Marine Brown Seaweed Research Articles

Cytotoxicity of Fucoidan from Three Tropical Brown Algae Against Breast and Colon Cancer Cell Lines

Introduction: Fucoidan is a sulfated polysaccharide that has a wide range of bioactivities including anti-cancer. This polysaccharide commonly is extracted from marine brown seaweed. There is lack of information on the fucoidan extracted from tropical brown algae and its anti-cancer activity. Objectives: The objectives of this study were to purify fucoidan from Sargassum sp., Turbinaria sp. and Padina sp., and to evaluate their cytotoxicity against breast cancer (MCF-7) and colon cancer cells (WiDr). Materials and Methods: Fucoidan extraction was conducted by using acid extraction method. Purified fucoidans were obtained by DEAE cellulose column chromatography and confirmed by HPLC and FT-IR spectrometry. The cytotoxicity was evaluated by using the MTT (3-[4,5-dimethylthiazol-2-yl] -2,5- diphenyltetrazolium bromide) assay. Results: Fucoidan from Sargassum sp. and Turbinaria sp. showed low cytotoxicity with IC50 ranging between 461-663 μg/mL. Higher cytotoxicity against MCF-7 and WiDr was showed by fucoidan from Padina sp. with IC50 of 144 and 118 μg/mL, respectively. While its IC50 against Vero cells was 501 μg/mL.Standard fucoidan from Fucus vesiculosus exhibited IC50 of 60, 63 and 211 μg/mL against MCF-7, WiDr and Vero Cells, respectively. Although the IC50 was higher than that of standard fucoidan, Padina sp. fucoidan showed cytotoxicity comparable with standard fucoidan at concentrations below 100 μg/mL. Conclusion: These results indicated that Padina sp.fucoidan showed potential selective cytotoxicity, and promising for the development of an anti-cancer compound.

Extraction of polyphenols in Himanthalia elongata and determination by high performance liquid chromatography with diode array detector prior to its potential use against oxidative stress.

Several studies have demonstrated the antioxidant capacity of seaweeds, which can be used for the development of biopharmaceuticals with extensive medical application. Antioxidant therapies appear to attenuate the organic deterioration originated by an excessive oxidative stress, which could prevent the harmful effects of various injuries such as ischemia-reperfusion (I/R) among others. Marine brown seaweeds play a significant role, as they are the only organisms on earth producing phlorotannins, which are polyphenols that exhibit important biological activity. To ensure obtaining an extract with the greatest antioxidant activity, some variables that affect the extraction of polyphenols are optimized, including seaweed amount, type of solvent, and time and temperature of extraction. Subsequently, the total phenolic content (TPC) and the antioxidant activity have been determined. The optimized condition was obtained for 6g of seaweed, ethanol: water proportion of 60:40 and 2h/60°C, achieving 548.33mg AG/100g seaweed and 76% of antioxidant activity. The characterization of the extracted polyphenols was made by HPLC/DAD. 11 polyphenols were identified in the extract: Phloroglucinol, Gallic Acid, Catechin, Rutin, Gentisic Acid, Chlorogenic Acid, Caffeic Acid, Coumaric, Ferulic, Myricetin and Quercetin.

A study on Bioactive Compounds Derived from Brown Seaweeds and their Therapeutic Applications towards Various Diseases

Traditionally seaweeds are used as food additives, flavouring agents and as foodstuffs in many countries and the research on the extraction of bioactive substances have been conducted all around the globe. In India even though the seaweeds are mainly exploited as a source of phycocolloids such as agar-agar, alginate and carrageenan, further information on the bioutilization of Indian seaweeds is limited as not much has been done to systemically study their therapeutic potential. Marine brown seaweeds are rich in bioactive metabolites that could be potentially exploited in many applications like industry, pharmacy etc. Several efforts have been made to isolate the bioactive compounds and to explore its mechanism of actions. Fucoidan, phloroglucinol, fucoxanthin are some of the bioactive compounds present in brown seaweeds showing antimicrobial, anti-inflammatory, anti-diabetic, antioxidant and antiviral properties. The present review attempts to discuss the reports available on the extraction and identification of compounds and to examine the potential and therapeutic effects of the metabolites existing in the brown macroalgae.

Isolation, Identification and Screening of Antimicrobial Properties of the Marine-Derived Endophytic Fungi from Marine Brown Seaweed

Marine seaweeds are known to produce valuable medicinal compounds such as antioxidants and anticoagulants, and have been reported to display antimicrobial activity against gram positive and gram negative bacteria. Several studies have identified so-called endophytic fungi living inside their hosts as the source of active compounds. In this study marine brown seaweed, Padina sp., was studied with regards to their endophytic fungi to assess if they are the source of the reported antimicrobial activity. Twenty fungal isolates were isolated from Padina sp. collected off Talang-Talang Island, Sarawak, Malaysia. All isolates were screened for their antimicrobial properties and 11 out of 20 isolates displayed positive results. DNA was successfully extracted for five isolates and sequence analysis grouped all of them with other endophytic fungi. “Fungus 2” seems to be related to a so far uncultured endophytic fungus. “Fungus 19” showed the most promising antimicrobial properties and was chosen for further agar well assay and cytotoxicity testing. Its ethyl-acetate extract showed positive results in the agar well assay and also a cytotoxic effect on Artemia nauplii. The extract was screened using HPLC and showed a compound similar to a known anti-cancer compound, dihydromyricetin, which is also an anti-intoxicant, anti-inflammatory and anti-oxidative agent which may be responsible for the observed antimicrobial activity.

Characterization and Immunological Evaluation of Low-Molecular- Weight Alginate Derivatives

Alginate is a naturally occurring acidic linear polysaccharide obtained from marine brown seaweed. Low molecular weight structurally diverse derivatives and oligosaccharides derived from alginate have shown various tremendous biological and pharmacological activities. It has been demonstrated that immuno-inflammation is involved in many prevalent human diseases, such as cancer, severe infection and neurodegeneration. Given the activities of marine natural products in the regulation of immune responses, increasing efforts are being made toward the development of lowmolecular- weight natural compounds that aid in the prevention and treatment of immune- and inflammatory-related diseases. In this review, we describe the development of chemical modification and molecular depolymerization methods that modify the physicochemical and biological characteristics of alginate. Additionally, current progress in research on immuno-inflammatory, anti-neurodegenerative and anti-tumor activities of alginate derivatives is highlighted.

Fucoidan induces G1 arrest of the cell cycle in EJ human bladder cancer cells through down-regulation of pRB phosphorylation

Fucoidan, a sulfated polysaccharide found in marine algae and brown seaweeds, has been shown to inhibit the in vitro growth of human cancer cells. This study was conducted in cultured human bladder cancer EJ cells to elucidate the possible mechanisms by which fucoidan exerts its anti-proliferative activity, which until now has remained poorly understood. Fucoidan treatment of EJ cells resulted in dose-dependent inhibition of cell growth and induced apoptotic cell death. Flow cytometric analysis revealed that fucoidan led to G1 arrest in cell cycle progression. It was associated with down-regulation of cyclin D1, cyclin E, and cyclin-dependent-kinases (Cdks) in a concentration-dependent manner, without any change in Cdk inhibitors, such as p21 and p27. Furthermore, dephosphorylation of retinoblastoma protein (pRB) by this compound was associated with enhanced binding of pRB with the transcription factors E2F-1 and E2F-4. Overall, our results demonstrate that fucoidan possesses anticancer activity potential against bladder cancer cells by inhibiting pRB phosphorylation.

알긴산을 분해하는 해양미생물인 Sphingomonas sp. MJ-3 균주의 올리고알긴산 분해효소의 상동성 모델링 및 특성연구

Alginates are found in marine brown seaweeds and in extracellular biofilms secreted by some bacteria. Previously, we reported an oligoalginate lyase from Sphingomonas sp. MJ-3 (MJ3-Oal) that had an exolytic activity and protein sequence homology with endolytic polymannuronate (polyM) lyase in the N-terminal region. In this study, the MJ3-Oal was tested for both exolytic and endolytic activity by homology modeling using the crystal structure of Alg17c from Saccharophagus degradans 2-40T. The tyrosine residue at the 426th position, which possibly formed a hydrogen bond with the substrate, was mutated to phenylalanine. The FPLC profiles showed that MJ3-Oal degraded alginate quickly to monomers as a final product through the oligmers, whereas the Tyr426Phe mutant showed only exolytic alginate lyase activity. 1H-NMR spectra also showed that MJ3-Oal degraded the endoglycosidic bond of polyM and polyMG (polymannuronate-guluronate) blocks. These results indicate that oligoalginate lyase from Sphingomonas sp. MJ-3 probably catalyzes the degradation of both exo- and endo-glycosidic bonds of alginate.

Microbicidal activity of crude extracts from Sargassum wightii against Bacillus cereus

The present study was investigated to explore the antibacterial activity of four different solvent (petroleum ether, chloroform, acetone and ethanol) crude extracts of marine brown seaweed Sargassum wightti. Crude extracts were screened against human pathogen Bacillus cereus. The antibacterial efficiency was performed by agar well diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. The results revealed that the crude extract of petroleum ether showed prominent inhibiting activity against B. cereus and other crude extracts showed below detectable level. The highest microbicidal activity (zone of inhibition) 9.0 ± 0.32 mm was obtained at the concentration of 250 ?g /ml and the lowest activity was 3 ± 0.20 mm at 31.25 ?g /ml concentration. The MIC and MBC values were found to be 125 and 250 ?g /ml respectively. Results of this study suggested that the compounds present in the crude extracts of petroleum ether showed high activity against B. cereus and further studies are required to purify the active principles.DOI: http://dx.doi.org/10.3329/icpj.v3i10.20338 International Current Pharmaceutical Journal, September 2014, 3(10): 326-327

Quorum quenching and antibacterial activity of silver nanoparticles synthesized from <i>Sargassum polyphyllum</i>

Development of efficient methodology for the green synthesis of silver nanoparticles using marine algae is a modern area of research in the field of phyconanotechnology. In this regard, the present study deals with green synthesis of silver nanoparticles (AgNPs) by using aqueous extracts of marine brown seaweed Sargassum polyphyllum. UV-visible spectral analysis reveals the formation of AgNPs by showing absorption maximum at 420 nm wavelength and SEM analysis clearly elucidate the polydispersed structure of AgNPs without aggregation and ranged in size from 37-43 nm. X-ray Diffraction pattern confirmed the AgNPs crystalline personality. The synthesized AgNPs showed more enduring antibacterial activity against test bacterial pathogens. Furthermore, the synthesized AgNPs exhibited varying level of inhibition of violacein production and swarming motility. In the near future, silver nanoparticles can be extremely useful in clinical medicine as an alternative method for the treatment of wound infection.

Cancer Preventive Efficacy of Marine Carotenoid Fucoxanthin: Cell Cycle Arrest and Apoptosis

Epidemiological investigations have shown that overcoming the risk of cancer is related to the consumption of green vegetables and fruits. Many compounds from different origins, such as terrestrial plants and marine and microbial sources, have been reported to have therapeutic effects of which marine sources are the most important because the diversity of marine life is more varied than other sources. Fucoxanthin is one important compound with a marine origin and belongs to the group of carotenoids; it can be found in marine brown seaweeds, macroalgae, and diatoms, all of which have remarkable biological properties. Numerous studies have shown that fucoxanthin has considerable medicinal potential and promising applications in human health. In this review, we summarize the anticancer effects of fucoxanthin through several different mechanisms including anti-proliferation, induction of apoptosis, cell cycle arrest and anti-angiogenesis, and its possible role in the treatment of cancer.

Mapping global effects of the anti-sigma factor MucA in Pseudomonas fluorescens SBW25 through genome-scale metabolic modeling

BackgroundAlginate is an industrially important polysaccharide, currently produced commercially by harvesting of marine brown sea-weeds. The polymer is also synthesized as an exo-polysaccharide by bacteria belonging to the genera Pseudomonas and Azotobacter, and these organisms may represent an alternative alginate source in the future. The current work describes an attempt to rationally develop a biological system tuned for very high levels of alginate production, based on a fundamental understanding of the system through metabolic modeling supported by transcriptomics studies and carefully controlled fermentations.ResultsAlginate biosynthesis in Pseudomonas fluorescens was studied in a genomics perspective, using an alginate over-producing strain carrying a mutation in the anti-sigma factor gene mucA. Cells were cultivated in chemostats under nitrogen limitation on fructose or glycerol as carbon sources, and cell mass, growth rate, sugar uptake, alginate and CO2 production were monitored. In addition a genome scale metabolic model was constructed and samples were collected for transcriptome analyses. The analyses show that polymer production operates in a close to optimal way with respect to stoichiometric utilization of the carbon source and that the cells increase the uptake of carbon source to compensate for the additional needs following from alginate synthesis. The transcriptome studies show that in the presence of the mucA mutation, the alg operon is upregulated together with genes involved in energy generation, genes on both sides of the succinate node of the TCA cycle and genes encoding ribosomal and other translation-related proteins. Strains expressing a functional MucA protein (no alginate production) synthesize cellular biomass in an inefficient way, apparently due to a cycle that involves oxidation of NADPH without ATP production. The results of this study indicate that the most efficient way of using a mucA mutant as a cell factory for alginate production would be to use non-growing conditions and nitrogen deprivation.ConclusionsThe insights gained in this study should be very useful for a future efficient production of microbial alginates.

Suppressive Effects of Fucoxanthin on Degranulation in IgE-antigen complex-stimulated RBL-2H3 Cells

The marine carotenoid fucoxanthin can be found in marine brown seaweeds, macroalgae, diatoms, and microalgae, and has remarkable biological properties. Numerous studies have shown that fucoxanthin has considerable potential and promising applications in human health, but the underlying mechanisms involved in its anti-allergic activity are not fully understood. We here investigated the mechanisms by anti-allergic activity of fucoxanthin fraction from Eisenia bicyclis in immunoglobulin E-antigen complex (IgE/DNP-BSA)-stimulated RBL-2H3 mast cells. This study we found that the fucoxanthin inhibits the release of <TEX>${\beta}$</TEX>-hexosaminidase and suppressed not only transcriptional activation of NF-<TEX>${\kappa}B$</TEX>, but also phosphorylation of ERK and JNK in IgE/DNP-BSA-treated RBL-2H3 cells. Fucoxanthin may be useful for preventing allergic diseases, including asthma and atopic dermatitis.

Brassica napus Growth is Promoted by Ascophyllum nodosum (L.) Le Jol. Seaweed Extract: Microarray Analysis and Physiological Characterization of N, C, and S Metabolisms

Despite its high capacity to take up nitrate from soil, winter rapeseed (Brassica napus) is characterized by a low N recovery in seeds. Thus, to maintain yield, rapeseed requires a high fertilization rate. Increasing nutrient use efficiency in rapeseed by addition of a biostimulant could help improve its agroenvironmental balance. The effects of marine brown seaweed Ascophyllum nodosum on plant growth have been well described physiologically. However, to our knowledge, no study has focused on transcriptomic analyses to determine metabolic targets of these extracts. A preliminary screening of different extracts revealed a significant effect of one of them (AZAL5) on rapeseed root (+102 %) and shoot (+23 %) growth. Microarray analysis was then used on AZAL5-treated or nontreated plants to characterize changes in gene expression that were further supported by physiological evidence. Stimulation of nitrogen uptake (+21 and +115 % in shoots and roots, respectively) and assimilation was increased in a similar manner to growth, whereas sulfate content (+63 and +133 % in shoots and roots, respectively) was more strongly stimulated leading to sulfate accumulation. Among the identified genes whose expression was affected by AZAL5, MinE, a plastid division regulator, was the most strongly affected. Its effect was supported by microscopic analysis showing an enhancement of chloroplast number per cell and starch content but without a significant difference in net photosynthetic rate. In conclusion, it is suggested that AZAL5, which promotes plant growth and nutrient uptake, could be used as a supplementary tool to improve rapeseed agroenvironmental balance.

Fucoidan, a sulfated polysaccharide from brown algae, improves cognitive impairment induced by infusion of Aβ peptide in rats

Fucoidan is a complex sulfated polysaccharide, derived from marine brown seaweed. In the present study, we investigated the effects of fucoidan on improving learning and memory impairment in rats induced by infusion of Aβ (1–40), and its possible mechanisms. The results indicated that fucoidan could ameliorate Aβ-induced learning and memory impairment in animal behavioral tests. Furthermore, fucoidan reversed the decreased activity of choline acetyl transferase (ChAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and content of acetylcholine (Ach), as well as the increased activity of acetylcholine esterase (AchE) and content of malondialdehyde (MDA) in hippocampal tissue of Aβ-injected rats. Moreover, these were accompanied by an increase of Bcl-2/Bax ratio and a decrease of caspase-3 activity. These results suggested that fucoidan could ameliorate the learning and memory abilities in Aβ-induced AD rats, and the mechanisms appeared to be due to regulating the cholinergic system, reducing oxidative stress and inhibiting the cell apoptosis.

Fucoxanthin, a Marine Carotenoid Present in Brown Seaweeds and Diatoms: Metabolism and Bioactivities Relevant to Human Health

The marine carotenoid fucoxanthin can be found in marine brown seaweeds, the macroalgae, and diatoms, the microalgae, and has remarkable biological properties. Numerous studies have shown that fucoxanthin has considerable potential and promising applications in human health. In this article, we review the current available scientific literature regarding the metabolism, safety, and bioactivities of fucoxanthin, including its antioxidant, anti-inflammatory, anticancer, anti-obese, antidiabetic, antiangiogenic and antimalarial activities, and its protective effects on the liver, blood vessels of the brain, bones, skin, and eyes. Although some studies have shown the bioavailability of fucoxanthin in brown seaweeds to be low in humans, many studies have suggested that a dietary combination of fucoxanthin and edible oil or lipid could increase the absorption rate of fucoxanthin, and thus it might be a promising marine drug.

Cloning and Characterization of a Novel Oligoalginate Lyase from a Newly Isolated Bacterium Sphingomonas sp. MJ-3

A bacterium possessing alginate-degrading activity was isolated from marine brown seaweed soup liquefied by salted and fermented anchovy. The isolated strain was designated as Sphingomonas sp. MJ-3 based on the analyses of 16S ribosomal DNA sequences, 16S-23S internal transcribed spacer region sequences, biochemical characteristics, and cellular fatty acid composition. A novel alginate lyase gene was cloned from genomic DNA library and then expressed in Escherichia coli. When the deduced amino acid sequence was compared with the sequences on the databases, interestingly, the cloned gene product was predicted to consist of AlgL (alginate lyase L)-like and heparinase-like protein domain. The MJ-3 alginate lyase gene shared below 27.0% sequence identity with exolytic alginate lyase of Sphingomonas sp. A1. The optimal pH and temperature for the recombinant MJ-3 alginate lyase were 6.5 and 50°C, respectively. The final degradation products of alginate oligosaccharides were analyzed by electrospray ionization mass spectrometry and proved to be alginate monosaccharides. Based on the results, the recombinant alginate lyase from Sphingomonas sp. MJ-3 is regarded as an oligoalginate lyase that can degrade oligoalginate and alginate into alginate monosaccharides.

Effect of phlorotannins isolated from Ecklonia cava on angiotensin I-converting enzyme (ACE) inhibitory activity.

Inhibition of angiotensin I-converting enzyme (ACE) activity is the most common mechanism underlying the lowering of blood pressure. In the present study, five organic extracts of a marine brown seaweed Ecklonia cava were prepared by using ethanol, ethyl acetate, chloroform, hexane, and diethyl ether as solvents, which were then tested for their potential ACE inhibitory activities. Ethanol extract showed the strongest ACE inhibitory activity with an IC50 value of 0.96 mg/ml. Five kinds of phlorotannins, phloroglucinol, triphlorethol-A, eckol, dieckol, and eckstolonol, were isolated from ethanol extract of E. cava, which exhibited potential ACE inhibition. Dieckol was the most potent ACE inhibitor and was found to be a non-competitive inhibitor against ACE according to Lineweaver-Burk plots. Dieckol had an inducible effect on the production of NO in EAhy926 cells without having cytotoxic effect. The results of this study indicate that E. cava could be a potential source of phlorotannins with ACE inhibitory activity for utilization in production of functional foods.

Heavy metal concentrations in marine green, brown, and red seaweeds from coastal waters of Yemen, the Gulf of Aden

The purpose of this study was to investigate the concentration levels of heavy metals in different species of the main three marine algal divisions from the Gulf of Aden coastal waters, Yemen. The divisions included Chlorophyta—green plants (Halimeda tuna, Rhizoclonium kochiamum, Caldophora koiei, Enteromorpha compressa, and Caulerpa racemosa species), Phaeophyta—brown seaweeds (Padina boryana, Turbinaria elatensis, Sargassum binderi, Cystoseira myrica, and Sargassum boveanum species), and Rhodophyta—red seaweeds (Hypnea cornuta, Champia parvula, Galaxaura marginate, Laurencia paniculata, Gracilaria foliifere, and species). The heavy metals, which included cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), Iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn), and vanadium (V) were measured by Atomic Absorption Spectrophotometer (AAs). The concentrations of heavy metals in all algal species are in the order of Fe >> Cu > Mn > Cr > Zn > Ni > Pb > Cd > V > Co. The results also showed that the uptake of heavy metals by different marine algal divisions was in the order of Chlorophyta > Phaeophyta > Rhodophyta. These heavy metals were several order of magnitude higher than the concentrations of the same metals in seawater. This indicates that marine alga progressively uptake heavy metals from seawater.

Loss of zinc and cobalt during dry ashing of biological material.

Loss of zinc and cobalt during dry ashing of marine mussels (Mytilus edulis) and brown seaweed (Fucus spiralis) has been studied by using material labelled by exposure of living organisms to sea water spiked with zinc-65 or cobalt-60. Even after ashing in porcelain crucibles at temperatures of up to 1000 °C, no significant loss of zinc or cobalt by volatilisation was observed. After ashing at 450 and 550 °C, both radionuclides could be removed quantitatively from the crucibles by leaching with hydrochloric acid. Adsorption on the crucible after ashing at 1000 °C was measured only for cobalt-60. A significant proportion of the cobalt tracer could not be removed from the crucibles by treatment of the latter with acid. From these results it is concluded that dry ashing is a reliable method of sample destruction for the determination of zinc and cobalt in M. edulis and F. spiralis.