Virucidal Activity of Gold Nanoparticles Synthesized by Green Chemistry Using Garlic Extract.

Measles virus (MeV) is a paramyxovirus that infects humans, principally children. Despite the existence of an effective and safe vaccine, the number of cases of measles has increased due to lack of vaccination coverage. The World Health Organization (WHO) reports that the number of cases worldwide multiplied fourfold between January and March 2019, to 112,000. Today, there is no treatment available for MeV. In recent years, it has been demonstrated that natural extracts (herbal or algal) with antiviral activity can also work as reducing agents that, in combination with nanotechnology, offer an innovative option to counteract viral infections. Here, we synthetized and evaluated the antiviral activity of gold nanoparticles using garlic extract (Allium sativa) as a reducing agent (AuNPs-As). These nanoparticles actively inhibited MeV replication in Vero cells at a 50% effective concentration (EC50) of 8.829 µg/mL, and the selectivity index (SI) obtained was 16.05. AuNPs-As likely inhibit viral infection by blocking viral particles directly, showing a potent virucidal effect. Gold nanoparticles may be useful as a promising strategy for treating and controlling the infection of MeV and other related enveloped viruses.

Inhibitory Effect of Cuphea aequipetala Extracts on Murine B16F10 Melanoma In Vitro and In Vivo.

Cuphea aequipetala (C. aequipetala) has been used in Mexican traditional medicine since prehispanic times to treat tumors. In this paper, we evaluated the antiproliferative and apoptotic effect of the methanolic and aqueous extracts of C. aequipetala on several cancer cell lines including the B16F10 cell line of murine melanoma and carried a murine model assay. In vitro assay analyzed the effect in the cellular cycle and several indicators of apoptosis, such as the caspase-3 activity, DNA fragmentation, phosphatidylserine exposure (Annexin-V), and induction of cell membrane permeabilization (propidium iodide) in the B16F10 cells. In vivo, groups of C57BL/6 female mice were subcutaneously injected with 5x105 B16F10 cells and treated with 25 mg/mL of C. aequipetala extracts via oral. Aqueous and methanolic extracts showed a cytotoxic effect in MCF-7, HepG2, and B16F10 cell lines. The methanolic extract showed more antiproliferative effect with less concentration, and for this reason, the in vitro experiments were only continued with it. This extract was able to induce accumulation of cells on G1 phase of the cell cycle; moreover, it was able to induce DNA fragmentation and increase the activity of caspase-3 in B16F10 cells. On the other hand, in the murine model of melanoma, the aqueous extract showed a greater reduction of tumor size in comparison with the methanolic extract, showing an 80% reduction versus one of around 31%, both compared with the untreated control, indicating a better antitumor effect of C. aequipetala aqueous extract via oral administration. In conclusion, the in vitro data showed that both C. aequipetala extracts were able to induce cytotoxicity through the apoptosis pathway in B16F10 cells, and in vivo, the oral administration of aqueous extract reduces the melanoma tumoral mass, suggesting an important antitumoral effect and the perspective to search for effector molecules involved in it.

Virucidal and Synergistic Activity of Polyphenol-Rich Extracts of Seaweeds against Measles Virus.

Although preventable by vaccination, Measles still causes thousands of deaths among young children worldwide. The discovery of new antivirals is a good approach to control new outbreaks that cause such death. In this study, we tested the antiviral activity against Measles virus (MeV) of Polyphenol-rich extracts (PPs) coming from five seaweeds collected and cultivated in Mexico. An MTT assay was performed to determine cytotoxicity effect, and antiviral activity was measured by syncytia reduction assay and confirmed by qPCR. PPs from Ecklonia arborea (formerly Eisenia arborea, Phaeophyceae) and Solieria filiformis (Rhodophyta) showed the highest Selectivity Index (SI), >3750 and >576.9 respectively. Both PPs extracts were selected to the subsequent experiments owing to their high efficacy and low cytotoxicity compared with ribavirin (SI of 11.57). The combinational effect of PPs with sulphated polysaccharides (SPs) and ribavirin were calculated by using Compusyn software. Synergistic activity was observed by combining both PPs with low concentrations of Solieria filiformis SPs (0.01 µg/mL). The antiviral activity of the best combinations was confirmed by qPCR. Virucidal assay, time of addition, and viral penetration evaluations suggested that PPs act mainly by inactivating the viral particle. To our knowledge, this is the first report of the virucidal effect of Polyphenol-rich extracts of seaweeds.

Synergistic Effects of Sulfated Polysaccharides from Mexican Seaweeds against Measles Virus.

Sulfated polysaccharides (SPs) extracted from five seaweed samples collected or cultivated in Mexico (Macrocystis pyrifera, Eisenia arborea, Pelvetia compressa, Ulva intestinalis, and Solieria filiformis) were tested in this study in order to evaluate their effect on measles virus in vitro. All polysaccharides showed antiviral activity (as measured by the reduction of syncytia formation) and low cytotoxicity (MTT assay) at inhibitory concentrations. SPs from Eisenia arborea and Solieria filiformis showed the highest antiviral activities (confirmed by qPCR) and were selected to determine their combined effect. Their synergistic effect was observed at low concentrations (0.0274 µg/mL and 0.011 µg/mL of E. arborea and S. filiformis SPs, resp.), which exhibited by far a higher inhibitory effect (96% syncytia reduction) in comparison to the individual SP effects (50% inhibition with 0.275 µg/mL and 0.985 µg/mL of E. arborea and S. filiformis, resp.). Time of addition experiments and viral penetration assays suggest that best activities of these SPs occur at different stages of infection. The synergistic effect would allow reducing the treatment dose and toxicity and minimizing or delaying the induction of antiviral resistance; sulfated polysaccharides of the tested seaweed species thus appear as promising candidates for the development of natural antiviral agents.