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Herminia Domínguez - One of the best experts on this subject based on the ideXlab platform.
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Acetone Precipitation of Heterofucoidans from Sargassum muticum Autohydrolysis Extracts
Waste and Biomass Valorization, 2020Co-Authors: Valeria Acevedo-garcía, Herminia Domínguez, Noelia Flórez-fernández, Marta López-garcía, José Manuel López Vilariño, María Dolores TorresAbstract:The brown seaweed Sargassum muticum was processed by non isothermal autohydrolysis under conditions selected to maximize fucoidan solubilization (170 °C). Acetone precipitation was tried for recovery of fucose-containing oligosaccharides present in hydrolyzates. The acetone:hydrolyzate volume ratio influenced both yields and composition of the precipitated fractions. The sugar components were mostly found as oligomers, their content increased with acetone:hydrolyzate volume ratio 2.0 (v/v) exhibited slight. The fractions precipitated with 0.1 and 0.9 acetone volumes showed higher phenolic and sulfate content, which was positively correlated with the antiradical activity, and exhibited slightly cytotoxic activity against human colon adenocarcinoma cells. The highest volumes of acetone used led to a slight increase in the apparent viscosity as well as the elastic and viscous moduli of formulated aqueous dispersions of alginate. Steady-state and oscillatory shear measurements of above representative dispersions indicated that the alginate extracted after acetone precipitation exhibited a slight enhancement of the viscoelastic features. Graphic Abstract
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Green technologies for cascade extraction of Sargassum muticum bioactives
Journal of Applied Phycology, 2019Co-Authors: Patricia Pérez-larrán, Andrés Moure, María Dolores Torres, Noelia Flórez-fernández, Elena M. Balboa, Herminia DomínguezAbstract:Sargassum muticum is an invasive brown seaweed which could not be eradicated from the Atlantic coasts. Therefore, periodic collection and valorization of its components has been suggested. Efficient multistage and multiproduct processes for the obtaining of valuable fractions from this seaweed, which also could be applicable to other brown seaweeds, were developed. This review discusses the potential of conventional and emerging technologies for the sequential extraction of S. muticum bioactives of interest for food, cosmetic, and pharmaceutical applications.
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ECOFRIENDLY EXTRACTION OF BIOACTIVE FRACTIONS FROM Sargassum muticum
Process Biochemistry, 2019Co-Authors: María P. Casas, Enma Conde, Herminia Domínguez, Andrés MoureAbstract:Abstract An ecofriendly process based on an enzyme-assisted extraction coupled with ultrasound extraction was proposed to obtain soluble bioactive fractions from Sargassum muticum. Whole algae (Sm) and residual algae from alginate production (AESm) were employed as feedstock. Aqueous enzyme treatment with commercial complex enzyme formulations or with mixture of enzymes lead to maximum solubilization yield, phenolic content and antioxidant activity extract after 3 h of extraction using 2–5% (wt%) enzyme loads. The enzyme-assisted treatment coupled with ultrasounds was tested for two different enzyme activities. The coupled treatment enhanced the solubilization yields from AESm samples, and increased the phenolic content and antioxidant activity of extracts from whole Sm samples. The extracts from Sm showed slightly higher proportion of unsaturated fatty acids than those from AESm and ω3:ω6 ratio close to 1. One gram of extract was equivalent to 30 mg ascorbic acid and 200 mg Trolox and the cytotoxic activity against murine melanoma B16F10 cells and human liposarcoma SW872 cells was observed at 50–250 μg/L, whereas on fibroblast occurred at more than 500 μg/L.
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Influence of molecular weight on the properties of Sargassum muticum fucoidan
Algal Research, 2019Co-Authors: Milena Álvarez-viñas, María Jesús González-muñoz, Noelia Flórez-fernández, Herminia DomínguezAbstract:Abstract The crude fucoidan extracted during hydrothermal treatment of Sargassum muticum was fractionated in a sequence of membranes (100 to 5 kDa) operating at a volume concentration ratio (VCR) of 5. The retentates and final permeate were further characterised for molecular weight, oligosaccharide content, sulfate and phenolic content, as well as for radical scavenging properties, expressed as Trolox equivalent antioxidant capacity (TEAC). The 50–100 kDa fraction contained 25% of solubles in the hydrolysates. The highest oligosaccharide content (69.34 g 100 g−1) was found in the 50–100 kDa fraction, whereas the maximal sulfate (12.30 g 100 g−1) and phenolic (6.63 g 100 g−1) content occurred in the >100 kDa fraction, which also presented the highest antiradical potency, 47 g Trolox-eq 100 g−1. However, the 10–30 kDa fraction was the most cytotoxic against cervix cancer HeLa 229 cells (EC50 = 44 μg mL−1). As a consequence, the membrane fractionation of the liquid phase obtained by autohydrolysis could provide fucoidans with different composition, molecular weight and properties.
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A green approach for alginate extraction from Sargassum muticum brown seaweed using ultrasound-assisted technique
International journal of biological macromolecules, 2018Co-Authors: Noelia Flórez-fernández, Herminia Domínguez, María Dolores TorresAbstract:Abstract Ultrasound assisted aqueous extraction of alginate from Sargassum muticum was proposed to minimize the use of chemicals, high temperatures and prolonged times, with comparable extraction yields to conventional acid/alkali procedures. The alginate, precipitated from the liquors obtained after ultrasound assisted extraction of fucoidan and phlorotannin fractions, and converted to alginic acid sodium salt by a green treatment was characterized by FTIR-ATR, 1H NMR, HPSEC, MALDI-TOF, rheology and citotoxitity. A clear influence of the sonication time was observed on the alginate molar mass, block structure, thermo-rheological and tumoral cell growth inhibition features. All tested hydrogels featured stable and thermo-reversible characteristics.
Noelia Flórez-fernández - One of the best experts on this subject based on the ideXlab platform.
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Acetone Precipitation of Heterofucoidans from Sargassum muticum Autohydrolysis Extracts
Waste and Biomass Valorization, 2020Co-Authors: Valeria Acevedo-garcía, Herminia Domínguez, Noelia Flórez-fernández, Marta López-garcía, José Manuel López Vilariño, María Dolores TorresAbstract:The brown seaweed Sargassum muticum was processed by non isothermal autohydrolysis under conditions selected to maximize fucoidan solubilization (170 °C). Acetone precipitation was tried for recovery of fucose-containing oligosaccharides present in hydrolyzates. The acetone:hydrolyzate volume ratio influenced both yields and composition of the precipitated fractions. The sugar components were mostly found as oligomers, their content increased with acetone:hydrolyzate volume ratio 2.0 (v/v) exhibited slight. The fractions precipitated with 0.1 and 0.9 acetone volumes showed higher phenolic and sulfate content, which was positively correlated with the antiradical activity, and exhibited slightly cytotoxic activity against human colon adenocarcinoma cells. The highest volumes of acetone used led to a slight increase in the apparent viscosity as well as the elastic and viscous moduli of formulated aqueous dispersions of alginate. Steady-state and oscillatory shear measurements of above representative dispersions indicated that the alginate extracted after acetone precipitation exhibited a slight enhancement of the viscoelastic features. Graphic Abstract
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Green technologies for cascade extraction of Sargassum muticum bioactives
Journal of Applied Phycology, 2019Co-Authors: Patricia Pérez-larrán, Andrés Moure, María Dolores Torres, Noelia Flórez-fernández, Elena M. Balboa, Herminia DomínguezAbstract:Sargassum muticum is an invasive brown seaweed which could not be eradicated from the Atlantic coasts. Therefore, periodic collection and valorization of its components has been suggested. Efficient multistage and multiproduct processes for the obtaining of valuable fractions from this seaweed, which also could be applicable to other brown seaweeds, were developed. This review discusses the potential of conventional and emerging technologies for the sequential extraction of S. muticum bioactives of interest for food, cosmetic, and pharmaceutical applications.
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Influence of molecular weight on the properties of Sargassum muticum fucoidan
Algal Research, 2019Co-Authors: Milena Álvarez-viñas, María Jesús González-muñoz, Noelia Flórez-fernández, Herminia DomínguezAbstract:Abstract The crude fucoidan extracted during hydrothermal treatment of Sargassum muticum was fractionated in a sequence of membranes (100 to 5 kDa) operating at a volume concentration ratio (VCR) of 5. The retentates and final permeate were further characterised for molecular weight, oligosaccharide content, sulfate and phenolic content, as well as for radical scavenging properties, expressed as Trolox equivalent antioxidant capacity (TEAC). The 50–100 kDa fraction contained 25% of solubles in the hydrolysates. The highest oligosaccharide content (69.34 g 100 g−1) was found in the 50–100 kDa fraction, whereas the maximal sulfate (12.30 g 100 g−1) and phenolic (6.63 g 100 g−1) content occurred in the >100 kDa fraction, which also presented the highest antiradical potency, 47 g Trolox-eq 100 g−1. However, the 10–30 kDa fraction was the most cytotoxic against cervix cancer HeLa 229 cells (EC50 = 44 μg mL−1). As a consequence, the membrane fractionation of the liquid phase obtained by autohydrolysis could provide fucoidans with different composition, molecular weight and properties.
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A green approach for alginate extraction from Sargassum muticum brown seaweed using ultrasound-assisted technique
International journal of biological macromolecules, 2018Co-Authors: Noelia Flórez-fernández, Herminia Domínguez, María Dolores TorresAbstract:Abstract Ultrasound assisted aqueous extraction of alginate from Sargassum muticum was proposed to minimize the use of chemicals, high temperatures and prolonged times, with comparable extraction yields to conventional acid/alkali procedures. The alginate, precipitated from the liquors obtained after ultrasound assisted extraction of fucoidan and phlorotannin fractions, and converted to alginic acid sodium salt by a green treatment was characterized by FTIR-ATR, 1H NMR, HPSEC, MALDI-TOF, rheology and citotoxitity. A clear influence of the sonication time was observed on the alginate molar mass, block structure, thermo-rheological and tumoral cell growth inhibition features. All tested hydrogels featured stable and thermo-reversible characteristics.
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Ultrasound-assisted extraction of fucoidan from Sargassum muticum
Journal of Applied Phycology, 2017Co-Authors: Noelia Flórez-fernández, Marta López-garcía, María Jesús González-muñoz, José Manuel López Vilariño, Herminia DomínguezAbstract:Ultrasound-assisted aqueous extraction (USAE) of crude fucoidan from Sargassum muticum using an ultrasonic bath (150 W and 40 kHz ) at room temperature (25 °C) for 5–30 min was studied. Fucoidan-containing extracts were separated by centrifugation and characterized by HPLC, HPSEC, FT-IR, and MALDI-TOF spectrometry. Crude fucoidan on the best conditions was composed by oligosaccharides of fucose:galactose:glucose:xylose:mannose:rhamnose in a mass ratio of 1:0.70:0.33:0.27:0.22:0.10. The maximum sulfate content was 39.54 ± 0.001-mg sulfate ion g^−1 extract. Furthermore, extract contained 25-mg phlorotannins g^−1 extract and showed an ABTS radical scavenging activity equivalent to 40-mg Trolox g^−1 extract measured with the Trolox Equivalent Antioxidant Capacity (TEAC) assay. The cell viability of selected tumoral human cell lines was reduced up to 30% in the presence of crude extracts at 500 mg L^−1.
Consolación Fernández - One of the best experts on this subject based on the ideXlab platform.
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Boom-bust of Sargassum muticum in northern Spain: 30 years of invasion
European Journal of Phycology, 2020Co-Authors: Consolación FernándezAbstract:The brown seaweed Sargassum muticum is one of the best-studied invasive marine species, although most studies are short-term and focus on the expansion phase of invasion. Here I report 30 years of ...
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CIRCUMGLOBAL INVASION BY THE BROWN SEAWEED Sargassum muticum
2015Co-Authors: Aschwin H. Engelen, Alexandra Serebryakova, Consolación Fernández, Put Ang, Kevin Britton-simmons, Frédéric Mineur, Morten F. Pedersen, Francisco Arenas, Henning Steen, Robin SvensonAbstract:Hundreds of macroalgal species have been spread outside their natural range by human activities, and many of these introductions are occurring at a worldwide scale. This review considers one of the best-studied and most widespread invasive macroalgae, Sargassum muticum, to determine the traits and processes important in marine invasions and to identify important lines of future research. Particular emphasis is placed on the ecology of S. muticum in its native range and on the four stages of invasion transport, colonization, establishment, and spread integrating taxonomy, invasion history, dispersal, impact, invasiveness and invasibility, and general ecology. Although S. muticum has received a lot of scientific attention, with more than 650 papers on this species, key information on its taxonomy, invasive biology, and evolutionary potential is still lacking. Most previous studies have been local or descriptive or provide circumstantial evidence, and too few have been hypothesis driven. Only by local-scale research conducted in different geographical regions, especially including the native range, and developed in an eco-evolutionary framework, will it be possible to greatly improve our understanding of the complex of factors, traits, and processes involved in macroalgal invasions.
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IMPACT OF THE INVASIVE SEAWEED Sargassum muticum (PHAEOPHYTA) ON AN INTERTIDAL MACROALGAL ASSEMBLAGE1
Journal of Phycology, 2005Co-Authors: Íñigo Sánchez, Consolación FernándezAbstract:The impact of the invasive seaweed Sargassum muticum (Yendo) Fensholt on a low intertidal macroalgal assemblage was assessed at a semiexposed rocky shore in northern Spain between 2002 and 2004. Sargassum muticum plants were removed from the mature macroalgal assemblage and from those occurring along the successional process of the assemblage. Biomass, richness, diversity, and percentage cover of macroalgae in experimental plots were compared with unmanipulated controls. The effect of S. muticum removal on the macroalgal assemblage more than 2 years after the beginning of the experiment was negligible. Moreover, no differences between treatments were detected in the general patterns of succession. Only significant differences in S. muticum abundance were detected between treatments at the end of the experiment. We suggest that the low abundance of S. muticum at this intertidal level and its pseudoperennial life cycle may limit competition with native macroalgae. However, long-term removal experiments may be a more indicator of the impact of S. muticum at the upper limit of its vertical distribution.
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SIZE STRUCTURE AND DYNAMICS IN A POPULATION OF Sargassum muticum (PHAEOPHYCEAE)
Journal of Phycology, 2000Co-Authors: Francisco Arenas, Consolación FernándezAbstract:Sargassum muticum (Yendo) Fensholt is an introduced brown seaweed with a very distinctive seasonal growth cycle on European shores. The present study links the dynamics of a population of S. muticum with the seasonal growth cycle of the species and the density-dependent processes operating throughout this cycle. Results indicate that both growth cycle and intraspecific competition influenced the structure and population dynamics. Size inequality increased during the slow growth phase (autumn‐winter) of the 2-year study. Mechanisms generating inequality of size could be the existence of asymmetric competition and the inherent differences in growth rates between old (regenerated) and new thalli (recruits). Inequality of size distributions decreased progressively during the last months of the growth phase (spring‐summer) and could be related to a process of self-thinning. There was a negative biomass‐density relationship (as a measure of biomass accumulation-driven mortality) that confirms the importance of self-thinning as a major demographic factor in the S. muticum population.
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Ecology of Sargassum muticum on the North Coast of Spain. II. Physiological Differences between Sargassum muticum and Cystoseira nodicaulis
Botanica Marina, 1997Co-Authors: José M. Rico, Consolación FernándezAbstract:The variations of photosynthesis and C, N and mannitol content were analyzed in the co-existing invasive species Sargassum muticum and the native Cystoseira nodicaulis. Both species exhibited similar seasonal patterns of photosynthesi s, with a significant decay in P max in summer, which can be attributed to nutrient limitation. Nitrogen content was the lowest in summer (< 1.5%) and this decrease was simultaneous with a significant increase in mannitol, to a value of over 15% of the organic weight, in both species. Cystoseira nodicaulis showed higher C/N values, typical of N-limited growth, both in February and June, while in Sargassum muticum high C/N values where found only in June. The variations in N content and C/N ratio in C. nodicaulis were very similar to those in protein content, while in S. muticum there was a striking similarity between the variation in C content and that of mannitol. Although the photosynthetic pattern may be similar in both species, these differences in biochemical status are interpreted as a consequence of different growth strategies. While Sargassum shows a response to the environment, with growth confined to a short period during the favourable season, Cystoseira must have some storage ability that allows it to 'anticipate' favourable conditions and to exhibit two growth periods during the year.
Andrés Moure - One of the best experts on this subject based on the ideXlab platform.
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Green technologies for cascade extraction of Sargassum muticum bioactives
Journal of Applied Phycology, 2019Co-Authors: Patricia Pérez-larrán, Andrés Moure, María Dolores Torres, Noelia Flórez-fernández, Elena M. Balboa, Herminia DomínguezAbstract:Sargassum muticum is an invasive brown seaweed which could not be eradicated from the Atlantic coasts. Therefore, periodic collection and valorization of its components has been suggested. Efficient multistage and multiproduct processes for the obtaining of valuable fractions from this seaweed, which also could be applicable to other brown seaweeds, were developed. This review discusses the potential of conventional and emerging technologies for the sequential extraction of S. muticum bioactives of interest for food, cosmetic, and pharmaceutical applications.
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ECOFRIENDLY EXTRACTION OF BIOACTIVE FRACTIONS FROM Sargassum muticum
Process Biochemistry, 2019Co-Authors: María P. Casas, Enma Conde, Herminia Domínguez, Andrés MoureAbstract:Abstract An ecofriendly process based on an enzyme-assisted extraction coupled with ultrasound extraction was proposed to obtain soluble bioactive fractions from Sargassum muticum. Whole algae (Sm) and residual algae from alginate production (AESm) were employed as feedstock. Aqueous enzyme treatment with commercial complex enzyme formulations or with mixture of enzymes lead to maximum solubilization yield, phenolic content and antioxidant activity extract after 3 h of extraction using 2–5% (wt%) enzyme loads. The enzyme-assisted treatment coupled with ultrasounds was tested for two different enzyme activities. The coupled treatment enhanced the solubilization yields from AESm samples, and increased the phenolic content and antioxidant activity of extracts from whole Sm samples. The extracts from Sm showed slightly higher proportion of unsaturated fatty acids than those from AESm and ω3:ω6 ratio close to 1. One gram of extract was equivalent to 30 mg ascorbic acid and 200 mg Trolox and the cytotoxic activity against murine melanoma B16F10 cells and human liposarcoma SW872 cells was observed at 50–250 μg/L, whereas on fibroblast occurred at more than 500 μg/L.
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Valorization of Sargassum muticum Biomass According to the Biorefinery Concept
Marine drugs, 2015Co-Authors: Elena M. Balboa, Andrés Moure, Herminia DomínguezAbstract:The biorefinery concept integrates processes and technologies for an efficient biomass conversion using all components of a feedstock. Sargassum muticum is an invasive brown algae which could be regarded as a renewable resource susceptible of individual valorization of the constituent fractions into high added-value compounds. Microwave drying technology can be proposed before conventional ethanol extraction of algal biomass, and supercritical fluid extraction with CO2 was useful to extract fucoxanthin and for the fractionation of crude ethanol extracts. Hydrothermal processing is proposed to fractionate the algal biomass and to solubilize the fucoidan and phlorotannin fractions. Membrane technology was proposed to concentrate these fractions and obtain salt- and arsenic-free saccharidic fractions. Based on these technologies, this study presents a multipurpose process to obtain six different products with potential applications for nutraceutical, cosmetic and pharmaceutical industries.
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Supercritical CO2 extraction of fatty acids, phenolics and fucoxanthin from freeze-dried Sargassum muticum
Journal of Applied Phycology, 2015Co-Authors: Enma Conde, Andrés Moure, Herminia DomínguezAbstract:The potential of compressed CO2 for the extraction of valuable compounds (fatty acids, phenolic compounds and fucoxanthin) from the brown alga, Sargassum muticum, has been explored. Pure supercritical CO2 (scCO2) allowed the extraction of up to 15 % of the ethanol extractables, with the highest yield attained at 10 MPa and 50 °C. The addition of ethanol as cosolvent increased by three both the extraction yields and the radical scavenging activity, and by 90 times the fucoxanthin yield. The extracts obtained with pure carbon dioxide contained higher proportion of ω3 fatty acids than those using with conventional solvents, showing an ω6/ω3 ratio of 2.12 and 2.84 for pure and ethanol modified scCO2, respectively. Selected extracts showed antibrowning activity on B16F10 murine cells and inhibition of lipogenesis in SW872 liposarcoma cells, although cytotoxic effects were observed at 50 μg mL−1.
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Simultaneous Extraction and Depolymerization of Fucoidan from Sargassum muticum in Aqueous Media
Marine drugs, 2013Co-Authors: Elena M. Balboa, Andrés Moure, Herminia Domínguez, Sandra Rivas, Juan Carlos ParajóAbstract:The biomass components of the invasive seaweed Sargassum muticum were fractionated to allow their separate valorization. S. muticum (Sm) and the solid residue remaining after alginate extraction of this seaweed (AESm) were processed with hot, compressed water (hydrothermal processing) to assess the effects of temperature on fucoidan solubilization. Fucose-containing oligosaccharides were identified as reaction products. Operating under optimal conditions (170 °C), up to 62 and 85 wt% of the dry mass of Sm and AESm were solubilized, respectively. The reaction media were subjected to precipitation, nanofiltration and freeze-drying. The dried products contained 50% and 85% of the fucoidan present in Sm and AESm, respectively; together with other components such as phenolics and inorganic components. The saccharidic fraction, accounting for up to 35% of the dried extracts, contained fucose as the main sugar, and also galactose, xylose, glucose and mannose. The concentrates were characterized for antioxidant activity using the TEAC assay.
Siobhan A Braybrook - One of the best experts on this subject based on the ideXlab platform.
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towards an understanding of spiral patterning in the Sargassum muticum shoot apex
Scientific Reports, 2017Co-Authors: Marina Linardic, Siobhan A BraybrookAbstract:In plants and parenchymatous brown algae the body arises through the activity of an apical meristem (a niche of cells or a single cell). The meristem produces lateral organs in specific patterns, referred to as phyllotaxis. In plants, two different control mechanisms have been proposed: one is position-dependent and relies on morphogen accumulation at future organ sites; the other is a lineage-based system which links phyllotaxis to the apical cell division pattern. Here we examine the apical patterning of the brown alga, Sargassum muticum, which exhibits spiral phyllotaxis (137.5° angle) and an unlinked apical cell division pattern. The Sargassum apex presents characteristics of a self-organising system, similar to plant meristems. In contrast to complex plant meristems, we were unable to correlate the plant morphogen auxin with bud positioning in Sargassum, nor could we predict cell wall softening at new bud sites. Our data suggests that in Sargassum muticum there is no connection between phyllotaxis and the apical cell division pattern indicating a position-dependent patterning mechanism may be in place. The underlying mechanisms behind the phyllotactic patterning appear to be distinct from those seen in plants.
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towards an understanding of spiral patterning in the Sargassum muticum shoot apex
bioRxiv, 2017Co-Authors: Marina Linardic, Siobhan A BraybrookAbstract:In plants and parenchymatous brown algae the body arises through the activity of an apical meristem (a niche of cells or a single cell). The meristem produces lateral organs in specific patterns, referred to as phyllotaxis. In plants, two different control mechanisms have been proposed; one is position-dependent and relies on morphogen accumulation at future organ sites whereas the other is a lineage-based system which links phyllotaxis to the apical cell division pattern. Here we examine the apical patterning of the brown alga, Sargassum muticum, which exhibits spiral phyllotaxis (137.5 degree angle) and an unlinked apical cell division pattern. The Sargassum apex presents characteristics of a self-organising system, similar to plant meristems. We were unable to correlate the plant morphogen auxin with bud positioning in Sargassum, nor could we predict cell wall softening at new bud sites. Our data suggests that in Sargassum muticum there is no connection between phyllotaxis and the apical cell division pattern indicating a position-dependent patterning mechanism may be in place. The underlying mechanisms behind the phyllotactic patterning appear to be distinct from those seen in plants.