RESUMEN
Mechanical alloying was performed to obtain a composite material with a homogeneous dispersion of silver particles in a poly(vinyl alcohol) (PVA) matrix. Silver is a bactericidal material, and PVA is a widely used biocompatible polymer. Therefore, this mix can lead to a potentially functional biomaterial. This study focuses on the combination of both materials, processed by mechanical alloying, which has a promising application potential. The silver (Ag) used was ultrafine, measuring between 200 and 400 nanometers, produced from silver nitrate (AgNO3) redox. The Attritor high-energy, water-cooled ball mill was used to mill PVA for 4 h, at 600 rpm speed rotation and 38:1 power milling. Mechanical alloying was demonstrated to cause particle refinement in PVA with a timespan of 1 h. A slight additional particle decrease occurred for long-time milling. A milling time of 4 h was used to disperse the silver particles in the polymer matrix homogeneously. Hot pressing films were produced from the obtained dispersion powders. The microstructural features were studied using several material characterization techniques. Antimicrobial Susceptibility Tests (AST), conducted in an in-vitro assay, showed a hydrophilic character of the films and a protection against bacterial growth, making the process a promising path for the production of surface protective polymeric films.
RESUMEN
Abstract The chemically complex essential oils of Baccharis species are associated with several biological activities, such as antimicrobial and antiulcerous properties. However, few studies have investigated Baccharis erioclada DC. Therefore, in this study, we aimed to characterize the essential oil of B. erioclada and evaluate its antioxidant, antimicrobial, and hemolytic potential. The essential oil was extracted by hydrodistillation using a Clevenger apparatus and analyzed via gas chromatography-mass spectrometry (GC-MS). Phosphomolybdenum complex formation, reducing antioxidant power, and thiobarbituric acid reactive substances (TBARS) methods were used to determine antioxidant potential. To evaluate the essential oil's antimicrobial activity, minimum inhibitory concentrations (MIC) in Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were calculated. Hemolytic activity was determined in sheep red blood cells. Thirty-one compounds were identified via GC-MS analysis, representing 81.60% of the total essential oil. These compounds included: turmerone (27.97%), fokienol (13.47%), ledol (9.78%), and santalol (5.35%). The class of compounds identified was the oxygenated sesquiterpenes (62.52%). Antioxidant activity was confirmed via phosphomolybdenum complex formation and TBARS methods. Moderate antimicrobial activity and low hemolysis rates were displayed at concentrations of 250 and 500 µg/mL
Asunto(s)
Aceites Volátiles/análisis , Baccharis/anatomía & histología , Antioxidantes/farmacología , Pruebas de Sensibilidad Microbiana/instrumentación , Asteraceae/clasificación , Cromatografía de Gases y Espectrometría de Masas/métodosRESUMEN
Abstract Green synthesis is an efficient method, frequently applied in nanobiotechnology, as it does not use toxic reagents or solvents. Biological organisms, including medicinal plants, have been used successfully for manufacturing of different types of metallic nanoparticles. The aim of this work was to synthesize, characterize and evaluate the antimicrobial activity of silver nanoparticles (AgNPs) obtained from the extract of the pulp, seed and leaves of Annona muricata L. The particle size, polydispersity index, zeta potential, as well as morphological aspects of AgNPs were evaluated. With the data obtained from the analyses, we concluded that the nanoparticles were successfully obtained by a simple and green method using the aqueous extract of the pulp, seeds and leaves of A. muricata. AgNPs obtained by A. muricata pulp extract without exposure to artificial light showed lowest average of hydrodynamic diameter and smallest size at field emission scanning electron microscope (FESEM). In addition, these nanoparticles showed the best polydispersity index (PDI), and zeta potential of - 29.6, which indicates good stability. AgNPs obtained from the extract of the pulp, seed and leaves showed antimicrobial activity, against strains of gram positive and gram negative bacteria, and antifungal activity, compared to the pure extract.
RESUMEN
Abstract Eucalyptus species possess anti-inflammatory, antifungal, antibacterial, and insecticidal properties. In this study, the chemical composition and biological activities of Eucalyptus cinerea essential oil (EO) and the leaf and stem anatomy were investigated. EO was extracted by Clevenger apparatus and the compounds were identified by GC/MS. The antioxidant activity was evaluated by DPPH, ABTS, and reducing phosphomolybdenum complex. Broth microdilution was used to determine antimicrobial activity. Cytotoxicity was verified against HeLa, HRT-18, and Calu-3 cells by MTT assay. The cytotoxic mechanism was studied by cell DNA content, cell cycle, and DNA fragmentation. The microscopic analyzes of the leaves and the stems were performed by light microscopy, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The main constituent of the EO was 1,8-cineole (55.24%). The EO showed low antioxidant and antimicrobial activities. Calu-3 cells showed a significant reduction in viability with IC50 of 689.79 ± 29.34 μg/mL. EO at 1000 μg/mL decreased the DNA content in Jurkat cells. In general, EO increased cell percentage in sub-G0 and S phases with concomitant reduction of cell percentage in G0/G1 and G2/M phases and provided DNA fragmentation of 29.73%. Anatomical and micromorphological features of the leaves and stems can help in the species identification and its differentiation from other Eucalyptus species.
Asunto(s)
Terpenos , Fenómenos Biológicos , Aceites Volátiles , Myrtaceae , MicroscopíaRESUMEN
Abstract Metallic nanoparticles have great potential as a chemotherapeutic agent. The aim of this study was to develop and characterize silver and gold nanoparticles using a simple method, as well as evaluating the potential cytotoxic activity in relation to the K-562 cell line. For the synthesis, a solution containing the metallic ions was subjected to magnetic stirring with the aqueous extract of Lavandula dentata L. and a change of colour was observed. With the data obtained from the analyses we concluded that the nanoparticles were successfully obtained by a simple and green method using the aqueous extract of L. dentata. The obtained nanoparticles presented a reduced size, a low level of polydispersion, and a homogenous spherical shape. The nanoparticles presented intense and characteristic diffraction peaks, which could be correlated to the planes of the centred cubic structure of the silver and gold. The two formulations presented predominantly crystalline characteristics. The infrared analysis suggested that the amides and alcohols present in the samples may have been responsible for the reduction and limitation of the size and dispersion of the silver and gold nanoparticles. The cytotoxic assay showed that the nanoparticles demonstrated great potential to reduce the cell viability of the K-562 cell line, especially the gold nanoparticles.
Asunto(s)
Leucemia Mieloide , Lamiaceae/toxicidad , Citotoxinas , Nanopartículas del Metal/análisisRESUMEN
ABSTRACT Lavandula dentata, popularly known as lavender, is commonly used in traditional medicine for the treatment of digestive and inflammatory disorders. The objective of this study was to analyzed the chemical oil composition, antioxidant and antimicrobial activities of the essential oil and anatomical markers of the leaf and stem of L. dentata cultivated in South Brazil. Essential oil showed an antioxidant activity similar to rutin and gallic acid when analyzed by phosphomolybdenum method. However, by the free radical DPPH and ABTS methods, it showed a slight potential antioxidant. Essential oil presented 1,8-cineol (63%) as major component, antimicrobial activity against Gram-positive, Gram-negative bacteria strains and Candida albicans, by broth microdilution. The anatomical profile provided the following main microscopic markers: hypostomatic leaves; diacytic stomata, thin and striate cuticle; multicellular and branched non-glandular trichomes; capitate glandular trichomes; peltate glandular trichomes; dorsiventral mesophyll; flat-convex shape midrib, truncated on the abaxial side; one collateral vascular bundle in the midrib; square stem shape, angular collenchyma alternated with cortical parenchyma; sclerenchymatic fibers well-developed on the four edges.
Asunto(s)
Aceites Volátiles , Lamiaceae , Lavandula/química , Antiinfecciosos , AntioxidantesRESUMEN
Ocimum selloi Benth. (Lamieceae), também conhecida como "alfavaca", é uma planta herbácea que ocorre no Brasil. O óleo essencial obtido das suas folhas tem sido usado como aditivo aromatizante em alimentos, produtos odontológicos e como ingrediente de fragrâncias. Na medicina popular brasileira, o O. selloi tem sido amplamente empregado como remédio antiinflamatório e antiespasmódico e, também, para tratar diarréia. O principal objetivo deste estudo foi avaliar a atividade repelente de mosquitos e o potencial de irritação dérmica do óleo de O. selloi em voluntários. Além disso, foram obtidos também dados sobre o perfil toxicológico (toxicidade aguda oral data e mutagenicidade no teste de Ames), e sobre as propriedades físico-químicas e constituintes químicas e constituintes químicos do óleo essencial do O. selloi coletado em Ponta Grossa, estado do Paraná. O óleo essencial foi obtido por hidrodestilação de folhas de O. selloi. Os constituintes químicos foram determinados por Cromatografia em Camada Delgada (CCD) e GC-MS/MSD. Os principais constituintes do óleo volátil analisado por GC-MS/MSD foram o estragol (55,38 por cento) e o trans-anetol (34,23 por cento). O óleo de O. selloi foi agudamente tóxico e letal para camundongos (fêmeas mais suscetíveis que machos) em doses iguais ou superiores a 1500 mg/kg de peso corporal. Não foi observada atividade mutagênica em ensaios in vitro com as linhagens de Salmonella thyphimurium TA97a, TA98 e TA100, sem e com adição de mistura S9. Não foi constatada irritação dérmica no antebraço de 30 voluntários expostos ao O. selloi por 4 horas. No estudo de campo em que seis voluntários (cada indivíduo é seu próprio controle) foram expostos Anopheles brasiliensis por 30 minutos o O. selloi (solução 10 por cento p/v em etanol) reduziu drasticamente a freqüência de picadas em relação ao etanol (redução de 88 por cento, P=0,01) demonstrando que é um repelente eficaz.