These results alongside with those previously obtained by other authors suggest that this group of natural compounds might be promising for future antiviral

drug design. This study was supported by CNPq/MCT/Brazil (grant number 470235/2009-8). J.W. Bertol, C.M.O. Simões, F.C. Braga, R.M. Pádua and C.R.M. Barardi are grateful to CNPq for their research fellowships, as well as C. Rigotto thanks to CAPES/MEC/Brazil for her postdoc fellowship. “
“Herpes click here Simplex Virus types 1 and 2 (HSV-1 and HSV-2) are human neurotropic viruses usually associated with infections of the skin and mucosae of different locations, most commonly the oral and genital regions. Although infections are often subclinical, HSV can cause mild to severe diseases, especially in neonates and immunocompromised individuals. Currently, there is no cure for find more the persistent infection, and prolonged therapy with the available antiherpes drugs has induced the emergence of drug-resistant virus strains.

Moreover, HSV has been described as a risk factor for HIV infection (Roizman et al., 2007). This scenario has triggered the search for new antiherpetic agents, especially those with mechanisms of action different from that of nucleoside analogs, the major class of antiviral agents used for the management of HSV infections. Besides, a treatment based on the combination of different antiviral agents can be considered a promising approach to increase antiviral selectivity while simultaneously enabling the reduction of the Glutamate dehydrogenase active concentrations of the drugs (Chou, 2006). Many synthetic or naturally occurring sulfated polysaccharides from different species of marine algae, bacteria, fungi, and animals have been previously shown to have antiviral activity against human and animal viruses (Ghosh et al., 2009). In the case of fungi, cell wall polysaccharides have been chemically modified to increase their solubility and enhance their biological activities (Liu et al., 2010), including their antiviral action (Zhang et al., 2004). The pharmacological effects of Agaricus brasiliensis,

a Basidiomycete fungus native to the Brazilian Atlantic forest region, have been mainly related to the presence of polysaccharides and protein–polysaccharide complexes ( Firenzuoli et al., 2008). Concerning its previous antiviral evaluation, Sorimachi et al. (2001) showed that the ethanolic fractions of A. brasiliensis mycelium and fruiting bodies inhibited HSV, poliovirus, and Western equine encephalitis virus replication. The inhibition of HSV-1 and herpes bovine virus by an aqueous extract of A. brasiliensis fruiting bodies was also demonstrated by Bruggemann et al. (2006). Additionally, both aqueous and ethanolic fruiting bodies extracts and an isolated polysaccharide from this species displayed antiviral activity against poliovirus 1, as reported by Faccin et al. (2007).