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Polysaccharides' derivatives are promising biologically active compounds for biotechnology, nutrition, industries, and are becoming increasingly important in medicine and pharmacy. Laminaran from brown alga Saccharina cichorioides (ScL) was chemically modified to obtain the carboxymethylated derivative (ScLCM) with improved structure and bioactivity. ScLCM was identified as (1 → 3)-β-D-glucan with -CH

The metabolic profile of the Aspergillus sp. 1901NT-1.2.2 sponge-associated fungal strain was investigated using the HPLC MS technique, and more than 23 peaks in the HPLC MS chromatogram were detected. Only two minor peaks were identified as endocrocin and terpene derivative MS data from the GNPS database. The main compound was isolated and identified as known anthraquinone derivative vismione E. The absolute stereochemistry of vismione E was established for the first time using ECD and quantum chemical methods. Vismione E showed high cytotoxic activity against human breast cancer MCF-7 cells, with an IC50 of 9.0 µM, in comparison with low toxicity for normal human breast MCF-10A cells, with an IC50 of 65.3 µM. It was found that vismione E inhibits MCF-7 cell proliferation and arrests the cell cycle in the G1 phase. Moreover, the negative influence of vismione E on MCF-7 cell migration was detected. Molecular docking of vismione E suggested the IMPDH2 enzyme as one of the molecular targets for this anthraquinone derivative.

There is a comparative analysis of primary structures and catalytic properties of two recombinant endo-1,3-β-D-glucanases from marine bacteria Formosa agariphila KMM 3901 and previously reported F. algae KMM 3553. Both enzymes had the same molecular mass 61 kDa, temperature optimum 45 °C, and comparable ranges of thermal stability and Km. While the set of products of laminarin hydrolysis with endo-1,3-β-D-glucanase from F. algae was stable of the reaction with pH 4-9, the pH stability of the products of laminarin hydrolysis with endo-1,3-β-D-glucanase from F. agariphila varied at pH 5-6 for DP 2, at pH 4 and 7-8 for DP 5, and at pH 9 for DP 3. There were differences in modes of action of these enzymes on laminarin and 4-methylumbelliferyl-β-D-glucoside (Umb), indicating the presence of transglycosylating activity of endo-1,3-β-D-glucanase from F. algae and its absence in endo-1,3-β-D-glucanase from F. agariphila. While endo-1,3-β-D-glucanase from F. algae produced transglycosylated laminarioligosaccharides with a degree of polymerization 2-10 (predominately 3-4), endo-1,3-β-D-glucanase from F. agariphila did not catalyze transglycosylation in our lab parameters.

Chitosan/fucoidan nanoparticles were created using two fucoidans from the Fucus evanescens algae. One of them was a regular fucoidan obtained for the first time from the alga harvested at the reproductive growth stage, using only standard extraction methods, without additional modifications. Its structure was established via NMR spectroscopy to consist of the repeating →3)-α-L-Fucp-(2,4SO3−)-(1 → 4)-α-L-Fucp-(2SO3−)-(1→ fragment. Such fragment also coustituted 55% of the other fucoidan's structure, however it also included long sequences of α-L-fucopyranose residues sulfated only at C2. The nanoparticles were re-dispersed in water and the influence of fucoidan/chitosan mass ratio on the nanoparticles' size and zeta potential was investigated. 3D models of the regular fucoidan and chitosan's sections were created and their molecular docking was performed, showing that either polymer could occupy the exterior of the complex, depending on their ratio. Thermodynamic parameters of fucoidan-chitosan binding process were accessed, with the results indicating that significant conformational changes of fucoidan and chitosan molecules take place during the interaction, presumably to allow for more effective binding.

Genomic analysis of the marine bacterium Wenyingzhuangia fucanilytica CZ1127T revealed the presence of four fucoidanase genes fwf1, fwf2, fwf3, fwf4 that belonged to the glycoside hydrolase family 107 (GH107, CAZy), which is located in one gene cluster putatively involved in fucoidan catabolism. Genes encoding two fucoidanases fwf1 and fwf2 were cloned, and the proteins FWf1 and FWf2 were produced in Escherichia coli cells. The recombinant fucoidanases were purified and the biochemical properties of these enzymes were studied. The amino acid sequences of FWf1 and FWf2 showed 41 and 51% identity respectively with a fucoidanase FcnA from the marine bacterium Mariniflexile fucanivorans, with the established 3D structure. Structures of the oligosaccharides produced during enzymatic hydrolysis of fucoidan by FWf1 and FWf2 have been determined by NMR spectroscopy. Detailed substrate specificities of FWf1 and FWf2 were studied using fucoidans and sulfated fucooligosaccharides with different structures. Both fucoidanases catalyzed hydrolysis of 1→4-glycosidic bonds between sulfated α-l-fucose residues but had different specificities regarding sulfation patterns of the fucose residues in fucoidan molecules. Specific cleavage sites recognizable by the fucoidanases in fucoidan molecules were determined. The obtained results provide new knowledge about differences between specificities of the fucoidanases belonging to the GH107 family.

Six fucoidan fractions were isolated from the brown alga Alaria angusta. Structures of enzymatic hydrolysis products of the fraction 1AaF2 (Fuc:Gal ~ 1:1; 33 % of sulfates) by fucanase from Wenyingzhuangia fucanilytica were studied by chemical and instrumental (NMR spectroscopy and mass-spectrometry) methods. It was shown that 1AaF2 consisted of two structurally different fucoidans: a sulfated 1,3;1,4-α-L-fucan and an enzyme-resistant sulfated and acetylated complex fucogalactan (Fuc:Gal ~ 1:2; 19 % of sulfates) 1AaF2_HMP containing extended 1,3-linked fucose and 1,3/1,4-linked galactose fragments (up to 5 residues). The fractions 1AaF2 and 1AaF2_HMP were a non-cytotoxic, possessed dose-dependent chemopreventive effect on EGF-induced neoplastic cell transformation of mouse normal epidermal JB6 Cl41 cells and inhibited the colony formation of human melanoma SK-MEL-28 cells.

Three new tripeptide derivatives asterripeptides A–C (1–3) were isolated from Vietnamese mangrove-derived fungus Aspergillus terreus LM.5.2. Structures of isolated compounds were determined by a combination of NMR and ESIMS techniques. The absolute configurations of all stereocenters were determined using the Murfey’s method. The isolated compounds 1–3 contain a rare fungi cinnamic acid residue. The cytotoxicity of isolated compounds against several cancer cell lines and inhibition ability of sortase A from Staphylococcus aureus of asterripeptides A–C were investigated.

The Hantaan orthohantavirus (genovariant Amur–AMRV) is a rodent-borne zoonotic virus, it is the causative agent of haemorrhagic fever with renal syndrome in humans. The currently limited therapeutic options require the development of effective anti-orthohantavirus drugs. The ability of native fucoidan from Fucus evanescens (FeF) and its enzymatically prepared high-molecular-weight (FeHMP) and low-molecular-weight (FeLMP) fractions to inhibit different stages of AMRV infection in Vero cells was studied. The structures of derivatives obtained were determined using nuclear magnetic resonance (NMR) spectroscopy. We found that fucoidan and its derivatives exhibited significant antiviral activity by affecting the early stages of the AMRV lifecycle, notably virus attachment and penetration. The FeHMP and FeLMP fractions showed the highest anti-adsorption activity by inhibiting AMRV focus formation, with a selective index (SI) &gt, 110, FeF had an SI of ~70. The FeLMP fraction showed a greater virucidal effect compared with FeF and the FeHMP fraction. It was shown by molecular docking that 2O-sulphated fucotetrasaccharide, a main component of the FeLMP fraction, is able to bind with the AMRV envelope glycoproteins Gn/Gc and with integrin β3 to prevent virus–cell interactions. The relatively small size of these sites of interactions explains the higher anti-AMRV activity of the FeLMP fraction.

Four new diketopiperazine alkaloids, citriperazines A-D were isolated from algae-derived Penicillium sp. KMM 4672. The structures of compounds 1-4 were determined using spectroscopic methods. The absolute configurations of compounds 1 and 4 were established by comparison of calculated and experimental ECD spectra. The cytotoxicity of compounds 1-4 against several human prostate cell lines was evaluated.

Two new auroglaucin-derived compounds, niveoglaucins A (1) and B (2), together with four known related compounds were isolated from extract of the marine sediment-derived strain of Aspergillus niveoglaucus. The structures of these compounds were determined by 1D and 2D NMR spectroscopy and high resolution MS. The plausible biosynthetic pathway was proposed for new compounds 1 and 2. The neuroprotective activity in 6-OHDA-induced Parkinson's disease cell model was shown for niveoglaucin A (1).

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-Fucp(2SO3-)-1→4-α-l-Fucp(2,3SO3-)-1→ fragment and side chains including the α-l-Fucp-1→2-α-l-Fucp-1→ or α-l-Fucp-1→3-α-l-Fucp(4SO3-)-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.

In the present study, three sulfated polysaccharides, two fractions of fucosylated chondroitin sulfates, and one sulfated fucan were isolated from the body wall of the Vietnamese sea cucumber Stichopus variegatus. The structure of the sulfated fucan fraction SvF3 from S. variegatus was investigated for the first time. According to NMR spectroscopy data, the sulfated fucan SvF3 contained 1,2- and 1,3-linked α- l -fucopyranose residues. Sulfate groups were found at the 2 and/or 4 positions. The structural analysis of fucoidan was assisted by tandem mass spectrometry; the recently-developed technique of autohydrolysis in heavy‑oxygen water for the obtaining of selectively labeled fucoidan fragments was applied. The labeling (+2 Da mass shift at the reducing end) allowed us to assign MS/MS data unambiguously, and thus to confirm the NMR data and revealed minor sulfation at position 3. It was shown that the sulfated fucan SvF3 was not cytotoxic to human breast cancer T-47D and MDA-MB-231 cell lines, and it inhibited colony formation of those cells in vitro. SvF3 also possessed slight activity against migration of MDA-MB-231 cells in vitro.

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 -Fucp2,4OSO3−-(1 → 4)-α- l -Fucp2,4OSO3−-(1 → 4)-α- l -Fucp2OSO3−-(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.

Fucoidans are a class of sulfated fucose-containing bioactive polysaccharides produced by brown algae. The biological effects exhibited by fucoidans are thought to be related to their sulfation. However, the lack of methods for sulfation control does not allow for a reliable conclusion about the influence of the position of certain sulfate groups on the observed biological effects. We identified the gene encoding the endo-acting fucoidan sulfatase swf5 in the marine bacterium Wenyingzhuangia fucanilytica CZ1127T. This is the first report on the sequence of fucoidan endo-sulfatase. Sulfatase SWF5 belongs to the subfamily S1_22 of the family S1. SWF5 was shown to remove 4O-sulfation in fucoidans composed from the alternating α-(1→3)- and α-(1→4)-linked residues of sulfated L-fucose but not from fucoidans with the α-(1→3)-linked backbone. The endo-sulfatase was used to selectively prepare 4O-desulfated fucoidan derivatives. It was shown that the 4O-desulfated fucoidans inhibit colony formation of DLD-1 and MCF-7 cells less effectively than unmodified fucoidans. Presumably, 4O-sulfation makes a significant contribution to the anticancer activity of fucoidans.

The application of an ultrasound-assisted extraction method, combined with ion-exchange chromatography, has allowed separation of the total fucoidan fraction (F1) from the brown alga Fucus evanescens into two fractions, F2 and F3, in the ratio 1:0.2. The traditionally extracted F1 differs from F3 only by the acetate groups at C3 being somewhat predominant. F2 is described as having acetate groups located chaotically, and contains galactose and xylose residues, in addition to fucose. F3 consists of fucose residues acetylated almost exclusively at C3. Therefore, with ultrasound-assisted extraction from the brown alga Fucus evanescens, a new regular 1 → 3;1 → 4-α-L-fucan was obtained. It is sulphated at C2 and acetylated at C3 of the fucose residue and showed anticancer activity in vitro towards human colon carcinoma cells comparable to the total fraction F1.

Four new diketopiperazine alkaloids, citriperazines A-D were isolated from algae-derived

Two new auroglaucin-derived compounds, niveoglaucins A (

A bifunctional alginate lyase (ALFA3) and mannuronate-specific alginate lyase (ALFA4) genes were found in the genome of polysaccharide-degrading marine bacterium Formosa algae KMM 3553T. They were classified to PL7 and PL6 polysaccharide lyases families and expressed in E. coli. The recombinant ALFA3 appeared to be active both on mannuronate- and guluronate-enriched alginates, as well as pure sodium mannuronate. For all substrates, optimum conditions were pH 6.0 and 35 &deg, C, Km was 0.12 &plusmn, 0.01 mg/ml, and half-inactivation time was 30 min at 42 &deg, C. Recombinant ALFA4 was active predominately on pure sodium mannuronate, with optimum pH 8.0 and temperature 30 &deg, C, Km was 3.01 &plusmn, 0.05 mg/ml. It was stable up to 30 &deg, half-inactivation time was 1h 40 min at 37 &deg, C. 1H NMR analysis showed that ALFA3 degraded mannuronate and mannuronate-guluronate blocks, while ALFA4 degraded only mannuronate blocks, producing mainly disaccharides. Products of digestion of pure sodium mannuronate by ALFA3 at 200 &micro, g/ml inhibited anchorage-independent colony formation of human melanoma cells SK-MEL-5, SK-MEL-28, and RPMI-7951 up to 17% stronger compared to native polymannuronate. This fact supports previous data and suggests that mannuronate oligosaccharides may be useful for synergic tumor therapy.

Fucoidans belong to a structurally heterogeneous class of sulfated polysaccharides isolated from brown algae. They have a wide spectrum of biological activities. The complex structures of these polysaccharides hinder structure-activity relationships determination. Fucoidan sulfatases can make useful tools for the determination of the fine chemical structure of fucoidans. In this study, identification and preparation of two recombinant sulfatases able to catalyze the cleavage of sulfate groups from fragments of fucoidan molecules is described for the first time. Two genes of sulfatases swf1 and swf4 of the marine bacterium Wenyingzhuangia fucanilytica CZ1127T were cloned and the proteins were produced in Escherichia coli cells. Sulfatases SWF1 and SWF4 are assigned to S1_17 and S1_25 subfamilies of formylglycine-dependent enzymes of S1 family (SulfAtlas). Some molecular and biochemical characteristics of recombinant fucoidan sulfatases have been studied. Detailed specificity and catalytic features of sulfatases were determined using various sulfated fucooligosaccharides. Structures of products produced by SWF1 and SWF4 were established by nuclear magnetic resonance (NMR) spectroscopy. Based on the obtained data, the enzymes are classified as fucoidan exo-2O-sulfatase (SWF1) and fucoidan exo-3O-sulfatase (SWF4). In addition, we demonstrated the sequential action of sulfatases on 2,3-di-O-sulfated fucooligosacchrides, which indicates an exolitic degradation pathway of fucoidan by a marine bacterium W. fucanilytica CZ1127T.

Four new indole-diterpene alkaloids asperindoles A&ndash, D (1&ndash, 4) and the known p-terphenyl derivative 3&Prime, hydroxyterphenyllin (5) were isolated from the marine-derived strain of the fungus Aspergillus sp., associated with an unidentified colonial ascidian. The structures of 1&ndash, 5 were established by 2D NMR and HRESIMS data. The absolute configurations of all stereocenters of 1&ndash, 4 were determined by the combination of ROESY data, coupling constants analysis, and biogenetic considerations. Asperindoles C and D contain a 2-hydroxyisobutyric acid (2-HIBA) residue, rarely found in natural compounds. Asperindole A exhibits cytotoxic activity against hormone therapy-resistant PC-3 and 22Rv1, as well as hormone therapy-sensitive human prostate cancer cells, and induces apoptosis in these cells at low-micromolar concentrations.

Four new indole-diterpene alkaloids asperindoles A–D (1–4) and the known p-terphenyl derivative 3″-hydroxyterphenyllin (5) were isolated from the marine-derived strain of the fungus Aspergillus sp., associated with an unidentified colonial ascidian. The structures of 1–5 were established by 2D NMR and HRESIMS data. The absolute configurations of all stereocenters of 1–4 were determined by the combination of ROESY data, coupling constants analysis, and biogenetic considerations. Asperindoles C and D contain a 2-hydroxyisobutyric acid (2-HIBA) residue, rarely found in natural compounds. Asperindole A exhibits cytotoxic activity against hormone therapy-resistant PC-3 and 22Rv1, as well as hormone therapy-sensitive human prostate cancer cells, and induces apoptosis in these cells at low-micromolar concentrations.

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 111kDa. 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-Fucp(2SO3-)-1→4-α-l-Fucp(2,3SO3-)-1→ fragment, with insertions of →3-α-l-Fucp(2,4SO3-)-1→ fragment. Unsulphated side chains with the α-l-Fucp-1→2-α-l-Fucp-1→ structure connect to the main one at the C4 of monosaccharide residue.

Four new compounds were isolated from the Vietnamese marine sediment-derived fungus Aspergillus flocculosus, one aspyrone-related polyketide aspilactonol G (2), one meroterpenoid 12-epi-aspertetranone D (4), two drimane derivatives (7,9), together with five known metabolites (1,3,5,6,8,10). The structures of compounds 1&ndash, 10 were established by NMR and MS techniques. The absolute stereoconfigurations of compounds 1 and 2 were determined by a modified Mosher&rsquo, s method. The absolute configurations of compounds 4 and 7 were established by a combination of analysis of ROESY data and coupling constants as well as biogenetic considerations. Compounds 7 and 8 exhibited cytotoxic activity toward human prostate cancer 22Rv1, human breast cancer MCF-7, and murine neuroblastoma Neuro-2a cells.