Polysaccharides from Gracilaria corticata: Sulfation, chemical characterization and anti-HSV activities

In this study, we have analyzed water-extracted polysaccharides of Gracilaria corticata. The water extract (WE), a galactan-containing sub-fraction (F3) and their hyper sulfated derivatives (WES1, WES2, F3S1 and F3S2) had anti-HSV activity with inhibitory concentration 50% (IC50) from 1.1 to 27.4 μg/ml. Sub-fraction F3, which has a molecular mass of 30 kDa, consists of a backbone of β-(1 → 3) and α-(1 → 4)-linked-galactopyranosyl residues. This linear galactan contained Gal2Xyl1, Gal2AnGal2, Gal4 and Me-Gal3AnGal2 as oligomeric building subunits. Sulfate group was located at C-4 of (1 → 3)-linked galactopyranosyl residues of the native galactan, and appeared to be very important for the anti-herpetic activity.