Structural analysis of a sulfated polysaccharidic fraction obtained from the coenocytic green seaweed Caulerpa cupressoides var. lycopodium

Resumo

Researches on structural chemistry of sulfated polysaccharides (SPs) have been mainly focused on red and brown algae. Caulerpa cupressoides var. lycopodium (Chlorophyta) contains three SPs fractions (Cc-SP₁, Cc-SP₂ and Cc-SP₃). Cc-SP₁ and Cc-SP₂ had anticoagulant (in vitro) and anti- and prothrombotic, antinociceptive and/or anti-inflammatory (in vivo) effects. However, their structural features have not yet been investigated. This study analyzed the chemical composition, elemental microanalysis and structural features by infrared (IR) and nuclear magnetic resonance (¹H NMR) spectroscopy of Cc-SPs. Fractionation of SPs by DEAE-cellulose yielded Cc-SP₁, Cc-SP₂ and CcSP₃ containing differences among the relative proportions of sulfate (14.67-26.72%), total sugars (34.92-49.73%) and uronic acid (7.15-7.22%). Carbon (21.76-29.62%), sulfate (2.16-4.55%), nitrogen (0.85-1.57%) and hydrogen (4.57-5.86%) contents were obtained using a CHN equipment. Data from IR indicated occurrence of sulfate ester, galactose-6-sulfate, uronic acid and glycoside linkages. For ¹H NMR spectrum of the soluble Cc-SP1 fraction, it was mainly found β-galactopyranose residues and CH₃ group. The results showed that Cc-SPs fractions have some structural features similar to others studied Caulerpaceae SPs.