Structural elucidation and antitumor activity of a fructan from Cyathula officinalis Kuan

A fructan named CoPS3 was isolated from Cyathula officinalis Kuan. The structure of CoPS3 was determined by methylation, by the reductive-cleavage method combined with GC-MS analysis, and both 1D and 2D 1H and 13C NMR spectroscopy. These results show that CoPS3 is a graminans-type fructan that is comprised of a beta-D-fructofuranosyl backbone having residues linked (2-->1)- and (2-->6) with branches and an alpha-D-glucopyranose residue on the nonreducing end of the fructan chain. Each branch is terminated by a beta-D-Fruf residue. Bioassay showed that it could inhibit growth of Lewis pulmonary carcinoma implanted in mice.