The chemical structure of galactans from some New Zealand red algae

The polysaccharides from six New Zealand species of red seaweed were examined by C-13 NMR spectroscopy, and found to have the following structures: Caulacanthus ustulatis (Caulacanthaceae): 3:1 kappa/iota-hybrid carrageenan; Craspedocarpus erosus (Cystocloniaceae): iota-carrageenan; Callophyllis hombroniana (Kallymeniaceae): theta-carrageenan together with minor components including up to 10% pyruvylation, and 4-linked Dand Lgalactose; Gracilaria truncata (Gracilariales) (two new samples): agar, agar with 45% 6-Omethylation on the 3-linked unit; Capreolia implexa (Gelidiales): agar with 10% 6-Omethylation on the 3-linked unit and 6% 2-Omethylation on the anhydrogalactosyl unit; Gymnogongrus torulosus: 1:1.15 kappa/iota-hybrid carrageenan with precursors. The C-13 NMR spectra of the two precursors are very similar to each other. The set of plants termed Gracilaria truncata may include more than one species.