Structure analysis of sulfated polysaccharides extracted from green seaweed Ulva lactuca: experimental and density functional theory studies

• Published in: Monatshefte für Chemie Vol. 149; no. 1; pp. 197 - 205
• Main Authors: Tran, Thi Thanh Van, Huy, Bui The, Truong, Hai Bang, Bui, Minh Ly, Thanh, Thi Thu Thuy, Dao, Duy Quang
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.01.2018; Springer Nature B.V
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Density functional theory; Inorganic Chemistry; NMR; Nuclear magnetic resonance; Organic Chemistry; Original Paper; Physical Chemistry; Polysaccharides; Structural analysis; Theoretical and Computational Chemistry; Two dimensional models; Density functional theory; Chemical shift; Sulfated polysaccharides; NMR prediction
• ISSN: 0026-9247; 1434-4475
• DOI: 10.1007/s00706-017-2056-z

The structure of sulfated polysaccharides extracted from green seaweed Ulva lactuca has been determined using NMR experiments. The obtained results indicate that this natural product is mainly composed of disaccharide A 3S : [→4)-β- d -GlcA-(1 → 4)- α - l -Rha3S-(1→] and B 3S : [→4)-α- l -IdoA-(1 → 4)-α- l -Rha3S-(1→]. The computational calculations using density functional theory (DFT) at the B3LYP/6–311+G(2d,p)//B3LYP/6–311G(d,p) model chemistries were also investigated to analyze the obtained structures based on the comparison of 1 H and 13 C NMR chemical shifts. The DFT results also confirm that the A 3S structure is more dominating than the B 3S one with the mean absolute error of 1 H and 13 C NMR chemical shifts, respectively, equal to 0.46 and 4.98 ppm for the A 3S and to 2.07 and 5.03 ppm for the B 3S . Graphical abstract