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This work reports the detailed structure of fucoidan from Sargassum miticum (2SmF2) and its ability to potentiate the inhibitory effect of glycolysis inhibitor 2-deoxy-d-glucose (2-DG). 2SmF2 was shown to be sulfated and acetylated galactofucan containing a main chain of alternating residues of 1,3- and 1,4-linked α-l-fucopyranose, fucose fragments with monotonous 1,3- and 1,4-type linkages (DP up to 3), α-d-Gal-(1→3)-α-L-Fuc disaccharides, and 1,3,4- and 1,2,4-linked fucose branching points. The sulfate groups were found at positions 2 and 4 of fucose and galactose residues. 2SmF2 (up to 800 µg/mL) and 2-DG (up to 8 mM) were not cytotoxic against MDA-MB-231 and SK-MEL-28 as determined by MTS assay. In the soft agar-based model of cancer cell colony formation, fucoidan exhibited weak inhibitory activity at the concentration of 400 µg/mL. However, in combination with low non-cytotoxic concentrations of 2-DG (0.5 or 2 mM), 2SmF2 could effectively inhibit the colony formation of SK-MEL-28 and MDA-MB-231 cells and decreased the number of colonies by more than 50% compared to control at the concentration of 200 µg/mL. Our findings reveal the metabolically oriented effect of fucoidan in combination with a glycolysis inhibitor that may be beneficial for a therapy for aggressive cancers. [ABSTRACT FROM AUTHOR]

Laminaran, fucoidan, and alginate were isolated from the brown alga Coccophora langsdorfii collected in the Japan Sea. The structural characteristics of polysaccharides were investigated by NMR spectroscopy. The laminaran was determined as β- d -glucan, which consisted of 80% of 1,3- and 20% of 1,6-linked residues and was terminated with mannitol. The alginate was a guluronic acid-rich polysaccharide ( M / G = 0.85). Fucoidan, sulfated α- l -fucan, contained a linear backbone of alternating (1 → 3)- and (1 → 4)- linked α- l -fucopyranose residues with sulfate at C2 and C4 of (1 → 3)-α- l -fucopyranose residues. Anticancer activity of this fucoidan was investigated in comparison with activity of fucoidan having similar linear backbone from the brown alga Fucus evanescens . The fucoidan from C. langsdorfii significantly inhibited colony formation of SK-MEL-5 and SK-MEL-28 melanoma cells (the percentage of inhibition was 28 and 76, respectively) and weakly inhibited colony formation of breast adenocarcinoma cells MDA-MB-231 (the percentage of inhibition was about 5). Similar results were obtained for fucoidan from F. evanescens ; the percentage of inhibition of colony formation of SK-MEL-5 and SK-MEL-28 melanoma cells was 54 and 56, respectively. The inhibition of colony formation of breast adenocarcinoma cells MDA-MB-231 was weak. We suppose that other sulfated and partially acetylated fucoidans consisting of (1 → 3)- and (1 → 4)-linked α- l -fucopyranose residues may suppress progression of melanoma cell colony formation similar to fucoidans of C. langsdorfii and F. evanescens . [ABSTRACT FROM AUTHOR]

Highlights: [•] Structure of HMW laminaran EbL from Eisenia bicyclis was established. [•] EbL was investigated by chemical methods, NMR spectroscopy and mass spectrometry. [•] Laminaran was depolymerised by endo- and exo-glucanases from marine sources. [•] EbL and its oligomers inhibited colony formation of melanoma and colon cancer cells. [ABSTRACT FROM AUTHOR]

Three different fucoidan fractions were isolated and purified from the brown alga, Sargassum mcclurei. The SmF1 and SmF2 fucoidans are sulfated heteropolysaccharides that contain fucose, galactose, mannose, xylose and glucose. The SmF3 fucoidan is highly sulfated (35%) galactofucan, and the main chain of the polysaccharide contains a ?3)-a-L-Fucp(2,4SO3-)-(1?3)-a-L-Fucp(2,4SO3-)-(1? motif with 1,4-linked 3-sulfated a-L-Fucp inserts and 6-linked galactose on reducing end. Possible branching points include the 1,2,6- or 1,3,6-linked galactose and/or 1,3,4-linked fucose residues that could be glycosylated with terminal ß-D-Galp residues or chains of alternating sulfated 1,3-linked a-L-Fucp and 1,4-linked ß-D-Galp residues, which have been identified in galactofucans for the first time. Both a-L-Fucp and ß-D-Galp residues are sulfated at C-2 and/or C-4 (and some C-6 of ß-D-Galp) and potentially the C-3 of terminal ß-D-Galp, 1,4-linked ß-D-Galp and 1,4-linked a-L-Fucp residues. All fucoidans fractions were less cytotoxic and displayed colony formation inhibition in colon cancer DLD-1 cells. Therefore, these fucoidan fractions are potential antitumor agents. [ABSTRACT FROM AUTHOR]

Abstract: Water-soluble polysaccharides were isolated from the brown alga Eisenia bicyclis, which was collected near the coast of the Republic of Korea. The structures of laminaran and fucoidan were investigated. Laminaran from E. bicyclis was determined to be a glucan with β-(1→6) side chains linked to a β-(1→3) backbone with relatively few branch points. Based on nuclear magnetic resonance (NMR) data, the ratio of the β-(1→3) and β-(1→6) linkages was estimated as 2.6:1. Fucoidan from E. bicyclis was found to contain 1,3-linked fucose residues, some 1,6-, 1,2,6-, 1,4,6-linked galactose residues and traces of mannose and xylose. In addition, the amount of sulfate in fucoidan was 13.2%. Those polysaccharides were non-cytotoxic to human melanoma SK-MEL-28 and colon cancer DLD-1 cells. Laminaran and fucoidan from E. bicyclis inhibited the colony formation of those cells. Therefore, they may have potential as antitumor agents. [Copyright &y& Elsevier]

The anticancer and radiosensitizing effects of high-molecular-weight phlorethols CcPh (Mw = 2520 Da) isolated from the brown algae of Costaria costata on human colorectal carcinoma HCT 116 and HT-29 cells were investigated. Phlorethols CcPh possessed cytotoxic activity against HT-29 (IC50 = 92 μg/mL) and HCT 116 (IC50 = 94 μg/mL) cells. CcPh at non-toxic concentrations inhibited the colony formation in colon cancer cells and significantly enhanced their sensitivity to low non-toxic X-ray irradiation. The combinatory effect of radiation and CcPh was synergistic (Combination index < 0.7). Algal phlorethols might be prospective candidates as radiosensitizers to improve the scheme of radiotherapy. [ABSTRACT FROM AUTHOR]

Laminaran and three fractions of fucoidan were isolated from brown alga Alaria angusta . The laminaran AaL was characterized as a typical 1,3;1,6-β-D-glucan (ratio of bonds 1,3:1,6 = 10:1). Fucoidans AaF1 and AaF2 are sulfated heteropolysaccharides, containing fucose, galactose, mannose and xylose. The fraction AaF3 is sulfated and acetylated galactofucan with the main chain represented by a repeating unit →3)-α-L-Fuc p -(2,4-SO 3 − )-(1→. According the data of methylation analysis, AaF3 contains mainly 1,3-linked fucose, less 1,4-linked and 1,4,6-linked galactose residues. The autohydrolysis (37 °C) of fucoidan AaF3 allowed to obtain selectively 2-desulfaled polysaccharide fraction, built up of fucose only, and low molecular weight (LMW) fraction. The negative-ion tandem mass spectrometry of LMW fraction, further hydrolyzed by acid hydrolysis identified the following fragments: Gal-2-SO 3 − -(1 → 4)-Gal, Gal-4-SO 3 − -(1 → 4)-Gal, Gal-(1 → 2)-Gal-4-SO 3 − , Fuc-2-SO 3 − -(1 → 4)-Gal, Gal-2-SO 3 − -(1 → 3)-Fuc-(1 → 3)-Fuc, Fuc-2-SO 3 − -(1 → 3)-Fuc-(1 → 4)-Gal. The laminaran AaL and the fucoidan AaF3 exhibited no cytotoxicity in vitro for HT 29, T-47D, and SK-MEL-28 cell lines. The AaF3 fraction suppressed colony formation of HT 29 and T-47D cells, AaL —only HT 29 cells. [ABSTRACT FROM AUTHOR]

The fucoidan SdeF was isolated from brown alga Saccharina dentigera. The structure of the obtained polysaccharide was studied by chemical methods, NMR spectroscopy of the fully and partially desulfated derivatives, and mass spectrometry of the fucoidan fragments, labeled with 18O. The SdeF was shown to be sulfated (40%) 1,3-linked α-L-fucan, with branches at C2. The sulfate groups were found at positions C2 and C4. Derivatives SdeFDS and SdeFPL were obtained by solvolytic desulfation and autohydrolysis of SdeF , respectively. According to 13C NMR data, SdeFDS is 1,3-linked α-L-fucan, while SdeFPL is 4-sulfated 1,3-linked α-L-fucan. Native fucoidan SdeF was shown to be a non-toxic anticancer substance in the model of human malignant melanoma RPMI-7951, colorectal adenocarcinoma HCT-116, and small intestine adenocarcinoma HuTu 80 cells. The partial desulfation of SdeF at C2 and/or the reduction of its Mw, from 229 to 28 kDa, decreased the anticancer activity; complete removal of the sulfated groups and/or Mw reduction to 4.7 kDa further reduced the effect of this polysaccharide. [ABSTRACT FROM AUTHOR]

Abstract: Fucoidan was isolated and purified from the brown algae Fucus evanescens and subjected to autohydrolysis to obtain low-molecular-weight fragments. MALDI-TOFMS analysis has shown that monosulfated fucose and more heavily sulfated (up to 5) fucooligosaccharides with polymerization degree (DP) 2, 4 and 6, including galactose-containing sulfated oligosaccharides were the products of autohydrolysis. The structural features of these fragments were elucidated by negative-ion potential lift tandem MALDI-TOF mass-spectrometry using arabinoosazone as a matrix, which allowed reducing the in-source fragmentation. Native fucoidan has been shown to exert anticancer activities in both human malignant melanoma cell lines SK-MEL-28 and SK-MEL-5. Low-molecular-weight fragments exhibited almost no action to cell proliferation in both cell lines and colony formation on SK-MEL-5 cells, but its inhibition activity to the colony formation of SK-MEL-28 cell lines was as high as was demonstrated by native fucoidan (70%). Probably, the inhibiting activity for SK-MEL-28 depended on the presence of sulfates and (1→4)-linked α-l-Fucp residues in the main chain of fucoidan/oligosaccharides. [Copyright &y& Elsevier]

• Fucoidan LlF from L. longipes was α-L-fucan with unusual structure. • LlF consisted of 1,2-, 1,3- and 1,4-linked α-L-Fuc residues. • Fucans LlF and ScF had anticancer effect on melanoma and colon cancer cells. • Fucans LlF and ScF possessed comparable radiosensitizing activity. The sulfated α- l -fucans ScF and LlF were obtained from brown algae of the Laminariaceae family (Saccharina cichorioides and Laminaria longipes). According to spectroscopy NMR, the LlF fucan predominantly contained the →3)-α- l -Fuc p- (2SO 3 –)-(1→4)-α- l -Fuc p -(1→2)-α- l -Fuc p- (4SO 3 –)-(1→ repeating units, with small amounts of disaccharide 1,4-linked fragments and 3-sulfated fucose residues. Mass spectrometric analysis revealed the presence of the following fragments in the fucan structure: α- l -Fuc p- (2SO 3 –)-(1→4)-α- l -Fuc p -(2SO 3 –)-(1→3)-α- l -Fuc p -(4SO 3 –); α- l -Fuc p- (2,4SO 3 –)-(1→3)-α- l -Fuc p -(1→3)-α- l -Fuc p- (4SO 3 –); α- l -Fuc p- (2SO 3 –)-(1→2)-α- l -Fuc p ; α- l -Fuc p- (2SO 3 –)-(1→2)-α- l -Fuc p- (4SO 3 –); α- l -Fuc p- (2SO 3 –)-(1→3)-α- l -Fuc p ; α- l -Fuc p- (2,4SO 3 –)-(1→3)-α- l -Fuc p ; α- l -Fuc p- (4SO 3 –)-(1→4)-α- l -Fuc p ; and α- l -Fuc p -(4SO 3 –)-(1→4)-α- l -Fuc p -(2SO 3 –). Both ScF and LlF fucoidans inhibited colony formation and growth of melanoma and colon cancer cells and sensitize-tested cancer cells to X-ray radiation to a comparable degree. [ABSTRACT FROM AUTHOR]

Fucoidans are complex fucose-containing sulfated polysaccharides with pronounced anticancer effects. Their structure-anticancer activity relationships are difficult to determine due to fucoidans' complex, often irregularities-including structures. Fucoidan-active enzymes can be used for this propose. We have investigated two new recombinant endo -fucanases FWf3 and FWf4 from the marine bacterium Wenyingzhuangia fucanilytica CZ1127T that belong to the 107 family of glycoside hydrolases (GH). Both enzymes cleaved α-(1→4)-glycosidic bonds but in fucoidan fragments with different sulfation patterns. FWf3 is the first characterized endo -fucanase that cleaves glycosidic bonds between 2O- and 2,4diO-sulfated L-fucose residues. The obtained endo -fucanases were used to produce low- and high-molecular weight fucoidan derivatives with different sulfate group locations. Low- and high-molecular weight fucoidan derivatives rich with 2,4diO-sulfation were shown to inhibit MDA-MB-231 cell colony formation more efficiently than the native fucoidan and the derivatives sulfated otherwise. Such derivatives effectively suppressed the mitochondrial membrane potential of MDA-MB-231 cells and reduced the expression of the glucose transporter 1 (GLUT1). Co-treatment of MDA-MB-231 cells with the fucoidan derivatives and oligomycin (an OXPHOS inhibitor) resulted in a synergistic anticancer effect. The data obtained demonstrate, that fucoidan and its 2,4diO-sulfated derivatives can be an effective adjunct in TNBC therapy targeting cell metabolism. [Display omitted] [ABSTRACT FROM AUTHOR]

Enzymatic depolymerization of fucoidans attracts many researchers due to the opportunity of obtaining standardized fucoidan fragments. Fucoidanase catalyzes the cleavage of fucoidan from Fucus evanescens (FeF) to form low molecular weight products (LMP) and a polymeric fraction (HMP) with 50.8 kDa molecular weight and more than 50% yield. NMR spectroscopy shows that the HMP fraction has regular structure and consists of a repeating fragment [→3)-α- l -Fuc p 2,4OSO 3 − -(1 → 4)-α- l -Fuc p 2,4 O SO 3 − -(1 → 4)-α- l -Fuc p 2OSO 3 − -(1→] n . The anticancer effects of FeF fucoidan and its derivative (HMP) were studied in vitro on colon cancer cells HCT-116, HT-29, and DLD-1. The anticancer activity of the HMP fraction was found to be slightly lower than that of the FeF fucoidan. Research and practical applications of the enzyme include modification of native fucoidans for purposes of regular and easier characterized derivatives acquisition. [ABSTRACT FROM AUTHOR]

The sulfated and acetylated fucoidan fraction, containing fucose, galactose, mannose, glucose and uronic acid residues, was isolated from the brown alga Padina boryana . The structure of galactofucan part was studied after different modifications by NMR spectroscopy and mass spectrometry. It was shown that galactofucan contained the main chain of alternating 1,4-linked α- l -fucopyranose and 1,3-linked β- d -Galactopyranose. Single fucose residues were found as branches at C4 of galactose residues. Also, fucoidan contained 1,3- or 1,4-linked Fuc-Fuc and Gal-Gal fragments. The sulfate groups occupied positions C2, C3 and C4 of both fucose and galactose residues, which was shown by tandem mass spectrometry of fragments, labeled with heavy-oxygen. The anticancer effect of native and modified fucoidan fractions was studied in vitro on the colorectal carcinoma cells DLD-1 and HCT-116. All fucoidans had no cytotoxicity under 400 μg/mL and inhibited colony formation of cancer cells at concentration of 200 μg/mL. [ABSTRACT FROM AUTHOR]

The laminaran DdL and fucoidan DdF were obtained from the brown alga Dictyota dichotoma . DdF was a sulfated (28.9%) and acetylated heteropolysaccharide containing fucose, galactose, mannose and glucose (57.9, 20.4, 12.4 and 9.2 mol%, respectively). DdL was a 1,3;1,6-β- d -glucan with the main chain built from 1,3-linked glucose residues and single glucose residue in branches at C6 (one branch on three glucose residues of the main chain). Sulfated (43.7%) laminaran DdLs was obtained from DdL by sulfation. It was determined that sulfates occur at C2, C4 and C6 of glucose residues. The anticancer effect of DdF, DdL, and DdLs (200 μg/mL) was studied in vitro on colon cancer cells HCT-116, HT-29, and DLD-1. The effect of polysaccharides (40 μg/mL) on colony formation of DLD-1 cancer cells after irradiation (4 Gy) was investigated first. All polysaccharides showed a synergistic effect with X-ray irradiation against cancer cells, decreasing the amount and size of cancer cells colonies. [ABSTRACT FROM AUTHOR]

The laminaran SdL and fucoidan SdF were isolated from brown algae Sargassum duplicatum . SdL was 1,3;1,6-β- d -glucan (1,3:1,6 = 6:1) with a main chain, represented by 1,3-linked glucose residues, due to NMR spectroscopy data. Single glucose residues could form branches at C6. Unusual structure of fucoidan SdF was studied by chemical and enzymatic methods, NMR spectroscopy of desulfated and deacetylated polysaccharide and mass spectrometry of fucoidan fragments labeled with 18 O. Fucoidan was sulfated (31.7%) and acetylated galactofucan (Fuc:Gal ∼ 1:1) with a main chain of 1,4-linked alternating α- l -fucose and β- d -galactose residues. Side chains were represented by extensive (DP ≥ 5) 1,3-linked 2,4-disulfated α- l -fucose residues with branching points at C2. Fucose residues in the main chain were sulfated at C2 and less at C3, while galactose residues were sulfated at C2, C3, and less at C4, C6. The fucoidan SdF was effective against colony formation of colon cancer cells in vitro . [ABSTRACT FROM AUTHOR]

Structure and anticancer activity of fucoidan from Sargassum horneri and from products of its enzymatic transformation were investigated. A gene that encodes fucoidanase ffa1 in the marine bacteria F. algae was identified, cloned and the protein (FFA1) was produced in Escherichia coli . The mass of the gene product FFA1 is 111 kDa. Sequence analysis has revealed that fucoidanase FFA1 belongs to the GH107 (CAZy) family. Recombinant fucoidanase FFA1 was used to produce fucooligosaccharides. Structure of 5 sulphated oligosaccharides with polymerization degree 4–10 was established by NMR-spectroscopy. The fucoidan extracted from S. horneri is almost pure fucan. The main chain of the fucoidan is established to consist mostly of the repeating →3-α- l -Fuc p (2 S O 3 − )-1 → 4-α- l -Fuc p (2,3 S O 3 − )-1→ fragment, with insertions of →3-α- l -Fuc p (2,4 S O 3 − )-1→ fragment. Unsulphated side chains with the α- l -Fuc p -1 → 2-α- l -Fuc p -1→ structure connect to the main one at the C4 of monosaccharide residue. [ABSTRACT FROM AUTHOR]

A fucoidan ScF from brown alga Saccharina cichorioides was extracted, purified and partially depolymerized by autohydrolysis at 37 °C for 24, 48 and 72 h. Supernatant (SN) and pellet (PL) fractions were obtained by ethanol precipitation of each sample. Unlike spectral data of ScF, NMR of PL derivatives clearly suggested the structure: 1,3-linked α- l -Fuc p -4- O SO 3 − repeating unit. Molecular weights (MWs) of PL fractions were 30, 26 and 18 kDa for 24, 48 and 72 h of autohydrolyis, respectively. MALDI-TOFMS, size-exclusion HPLC and carbohydrate polyacrylamide-gel electrophoresis (C-PAGE) indicated a similarity of SN mixtures. They consisted mainly of a polysaccharide part (MW 6 kDa, C-PAGE data) with a structure similar to PL components (NMR data) and monosaccharides α- l -Fuc p -4- O SO 3 − , α- l -Fuc p -2,4-di- O SO 3 − . PL fractions exhibited almost identical antiproliferative activity in vitro as native fucoidan, while an SN sample for 72 h of autohydrolysis was slightly more active against colony formation of colorectal carcinoma cells HT-29. [ABSTRACT FROM AUTHOR]

Laminaran and three fucoidan fractions were obtained from the brown alga Alaria marginata . Alaria angusta, studied earlier by us, has the same polysaccharide composition. Galactofucan AmF3 from A. marginata has a main chain of → 3)-α- l -Fuc p -(2,4- S O 3 − )-(1 → residues, similar to galactofucan from A. angusta . However, the structure of the branches in fucoidan AmF3 can differ from those in the fucoidan from A. angusta. The following fragments were identified in AmF3: HexA-(1 → 2)-Fuc, HexA-(1 → 2)-Gal, Gal-(1 → 4)-HexA, Fuc-(1 → 2)-Gal-6-SO 3 − , Fuc-4-SO 3 − -(1 → 6)-Gal, Gal-(1 → 2)-Gal-2-SO 3 − , Gal-4-SO 3 − -(1  → 6)-Gal, Gal-4-SO 3 − -(1 → 3)-Fuc-(1 → 3)-Fuc, Fuc-4-SO 3 − -(1 → 6)-Gal-(1 → 4)-Gal, Gal-(1 → 4)-Gal-(1 → 3)-Fuc, Gal-2-SO 3 − -(1 → 4)-Gal-(1 → 4)-Gal, Gal-(1 → 4)-Gal-6-SO 3 − -(1 → 2)-Gal. Chains of galactose residues (DP up to 9) were found in AmF3 fucoidan. The laminarans, galactofucans and their derivatives from both algae exhibited no cytotoxicity in vitro . Polysaccharides from A. angusta were more effective against colony formation of HT-29 cells, while those from A. marginata had a greater effect on T-47D cells. Sulfated and desulfated fucoidans possessed weak antitumor activity using SK-MEL-28 cells. [ABSTRACT FROM AUTHOR]

• Aminated laminaran, ScLNH 2 , is β- d -glucan with −CH 2 −CH(OH)−CH 2 -NH 2 group at the C6 of branches. • ScLNH 2 selectively inhibited the viability and colony formation in the MDA-MB-231 cell line. • ScLNH 2 sensitized MDA-MB-231 cells to radiation and induced apoptosis of irradiated cells. • The amination of laminaran led to heighten its anticancer and radiosensitizing activities. Laminarans are currently the focus of attention in regard to the selection of prospective agents for the prevention and treatment of cancer. Laminaran from Saccharina cichorioides was aminated to heighten anticancer and radiosensitizing activities and elucidate its molecular mode of action. Aminated laminaran, ScLNH 2 , was identified as 1,3-β- d -glucan with −CH 2 −CH(OH)−CH 2 -NH 2 group at the C6 of branches. ScLNH 2 selectively inhibited the viability and colony formation in the MDA-MB-231 cell line of triple negative breast cancer cells. ScLNH 2 possessed synergism with radiation, resulting in a decreased number of colonies of MDA-MB-231 cells. The mechanism underling the radiosensitizing effect of ScLNH 2 was associated with apoptosis induction via regulation of caspases 9 and 3 and PARP enzyme, preventing the repair of DNA damage in irradiated cells. These findings confirmed that combination therapy by aminated laminaran and radiation might play a role in the optimization of therapy for an aggressive form of human breast cancer. [ABSTRACT FROM AUTHOR]

• Fucoidan from S. horneri was fractionated via enzyme treatment. • Structures of its high molecular weight products were elucidated. • Fucoidan and its derivatives' antitumor effects were determined. Structure of the fucoidan from Sargassum horneri and products of its enzymatic transformation with molecular weight over 20 kDa were investigated. Fucoidan was hydrolyzed by recombinant fucoidanase FFA1 and its fraction of higher molecular weight was fractionated using anion-exchange chromatography, resulting in three sulphated polysaccharides of various molecular weight (63−138 kDa). Their structures were analyzed using NMR spectroscopy, showing the fucoidan (ShF) to be a branched polysaccharide with the backbone consisting of the repeating →3-α- l -Fuc p (2SO 3 −)-1→4-α- l -Fuc p (2,3SO 3 −)-1→ fragment and side chains including the α- l -Fuc p -1→2-α- l -Fuc p -1→ or α- l -Fuc p -1→3-α- l -Fuc p (4SO 3 −)-1→ fragments attached to the main chain at C4. The fragment F3 differing by molecular weight and side chain from other fucoidans fragments possessed the most significant anticancer and radiosensitizing activities. [ABSTRACT FROM AUTHOR]