Sulfated Polysaccharides from Seaweed Strandings as Renewable Source for Potential Antivirals against Herpes simplex Virus 1.

Herpes simplex virus 1 (HSV-1) remains a prominent health concern widespread all over the world. The increasing genital infections by HSV-1 that might facilitate acquisition and transmission of HIV-1, the cumulative evidence that HSV-1 promotes neurodegenerative disorders, and the emergence of drug resistance signify the need for new antiviral agents. In this study, the in vitro anti-herpetic activity of sulfated polysaccharides (SPs) extracted by enzyme or hot water from seaweeds collected in France and Mexico from stranding events, were evaluated. The anti-herpetic activity evaluation of the semi-refined-polysaccharides (sr-SPs) and different ion exchange purified fractions showed a wide range of antiviral activity. Among them, the sr-SPs from the Rhodophyta Halymenia floresii showed stronger activity EC50 0.68 µg/mL with SI 1470, without cytotoxicity. Further, the antiviral activity of the sr-SPs evaluated at different treatment schemes showed a high EC50 of 0.38 µg/mL during the viral adsorption assays when the polysaccharide and the virus were added simultaneously, whilst the protection on Vero cell during the post-infection assay was effective up to 1 h. The chemical composition, FTIR and 1H NMR spectroscopic, and molecular weights of the sr-SPs from H. floresii were determined and discussed based on the anti-herpetic activity. The potential utilization of seaweed stranding as a source of antiviral compounds is addressed.

Trace elements in pelagic Sargassum species in the Mexican Caribbean: Identification of key variables affecting arsenic accumulation in S. fluitans.

Since 2014, the Mexican Caribbean beaches have received massive influxes of the brown seaweed Sargassum (S. fluitans III, S. natans I and S. natans VIII), causing serious ecological and economic effects. Concentrations of arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), and zinc (Zn) were determined over an annual cycle in pelagic Sargassum species from massive influxes into the Mexican Caribbean. The contribution of trace elements, polysaccharides (alginate and fucoidans), and their main functional groups (uronic acids and sulfate) to arsenic content in Sargassum fluitans - the most abundant species in the Sargassum influx - is discussed. Arsenic was recorded in all samples, yielding mean concentrations of 74.2 ± 2.84 mg kg-1. Significant differences were found between species for As, Cu, Fe, and Pb, but not for Cd and Zn; also, S. fluitans showed significant differences in metal content between seasons for all elements, as well as in alginate and uronic acids from fucoidan. The season of the year, copper, iron, uronic acids, and sulfate content in fucoidan were the main variables associated with arsenic accumulation in S. fluitans as evidenced with a Generalized Linear Model. Arsenic content in Sargassum biomass exceeded the maximum allowable level in the rainy season; therefore, the content of this trace element should be carefully monitored for safe usage of Sargassum biomass.

Species composition and chemical characterization of Sargassum influx at six different locations along the Mexican Caribbean coast.

In the last decade, unprecedented arrivals of pelagic Sargassum (Sargassum influx) have been reported for the Caribbean coasts causing severe ecological and economical affectations and remarking the necessity to characterize the phenomenon. In the north coast of the Mexican Caribbean, spatial characterization of Sargassum influx was performed in terms of its abundance, species composition and chemical content using a combination of in situ sampling and remote sensing evaluations. Sargassum influx was detected within the 25 km fringe near to Quintana Roo coast in coincidence with beach-cast events during September 2018. Significant spatial variation in abundance and species composition of the stranded biomass was found for the six localities studied, which was related to the local environmental conditions. Pelagic species of Sargassum were the main component ranging from 78.1 to 99.6% of the total beach-cast (wrack) fresh biomass, whereas benthic macrophytes (seagrasses and macroalgae) were a minor component reaching up to 21% in some localities. The biochemical composition of beach-cast Sargassum resulted spatially homogeneous for most of the components analyzed; only carbon tissue content, ash metals (particularly Fe and As) and isotopic composition changed spatially. This study represents baseline information for the region. Long-term seasonal evaluations of Sargassum influx along Mexican Caribbean are required to define adequate management strategies and exploitation.

NMR Metabolic Profiling of Sargassum Species Under Different Stabilization/Extraction Processes.

The genus Sargassum is well represented by benthic and pelagic species, some of which form massive aggregates that can travel long distances due to the force of the ocean currents. Although they constitute an essential habitat for fish and invertebrate species, large accumulations of Sargassum in coastal areas generate several economic, environmental, and health impacts. It is important to recognize the species forming these aggregates, and identify the metabolites they produce, allowing for its exploitation, and therefore, better management practices. NMR metabolic profiling is a technique that can discriminate samples while detecting their unique or differential chemical features, and has been successfully used in the study and classification of several algal species. The present investigation studied the metabolic profiling of Sargassum species found on strandings at Puerto Morelos (Quintana Roo) east coast of the Mexican Caribbean. PCA of the 1 H-NMR profiles corresponding to S. natans, S. natans (morphotype VIII), S. fluitans, and a benthic Sargassum buxifolium allowed the discrimination of samples amongst them. Furthermore, discrimination between the two forms of S. natans was also possible. The PCA loading plot revealed that glutamine and glutamate have the highest influence in the clustering of the benthic Sargassum, while a high abundance of lactate, Myo-inositol, and trimethylamine is a unique feature from the S. natans morphotype VIII. Additional PLS-DA models showed that a heat-drying process improved the extraction of metabolites. Maceration and microwave-assisted extraction with water-ethanol led to similar profiles and thus any of them could be used in future investigations.

Epibiont hydroids on beachcast Sargassum in the Mexican Caribbean.

Massive accumulations of pelagic species of Sargassum have generated recent social, economic and ecological problems along Caribbean shores. In the Mexican Caribbean, these events have prompted the study of diverse biological and ecological aspects of these macroalgae. However, studies on their associated biota, including Hydrozoa, remain scarce. This research provides important species observations in an area where data is lacking. The occurrence and percent cover of hydroids on Sargassum thalli collected on the beach at Puerto Morelos, Quintana Roo, Mexico from April 2018 to March 2019 was studied. Three pelagic species and morphotypes of Sargassum from this area were analyzed: Sargassum fluitans III, S. natans I and S. natans VIII, as well as a benthic species, S. polyceratium var. ovatum. A total of 14 taxa of hydroids, belonging to the superorders "Anthoathecata" and Leptothecata, were identified. In our study, more hydroid taxa were observed on axes of the different species of Sargassum than on leaves or aerocysts. In general, the greatest species richness of hydroids was observed from February to April. Results show that live hydrozoans attached to pelagic Sargassum are transported into the area. This should be considered in future management measures that address the recurring coastal abundance of Sargassum and its associated biota in the Caribbean region.

Physicochemical and transport properties of biodegradable agar films impregnated with natural semiochemical based-on hydroalcoholic garlic extract.

Biodegradable films based on agar with glycerol (GLY) as a plasticizer were developed by incorporating hydroalcoholic garlic extract (HGE) on the film surface. The effect of GLY content (0, 15, or 30 wt%) and different concentrations of HGE (0, 0.5, 1, or 1.5 µg/mL) on the physicochemical and transport properties of the films was evaluated. The optical (color and transparency), mechanical (tensile test), transport (diffusion and water vapor transmission rate), thermal (thermogravimetric analysis) structural (infrared spectroscopy and X-ray diffraction), and morphological (scanning electron microscope) properties were analyzed. The impregnation of HGE increased the transparency values and decreased the luminosity, tensile strength, elastic modulus, and crystallinity of the agar films. The formulation of 30 wt% GLY with 1.5 µg/mL HGE, identified as 30 GLY [1.5], showed a similar thermal stability that of a neat agar film. The agar films with 30 wt% GLY showed the lowest diffusion coefficient and water vapor transmission rate, indicating that volatile compounds are slowly released. From the results the formulation 30 GLY [1.5] could be used as a film to transport and to release HGE which is supported by a biodegradable matrix and this system has a potential use as insect semiochemical for plague control.

Environmentally Friendly Valorization of Solieria filiformis (Gigartinales, Rhodophyta) from IMTA Using a Biorefinery Concept.

Marine macroalgae (seaweed) are an excellent source of novel bioactive metabolites. The biorefinery concept applied to seaweed facilitates the extraction of many chemical constituents from the same biomass ensuring that the resource is used fully, generating few residues through a succession of extraction steps. In the present study, the biomass of the carragenophyte Solieria filiformis (Rhodophyta, Gigartinales) cultured in an integrated multi-trophic aquaculture (IMTA) system was evaluated to obtain valuable products by a biorefinery approach. Enzymatic-assisted extraction (EAE) and microwave-assisted extraction (MAE) were the eco-friendly technologies used to ensure an environmentally friendly valorization of the biomass. Three valuable products were successfully recovered: a water-soluble extract rich in proteins and sulfated polysaccharides suitable as a food supplement; a lipid fraction rich in polyunsaturated fatty acids (PUFAs) with potential to be used in the nutraceutical industry; and a pure ι-carrageenan with a powerful antiviral activity against Herpes simplex virus (EC50 = 6.3 µg mL-1) comparable to the commercial antiviral acyclovir (EC50 = 3.2⁻5.4 µg mL-1).

Synergistic Effects of Sulfated Polysaccharides from Mexican Seaweeds against Measles Virus.

Sulfated polysaccharides (SPs) extracted from five seaweed samples collected or cultivated in Mexico (Macrocystis pyrifera, Eisenia arborea, Pelvetia compressa, Ulva intestinalis, and Solieria filiformis) were tested in this study in order to evaluate their effect on measles virus in vitro. All polysaccharides showed antiviral activity (as measured by the reduction of syncytia formation) and low cytotoxicity (MTT assay) at inhibitory concentrations. SPs from Eisenia arborea and Solieria filiformis showed the highest antiviral activities (confirmed by qPCR) and were selected to determine their combined effect. Their synergistic effect was observed at low concentrations (0.0274 µg/mL and 0.011 µg/mL of E. arborea and S. filiformis SPs, resp.), which exhibited by far a higher inhibitory effect (96% syncytia reduction) in comparison to the individual SP effects (50% inhibition with 0.275 µg/mL and 0.985 µg/mL of E. arborea and S. filiformis, resp.). Time of addition experiments and viral penetration assays suggest that best activities of these SPs occur at different stages of infection. The synergistic effect would allow reducing the treatment dose and toxicity and minimizing or delaying the induction of antiviral resistance; sulfated polysaccharides of the tested seaweed species thus appear as promising candidates for the development of natural antiviral agents.

Cytotoxic and antiproliferative constituents from Dictyota ciliolata, Padina sanctae-crucis and Turbinaria tricostata.

CONTEXT: The hexane extracts of Dictyota ciliolata Sonder ex Kützing (Dictyotaceae), Padina sanctae-crucis Børgesen (Dictyotaceae), and Turbinaria tricostata E.S. Barton (Sargassaceae) were found to exhibit cytotoxic and antiproliferative activities in vitro. Bioactive compounds responsible for these activities have not been studied in detail for these species and phytochemical studies are very limited. OBJECTIVE: Isolate, evaluate, and elucidate the bioactive constituents of D. ciliolata, P. sanctae-crucis, and T. tricostata. MATERIALS AND METHODS: Bioassay-guided cytotoxicity fractionations using the Hep-2 cell line of the hexane extracts from these brown algae were analyzed using various chromatographic techniques. Cytotoxic and antiproliferative activities of all isolated compounds were also evaluated on a panel of cell lines (KB, Hep-2, MCF-7, and SiHa). Furthermore, their selectivity index, the ratio of cytotoxicity on normal cells to cancer cells, was evaluated using the HEK-293 cell line. RESULTS: Four compounds were isolated from studied species: two sterol, fucosterol (1) and 24ξ-hydroperoxy-24-vinylcholesterol (2); and two diterpenes, pachydictyol A (3) and dictyol B acetate (4). The major bioactive components of the hexane extracts of T. tricostata and P. sanctae-crucis were compounds 1 and 2 (with CC50 varying around 3.1-25.6 µg/mL) on cell lines tested. Whereas compounds 1, 3, and 4 showed cytotoxic activity against cancer cell lines (CC50 varying between 14.8 and 41.2 µg/mL) and were major bioactive constituents of hexane extract of D. ciliolata. Compounds 1 and 4 showed antiproliferative activity on MCF-7 (IC50 = 43.3 µg/mL for compound 1 and 38.3 µg/mL for compound 2) and SiHa (IC50 = 43.3 µg/mL for compound 1 and 38.3 µg/mL for compound 2) cell lines. CONCLUSION: This study is the first investigation on the bioactive components of D. ciliolata, P. sanctae-crucis, and T. tricostata. Although compounds 1-3 were described previously, the pharmacological activity of compound 4 is presented here for the first time.

Polyamines increase carpospore output and growth during in vitro cultivation of Hydropuntia cornea.

Carpospore output and development in the marine red alga Hydropuntia cornea J. Agardh. were increased by adding polyamines (PAs) (putrescine, spermidine and spermine) singly or in combinations at 10(-9), 10(-6) and 10(-3) M. Cell divisions after spore release and development of apical axis between 17 and 21 days characterized carpospore development. PAs increased carpospore development by promoting cell divisions to form cell masses between day 2 and 3. Morphogenesis to develop apical axes occurred at day 7. Spermine at 10(-6) M and a combination of putrescine 10(-9) M + spermidine 10(-9) M + spermine 10(-9) M gave a higher number of carpospores and enhanced their further development to sporelings.

Enhanced Antitumoral Activity of Extracts Derived from Cultured Udotea flabellum (Chlorophyta).

Very few studies have been performed to evaluate the effect of culture conditions on the production or activity of active metabolites in algae. Previous studies suggest that the synthesis of bioactive compounds is strongly influenced by irradiance level. To investigate whether the antiproliferative activity of Udotea flabellum extracts is modified after cultivation, this green alga was cultured under four photon flux densities (PFD) for 30 days. After 10, 20, and 30 days, algae were extracted with dichloromethane: methanol and screened for antiproliferative activity against four human cancer cell lines (laryngeal-Hep-2, cervix-HeLa, cervix squamous-SiHa and nasopharynx-KB) by SRB assay. Lipid and phenol content were evaluated by standardized methods on algae organic extracts. After 10 days of cultivation, organic U. flabellum extracts showed a significant increase in antiproliferative activity on Hela and SiHa cells when compared to noncultured algae extracts. Extracts obtained after 10 and 20 days of culture were active on KB and Hep-2 cells. Total phenol and polyunsaturated fatty acid content in organic extracts changed with cultivation time but not by irradiance treatment. Extracts from U. flabellum obtained after 10 and 20 days of culture have been selected for fractionation and isolation of active compounds.

Physicochemical properties of biodegradable polyvinyl alcohol-agar films from the red algae Hydropuntia cornea.

Agar obtained from the red alga Hydropuntia cornea was blended with polyvinyl alcohol (PVOH) in order to produce biodegradable films. In this study, we compare the properties of biopolymeric films formulated with agars extracted from H. cornea collected at different seasons (rainy and dry) in the Gulf of Mexico coast and PVOH as synthetic matrix. The films were prepared at different agar contents (0%, 25%, 50%, 75%, and 100%) and their optical, mechanical, thermal, and morphological properties analyzed. The tensile strength of PVOH-agar films increased when agar content was augmented. The formulation with 50% agar from rainy season (RS) had a significant higher tensile strength when compared to those from dry season (DS; p < 0.05). Tensile modulus also displayed an increasing trend and likewise, for 50% and 75% agar blends from RS showed higher values than those from DS (p < 0.05). In contrast, elongation at break decreased as the agar content increased, independently of the season. Environmental scanning electron microscopy images of PVOH-agar 75% biofilms from RS showed a homogeneous structure with good interfacial adhesion between the two components. The changes evidenced in the FTIR spectrum of this blend suggest that hydrogen bonding is taking place between the agar ether linkages (C-O-C) and the hydroxyl groups (OH) of the PVOH. Based on the above mentioned results, blends of PVOH and 75% agar from H. cornea collected in rainy season showed good properties for applications in the biodegradable packaging industry.

The tropical brown alga Lobophora variegata: a source of antiprotozoal compounds.

Lobophora variegata, a brown alga collected from the coast of the Yucatan peninsula, Mexico, was studied for antiprotozoal activity against Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. The whole extract showed the highest activity against T. vaginalis, with an IC(50) value of 3.2 microg/mL. For the fractions, the best antiprotozoal activity was found in non-polar fractions. The chloroform fraction of the extract contained a major sulfoquinovosyldiacylglycerol (SQDG), identified as 1-O-palmitoyl-2-O-myristoyl-3-O-(6'''-sulfo-alpha-D-quinovopyranosyl)-glycerol (1), together with small amounts of 1,2-di-O-palmitoyl-3-O-(6'''-sulfo-alpha-D-quinovopyranosyl)-glycerol (2) and a new compound identified as 1-O-palmitoyl-2-O-oleoyl-3-O-(6'''-sulfo-alpha-D-quinovopyranosyl)-glycerol (3). Their structures were elucidated on the basis of chemical and enzymatic hydrolysis and careful analysis of FAB-MS and NMR spectroscopic data. This is the first report on the isolation of SQDGs from L. variegata. The mixture of 1-3 showed good activity against E. histolytica and moderate activity against T. vaginalis with IC(50s) of 3.9 and 8.0 microg/mL, respectively, however, the activity of 1-3 is not as effective as metronidazole. These results afford ground information for the potential use of the whole extract and fractions of this species in protozoal infections.

Cell wall composition affects Cd2+ accumulation and intracellular thiol peptides in marine red algae.

Two red macroalgae species, Gracilaria cornea and Chondrophycus poiteaui, were evaluated for their intra and extracellular Cd2+ accumulation capacity, photosynthetic response and thiol peptide production. Algae were exposed for 3 and 7 days to 0.1 and 1 microg CdCl2 ml(-1) (0.89 and 8.9 microM). Intracellular accumulation of Cd2+ by G. cornea was relatively low, only comprising 20% of total metal (intracellular+extracellular). In contrast, C. poiteaui accumulated intracellularly close to 100% of total Cd2+. In both species, metal uptake was dependent on the external Cd2+ concentration, metal exposure time and cell wall composition. In response to Cd2+ exposure, low amounts of thiol peptides were synthesized and the major difference between G. cornea and C. poiteaui was in the cell wall composition. The absence of insoluble polysaccharides in the cell wall of C. poiteaui suggested that this insoluble fraction might be involved in establishing an efficient barrier for the intracellular accumulation of Cd2+. This is the first study in which the cell wall composition, its influence on Cd2+ accumulation and intracellular responses in red macroalgae are evaluated.

Physiological characterization of Dunaliella sp. (Chlorophyta, Volvocales) from Yucatan, Mexico.

Physiological responses of Dunaliella salina and Dunaliella viridis, isolated from solar saltworks on the Yucatan Peninsula, were studied. Optimal growth temperature for D. salina was 22 degrees C (3.06 x 10(6) cells mL(-1)) and 26 degrees C for D. viridis (4.04 x 10(6)cells mL(-1)). Total carotenoid content in D. salina increased with temperature to a maximum of 35.14 pg cell(-1) at 38 degrees C. Dunaliella salina alpha-carotene and beta-carotene content was 0.083+/-0.003 and 0.598+/-0.020 mg 100g dry wt(-1) respectively, whereas lower values were found in D. viridis cultured under same experimental conditions (0.018+/-0.002 and 0.136+/-0.012 mg 100g dry wt(-1) respectively). The highest specific growth rate in D. salina was obtained at 10% NaCl (0.28 d(-1)), while its cell volume increased from 524 to 2066.93 microm(3) when cultured from 10% to 35% NaCl. Maximum photosynthetic rates were attained when increasing from optimal growing temperature to 30 degrees C for D. viridis (108 n mol O(2)microg chl alpha h(-1)) and D. salina (139 n mol O(2)microg chl alpha h(-1)). Photosynthetic responses to temperature variations indicated physiological adjustments in both species, with higher acclimation in D. salina. Evaluation of physiological attributes of these species will be used for to carry out mass cultivation.

Regulation of two photosynthetic pigment-related genes during stress-induced pigment formation in the green alga, Dunaliella salina.

The expression of mRNAs coding for 1-deoxyxylulose-5-phosphate synthase (DXS) and phytoene synthase (PSY) were studied in Dunaliella salina grown under nitrogen-sufficient (NS) and nitrogen-limited (NL) conditions. Under NS conditions growth was 2.5 times higher than under NL conditions. No differences were found in chlorophyll a content per cell, and total carotenoid content per cell was 5.33 pg 1(-1) for the NS treatment and 7.76 pg 1(-1) for the NL. DXS transcripts exhibited diminished expression under NL conditions, peaking at day 15 of cultivation in both treatments. Simultaneously, PSY transcripts exhibited constant expression under both conditions. These results suggest that these genes play an important role in the balance of photosynthetic pigments during pigment accumulation.