A nearly idealized 6'-O-methylated iota-carrageenan from the Australian red alga Clavidonium ovatum(Acrotylaceae,Gigartinales)

摘要

The polysaccharides extracted from Clavidonium ovatum were studied by a combination of compositional assays,reductive partial hydrolysis,linkage analysis,Fourier Transform infrared(FTIR)spectroscopy,and ~(13)C,~1H,and ~(13)C/~1H hetero-nuclear multiple quantum correlation(HMQC)two-dimensional nuclear magnetic resonance(NMR)spectroscopy.The chemical and spectroscopic data showed that the alkali-modified C.ovatum polysaccharides are composed of a nearly idealized repeating unit of 6'-O-methylcarrabiose 2,4'-disulfate(the repeating unit of 6'-O-methylated i-carrageenan),although some minor components were also present.The C ovatum galactans are the most highly methylated carrageenans reported.