Inhibition by Marine Algae of Chikungunya Virus Isolated From Patients in a Recent Disease Outbreak in Rio de Janeiro.

Chikungunya virus (CHIKV) infection is one of the most challenging re-emergent diseases caused by a virus, and with no specific antiviral treatment it has now become a major public health concern. In this investigation, 25 blood samples were collected from patients with characteristic CHIKV symptoms and submitted to a virus isolation protocol, which detected 3 CHIKV isolates. These samples were evaluated by sequencing for the characterization of the strains and any homology to viruses circulating in Brazil during a recent outbreak. These viruses were used for the development of antiviral assays. Subsequently, the inhibitory effects of seaweed extracts on CHIKV replication were studied. The marine species of algae tested were Bryothamnion triquetrum, Caulerpa racemosa, Laurencia dendroidea, Osmundaria obtusiloba, Ulva fasciata, and Kappaphycus alvarezii, all of which are found in different countries including Brazil. The results revealed high levels of CHIKV inhibition, including extracts of O. obtusiloba with inhibition values of 1.25 µg/mL and a selectivity index of 420. Viral inhibition was dependent on the time of addition of extract of O. obtusiloba to the infected cells, with the optimal inhibition occurring up to 16 h after infection. Neuron evaluations with O. obtusiloba were performed and demonstrated low toxicity, and in infected neurons we observed high inhibitory activity in a dose-dependent manner. These results indicate that the algal extracts may be promising novel candidates for the development of therapeutic agents against CHIKV infections.

Early Evidence for Zika Virus Circulation among Aedes aegypti Mosquitoes, Rio de Janeiro, Brazil.

During 2014-2016, we conducted mosquito-based Zika virus surveillance in Rio de Janeiro, Brazil. Results suggest that Zika virus was probably introduced into the area during May-November 2013 via multiple in-country sources. Furthermore, our results strengthen the hypothesis that Zika virus in the Americas originated in Brazil during October 2012-May 2013.

Antiherpetic activity of an Agaricus brasiliensis polysaccharide, its sulfated derivative and fractions.

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.

The in vitro antiviral property of Azadirachta indica polysaccharides for poliovirus.

ETHNOPHARMACOLOGICAL RELEVANCE: Azadirachta indica A. Juss, popularly known as neem, has been extensively used in Ayurvedic medicine by Indian population for over 2000 years. It is used traditionally for the healing of various diseases. Natural products and their derivatives provide an excellent source for new anti-viral drugs. AIM OF THE STUDY: The present study aims at evaluating the activity of two polysaccharides (P1 and P2) isolated from the leaves of Azadirachta indica and their chemical sulfated derivatives (P1S and P2S) against poliovirus type 1 (PV-1). MATERIALS AND METHODS: The cytotoxicity of the compounds was analyzed by MTT and the antiviral effect was determined by plaque reduction assay in different protocols. RESULTS: The polysaccharides did not show any cytotoxic effects on HEp-2 cells at the highest tested concentration (200 µg/ml) and exhibited significant antiviral activity with inhibitory concentrations (IC50) of 80 µg/ml, 37.5 µg/ml, 77.5 µg/ml, and 12.1 µg/ml for P1, P1S, P2 and P2S, respectively, and the selectivity indexes (SI) ranged from 18 to 131.9. The compounds demonstrated better inhibitory effect when added concomitantly with the virus infection with a dose-dependent curve inhibition. Lesser effect was observed when the compounds were added after viral infection and the least effect at pre-treatment. CONCLUSIONS: We suggested that the polysaccharides obtained from Azadirachta indica act against PV-1 by inhibiting the initial stage of viral replication. Importantly, original polysaccharides showed better virucidal effect than their sulfated derivatives at all tested concentrations. This study provides a scientific basis for the past and present ethnomedical uses of this plant.

Polysaccharide and extracts from Lentinula edodes: structural features and antiviral activity.

BACKGROUND: Lentinula 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). METHODS: The 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. RESULTS: The 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. CONCLUSIONS: The results allowed us to conclude that AqE, EtOHE and LeP act on the initial processes of the replication of both strains of virus.