± 0.08 mg galactose and 0.6 ± 0.11 mg glucuronic acid); 58 ± 11.78 mg protein (corresponding to 84.9 ± 13.2% of the total protein); and free amino acids (3.64 ± 0.07 mg leucine, 2.08 ± 0.13 mg arginine, 1.54 ± 0.01 mg isoleucine and 1.06 ± 0.03 mg alanine). Two-step fermentation optimization was done with Saccharomyces cerevisiae and Escherichia coli in Ulva hydrolysate following the SWH, with ethanol yield of 4.67 ± 0.76 mg g−1 DW Ulva. Based on these process results, some economics and sustainability indicators were estimated for large-scale macroalgae-based biorefinery. The required offshore areas for Ulva cultivation to satisfy the entire national demand in Israel for plant-based protein, char for electricity production (20% blend co-firing with coal), or ethanol for transportation (10% blend in gasoline), are 0.8%, 3.1% and 34.3%, respectively of the Israeli exclusive economic zone in the Mediterranean sea. The total revenue expected for the co-products derived from Ulva sp. via SWH varies between $0.26 and $1.06 kg−1 DW.

Production of Extracellular Reactive Oxygen Species by Marine Biota.

Reactive oxygen species (ROS) are produced ubiquitously across the tree of life. Far from being synonymous with toxicity and harm, biological ROS production is increasingly recognized for its essential functions in signaling, growth, biological interactions, and physiochemical defense systems in a diversity of organisms, spanning microbes to mammals. Part of this shift in thinking can be attributed to the wide phylogenetic distribution of specialized mechanisms for ROS production, such as NADPH oxidases, which decouple intracellular and extracellular ROS pools by directly catalyzing the reduction of oxygen in the surrounding aqueous environment. Furthermore, biological ROS production contributes substantially to natural fluxes of ROS in the ocean, thereby influencing the fate of carbon, metals, oxygen, and climate-relevant gases. Here, we review the taxonomic diversity, mechanisms, and roles of extracellular ROS production in marine bacteria, phytoplankton, seaweeds, and corals, highlighting the ecological and biogeochemical influences of this fundamental and remarkably widespread process.