Effect of polycaprolactone nanocapsules loaded with essential oils on biofilm formation by Staphylococcus aureus strains isolated from bovine mastitis cases

Abstract Bovine infectious mastitis is largely resistant to antibacterial treatment, mainly due to mechanisms of bacterial resistance in the biofilms formed by Staphylococcus aureus. Melaleuca (MEO) and citronella essential oils (CEO) are promising agents for reducing or eliminating biofilms. Free melaleuca oil presented a medium Minimum Inhibitory Concentration (MIC) of 0.625% and a Minimum Bactericidal Concentration (MBC) of 1.250%, while free citronella oil showed medium MIC and MBC of 0.313%. Thus, free CEO and MEO demonstrate bacteriostatic and bactericidal potential. We generated polymeric nanocapsules containing MEO or CEO and evaluated their efficacy at reducing biofilms formed by S. aureus. Glass and polypropylene spheres were used as test surfaces. To compare the responses of free and encapsulated oils, strains were submitted to 10 different procedures, using free and nanoencapsulated essential oils (EOs) in vitro. We observed no biofilm reduction by MEO, free or nanoencapsulated. However, CEO nanocapsules reduced biofilm formation on glass (p=0.03) and showed a tendency to diminish biofilms on polypropylene (p=0.051). Despite nanoencapsulated CEO reducing biofilms in vitro, the formulation could be improved to modify the CEO component polarity and, including MEO, to obtain more interactions with surfaces and the biofilm matrix

In vitro antioxidant extracts evaluation from the residue of the Hevea brasiliensis seed.

The antioxidants used in the food industry are essential to inhibit the formation of free radicals, preserving the existing properties in the different matrices. However, the insecurity of the synthetic antioxidants regarding human health propels search for natural substrates with potential antioxidant activity as an alternative to synthetic compounds. In this way, the work had as objective obtaining extracts from the seed pomace of the Hevea brasiliensis (rubber tree), relating the contents of flavonoids and total phenols in the application as an antioxidant. The methodology consisted of the extraction using four solvents, varying extractive methods, time, and seed concentrations. The antioxidant activity in vitro was evaluated by capturing the DPPH (2,2-diphenyl-1-picryl-hydrazil) radical. The optimized results demonstrate that the aqueous extracts produced in the Soxhlet in the concentrations of 85 g L-1 and retention time of 4 h reached 37.73 ± 1.69% in the antioxidant tests of the free radical DPPH capture, 1405.15 mg EAC 100 g-1 in the quantification of phenolic compounds and 223.34 mg 100 g-1 of total flavonoids. Thus, this work may contribute to the realization of studies and future research for characterization and identification concerning which phenolic compounds and flavonoids attribute the antioxidant characteristic to the extracts produced, enabling the discovery of products with high added value in the production chain. In addition, because the water used as a solvent showed greater antioxidant potential between the extracts, the non-toxic and environmentally friendly character is highlighted, allowing a wide variety of applications in the food industry.

Avaliação do status oxidativo, consumo alimentar de zinco e zinco plasmático em indivíduos infectados pelo HIV / Evaluation of oxidative status, food consumption of zinc and plasma zinc in HIV-infected individuals

Objetivo: Objetivou-se analisar o consumo alimentar e os níveis plasmáticos de zinco além de biomarcadores do status oxidativo de pacientes com infecção pelo HIV. Métodos: Foram selecionados indivíduos adultos com HIV e contagem de linfócitos T CD4<500 células/mm3, assistidos por um centro especializado, localizado na região oeste do Paraná. Realizou-se a aplicação de questionários, avaliação antropométrica e coleta sanguínea para análise de zinco e biomarcadores do status oxidativo. Resultados: Avaliou-se um total de quarenta indivíduos adultos, nos quais se observaram consumo adequado de zinco e grande frequência de eutrofia e sobrepeso. Obteve-se correlação positiva entre tióis proteicos (SH-P) e os níveis plasmáticos de zinco e correlação negativa entre SH-P e a peroxidação lipídica (PL) no plasma e nos eritrócitos. Além disso, verificou-se um aumento nos níveis de SH-P em pacientes com presença de doença oportunista em alguma fase da infecção viral. Conclusão: Apesar de não ter sido observada relação entre níveis de zinco sanguíneo e a contagem de linfócitos T CD4 e carga viral, as propriedades do mineral ainda são defendidas como essenciais.