Encapsulation of Red Propolis in Polymer Nanoparticles for the Destruction of Pathogenic Biofilms.

Microbial biofilms, structured communities of microorganisms, have been often associated to the infection and bacterial multiresistance problem. Conventional treatment of infection involves the use of antibiotics, being an alternative approach is the use of red propolis, a natural product, to prepare polymer nanoparticles. The aim of the present study was to encapsulate red propolis extract in poly(lactic-co-glycolic acid) (PLGA) nanoparticles for destruction in vitro of pathogenic biofilms. Poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) containing red propolis hydroethanolic extract (2 mg/mL) were produced by emulsification solvent diffusion method. The extract and developed nanoparticles were analyzed for antimicrobial activity and inhibition of bacterial biofilm formation in vitro against Staphylococcus aureus and Pseudomonas aeruginosa. Transmission electron microscopy images confirmed spherical nanoparticles in the range size from 42.4 nm (PLGA NPs) to 69.2 nm (HERP PLGA NPs), with encapsulation efficiencies of 96.99%. The free extract and encapsulated in polymer nanoparticle presented antimicrobial potential, with a minimum inhibitory concentration from 15.6 to 125 µg mL-1 and from 100 to 1560 µg mL-1 to inhibit biofilm formation for the Staphylococcus aureus and Pseudomonas aeruginosa, respectively.

Effect of Tamarindus indica L. and Manihot esculenta Extracts on Antibiotic-resistant Bacteria.

BACKGROUND: The chemical composition of plants used in traditional medicine exhibits biologically active compounds, such as tannins, flavonoids, and alkaloids and becomes a promising approach to treat microbial infections, mainly with drug-resistant bacteria. OBJECTIVE: The aim of the present study was to evaluate the hydroethanolic leaf extracts of Tamarindus indica (tamarind) and Manihot esculenta (cassava) as antimicrobial potential against Pseudomonas aeruginosa clinical isolated and Methicillin-resistant Staphylococcus aureus. MATERIALS AND METHODS: Hydroethanolic leaf extracts were prepared and characterized by high-performance liquid chromatography/diode array detection, Fourier transform infrared, 1,1-diphenyl-2-picrylhydrazyl, and ultraviolet-visible methods. The antimicrobial activity against four strains of clinical relevance was evaluated by the microdilution method at minimum inhibitory concentrations. RESULTS: Phenolic compounds such as flavonoids were detected in the plant extracts. T. indica extract at 500 µg/mL showed antimicrobial activity against S. aureus and P. aeruginosa; however, M. esculenta showed only activity against P. aeruginosa in this concentration. CONCLUSIONS: Our results suggested that polyphenols and flavonoids present in T. indica leaf extracts are a potential source of antimicrobial compound. The T. indica extract showed antibacterial activity against S. aureus and P. aeruginosa while M. esculenta had effect only on P. aeruginosa meropenem resistant. SUMMARY: Antibacterial effect of T. indica and M. esculenta leaf extract was evaluated.T. indica extract displayed activity against S. aureus and P. aeruginosa strains.M. esculenta showed effect on P. aeruginosa meropenem resistant. Abbreviations Used: BHI: Agar brain heart infusion, CAPES: Coordination for the improvement of higher education personnel, DPPH: 1,1-diphenyl-2-picrylhydrazyl, FAPITEC/SE: Foundation for support to research and technological innovation of the state of sergipe, FTIR: Fourier transform infrared spectroscopy, HPLC: High-performance liquid chromatography, KBr: Potassium bromide, MIC: Minimum inhibitory concentration, MRSA: Methicillin-resistant Staphylococcus aureus, RSC: Radical scavenging capacity, UV-vis: Ultraviolet-visible.

Solid phase extraction of petroleum carboxylic acids using a functionalized alumina as stationary phase.

Petroleum essentially consists of a mixture of organic compounds, mainly containing carbon and hydrogen, and, in minor quantities, compounds with nitrogen, sulphur, and oxygen. Some of these compounds, such as naphthenic acids, can cause corrosion in pipes and equipment used in processing plants. Considering that the methods of separation or clean up the target compounds in low concentrations and in complex matrix use large amounts of solvents or stationary phases, is necessary to study new methodologies that consume smaller amounts of solvent and stationary phases to identify the acid components present in complex matrix, such as crude oil samples. The proposed study aimed to recover acid compounds using the solid phase extraction method, employing different types of commercial stationary ion exchange phases (SAX and NH(2)) and new phase alumina functionalized with 1,4-bis(n-propyl)diazoniabicyclo[2.2.2]octane chloride silsesquioxane (Dab-Al(2)O(3)), synthesized in this work. Carboxylic acids were used as standard mixture in the solid phase extraction for further calculation of recovery yield. Then, the real sample (petroleum) was fractionated into saturates, aromatics, resins, and asphaltenes, and the resin fraction of petroleum (B1) was eluted through stationary ion exchange phases. The stationary phase synthesized in this work showed an efficiency of ion exchange comparable to that of the commercial stationary phases.