Molecular Characteristics and Gelling Properties of the Carrageenan Family, 1. Preparation of Novel Carrageenans and their Dilute Solution Properties

Molecular characteristics and gelling properties of carrageenan family 2. Tri-sulfated and tetra-sulfated carrageenans

“…1 M NaCl aqueous solution at 25°C indicate that the conformation of τ-and ρ-carrageenan would be classified as a random coil as the ρ values are in the range of 1.6 to 1.7 [14] . In the preceding paper [3] , κ-, ι-and θ-carrageenans were found to possess relatively large ρ (=R g /R h ) values, indicating the chains are relatively stiff and rod-like. On the contrary, λ-carrageenan was found to possess a small ρ value, suggesting a relatively compact structure.…”

“…On the contrary, λ-carrageenan was found to possess a small ρ value, suggesting a relatively compact structure. β-carrageenan has the ρ value around 1.5, and its conformation could be specified as a random coil [3,14] . However, the ρ value around 1.5 does not necessarily correspond to the chain flexibility in the case of the carrageenan family, since the B values (the flexibility parameter) were found to be small in the range of 0.05 to 0.12 for all cases, indicating the semi-rigid nature of carrageenan chains.…”

“…The reaction route is now well established to sulfated or desulfated carrageenans regioselectively. In this report, we prepare new series of tri-sulfated (τ-carrageenan) and tetra-sulfated (ρ-carrageenan) carrageenans by the sulfating reaction with H 2 SO 4 -N,N'-dicyclohexylcarbodiimide (see Figure 2 for the reaction scheme) from ι-carrageenan in compliment to β-and θ-carrageenan prepared in the preceding paper [3] , and their dilute solution properties are examined by means of static/dynamic light scattering and small-angle X-ray scattering. The gelling properties are also examined and the effect of sulfate groups on gelation is discussed to understand the mechanism of gelation from the viewpoint of the conformational characteristics of tri-sulfated and tetra-sulfated carrageenans.…”

Interference with Chemical Crosslinking of Sulfated Polysaccharides by Sulfuric Acid Groups of Polysaccharide Chain

“…It was reported that the bulky sulfuric acid groups of -and -carrageenan protrude out from their main chain and surround the chain 7,8,9 . In the same way, the sulfuric acid groups of funoran-1 can also stick out from and surround its main chain.…”

Intravaginal Delivery Approaches for Contraception: An Overview with Emphasis on Gels

“…Its chemical structure is comprised of repeating units of galactose and 3, 6-anhydrogalactose (3, 6-AG) copolymer (both sulfated and non-sulfated). Alternating α-1,3 and β-1,4 glycosidic linkages join these units (58). High flexibility and double helical structure of carrageenans enable them to shape a range of diverse gels at room temperature.…”