Structure of Ulvan Isolated from the Edible Green Seaweed, Ulva pertusa

Masakuni Tako,Yoshiyuki Tamashiro,Shuntoku Uechi,Makie Tamanaha

doi:10.4236/abb.2015.610068

Abstract

Ulvan, rhamnan sulfate, was extracted from the edible green seaweed, Ana-aosa (Ulva pertusa), which is grown on the coast of the Okinawa Islands. The yield of ulvan was 8.5% (W/W), and the total carbohydrates, uronic acid and sulfuric acid and ash contents were 67.3%, 23.8%, 19.7% and 22.6%, respectively. L-Rhamnose, D-xylose and D-glucose residues were identified by liquid chromatography, and their molar ratio was 4.0:0.1:0.3. D-Glucuronic and L-idulonic acid residues were also identified in molar ratio of 1.0:0.2. The NMR (13C and 1H) and methylation analysis revealed terminal β-D-glucruonic acid, terminal α-L-idulonic acid, 1,3-linked α-L-rhamnose, 1,4-linked α-L-rhamnose, 1,2,4-linked α-L-rhamnose, 1,3,4-linked α-L-rhamnose, 1,2,3,4-linked α-L-rhamnose and 1,3,4-linked β-D-xylose. The sulfate groups were attached at the C-2 and C-3 positions of the 1,4-linked α-L-rhamnose as well as C-3 of the 1,4-linked β-D-xylose residues. The chemical structure of the ulvan from Ulva pertusa was determined.

Highlights

In the course of the chemical, physicochemical and biological studies of polysaccharides, we investigated structure-function relationship of κ-carrageenan [1] [2], ι-carrageenan [3], agarose [4], gellan gums [5] [6], rhamsan gums [7] [8], amyloses [9] [10], amylopectins [11]-[15], and starches [16]-[20]
[26], ι-carrageenan [27], fucoidans [28]-[30], alginates [31] [32], galactomannans [33] [34], pectins [35]-[37], and rhamnan sulfate [38] from the subtropical biomasses grown in Okinawa Islands, Japan
We identified fucoidans from commercially cultured Okinawamozuku (Cladosiphon okamuranus) [28] and Itomozuku (Nemacystus decipiens) [29]

Summary

Introduction

In the course of the chemical, physicochemical and biological studies of polysaccharides, we investigated structure-function relationship of κ-carrageenan [1] [2], ι-carrageenan [3], agarose [4], gellan gums [5] [6], rhamsan gums [7] [8], amyloses [9] [10], amylopectins [11]-[15], and starches [16]-[20]. We isolated many industrially useful polysaccharides, such as agar [24], methylated agar [25], κ-carrageenan [26], ι-carrageenan [27], fucoidans [28]-[30], alginates [31] [32], galactomannans [33] [34], pectins [35]-[37], and rhamnan sulfate [38] from the subtropical biomasses grown in Okinawa Islands, Japan. A novel fucoidan which was substituted with an acetyl group from the commercially cultured brown seaweed, Cladosiphon okamuranus [28] [32] was identified and patented [39]. The sulfate and acetyl groups branched at C-4 on the main chain. We isolated a rhamnan sulfate from commercially cultured Hitoegusa (Monostroma nitidum: green seaweed) in Okinawa Prefecture, Japan and determined its chemical structure [38]. The rhamnan sulfate consists of 1,3-linked α-L-rhamnopyranosyl residues that branch at C-2 with trisaccharide side chains, D-GlcA(1→2)α-L-Rha-(1→2)-α-L-Rha-(1→. The acetyl fucoidan is used as a supplement in health food, food and cosmetic industries in the world

Methods

Results

Conclusion