Sulfated mannans from the red seaweed Nemalion helminthoides of the South Atlantic

MERCEDES PÉREZ RECALDE; MIGUEL D. NOSEDA; CARLOS A. PUJOL; MARÍA J. CARLUCCI; NARÍA C. MATULEWICZ

PHYTOCHEMISTRY

Elsevier Ltd.

Lugar: Oxford, Gran Bretaña; Año: 2009 vol. 70 p. 1062 - 1068

0031-9422

Nemalion helminthoides, collected in the Argentine South Atlantic coast, was extracted with hot water and the crude product was fractionated with cetrimide. The complexed material was subjected to fractional solubilization in solutions of increasing sodium chloride concentration and seven fractions were separated and analyzed. Structural analysis of the main fractions, those soluble in 3.0 and 4,0 M NaCl (yields, 21.0 and 13.8%, respectively) and that insoluble in 4.0 M NaCl (yield, 20.0%), indicated that this seaweed biosynthesizes (1,3)-linked alpha-D-mannans 4- and 6-sulfated. Three mannan fractions comprising considerable amounts of xylose were also isolated but in very low total yield (2.0%). The fractions soluble in 3.0 and 4.0 M NaCl showed low antiherpetic activity but the activity was considerable for the fraction soluble in 2.0 M NaCl (yield, 0.5%) which contained single stubs of beta-D-xylose. A xylan, soluble in cetrimide solution, containing (1,3, 1,4)-linked beta-D-xylose residues was also isolated in minor amount.