Structure of Fucoidan from Brown Seaweed Turbinaria ornata as Studied by Electrospray Ionization Mass Spectrometry (ESIMS) and Small Angle X-ray Scattering (SAXS) Techniques

Abstract

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.

Sulfur-Containing Carotenoids from A Marine Coral Symbiont Erythrobacter flavus Strain KJ5

“…The product ion at m / z 97, which indicated sulfate ion [HSO 4 ] − could also be well recorded by the ESI-MS/MS spectra (Figure 4A). Previously, electrospray ionization has been shown to be an effective method for tracing the SO 4 2− ion [39,40,41,42]. It was shown that nostoxanthin with m / z 600 [M] + could lose one atom OH ( m / z 17) from the 3-position, which then it was replaced by a sulfate ion group (HSO 4 − ) resulting nostoxanthin sulfate at m / z 679.4 [M − Na] − and a fragment ion at m / z 97.3.…”

Novel Enzyme Actions for Sulphated Galactofucan Depolymerisation and a New Engineering Strategy for Molecular Stabilisation of Fucoidan Degrading Enzymes

“…Fucoidan from S. mcclurei was purified further by ion-exchange chromatography [ 12 ]. Turbinaria ornata fucoidan was extracted as described by Thanh et al (2013) [ 13 ]. Fucoidans from F. evanescens , U. pinnatifida , and S. cichorioides were purified as described by Kusaykin et al (2006) [ 39 ].…”

“… Representative fucoidan structures of brown macroalgae Fucus evanescens , Fucus vesiculosus , Sargassum mcclurei , Turbinaria ornata , Saccharina cichorioides , and Undaria pinnatifida : ( A ) main chain of S. cichorioides composed of α(1→3)- l -fucosyls; ( B ) main chain of U. pinnatifida fucoidan also composed of α(1→3)- l -fucosyls; ( B’ ) branches of U. pinnatifida fucoidan [ 11 ]; ( C ) main chain of F. evanescens [ 1 ] and F. vesiculosus fucoidan [ 8 , 9 , 10 ], both composed of α(1→3)- and α(1→4)-linked l -fucosyls; ( D ) main chain of T. ornata fucoidan composed of α(1→3)- l -fucosyls [ 13 , 14 ]; ( D’ ) branches of T. ornata of α(1→3)- l -fucosyls or of β(1→4)galactosyls and mixed fucosyl-galactosyls; ( E ) main chain of S. mcclurei fucoidan made up of mainly α(1→3)- l -fucosyls [ 12 ]; and ( E’ ) branches or inserts in the main chain of S. mcclurei fucoidan. In all fucoidan structures: R 1 : −H or −SO 3 − ; R 2 : −H, −SO 3 − or H 3 COC−; R 3 : SO 3 − , H 3 COC− or branches; and R 4 : SO 3 − or branches.…”

“…Fucoidan extracted from T. ornata collected at Nha-Trang bay, Vietnam, also seems to be a galactofucan. The backbone of T. ornata fucoidan has thus been proposed to consist of α(1→3)-linked l -fucosyls with galactosyl branches (Fuc:Gal ≈ 3:1) and has been found to have a high sulphate content of about 25% with sulphate attached mostly at C2, and to a lesser extent at C4, of both the fucosyl and the galactosyl residues [ 13 , 14 ] ( Figure 1 ). The biological function of fucoidans in brown macroalgae is uncertain, but fucoidans have long been known to exert beneficial biological activities including anti-tumorigenic, immune-modulatory, anti-inflammatory, anti-coagulant and anti-thrombotic effects, as demonstrated in vitro and in vivo [ 14 , 15 , 16 ].…”

Targeting P-Selectin by Gallium-68–Labeled Fucoidan Positron Emission Tomography for Noninvasive Characterization of Vulnerable Plaques

“…[27][28][29] Its chemical composition is relatively simpler because it is mainly composed of l-fucose and sulfate residues. On the basis of the results of methylation, fractionation, and on recent gas chromatography-mass spectrometry data, [27][28][29] it was suggested that the core region of Fucoidan was primarily a polymer of α-(1→3)-linked L-fucose with sulfate groups substituted at the C-4 position on some of the fucose units; fucose was also attached to this polymer to form branched points, one for every 2 to 3 fucose residues within the chain. Although the main goal of our study was to provide a stable 68 Ga-Fucoidan for imaging P-selectin expression on plaques rather than to characterize its structure, it is assumed that in the stable TcFucoidan.…”