BackgroundLentinula edodes, known as shiitake, has been utilized as food, as well as, in popular medicine, moreover, compounds isolated from its mycelium and fruiting body have shown several therapeutic properties. The aim of this study was to determine the antiviral activity of aqueous (AqE) and ethanol (EtOHE) extracts and polysaccharide (LeP) from Lentinula edodes in the replication of poliovirus type 1 (PV-1) and bovine herpes virus type 1 (BoHV-1).MethodsThe time-of-addition assay was performed at the times -2, -1, 0, 1 and 2 h of the infection. The virucidal activity and the inhibition of viral adsorption were also evaluated. Plaque assay was used to monitor antiviral activity throughout.ResultsThe AqE and LeP were more effective when added at 0 h of infection, however, EtOHE was more effective at the times 1 h and 2 h of the infection. AqE, EtOHE and LeP showed low virucidal activity, and the inhibition of viral adsorption was not significant.ConclusionsThe results allowed us to conclude that AqE, EtOHE and LeP act on the initial processes of the replication of both strains of virus.

Works on antiviral compounds date back to the 1950s, but for several reasons, only a couple of drugs were approved for clinical use about a decade later. To date, many antiviral drugs have been developed after extensive research and demanding trials, some of them with selective mechanisms against viral replication. 1) Although the primary focus has been on synthetic products, the number of natural compounds with antiviral action for different DNA and RNA viruses that are being studied is increasing. Many phytochemical compounds are being investigated based primarily on ethnopharmacologic knowledge and have been considered of great importance in new drug development. 2)Extracts of many plant species, such as Tridax procumbens, Carissa carandas, Mallotus philippensis, Streblus aspere, Terminatta alata, Macaranga pustulata, Sibbaldia micropetala, Hypericum cordifolium, H. uralum and Maesa macrophylla were found to be active against the replication of poliovirus and herpes simplex-1 (HSV-1), with some of them also active against Sindbis virus.3,4) A methanol extract of Annona muricata and aqueous extract of Petunia myctaginiflora were shown to inhibit HSV-1 cytopathic effect in Vero cells, at a concentration of 1 mg/ml. 5)Methanol extracts of Indonesian plants were tested for cytotoxicity and antiviral activity (HSV-1 and poliovirus) in murine and human cell lines. Piper aduncum was found to be active on poliovirus, while Elytranthe tubaeflora and Melastoma malabathricum inhibited HSV-1. 6) Dengue virus was inhibited by an aqueous extract of Azadirachta indica when assayed in mice. 7)Stem bark of Stryphnodendron adstringens (MART.) COV-ILLE, Leguminosae, popularly known in our country as barbatimão, has been empirically used as wound healing, astringent, antimicrobial, antifungal, antidiarrheal and hypoglycemic agents.8) Similarly, Guazuma ulmifolia LAM., Sterculiaceae, popularly known as mutamba, is known to have medicinal properties, such as wound healing, antiulcerogenic, hypoglycemic and antimicrobial. 9) G. ulmifolia aqueous and methanol fractions were found to inhibit HSV-1 replication, respectively, by 16.8% and 4.5%, at a concentration of 100 mg/ml, in a study of various plants. Those showing antiviral activity in vitro were also tested in HSV-1 infected mice. Melaleuca leucadendron and Nephelium lappaceum reduced mortality and delayed the appearance of lesions. 10)Among plant antiviral compounds, anthraquinones found in Aloe barbadensis inhibited HSV-1, HSV-2, varicela-zoster, pseudorabies and influenza.11) Stevia rebaudiana polysaccharides inhibited adsorption of human rotavirus in MA-104 cells.12) Flavonoids present in Troillius chinensis flowers also inhibited parainfluenza in HEp-2 cells.13) Quassia africana extracts were tested for HSV-1, coxsackie B2, polio-1, measles, Semliki Forest virus and vesicular stomatitis virus, where simalikalactone D was found to be responsible for the antiviral effect.14) Anagyrine, oxymatrine, sophoranol, wogonin and oroxylin found in Sophora flavescens and Scutellaria b...

Agaricus brasiliensis is an edible mushroom, traditionally used for the treatment of several diseases. In this paper, a polysaccharide (PLS) from A. brasiliensis, its carboxymethylated (CPLS) and sulfated (SPLS) derivatives, as well as, fractions (F1-F3) obtained from the PLS were investigated for their effect in the replication of herpes simplex virus and bovine herpes virus in HEp-2 cell cultures. The PLS, SPLS and F3 inhibited both virus strains similarly, in a dose-dependent curve. F1, F2 and CPLS did not show significant effect even at higher concentrations. All the compounds showed neither virucidal or viral adsorption inhibition activities nor effect when cells were treated prior to infection. Our study demonstrated that the extracts of A. brasiliensis, can be promising for future antiviral drug design and its biotechnological production is economically feasible.

Herpesvirus and poliovirus are responsible for important diseases in human and animal. Trichilia catigua a Brazilian native plant known as catiguá has several medicinal properties among them antimicrobial for bacteria and protozoa, however, no antiviral activity has been reported yet. This study evaluated the antiviral activity of the crude extract (CE) and aqueous and ethyl acetate fractions (AF, EAF) obtained from T. catigua in the replication of the Herpes simplex virus (HSV-1), bovine herpesvirus (BoHV-1) and poliovirus (PV-1). The cytotoxicity was analyzed by MTT assay and the antiviral effect was determined by the addition of extracts (0.25 to 100.0 μg/ml), before (-2h and -1h), during (Oh) and after (1h and 2h) the viral infection, by plaque reduction assay, in HEp-2 cell culture. The virucidal activity and inhibition of viral adsorption were also evaluated. In addition, the combination index (CI) with Acyclovir (ACV - reference drug) was determined for HSV-1. CE, AF and EAF showed a low toxicity (CC(50) >400 µg/ml) and low inhibitory concentration (IC50), ranging from 2.44-34.25 µg/ml for herpesvirus and 0.67 to 1.8 µg/ml for PV-1, associated with high selectivity index. The tested compounds showed high virucidal effect and high ability to inhibit viral adsorption, for all virus. The CI demonstrated a synergic effect (CI<1) for AF and EAF comparatively to acyclovir (ACV). Our study demonstrated that the extract and fractions of T. catigua is promising for future antiviral drug design with economically feasible production.