Chloroquinolone Carboxamide Derivatives as New Anti-HSV-1 Promising Drugs

BACKGROUND

Since the emergence of HSV resistant strains, new antiviral agents have emerged and still are urgently needed, especially those with alternative targets.

OBJECTIVE

In this work, we evaluated new quinolone derivatives as anti-HSV.

METHODS

For this study, cells were infected and treated with different components to evaluate the profile of HSV replication in vitro. In addition, studies were performed to determine the pharmacokinetic toxicity and profile of the compound.

RESULTS

Indeed the EC₅₀ values of these promising molecules ranged between 8 μM and 32 μM. We have also showed that all compounds inhibited the expression of ICP27 viral proteins, which gives new insights in the search for new target for antiherpetic therapy. Chlorine in positions C6 and phosphonate in position C1 have shown to be important for viral inhibition. The chloroquinolone carboxamide derivatives fulfilled "Lipinsky Rule of Five" for good oral bioavailability and showed higher intestinal absorption and blood brain barrier penetration, as well as lower toxicity profile.

CONCLUSION

Although the inhibition activities of chloroquinolone carboxamide derivatives were lower than acyclovir, they showed different modes of action in comparison to the drugs currently available. These findings encourage us to continue pre-clinical studies for the development of new anti-HSV-1 agents.

Antiviral Potential of Naphthoquinones Derivatives Encapsulated within Liposomes

HSV infections, both type 1 and type 2, are among the most widespread viral diseases affecting people of all ages. Their symptoms could be mild, with cold sores up to 10 days of infection, blindness and encephalitis caused by HSV-1 affecting immunocompetent and immunosuppressed individuals. The severe effects derive from co-evolution with the host, resulting in immune evasion mechanisms, including latency and growing resistance to acyclovir and derivatives. An efficient alternative to controlling the spreading of HSV mutations is the exploitation of new drugs, and the possibility of enhancing their delivery through the encapsulation of drugs into nanoparticles, such as liposomes. In this work, liposomes were loaded with a series of 2-aminomethyl- 3-hydroxy-1,4-naphthoquinones derivatives with n-butyl (compound 1), benzyl (compound 2) and nitrobenzene (compound 3) substituents in the primary amine of naphthoquinone. They were previously identified to have significant inhibitory activity against HSV-1. All of the aminomethylnaphthoquinones derivatives encapsulated in the phosphatidylcholine liposomes were able to control the early and late phases of HSV-1 replication, especially those substituted with the benzyl (compound 2) and nitrobenzene (compound 3), which yields selective index values that are almost nine times more efficient than acyclovir. The growing interest of the industry in topical administration against HSV supports our choice of liposome as a drug carrier of aminomethylnaphthoquinones derivatives for formulations of in vivo pre-clinical assays.

Subchronic toxicity and anti-HSV-1 activity in experimental animal of dolabelladienetriol from the seaweed, Dictyota pfaffii

This study examined in rats the subchronic toxicity and anti- HSV-1activity after oral administration of dolabelladienetriol (D1), a diterpene isolated from the seaweed Dictyota pfaffii. In subchronic toxicity (SCT) tests, female rats received D1 by gavage 15 mg/kg/day (n = 5) for 50 days, and general behavior, death, hematological, biochemical and histological changes in the liver, kidney, stomach, and duodenum were determined. For the anti-HSV-1 activity, female mice were infected and treated orally with a dose of 20 mg/kg (n = 5) twice a day with D1 and any lesions in the skin were then recorded for 18 days. Dolabelladienetriol in SCT did not significantly change behavior, body weight, hematological or biochemical profiles. The liver and kidneys, however, showed some alterations in rats treated with D1, similar to those in rats treated with ACV, while the other tissues had no significant changes. The anti-HSV-1 activity of D1 had a similar efficacy to the ACV drug control in mice. Our results showed that D1 has potential commercial development as a new HSV-1drug.

Biogeochemical cycling in terrestrial ecosystems of the Caatinga Biome

The biogeochemical cycles of C, N, P and water, the impacts of land use in the stocks and flows of these elements and how they can affect the structure and functioning of Caatinga were reviewed. About half of this biome is still covered by native secondary vegetation. Soils are deficient in nutrients, especially N and P. Average concentrations of total soil P and C in the top layer (0-20 cm) are 196 mg kg-1 and 9.3 g kg-1, corresponding to C stocks around 23 Mg ha-1. Aboveground biomass of native vegetation varies from 30 to 50 Mg ha-1, and average root biomass from 3 to 12 Mg ha-1. Average annual productivities and biomass accumulation in different land use systems vary from 1 to 7 Mg ha-1 year-1. Biological atmospheric N2 fixation is estimated to vary from 3 to 11 kg N ha-1 year-1and 21 to 26 kg N ha-1 year-1 in mature and secondary Caatinga, respectively. The main processes responsible for nutrient and water losses are fire, soil erosion, runoff and harvest of crops and animal products. Projected climate changes in the future point to higher temperatures and rainfall decreases. In face of the high intrinsic variability, actions to increase sustainability should improve resilience and stability of the ecosystems. Land use systems based on perennial species, as opposed to annual species, may be more stable and resilient, thus more adequate to face future potential increases in climate variability. Long-term studies to investigate the potential of the native biodiversity or adapted exotic species to design sustainable land use systems should be encouraged.

Pressure-induced formation of inactive triple-shelled rotavirus particles is associated with changes in the spike protein Vp4

Rotaviruses are non-enveloped, triple-shelled particles that cause enteritis in animals and humans. The interactions among the different viral proteins located in the three concentric layers make the rotavirus particle an excellent model for physico-chemical and biological studies of viral assemblage. SA11-4S rotaviruses subjected to high pressure were inactivated by more than five log units. After pressure treatment, the particles were recovered with slight structural changes when compared to the control. Electron microscopy suggested subtle changes in the viral outer layer in some pressurised particles. Fluorescence spectroscopy showed that much more dramatic changes were produced by urea denaturation than by pressure. Based on the fluorescence spectrum, the genome resistance to ribonuclease, and the absence of changes in hydrodynamic properties, there was little or no disruption of the capsid under pressure. On the other hand, hemagglutination assays indicated that the main component affected by pressure was the spike protein VP4, thus accounting for changes in interaction with host cells and greatly reduced infectivity. The changes leading to inactivation did not cause removal of VP4 from the outer capsid, as verified by size-exclusion chromatography. Antibodies raised against pressurised material were as effective as antibodies raised against the intact virus, based on their neutralisation titre in plaque reduction assays, enzyme-linked immunosorbent assays and direct interaction with the particle, as measured by gel-filtration chromatography. Therefore, the new conformation of the pressurised particle did not result in loss of immunogenicity. We propose that pressure alters the receptor-binding protein VP4 by triggering changes similar to those produced when the virus interacts with target cells. As the changes in VP4 conformation caused by pressure occur prior to virus exposure to target cells, it leads to non-infectious particles and may lead to the exposure of previously occult epitopes, important for vaccine development.

Effects of hydrostatic pressure on the Leptospira interrogans: high immunogenicity of the pressure-inactivated serovar hardjo

The Hardjoprajitno strain of Leptospira interrogans serovar hardjo was subjected to different hydrostatic pressures. Complete inactivation occurred when the leptospires were treated with 2 kbar for 60 min. Electron microscopy showed dislocation of the outer membrane, partial loss of the helical shape and extrusion of the axial filament from the cytoplasmic cylinder of the pressurized leptospires. When the pressure-treated leptospires were inoculated into rabbits they were highly immunogenic. The sera of these animals presented a titer of 2048 in the microscopic serum agglutination reaction. Fluorescence measurements indicated that the action of pressure on the leptospires might have resulted from perturbation on membrane protein components, permitting the binding of the fluorescent probe bis (8-anilinonaphthalene-1-sulfonate) (Bis-ANS). This is the first report of the use of hydrostatic pressure to inactivate pathogenic bacteria with the potential to lead to a vaccine.