Herpes simplex virus types 1 and 2 (HSV-1, HSV-2) infections are common, but can cause serious infections in neonates and the immunocompromised. Drugs currently used to treat cutaneous or genital HSV infections are effective in limiting disease, but the emergence of drug resistant viruses in immunocompromised individuals can be problematic. While the prophylactic oral treatment with antiviral drugs can reduce virus shedding and transmission, there is a need for topical microbicides that have the potential to limit sexual transmission of the virus. Previous reports demonstrated the antiviral activity of complex sulfated polysaccharides extracted from various species of marine algae and suggested that they interfered with the attachment of virions to host cells. Here, we evaluated the antiviral activity of extracts from Undaria pinnatifida, Splachnidium rugosum, Gigartina atropurpurea, and Plocamium cartilagineum against HSV-1 and HSV-2. These extracts exhibited good activity when added during the first hour of viral infection, but were ineffective if added later. Plaque reduction assays, when the extracts were added prior to viral inoculation, yielded EC50 values that ranged from 1.5-36 μg/ml for HSV-1 and 0.7-6.6 μg/ml for HSV-2. None of the extracts exhibited significant toxicity in a neutral red uptake assay (IC50 >100 μg/ml). Subsequent assays showed that the compounds had potent virucidal activity and were active at very low concentrations. We conclude that these extracts are nontoxic and effective virucidal agents that warrant further investigation to examine their potential role in the prevention of HSV infections of humans.

The galactofucan sulfate extract (GFS) obtained from the brown seaweed Undaria pinnatifida by extraction with dilute acid is a potent inhibitor of the herpes viruses HSV-1, HSV-2 and HCMV, with IC 50 values determined in vitro of 1.1, 0.2 and 0.5 μgmL −1 , respectively. Fractionation of GFS by anion exchange chromatography gave three fractions which differed in their uronic acid and sulfate contents and in their antiviral activity, as well as in having somewhat reduced molecular weights compared to GFS. The low uronic acid/high sulfate fraction (F2M), obtained in 63% yield, had similar molar proportions of galactopyranosyl and fucopyranosyl residues, little associated protein and was equipotent with GFS (IC 50 values of 1.1, 0.1 and 0.5 μgmL −1 , respectively). The high uronic acid/low sulfate fraction (F1M), obtained in 18% yield, had a much lower proportion of galactopyranosyl residues and was less active (IC 50 values of 4.6, 1.0 and 4.0 μgmL −1 , respectively). The minor low uronic acid/high sulfate fraction (F4M) had a significant amount of associated protein and was also less active (IC 50 = 3.1, 1.0 and 2.0 μgmL −1 , respectively). The structure of the major fraction (F2M) was shown to be complex by glycosyl linkage analysis before and after solvolytic desulfation, with many component sugar residues being identified, although 3-linked fucopyranosyl 2,4-disulfate residues were a prominent feature.

No abstract

No abstract

No abstract