Carrageenans from chilean samples of Stenogramme interrupta (Phyllophoraceae): structural analysis and biological activity

Carrageenans extracted from cystocarpic and tetrasporic Stenogramme interru pta were analysed by chemical and spectroscopic methods. The carrageenan fr om cystocarpic plants is composed predominantly of 0.5 M KCl-insoluble and 1 M KCl-soluble fractions. The insoluble fraction contained iota-carrageena n as the major component with alpha-carrageenan and pyruvated carrageenan a s minor components. The soluble fraction is highly heterogeneous and did no t contain the precursors mu- and nu-carrageenans. The polysaccharide from t etrasporic plants is composed of xi- and lambda-carrageenans, and low sulfa ted galactans. It is soluble in KCl and partly cyclized by alkaline treatme nt. The antiviral and anticoagulant properties of the insoluble polysacchar ide fraction from cystocarpic S. interrupta and the polysaccharide from tet rasporic S. interrupta are reported the results of which suggest promising antiherpetic activity. (C) 2000 Elsevier Science Ltd. All rights reserved.