Olesya S. Malyarenko

Structural elucidation of polysaccharide fractions from the brown alga Coccophora langsdorfii and in vitro investigation of their anticancer activity.

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.

In vitro anticancer activity of the laminarans from Far Eastern brown seaweeds and their sulfated derivatives

Brown seaweeds have drawn worldwide attention due to their involvement in many industrial applications. They produce neutral low molecular weight polysaccharides (laminarans) with beneficial biological activities. However, the anticancer activity and molecular mechanism of the laminarans and their sulfated derivatives have not been investigated in detail. Herein, the laminarans from brown seaweeds Saccharina cichorioides, Saccharina japonica, and Fucus evanescens were isolated. The laminarans from S. cichorioides and S. japonica were confirmed to contain a main chain of β-(1→3)-D-glucopyranose with single branches at C6. The laminaran from F. evanescens consisted of not only β-(1→3)-linked D- glucopyranose but also includes single β-(1→6)-linked D-glucose residues. The branches at C6 are presented as glucose or as gentiobiose. The sulfated laminarans with different degrees of sulfation were obtained by the chlorosulfonic acid-pyridine assay. In modified polysaccharides, the positions of sulfates are directly predetermined by the structure of native laminarans. The laminarans and their sulfated derivatives inhibited proliferation, colony formation, and migration of human colorectal adenocarcinoma, melanoma, and breast adenocarcinoma cells in different manners. The sulfated laminaran from F. evanescens possessed the highest anticancer activity in vitro and effectively prevented migration of breast adenocarcinoma cells by inhibiting of the Matrix Metalloproteinases 2 and 9 activity.

Four New Sulfated Polar Steroids from the Far Eastern Starfish Leptasterias ochotensis: Structures and Activities

Three new sulfated steroid monoglycosides, leptaochotensosides A–C (1–3), and a new sulfated polyhydroxylated steroid (4) were isolated from the alcoholic extract of the Far Eastern starfish Leptasterias ochotensis. The structures of compounds 1–4 were established by extensive nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESIMS) analyses and chemical transformations. Although the isolated compounds did not show any apparent cytotoxicity against melanoma RPMI-7951 and breast cancer T-47D cell lines, leptaochotensoside A (1) demonstrated inhibition of T-47D cell colony formation in a soft agar clonogenic assay at nontoxic doses. In addition, this compound decreased the epidermal growth factor (EGF)-induced colony formation of mouse epidermal JB6 Cl41 cells. The cancer preventive action of 1 is realized through regulation of mitogen-activated protein kinase (MAPK) signaling pathway.

Structure, chemical and enzymatic modification, and anticancer activity of polysaccharides from the brown alga Turbinaria ornata

In this study, water-soluble polysaccharides from the brown alga Turbinaria ornata (laminaran ToL, fucoidans ToF1 and ToF2) were obtained. The anticancer activity of these polysaccharides and modified derivatives of fucoidan ToF2 against several cancer cell lines was studied. The structure of fucoidan ToF2 was thoroughly investigated using methylation analysis of polysaccharides and mass spectrometry of low molecular weight derivatives of fucoidan, released by fucoidanase from the marine mollusk Patinopecten yessoensis. Fucoidan ToF2 contained a main chain, built up of (1 → 3)-linked fucose residues with branches of single residues or short chains, consisting of fucose and galactose at C2 and C4, and single HexA residues at C2. The following fragments were identified in the structure of fucoidan: Fuc-2,4-SO3−-(1 → 2)-Fuc, Fuc-2-SO3−-(1 → 4)-Fuc-2-SO3−, Gal-2-SO3−-(1 → 3)-2-SO3−-Fuc, Fuc-4-SO3−-(1 → 4)- Gal-3-SO3−, Fuc-2-SO3−-(1 → 4)-Gal-3-SO3−-(1 → 4)-Fuc, Gal-4-SO3−-(1 → 4)-, Fuc-4-SO3−-(1 → 3)-Fuc, and HexA-(1 → 2)-Fuc-4-SO3−. Sulfate groups occupied the positions at C2 and/or at C4 of fucose and C2, C3, and C4/C6 of galactose residues. The fucoidan ToF2 and its derivative obtained by enzymatic hydrolysis inhibited colony formation of human colorectal, breast adenocarcinoma, and malignant melanoma cell lines in vitro.

Nine New Triterpene Glycosides, Magnumosides A1–A4, B1, B2, C1, C2 and C4, from the Vietnamese Sea Cucumber Neothyonidium (=Massinium) magnum: Structures and Activities against Tumor Cells Independently and in Synergy with Radioactive Irradiation

Nine new sulfated triterpene glycosides, magnumosides A1 (1), A2 (2), A3 (3), A4 (4), B1 (5), B2 (6), C1 (7), C2 (8) and C4 (9) as well as a known colochiroside B2 (10) have been isolated from the tropical Indo-West Pacific sea cucumber Neothynidium (=Massinium) magnum (Phyllophoridae, Dendrochirotida) collected in the Vietnamese shallow waters. The structures of new glycosides were elucidated by 2D NMR spectroscopy and mass-spectrometry. All the isolated new glycosides were characterized by the non-holostane type lanostane aglycones having 18(16)-lactone and 7(8)-double bond and differed from each other by the side chains and carbohydrate moieties structures. Magnumoside A1 (1) has unprecedented 20(24)-epoxy-group in the aglycone side chain. Magnumosides of the group A (1–4) contained disaccharide monosulfated carbohydrate moieties, of the group B (5, 6)—tetrasaccharide monosulfated carbohydrate moieties and, finally, of the group C (7–9)—tetrasaccharide disulfated carbohydrate moieties. The cytotoxic activities of the compounds 1–9 against mouse spleen lymphocytes, the ascites form of mouse Ehrlich carcinoma cells, human colorectal carcinoma DLD-1 cells as well as their hemolytic effects have been studied. Interestingly, the erythrocytes were more sensitive to the glycosides action than spleenocytes and cancer cells tested. The compounds 3 and 7 significantly inhibited the colony formation and decreased the size of colonies of DLD-1 cancer cells at non-cytotoxic concentrations. Moreover, the synergism of effects of radioactive irradiation and compounds 3 and 7–9 at subtoxic doses on proliferation of DLD-1 cells was demonstrated.

Structure, enzymatic transformation, anticancer activity of fucoidan and sulphated fucooligosaccharides from Sargassum horneri.

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.

Fucoidans from Brown Alga Fucus evanescens: Structure and Biological Activity

Brown alga Fucus evanescens, widespread in the Far Eastern seas of Russia, is valuable source of sulfated polysaccharides – fucoidans with beneficial biological activities. The most homogenous fraction of fucoidan from F. evanescens was shown to be molecule containing linear main chain of alternating 2-sulfated 1,3- and 1,4-linked α-L-fucose residues. Few sulfate groups were found in position 4 of some 1,3-linked fucose residues. Acetyl groups occupied free C-3 of 1,4-linked residues and/or the C-4 of 1,3-linked fucose residues. Enzymatic hydrolysis, mild acid hydrolysis and autohydrolysis of native fucoidan were used for elucidation of the fine structural characteristics of fucoidan from F. evanescens. The aim of this review to summarize published data on biological activities of fucoidan from F. evanescens: antiviral, anticoagulant, thrombolytic, hepatoprotective, immunomodulatory, anticancer, and their practical application.

Fucoidans: Anticancer Activity and Molecular Mechanisms of Action

Abstract Cancer is a major public health concern worldwide. That is why many scientists are trying to develop effective methods of cancer prevention using different approaches, methods, and modern equipment. The sulfated polysaccharides from brown algae, fucoidans, are known to be a topic of numerous studies because of their beneficial biological activities including anticancer activity. Unlike drugs, fucoidans possess anticancer effect by targeting multiple cellular signaling pathways including growth factors, tumor cell survival factors, receptors, protein kinases, transcription factors, and so on that are often deregulated in cancers. Their simultaneous targeting by these polysaccharides could result in efficacious and selective prevention of cancer. In this chapter, our aim is to discuss data on anticancer activity of algal fucoidans, their mechanism of actions with specific emphasis on cell cycle, apoptosis, neoplastic cell transformation, metastasis, and angiogenesis pathways.

The Inhibitory Activity of Luzonicosides from the Starfish Echinaster luzonicus against Human Melanoma Cells

Malignant melanoma is the most dangerous form of skin cancer, with a rapidly increasing incidence rate. Despite recent advances in melanoma research following the approval of several novel targeted and immuno-therapies, the majority of oncological patients will ultimately perish from the disease. Thus, new effective drugs are still required. Starfish steroid glycosides possess different biological activities, including antitumor activity. The current study focused on the determination of the in vitro inhibitory activity and the mechanism of action of cyclic steroid glycosides isolated from the starfish Echinaster luzonicus—luzonicoside A (LuzA) and luzonicoside D (LuzD)—in human melanoma RPMI-7951 and SK-Mel-28 cell lines. LuzA inhibited proliferation, the formation of colonies, and the migration of SK-Mel-28 cells significantly more than LuzD. Anti-cancer activity has been ascribed to cell cycle regulation and apoptosis induction. The molecular mechanism of action appears to be related to the regulation of the activity of cleaved caspase-3 and poly(ADP-ribose) polymerase (PARP), along with Survivin, Bcl-2, p21 and cyclin D1 level. Overall, our findings support a potential anti-cancer efficacy of luzonicosides A and D on human melanoma cells.

Six New Polyhydroxysteroidal Glycosides, Anthenosides S1 - S6, from the Starfish Anthenea sibogae

Six new polyhydroxysteroidal glycosides, anthenosides S1 – S6 (1 – 6), along with a mixture of two previously known related glycosides, 7 and 8, were isolated from the methanolic extract of the starfish Anthenea sibogae. The structures of 1 – 6 were established by NMR and HR‐ESI‐MS techniques as well as by chemical transformations. All new compounds have a 5α‐cholest‐8(14)‐ene‐3α,6β,7β,16α‐tetrahydroxysteroidal nucleus and differ from majority of starfish glycosides in positions of carbohydrate moieties at C(7) and C(16) (1 – 4, 6) or only at C(16) (5). The 4‐O‐methyl‐β‐d‐glucopyranose residue (2) and Δ24‐cholestane side chain (3) have not been found earlier in the starfish steroidal glycosides. The mixture of 7 and 8 slightly inhibited the proliferation of human breast cancer T‐47D cells and decreased the colony size in the colony formation assay.