8-Hydroxyquinoline 1,2,3-triazole derivatives with promising and selective antifungal activity.

Fungal infections that affect humans and plants have increased significantly in recent decades. However, these pathogens are still neglected when compared to other infectious agents. Due to the high prevalence of these infections, the need for new molecules with antifungal potential is recognized, as pathogenic species are developing resistance to the main drugs available. This work reports the design and synthesis of 1,2,3-triazole derivatives of 8-hydroxyquinoline, as well as the determination of their activities against a panel of fungal species: Candida spp., Trichosporon asahii, Magnusiomyces capitatus, Microsporum spp., Trichophyton spp. and Fusarium spp. The triazoles 5-(4-phenyl-1H-1,2,3-triazol-1-yl)quinolin-8-ol (12) and 5-(4-(cyclohex-1-en-1-yl)-1H-1,2,3-triazol-1-yl)quinolin-8-ol (16) were more promising, presenting minimum inhibitory concentration (MIC) values between 1-16 µg/ml for yeast and 2-4 µg/ml for dermatophytes. However, no relevant anti-Fusarium spp. activity was observed. In the time-kill assays with Microsporum canis, 12 and 16 presented time-dependent fungicide profile at 96 h and 120 h in all evaluated concentrations, respectively. For Candida guilliermondii, 12 was fungicidal at all concentrations at 6 h and 16 exhibited a predominantly fungistatic profile. Both 12 and 16 presented low leukocyte toxicity at 4 µg/ml and the cell viability was close to 100% after the treatment with 12 at all tested concentrations. The sorbitol assay combined with SEM suggest that damages on the fungal cell wall could be involved in the activity of these derivatives. Given the good results obtained with this series, scaffold 4-(cycloalkenyl or phenyl)-5-triazol-8-hydroxyquinoline appears to be a potential pharmacophore for exploration in the development of new antifungal agents.

Low Dose of Nanocapsules Containing Eucalyptus Oil Has Beneficial Repellent Effect Against Horn Fly (Diptera: Muscidae).

For the first time, the repellent and insecticidal effects of eucalypt essential oil (Eucalyptus globulus) in its free form and associated with different nanostructures (nanoemulsion and nanocapsules) were investigated against Musca domestica (Diptera: Muscidae) and Haemotobia irritans (Diptera: Muscidae) flies. Specimens of M. domestica were collected, separated into groups (n = 10), treated with aspersion of essential oil of eucalypt in its free (1, 5, and 10%) and nanostructured (nanoemulsion or nanoencapsulated at 1, 3, and 5%, respectively) forms. The determination of the insecticidal effect was performed by counting the number of dead flies at intervals of 30, 60, 120, 360 and 750 min after oil aspersion. E. globulus essential oil showed insecticidal effect against M. domestica at concentrations of 1 and 5%. Eucalypt essential oil (10%) caused 100% mortality of M. domestica after 750 min of the treatment. Nanocapsules (3 and 5%) showed efficacy by reducing the number of flies. On the other hand, nanoemulsion did not show insecticidal effect. The repellent action of E. globulus concentrations of 5% was tested against H. irritans on naturally infested cows. The repellent action against H. irritans was verified soon after pulverization. After 24 h, a significant reduction on horn flies' population (83.33 and 66.66%) was observed using free and nanoencapsulated forms tested, respectively. E. globulus essential oil demonstrated insecticidal and repellent effects against M. domestica and H. irritans flies.

Insecticidal and repellent effect of cinnamon oil on flies associated with livestock / Efecto insecticida y repelente del aceite de canela sobre moscas asociadas con el ganado

Abstract Objective. Due to the increased parasitic resistance, there is a need to explore alternative insecticides, including natural products, such essential oils. In this sense, the aim of this study was to evaluate, for the first time, the insecticidal and repellent effect of Cinnamomun zeylanicum (free and nanoemulsion forms) in vitro and in vivo. Materials and methods. For that, the insecticidal effect of the free form was tested at 1.0, 5.0 and 10%, while the nanoemulsion form was tested at 0.5, 1.0 and 5.0% against adult house flies, Musca domestica. For validation of the test, the flies were sprayed with the diluent (water and triton 10%) and with blank nanoemulsion (without C. zeylanicum essential oil). Moreover, in vivo test was performed using cows naturally infested with Haemotobia irritans. Results. The results demonstrated that cinnamon oil (10%) and the nanoemulsion (5%) were 100% effective against M. domestica after 90 minutes of exposure. The repellent effect was tested in vivo using 5% of cinnamon oil on Holstein cows naturally infested by Haemotobia irritans. The flies were counted at 0, 1, 2, 3, 9 and 24 h after cinnamon oil treatment. It was verified significant decrease (p<0.05) in the number of flies on cows sprayed with cinnamon in all times. Conclusions. Based on these results, C. zeylanicum showed insecticidal effect (in vitro) against domestic flies and repellent effect (in vivo) against the horn fly.

Resumen Objetivo. Debido a la mayor resistencia parásita, hay una necesidad de explorar insecticidas alternativos, incluidos los productos naturales, tales como aceites esenciales. En este sentido, el objetivo de este estudio fue evaluar, para el primer equipo, el efecto insecticida y repelente de Cinnamomum zeylanicum (formas libres y nanoemulsión) in vitro e in vivo. Materiales y métodos. Para ello, el efecto insecticida de la forma libre se ensayó a 1.0, 5.0 y 10%, mientras que la forma nanoemulsión se ensayó a 0.5, 1.0 y 5.0% frente a las moscas domésticas adultas, Musca domestica. Para la validación de la prueba, las moscas fueron rociados con el diluyente (agua y triton 10%) y con nanoemulsión en blanco (sin aceite esencial de C. zeylanicum). También, fueron realizados pruebas in vivo usando vacas naturalmente infestadas con Haemotobia irritans. Resultados. Los resultados demostraron que el aceite de canela (10%) y la nanoemulsión (5%) fueron 100% eficaz contra M. domestica después de 90 minutos de exposición. El efecto repelente se ensayó in vivo usando 5% de aceite de canela en vacas Holstein, naturalmente infestados por Haemotobia irritans. Se contaron las moscas a las 0, 1, 2, 3, 9 y 24 h después del tratamiento el aceite de canela. Se verificó disminución significativa (p<0.05) en el número de moscas vivas de vacas canela pulverizada en todo momento. Conclusiones. En base a estos resultados, C. zeylanicum mostró un efecto insecticida (in vitro) contra las moscas domésticas y efecto repelente (in vivo) contra la mosca de los cuernos.

Nanostructured cinnamon oil has the potential to control Rhipicephalus microplus ticks on cattle.

The aim of this study was to evaluate the capacity of pure and nanostructured cinnamon oil to control the infestation and reproductive efficiency of Rhipicephalus microplus on dairy cows. In vitro (stage I)-engorged female ticks were immersed in concentrations of 1.0, 5.0 and 10% of cinnamon oil on its pure form, and 0.5, 1.0, and 5.0% of the nanostructured form. 10% cinnamon oil (pure form) showed 100% efficacy, whereas concentrations of 1 and 5% were 62 and 97% efficacious, respectively. Nanocapsules and nanoemulsions containing cinnamon oil at 5% showed 95 and 97% efficacy, respectively. In vivo (stage II)-16 naturally tick-infested cows were divided into four groups of four animals each: Group A was composed of dairy cows sprayed with Triton (control); Group B was composed of dairy cows sprayed with cinnamon oil in its pure form (5%), whereas groups C and D were composed of dairy cows sprayed with nanocapsules and nanoemulsions, respectively, containing cinnamon oil at 0.5%. The ticks on each animal were counted on days 0, 1, 4 and 20 after spraying. Animals sprayed with pure and nanoencapsulated cinnamon oil carried significantly fewer ticks on days 1 and 4 post-treatment and were free of ticks on day 20 post-treatment. Ticks collected from these dairy cows (24 h after application) had impaired oviposition and larval inhibition, resulting in 90.5 and 100% efficacy when using pure and nanocapsules, respectively. In conclusion, the pure and nanostructured forms of cinnamon oil interfered with tick reproduction, whereas a significant acaricidal effect was found when applied onto cattle.

Influence of Melaleuca alternifolia oil nanoparticles on aspects of Pseudomonas aeruginosa biofilm.

The Pseudomonas aeruginosa is a gram-negative bacillus and frequent cause of infection. This microorganism is resistant intrinsically to various drugs. The P. aeruginosa is associated with the biofilm formation, which causes worsen the prognosis and difficulty the treatment. The influence of Melaleuca alternifolia oil or "tree of tee" oil (TTO) and TTO nanoparticles on adhesion of P. aeruginosa in buccal epithelial cells was investigated. Also was determined the antimicrobial and antibiofilm activity against this microorganism. The TTO nanoparticles were produced by deposition of preformed polymer and the physic-chemical properties of nanoparticles were measured by electrophoresis and dynamic light scattering. The characterization of nanoparticle showed acceptable values for diameter and zeta potential. The evaluation of antimicrobial and antibiofilm activity against P. aeruginosa PAO1 was performed by microdilution indicating the minimal inhibitory concentration, and the potential antibiofilm. It was verified the action on virulence factors such the motility, besides the influence on adhesion in buccal epithelial cells. Both oil and nanoparticles showed a decrease in adhesion of microorganisms to buccal cells, decrease of biofilm and interfering on P. aeruginosa PAO1 motility. The nanostructuration of TTO, shows be a viable alternative against formed biofilm microorganisms.