Structural Studies on <i>ι</i>-Carrageenan Derived Oligosaccharides and Its Application

Abstract

Mild hydrochloric acid hydrolysis of ι-carrageenan from Eucheuma spinosum yielded two oligosaccharides of sulfated tetrasaccharide structure. These were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESIMS). Both oligosaccharides have structure of β-D-galactopyranose(Galp)4S-(1→4)-α-D-AnGalp2S-(1→3)-β-D-galactopyranose Galp)4S-(1→4)-α-D-AnGalp2S-(1→3). Application of the resulting oligosaccharides on protein delivery system in terms of encapsulation efficiency was performed.

The Use of FTIR Spectroscopy as a Tool for the Seasonal Variation Analysis and for the Quality Control of Polysaccharides from Seaweeds

“…The reference band is between 1240 and 800 cm −1 . According to the literature [ 40 , 41 ], polysaccharide structures can be identified from the following bands: 1240 cm −1 , S=O of the ester-sulfate is identified by carrageenan ι-, κ- and ν-; 1070 cm −1 (shouldered), C-O of 3,6-anhydrogalactose (DA: 4-Linked 3,6-anhydro-α- d -galactopyranose) for ι-, κ-; band 970–975 cm −1 , Galactose (G/D: 3-Linked β- d -galactopyranose/4-Linked α- d- galactopyranose) of ι-, κ- and ν- (shouldered peaks); 930 cm −1 C-O of 3,6-anhydrogalactose (DA: 4-Linked 3,6-anhydro-α- d -galactopyranose) specific for ι- and κ- ; intensity at 905 cm −1 (shouldered), C-O-SO 4 (group ester) on C 2 of 3,6-anhydrogalactose (DA2S: 4-Linked 3,6-anhydro-α- d -galactopyranose 2-sulphate) specific for ι-carrageenan; 867 cm −1 (shouldered), C-O-SO 4 on C 6 galactose (G/D6S: 3-Linked β- d -galactopyranose / 4-Linked α- d -galactopyranose 6-sulphate) for ν-carrageenan; 845 cm −1 is C-O-SO 4 on galactose C 4 (G4S: 3-Linked β- d -galactopyranose 4-sulphate) for ι-, κ- and ν-; band 825–830 cm −1 , C-O-SO 4 on galactose C 2 (G/D2S: 3-Linked β- d -galactopyranose /3-Linked β- d -galactopyranose 2-sulphate) specific for ν-carrageenan ; 815–820 cm −1 C-O-SO 4 on galactose C 6 (G/D6S: 3-Linked β- d -galactopyranose / 4-Linked α- d -galactopyranose 6-sulphate) for ν-carrageenan and for intensity 805 cm −1 C-O-SO 4 on 3,6-anhydrogalactose C 2 (DA2S: 4-Linked 3,6-anhydro-α- d -galactopyranose 2-sulphate) specific for ι-carrageenan. Table 2 shows the results of identifying the peak traces to identify the molecular structures of the extracts, and this table already shows the difference of the peaks for each season.…”

Biocompatible ι-carrageenan-γ-maghemite nanocomposite for biomedical applications – synthesis, characterization and in vitro anticancer efficacy

“…Presence of 3, 6-anhydro-D-galactopyranose units in both was confirmed from the presence of bands at 894 and 917 cm −1 , and that of D-galactopyranose-4-sulfate (G4S) units by the presence of bands at 848 and 846 cm −1 . The band specific to ι-car appears at 805 cm −1 ,which indicates the presence of sulfate group at C2-position in the 3, 6-anhydrogalactose unit (DA2S) [ 30 ]. This band however shifts to lower wavenumbers in the spectrum of the nanocomposite.…”