Fucoidan from brown seaweed Tubinaria decurrens: Structure and structure - anticancer activity relationship.

The aims of this study are to determine the structure of a fucoidan from brown seaweed Turbinaria decurrens, to investigate its anticancer activity and structure-activity relationship. SEC-MALLS, IR, ESI-MS and NMR spectra analysis indicated that dominant structure of the fucoidan, with a Mw 122.6 KDa, has a backbone of (1 â†’ 3)- and (1 â†’ 4)-α-L-Fucp residues, branched at C-4, sulfate groups are attached at C-2, C-3 and C-4; branches are (1 â†’ 4)-ß-D-Galp residues and sulfated at C-2. The fucoidan was hydrolyzed by HCl aqueous solution to obtain hydrolyzed fucoidans. It is assumed that native and hydrolyzed fucoidans have a rod-like conformation in solution with cross-sectional radius of gyration (Rgc) ranged from 0.53 to 1.52 nm as estimated from SAXS measurements. The fucoidans show great anticancer activity against HT29 human colon cancer cell line with IC50 ranging from 5.41 ± 0.36 to 73.52 ± 2.54 µg/mL. Anticancer activity of the fucoidan could be significantly improved by lowering molecular weight, furthermore, fucoidan required small molecular weight, small molecular weight distribution and rod-like structure with a short branch length for high anticancer activity.

Structure, anticoagulant and cytotoxic activity of a sulfated polysaccharide from green seaweed Chaetomorpha linum.

In this article, chemical structure and conformation in an aqueous solution of a new sulfated polysaccharide, PCL, extracted from green seaweed Chaetomorpha linum were elucidated by SEC-MALL, IR, NMR and SAXS. The results indicated that the obtained polysaccharide is a sulfated arabinogalactan with a molecular weight of 223 kDa, and is mainly composed of →3,6)-α-D-Galp4S→ and →2)-α-L-Araf→ connecting together through 1→3 glycoside linkages. It has a broken rod-like conformation in solution with Rgc estimated as 0.43 nm from SAXS measurements. The polysaccharide exhibited a notable anticoagulant activity measured by the assays of activated partial thromboplastintime, thrombintime and prothrombine time as well as a significant cytotoxic activity against hepatocellular, human breast cancer, and cervical cancer cell lines.

Primary structure, conformation in aqueous solution, and intestinal immunomodulating activity of fucoidan from two brown seaweed species Sargassum crassifolium and Padina australis.

We studied the structure of fucoidans extracted from two brown seaweed species, Sargassum crassifolium and Padina australis, and their intestinal immunomodulating activity via Peyer's patch cells of C3H/HeJ mice. ESI-MS analysis indicated that the dominant structure of both fucoidans has a backbone of α-(1→4)-linked and α-(1→3)-linked l-fucose residues and sulfate groups are attached at the C-2 and C-4 positions; branches of fucoidan from S. crassifolium are galactose residues with (1→4)- linkage and branching points are at C-4 of fucose, while fucoidan from P. australis, branches are sulfated galactose-fucose disaccharides and sulfated galactose monosaccharides attached to the main chain through (1→3)- or (1→4)- linkages. According to small angle X-ray scattering (SAXS) measurements, the two fucoidans have a branched structure. We simulated them with molecular models based on our proposed primary structure. These fucoidan samples have the ability to stimulate intestinal immunological activity via Peyer's patch cells.

Structure of fucoidan from brown seaweed Turbinaria ornata as studied by electrospray ionization mass spectrometry (ESIMS) and small angle X-ray scattering (SAXS) techniques.

The purpose of this study is to elucidate both the chemical and conformational structure of an unfractionated fucoidan extracted from brown seaweed Turbinaria ornata collected at Nha-trang bay, Vietnam. Electrospray ionization mass spectrometry (ESI-MS) was used for determining the chemical structure and small angle X-ray scattering (SAXS) provided conformational of the structure at the molecular level. The results showed that the fucoidan has a sulfate content of 25.6% and is mainly composed of fucose and galactose residues (Fuc:Gal ≈ 3:1). ESIMS analysis suggested that the fucoidan has a backbone of 3-linked α-l-Fucp residues with branches, →4)-Galp(1→ at C-4 of the fucan chain. Sulfate groups are attached mostly at C-2 and sometimes at C-4 of both fucose and galactose residues. A molecular model of the fucoidan was built based on obtained chemical structure and scattering curves estimated from molecular model and observed SAXS measurement were fitted. The results indicated that fucoidan under study has a rod-like bulky chain conformation.