Evaluation of the Biotechnological Potential of Monteverdia salicifolia (Mart ex. Reissek) Biral

Plant extracts are a good alternative of reducing agents in the synthesis of metal nanoparticles. In this paper, we report the evaluation of the cytotoxic activity against T3 cell lines of the ethanolic extract of Monteverdia salicifolia (Mart ex. Reissek) Biral roots (MS) as well as a green one-pot route of synthesis of silver nanoparticles (AgNPs) using that extract as reducing and stabilizing agent. The extract exhibited dose dependent activity. The smallest particle size (48.01 nm) was achieved in just 25 minutes by employing a temperature of 65 °C and AgNO3 and MS concentrations equal to 0.9 mmol.L−1 and 0.67 mg.mL−1, respectively. The AgNPs-MS nanocomposite was characterized by UV–vis spectroscopy, FEG microscope and zeta potential, which proved that MS was effective at reducing and capping the AgNPs. In order to emphasize the advantage of the methodology applied in this synthesis, it was compared to a usual procedure using NaBH4 as a reducing agent and the greenness analysis was also carried out, using the Green Star. DOI: http://dx.doi.org/10.17807/orbital.v13i2.154

Obtaining Ultrafine Dispersions of Silver Particles in Poly(vinyl Alcohol) Matrix Using Mechanical Alloying

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

Chemical Composition and Biological Activities of The Essential Oil And Anatomical Markers Of Lavandula Dentata L. Cultivated In Brazil

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

Chemical composition and biological activity of Baccharis erioclada DC. essential oil

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

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved