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A phlorotannin extract was obtained from Himanthalia elongata, revealing a profile rich in fucophlorethol-type and carmalol-type compounds. When subjected to simulated gastrointestinal digestion, its levels of total phlorotannins and antioxidant activity, measured in vitro via NO● and O2●− scavenging assays, were reduced, thus suggesting that these compounds’ integrity and bioactivity are negatively affected by the digestive process. Nevertheless, when undigested vs. digested extracts were used on lipopolysaccharide-stimulated Raw 264.7 macrophages, both showed a strong inhibitory effect on the cellular NO● production. In fact, although not statistically significant, the digested extract revealed a tendentially stronger effect compared to its undigested counterpart, suggesting that even though there is a decrease in the phlorotannins’ concentration after digestion, with a consequent loss of their scavenging properties, the possible degradation products being formed may exert their effects through the modulation of the intracellular signaling mechanisms. Overall, this study not only contributes to a better understanding of the phlorotannins’ composition of the species H. elongata, but also shows that, although the digestive process may affect the integrity and concentration of these compounds, this does not necessarily translate into loss of bioactivity, in particular the anti-inflammatory activity, probably owing to the bioactive effects that the degradation products of these phenolics may have at an intracellular level.

The recovery of bioactive and biopolymer-based compounds from Himantalia elongata brown seaweed was studied using a hydrothermal treatment operating under non-isothermal conditions in a broad temperature range (120–220 °C). Maximum extraction yields were observed at 180 °C, since up to 70.7% dry basis (d.b.) of the initial biomass was solubilized. Initial raw material was chemically characterized. The highest crude fucoidan obtained by hydrothermal extraction was achieved at 160 °C. Maximal sulfate and phlorotannin content in the soluble fraction was obtained under non-isothermal autohydrolysis at 160 °C and at 220 °C, respectively. Both extracts showed cytotoxic effects against lung, ovarian and breast carcinoma cells, achieve the half maximal inhibitory concentration to 1.31 ± 0.98 mg/mL of autohydrolysis extract at 220 °C for ovarian cell line tested. The mildest processing condition with suitable bioactive properties (160 °C) was selected to assess the precipitated alginate features in terms of rheological properties, following a biorefinery approach.

Seaweed has been associated with the prevention and/or treatment of various diseases related to oxidative stress because of its antioxidant activity. We investigated the protective potential of extract of Himanthalia elongata against ischemia-reperfusion (I/R) injury in the intestine of rats.Seventy-two (72) male Wistar albino rats were randomly assigned into 12 groups as follows: sham, I/R only, I/R plus vehicle at 3 time points, and I/R plus extract at 3 time points. The degree of intestinal injury was determined by oxidative stress using lipid peroxidation, superoxide dismutase, catalase, and glutathione peroxidase after mesenteric ischemia-reperfusion. A histological study was also performed.The algae extract helps to maintain normal enzymatic levels because, for all the studied parameters, groups treated with the extract showed significant differences (P .05) compared with the I/R groups, and there were no differences compared with the sham group. The histological study showed that damage to the intestinal mucosa was less severe in animals treated with extract of H elongata after up to 24 hours of reperfusion compared with the I/R group.These results suggest that the extract of H elongata can protect intestinal tissue against ischemia-reperfusion injury.

Lipophilic compounds of seaweed have been linked to their potential bioactivity. Low polarity solvents such as chloroform, diethyl ether, n-hexane and their various combinations were used to extract the lipophilic antioxidants from brown seaweed namely Himanthalia elongata, Laminaria saccharina and Laminaria digitata. An equal-volume mixture of chloroform, diethyl ether and n-hexane (Mix 4) gave the highest total phenol (52.7 &plusmn, 1.93 to 180.2 &plusmn, 1.84 mg gallic acid equivalents/g), flavonoid (31.9 &plusmn, 2.65 to 131.3 &plusmn, 4.51 mg quercetin equivalents/g), carotenoid (2.19 &plusmn, 1.37 to 3.15 &plusmn, 0.91 &mu, g/g) and chlorophyll content (2.88 &plusmn, 1.08 to 3.86 &plusmn, 1.22 &mu, g/g) in the tested seaweeds. The extracts were screened for their potential antioxidant capacity and the extracts obtained from the selected solvents system exhibited the highest radical scavenging capacity against 2,2&prime, diphenly-1-picrylhydrazyl radical (EC50 98.3 &plusmn, 2.78 to 298.8 &plusmn, 5.81 mg/L) and metal ions (EC50 228.6 &plusmn, 3.51 to 532.4 &plusmn, 6.03 mg/L). Similarly, the same extract showed the highest ferric reducing antioxidant power (8.3 &plusmn, 0.23 to 26.3 &plusmn, 0.30 mg trolox equivalents/g) in all the seaweeds. Rapid characterization of the active extracts by liquid chromatography coupled with photodiode array detector and electrospray ionization tandem mass spectrometry (LC-PDA&ndash, ESI-MS/MS) identified cyanidin-3-O-glucoside, fucoxanthin, violaxanthin, &beta, carotene, chlorophyll a derivatives and chlorophyll b derivatives in the tested seaweed. The study demonstrated the use of tested brown seaweed as potential species to be considered for future applications in medicine, cosmetics and as nutritional food supplement.

Seaweed antidiabetic properties have been linked to changes in carbohydrate digestion and absorption. The effect of aqueous extracts and suspensions of restructured pork (RP) with 5 g/100 g of Porphyra umbilicalis (Nori), Undaria pinnatifida (Wakame) or Himanthalia elongata (Sea spaghetti) on α-glucosidase activity and glucose diffusion were in vitro tested. α-Glucosidase inhibition type was also assayed. Sea spaghetti-RP suspensions displayed, through a competitive mechanism, the highest α-glucosidase inhibitory effects (19.8% vs . control-RP at 45 min). Control-RP extracts vs. blank increased (15.4%) glucose diffusion while Nori-RP followed by Wakame-RP extracts significantly inhibited glucose diffusion (26.7% and 20%, respectively) and decreased AUC (18–20%) respect to control-RP counterpart. Stepwise analyses showed that maltose and polyphenols in the α-glucosidase inhibition- and Na in glucose diffusion-test, were significantly involved. In conclusion, Sea spaghetti-RP should be selected as α-glucosidase inhibitor while Nori-RP and Wakame-RP should be used as glucose diffusion reducers. As both hypoglycaemic effects were non-concatenated, generalizations about seaweed-RP should be avoided.

International audience; Brown algae are photosynthetic multicellular marine organisms evolutionarily distant from land plants, with a distinctive cell wall. They feature carbohydrates shared with plants (cellulose), animals (fucose-containing sulfated polysaccharides, FCSPs) or bacteria (alginates). How these components are organized into a three-dimensional extracellular matrix (ECM) still remains unclear. Recent molecular analysis of the corresponding biosynthetic routes points toward a complex evolutionary history that shaped the ECM structure in brown algae. Exhaustive sequential extractions and composition analyses of cell wall material from various brown algae of the order Fucales were performed. Dedicated enzymatic degradations were used to release and identify cell wall partners. This approach was complemented by systematic chromatographic analysis to study polymer interlinks further. An additional structural assessment of the sulfated fucan extracted from Himanthalia elongata was made. The data indicate that FCSPs are tightly associated with proteins and cellulose within the walls. Alginates are associated with most phenolic compounds. The sulfated fucans from H. elongata were shown to have a regular α-(1→3) backbone structure, while an alternating α-(1→3), (1→4) structure has been described in some brown algae from the order Fucales. The data provide a global snapshot of the cell wall architecture in brown algae, and contribute to the understanding of the structure-function relationships of the main cell wall components. Enzymatic cross-linking of alginates by phenols may regulate the strengthening of the wall, and sulfated polysaccharides may play a key role in the adaptation to osmotic stress. The emergence and evolution of ECM components is further discussed in relation to the evolution of multicellularity in brown algae.

The intake of Himanthalia elongata and Gigartina pistillata from the Spanish Atlantic coasts was evaluated in Wistar rats. Both seaweed diets showed higher (p < 0.001) faecal excretion. Colonic fermentation increased (p < 0.001) total short-chain fatty acids (SCFAs) in Himanthalia-fed rats due to the higher (p < 0.001) levels of acetic, propionic and butyric acids. The intake of Gigartina increased (p < 0.001) propionic acid and decreased (p < 0.001) butyric acid. The apparent absorption and true retention of calcium and magnesium enhanced (p < 0.05) with Himanthalia diet, while Gigartina produced no significant effect. The serum concentration of HDL-C increased (p < 0.01), triglycerides (TGL) decreased (p < 0.001) and bile acids diminished (p < 0.001) in faeces of Himanthalia-fed rats. The Gigartina diet produced a decrease (p < 0.001) in TGL, total cholesterol (p < 0.01) and LDL-C (p < 0.05) in serum and reduced TGL in liver (p < 0.001). Thus, both seaweeds improved the lipid profile, and Himanthalia increased SCFA production and the absorption and retention of Ca and Mg as a result of the gut fermentation.

The aim of this study was to evaluate the potential anticoagulant activity of sulphated polysaccharide-containing extracts of six french edible marine macroalgae. Aqueous extracts of brown (Himanthalia elongata, Laminaria digitata, Ascophyllum nodosum, Fucus vesiculosus), green (Ulva lactuca) and red (Chondrus crispus) macroalgae were prepared and their biochemical properties were determined, including major biomolecules, sulphate and ash contents. The anticoagulant activity of each extract was investigated using different scales from the specific antithrombin-dependent pathway (anti-Xa and anti-IIa) to the intrinsic and/or common (Activated Partial Thromboplastin Time, APTT), extrinsic (Prothrombin Time, PT) or common (Thrombin Time, TT) anticoagulant pathways, and compared with those of commercial anticoagulants, heparin and Lovenox®. Laminaria digitata, Fucus vesiculosus and Chondrus crispus extracts showed a significant APTT anticoagulant capacity, only 5-fold lower than that of Lovenox®, which is a pure low molecular weight heparin used as an anticoagulant agent to prevent pulmonary embolism in patients undergoing surgery.

Meat and pork consumptions are very high in Spain. Seaweeds are rich in fibre, minerals, and bioactive substances. Due to the growing demand for healthier meats, this work studied the effect of diets containing restructured pork (RP) enriched with Himanthalia elongata (Sea Spaghetti) on: (1) cholesterolaemia; (2) liver cytochrome P450 7A1 (CYP7A1) expression; (3) liver antioxidant enzyme activities and gene expression; (4) the liver antioxidant substrate concentrations. Four groups of 10 Wistar rats each were fed a mix of 85% AIN-93 M rodent diet and 15% freeze-dried RM for 35 days. The control group (C) consumed control RP; the Sea Spaghetti (SS) group, RP with 5% Sea Spaghetti. Animals on added cholesterol diets (CholC and CholSS) consumed their basal C and SS diets enriched with cholesterol and cholic acid as hypercholesterolaemic agent. Food intake was significantly affected by the alga × cholesterol interaction and by dietary cholesterol (both p

The aim of the present study was to see the applicability of using brown edible seaweeds as a sole source of nutrition for the growth of lactic acid bacteria. Growth kinetics of lactic acid bacteria (LAB; Lactobacillus plantarum) was studied using three species of edible Irish brown seaweeds Himanthalia elongata, Laminaria digitata and Laminaria saccharina. As part of the screening process, growth of the LAB was carried out on raw and heat treated forms of seaweeds. The seaweed species in their raw state could not support the growth of L. plantarum. Heat treatment resulted in almost 4 times increase in the total sugar content in L. digitata and L. saccharina broth which allowed the growth of L. plantarum for 24 h after which the cell number started decreasing. The Laminaria spp. contains a high content of laminaran polysaccharide which can be fermented by LAB. In case of H. elongata, neither raw nor heat treated forms could be fermented; even though the total sugar content increased 4.6 times upon the application of heat. Kinetics of cell growth, lactic acid and acetic acid production was evaluated at different agitation rates in heat treated seaweeds. A maximum log CFU/ml of 10 was achieved at the end of 16 h to 24 h of fermentation for L. saccharina and L. digitata, respectively. The cell growth increased and lactic acid accumulation decreased as the agitation speed was increased from 0 to 100 rpm. Maximum lactic acid accumulation of 2.5 g/l was achieved under static (0 rpm) conditions. The production of acetic acid was very minimal during the entire course of fermentation. Experimental data was mathematically modelled to optimize the cell growth and lactic acid production with respect to the different rotation conditions. The results of this study present an indication of the potential of fermentation of seaweeds using LAB with a possibility towards the development of a range of functional foods.

Seaweeds are an excellent source of compounds with biological activity. Among the bioactive substances identified, antioxidants have received particular interest due to their beneficial effects on health. In the present study, the total phenolic content and the pigment contents in edible seaweeds were evaluated. The total phenolic content was determined by Folin-Ciocalteu’s method for four species of brown algae included Himanthalia elongata, Laminaria sp., Laminaria saccharina and Undaria pinnatifida. The total polyphenol content varied between 1.3 and 10.0 g phloroglucinol/kg wet weight of sample. The components responsible of the colour (carotenoids and chlorophylls) of the seaweeds were evaluated by using a spectrophotometric method. In addition, pigments were separated and identified by on line HPLC coupled with UV–Vis and fluorescence detectors and confirmed by liquid chromatography coupled to mass spectrometry (LC–MS APCI). Fucoxanthin, β-carotene, chlorophyll a and phaeophytin a were identified in the samples analysed.

In the present work, a comprehensive methodology to carry out the screening for novel natural functional compounds is presented. To do that, a new strategy has been developed including the use of unexplored natural sources (i.e., algae and microalgae) together with environmentally clean extraction techniques and advanced analytical tools. The developed procedure allows also estimating the functional activities of the different extracts obtained and even more important, to correlate these activities with their particular chemical composition. By applying this methodology it has been possible to carry out the screening for bioactive compounds in the algae Himanthalia elongata and the microalgae Synechocystis sp. Both algae produced active extracts in terms of both antioxidant and antimicrobial activity. The obtained pressurized liquid extracts were chemically characterized by GC-MS and HPLC-DAD. Different fatty acids and volatile compounds with antimicrobial activity were identified, such as phytol, fucosterol, neophytadiene or palmitic, palmitoleic and oleic acids. Based on the results obtained, ethanol was selected as the most appropriate solvent to extract this kind of compounds from the natural sources studied. © 2009 Elsevier B.V. All rights reserved.

Induced chemical defense reactions are widespread in marine brown algae. Despite the evidence that the biosynthesis of defense metabolites can be up-regulated upon herbivory, we do not know how this regulation of biosynthetic pathways to secondary metabolites is achieved in brown algae. In higher plants, the phytohormone jasmonic acid (JA) is crucial for the mediation of induced chemical defenses, and several findings of this metabolite from marine sources have been reported. We tested the hypothesis that JA or related metabolites play a role in induced brown algal defense. Quantification of oxylipins with a detection limit around 20 ng g(-1) algal tissue did not reveal the presence of JA in the seven examined brown algal species Dictyota dichotoma, Colpomenia peregrina, Ectocarpus fasciculatus, Fucus vesiculosus, Himanthalia elongata, Saccharina latissima (formerly Laminaria saccharina), and Sargassum muticum. Moreover, treatment with ecologically relevant concentrations of JA and methyl jasmonate did not lead to a significant change in the profile of medium- and non-polar metabolites of the tested algae. Only when high concentrations ofor =500 microg ml(-1) medium of the phytohormones were applied that a metabolic response which could be attributed to unspecific stress was observed. Bioassays with D. dichotoma that focused on medium- and non-polar compounds confirmed the lack of a biological role of JA and methyl jasmonate in the induction of algal induced chemical defenses. The phytohormone-treated samples did not exhibit any increased defense potential towards the amphipod Ampithoe longimana and the isopod Paracerceis caudata. JA and related phytohormones, known to be active in higher plants, thus appear to play no role in brown algae for induction of the defense chemicals studied here.

The in vitro degradation of dietary fibre from three brown seaweeds (Himanthalia elongata, Laminaria digitata and Undaria pinnatifida) was studied, using human faecal flora. Two sets of fibre were tested: (1) total algal fibres extracted from the whole algae, mainly composed of alginates, and (2) purified fibres (sulphated fucans, Na-alginates and laminarans) representative of those contained in the whole brown algae. Mannuronate, one algal component, was also investigated. Substrate disappearance and short-chain fatty acid (SCFA) production were monitored after 6, 12 and 24 h fermentation. Gas production was followed hourly during the first 9 h and then at 12 and 24 h. Sugarbeet fibre was used as a fermentation reference substrate. According to the fermentative indices used, most of each of the total algal fibres disappeared after 24 h (range 60-76%) but, unlike the reference substrate, they were not completely metabolized to SCFA (range 47-62%). Among the purified algal fibres, disappearance of laminarans was approximately 90% and metabolism to SCFA was approximately 85% in close agreement with the fermentation pattern of reference fibres. Sulphated fucans were not degraded. Na-alginates exhibited a fermentation pattern quite similar to those of the whole algal fibres with a more pronounced discrepancy between disappearance and production of SCFA: disappearance was approximately 83% but metabolism was only approximately 57%. Mannuronate was slowly fermented but its metabolism corresponded to its disappearance from the fermentative medium. Thus, the characteristic fermentation pattern of the total fibres from the three brown algae investigated was attributed to the peculiar fermentation of alginates, and mannuronate was shown not to be directly involved.

Phlorotannins have received much attention due to their ecophysiological importance and potential applications in the biotechnology and food industries. Antioxidant activity studies in seaweeds have mainly focused on in vitro assays; however, there is a paucity of data regarding the effect of brown algal phlorotannins on living cultured cells. The aim of the present study was to investigate both direct and protective effects of phlorotannin-rich extracts on cell viability and the cellular oxidative status of cultured liver cells HepG2 against oxidative stress induced by tert-butyl hydroperoxide (t-BOOH). Extracts of the Phaeophyceae Ascophyllum nodosum (Fucaceae) and Himanthalia elongata (Himanthaliaceae) were submitted to gastrointestinal digestion prior to incubation for 20 h in a HepG2 culture at physiological concentrations (0.5-50 οg mL-1). Various markers of cellular oxidative stress were then assessed, such as the generation of reactive oxygen species (ROS), antioxidant defences (concentration of reduced glutathione and activities of glutathione peroxidase, reductase and glutathione-S-transferase) and the levels of malondialdehyde as a marker for lipid peroxidation. The direct effect on cellular markers was assessed immediately after the incubation period, whereas for the protective effect, the incubation period was followed by a 3-h treatment with t-BOOH. The results indicated no effect on cell viability, and both extracts showed reduced levels of ROS and increased antioxidant defences in the direct treatment. Moreover, the extracts showed a significant protective effect against chemically induced oxidative stress in HepG2 cells by reducing ROS generation and enhancing antioxidant defences, hence supporting the utility of including brown algal extracts in functional food products. © 2012 Springer Science+Business Media B.V., This work was supported by grant AGL2007-64042/ALI and project CSD 2007-00063 from Programa Consolider-Ingenio from the Spanish Ministry of Science and Innovation (CICYT), an EU Erasmus grant under the Lifelong Learning Programme and a Mobility/Training grant from the Sea Change Networking Initiative of the Marine Institute, Ireland.

13C nuclear magnetic resonance spectroscopy (NMR) has been used to study the metabolic flux of carbon through the intracellular pools of the isomeric hexitols d-altritol and d-mannitol in Himanthalia elongata. Natural abundance 13C NMR spectra of freshly collected plant material showed altritol as the dominant intracellular low-molecular-weight organic solute, with mannitol present at less than 20% of the altritol concentration. Plant material incubated in seawater medium with added 13C-enriched bicarbonate showed a rapid increase in the 13C signal due to mannitol, with an increase of more than 12-fold in under 48 h, in contrast to the altritol signal, which increased by approximately 2-fold over the same period. The intracellular mannitol signal decreased rapidly when 13C-enriched plant material was transferred to a non-enriched medium, while altritol showed a slower decline. These results are consistent with previous observations on the effects of salinity on the intracellular hexitol pools of H. elonga...

Pressurized liquid extraction (PLE), an environmentally friendly technique, was used to obtain antiviral compounds from the edible seaweed Himanthalia elongata. The antiviral properties of PLE extracts (hexane, ethanol, and water) were evaluated against herpes simplex virus type 1 (HSV-1) at different stages during viral infection. Pre-treatment of Vero cells with 75 ¿g mL-1 of ethanol extract inhibited virus infection by approximately 90%, whereas the same concentration of water and hexane extracts reduced the virus infectivity to 78% and 70%, respectively. Moreover, ethanol extract was also more effective against HSV-1 intracellular replication than water and hexane extracts. The antiviral activity of water PLE extract was found to correlate with polysaccharides, since the polysaccharide-rich fraction isolated from this extract showed higher antiviral activity than the original water extract. A GC-MS characterization of the hexane and ethanol extracts showed that the antiviral activity of the hexane extract seemed to be related with the presence of fucosterol; meanwhile, in the case of the ethanol extract, other compounds, besides fucosterol, could be involved in this activity. Results demonstrated that PLE was an appropriate technique to obtain antiviral agents from H. elongata. These antiviral compounds were in addition to polysaccharides, which are the antiviral agents usually proposed when studying seaweeds. © 2010 Springer Science+Business Media B.V.

The study was designed to determine the influence of the addition of edible seaweeds, Sea Spaghetti (Himanthalia elongata), Wakame (Undaria pinnatifida), and Nori (Porphyra umbilicalis), on fatty acid composition, amino acid profile, protein score, mineral content and antioxidant capacity in low-salt meat emulsion model systems. The addition of seaweeds caused an increase (P < 0.05) in n-3 polyunsaturated fatty acids (PUFA) and a decrease (P < 0.05) in the n-6/n-3 PUFA ratio. The thrombogenic index significantly decreased (P < 0.05) in Nori and Wakame meat samples. Meat systems made with added seaweeds had lower (P < 0.05) sodium contents than control samples. In general, addition of seaweeds to products increased (P < 0.05) the concentrations of K, Ca, Mg and Mn. The presence of Nori caused an increase (P < 0.05) in levels of serine, glycine, alanine, valine, tyrosine, phenylalanine and arginine, whereas Wakame and Sea Spaghetti produced no significant changes in amino acid profiles in the model systems. The inclusion of Sea Spaghetti increased the sulphur amino acid score by 20%. The added seaweeds supplied the meat samples with soluble polyphenolic compounds, which increased the antioxidant capacity of the systems. The polyphenol supply and antioxidant increase were greatest (P < 0.05) in the samples containing Sea Spaghetti.

The antioxidant effect of seven species of marine algae on the preservation of sunflower oil were investigated by storage experiments at 75°. Laminaria digitata (Kombu) and Himanthalia elongata were the most effective in extending the induction period. Extracts of these two seaweeds were then compared with vitamin E and BHT as regards to their antioxidative activities, by kinetic studies in a model system. The thermal initiated oxidation of methyl linoleate was performed at 60° in heptanol, with or without antioxidants. When they reached 1 % of the substrate, seaweed extracts exhibited antioxidant activities by extending the induction period but they were not actually effective. Effects of the addition of algal extracts together with vitamin E on the preservation of methyl linoleate, sunflower oil or mixed ethyl eicosapentaenoate and docosahexaenoate were investigated at 60° by the same kinetic studies. Algal extracts synergistically enhance the antioxidant effect of vitamin E when the latter is present at a level higher than 1 × 10 −4 M. On mechanistic grounds, the understanding of this synergism is outlined. Seaweed extracts should find applications in the cosmetic and food industries without any further purification.

This study presents an HPLC method for the quantification of sterols in edible seaweeds. Sterols were identified by HPLC/mass spectrometry (HPLC-MS) in positive APCI mode. The samples were saponified by refluxing with 1 m ethanolic KOH, and the non-saponifiable fraction was extracted with hexane. Sterols were quantified by HPLC with UV detection (HPLC-UV), on a 15 x 0.4 cm Kromasil 100 C(18) 5 micro m column (mobile phase 30:70 v/v methanol:acetonitrile; fl ow rate 1.2 mL/min; column temperature 30 degrees C; detection wavelength 205 nm). Method repeatability for fucosterol was good (coefficient of variation 2.4%). Sterol contents were determined in canned or dried brown seaweeds (Himanthalia elongata, Undaria pinnatifida, Laminaria ochroleuca) and red seaweeds (Palmaria sp., Porphyra sp.). The predominant sterol was fucosterol in brown seaweeds (83-97% of total sterol content; 662-2320 micro g/g dry weight), and desmosterol in red seaweeds (87-93% of total sterol content; 187-337 micro g/g dry weight).

A reversed-phase high-performance liquid chromatography (HPLC) method, with a combination of fluorescence and ultraviolet detectors, to determine the folate forms present in commercial macroalgae products form northwest Spain as part of nutritional studies in dehydrated and canned seaweeds is reported. The method includes extraction of folates from seaweed by heat treatment, deconjugation of folate polyglutamates by incubation with hog kidney conjugase and purification by solid-phase extraction (SPE) with strong anion-exchange (SAX) cartridges. Separation was achieved with a Tracer Extrasil ODS 5 μm 25 cm ×0.4 cm column using acetonitrile and potassium phosphate buffer (pH 2.2) as mobile phase. Good results were obtained with respect to repeatability (relative standard deviation (R.S.D.) ≤4.12%) and recovery (≥90.80%). The amount of folate (as folic acid) in the six species ranged from 61.4 to 161.6 μg per 100 g dry mass. In all the seaweeds studied (Himanthalia elongata, Laminaria ochroleuca, Palmaria spp., Undaria pinnatifida and Porphyra spp. and Saccorhiza polychides) the single most abundant form is 5-CH3H4-folate, except Porphyra and Himanthalia.

A high-performance liquid chromatographic (HPLC) method is described for determination of the ratio of beta-d-mannuronic acid to alpha-l-guluronic acid (M/G ratio) in dietary fibre of edible seaweeds. Total dietary fibre (TDF) content was determined gravimetrically. The TDF fraction was hydrolysed with 12 m and 1 m H(2)SO(4), then neutralized with AG 4 x 4 resin. The uronic acids were separated in a Tracer Extrasil SAX 5 micro m column (25 cm x 4 mm) at 35 degrees C, with 2 mm KH(2)PO(4) containing 5% methanol as mobile phase at a fl ow rate of 1.5 mL/min. The detection wavelength was UV 210 nm. The chromatographic identifications of beta-d-mannuronic acid and alpha-l-guluronic acid were confirmed by liquid chromatography-mass spectrometry (LC-MS). The method precision was 1.4% for beta-d-mannuronic acid and 3.5% for alpha-l-guluronic acid. The method was used to determine M/G ratio in canned seaweeds (Saccorhiza polyschides and Himanthalia elongata) and in dried seaweeds (H. elongata, Laminaria ochroleuca, Undaria pinnatifida, Palmaria sp. and Porphyra sp.).

From an acetylated fraction of Himanthalia elongata extract, an eight-ring phenolacetate was isolated and its structure elucidated with the aid of field desorption mass spectrometry and other spectroscopic methods.

A method is described for the separation and quantification of a range of low-molecular-weight organic solutes, which are major osmolytes, in crude ethanolic extracts of marine algae. The method relies on the use of a silica amine modified column and refractive index detection. The acetonitrile to water ratio was varied to maximise separations. The method is suitable for the detection of simple carbohydrates, amino acids and their derivatives and is particularly suitable for the separation of the isomeric hexitols, altritol and mannitol, found in the brown alga Himanthalia elongata .

Natural abundance 13 C NMR spectroscopy has shown that altritol (talitol) is a major constituent within vegetative and reproductive tissues of Himanthalia elongata . Quantitative GC studies have confirmed that altritol concentrations are 80–160% higher than for the hexitol mannitol (which occurs throughout the Phaeophyta). The data suggest an osmotic role for altritol.