Silver nanoparticles have been shown to possess considerable antibacterial activity, but in vivo applications have been limited due to the inherent, but low, toxicity of silver. On the other hand, silver nanoparticles could provide cutaneous protection against infection, due to their ability to liberate silver ions via a slow release mechanism, and their broad-spectrum antimicrobial action. Thus, in this work, we describe the development of a carboxymethyl cellulose-based hydrogel containing silver nanoparticles. The nanoparticles were prepared in the hydrogel in situ, utilizing two variants of cashew gum as a capping agent, and sodium borohydride as the reducing agent. This gum is non-toxic and comes from a renewable natural source. The particles and gel were thoroughly characterized through using rheological measurements, UV-vis spectroscopy, nanoparticles tracking analysis, and transmission electron microscopy analysis (TEM). Antibacterial tests were carried out, confirming antimicrobial action of the silver nanoparticle-loaded gels. Furthermore, rat wound-healing models were used and demonstrated that the gels exhibited improved wound healing when compared to the base hydrogel as a control. Thus, these gels are proposed as excellent candidates for use as wound-healing treatments.
The purpose of this review was to collect relevant chemical data about lycopene and its isomers, which can be extracted using different non-polar or polar aprotic solvents by SC-CO2 or biosynthesis as a friendly technique. Lycopene and other carotenoids can be identified and quantified by UV–Vis and HPLC using a C18 or C30 column, while their characterization is possible by UV–Vis, Fluorescence, FTIR, MS, NMR, and DSC assays. Among these techniques, the last four can compare lycopene isomers and identify cis or all-trans-lycopene. FTIR, MS, and NMR techniques are more suitable for the verification of the purity of lycopene extracts due to the signal complexity generated for each isomer, which enables identification by subtle differences. Additionally, some biological activities of lycopene isolated from red vegetables have already been confirmed, such as anti-inflammatory, antioxidant, and cytotoxic activity against cancer cells, probably by activating several pathways. The encapsulation of lycopene in nanoparticles demonstrated an improvement in oral delivery, and ex vivo assessments determined that these nanoparticles had better permeation and low cytotoxicity against human cells with enhanced permeation. These data suggest that lycopene has the potential to be applied in the food and pharmaceutical industries, as well as in cosmetic products.
Bioactive compounds extracted from natural sources can benefit human health. The aim of this work was to determine total phenolic content and antioxidant activity in extracts of Euphorbia tirucalli L. followed by identification and quantification of the phenolic compounds, as well as their antibacterial activities. Antioxidant activities were determined by DPPH and ABTS•+ assay. Identification of phenolic compounds was performed using high-performance liquid chromatography (HPLC), and antimicrobial activities were verified by agar dilution methods and MIC values. Total phenolic content ranged from 7.73 to 30.54 mg/100 g gallic acid equivalent. Extracts from dry plants showed higher antioxidant activities than those from fresh ones. The DPPH EC50 values were approximately 12.15 μg/mL and 16.59 μg/mL, respectively. Antioxidant activity measured by the ABTS method yielded values higher than 718.99 μM trolox/g for dry plants, while by the Rancimat® system yielded protection factors exceeding 1 for all extracts, comparable to synthetic BHT. Ferulic acid was the principal phenolic compound identified and quantified through HPLC-UV in all extracts. The extracts proved effective inhibitory potential for Staphylococcus epidermidis and Staphylococcus aureus. These results showed that extracts of Euphorbia tirucalli L. have excellent antioxidant capacity and moderate antimicrobial activity. These can be attributed to the high concentration of ferulic acid.
2 March 2020 in Journal of Dispersion Science and Technology
The nanoemulsion system can improve stability to antioxidant molecules when compared to the isolated molecule. Therefore, this study aimed to establish conditions on thermal stability, chemical characterization, antioxidant and anti-inflammatory activity of lycopene nanoemulsion. Different chemical assays were used to characterize the lycopene nanoemulsion (LN) and the purified lycopene from guava (LPG) as HPLC, UV-Vis, DLS, and ABTS to analyze the antioxidant activity of lycopene nanoemulsion. To test its thermal stability as an antioxidant in nanoemulsion it was used the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. The carrageenan-induced paw edema model in Swiss mice and histopathological analysis were used to evaluate anti-inflammatory activity. Emulsion with a mean droplet size of z-Average diameter 167.1 d.nm was produced. UV-vis detected λmax = 447.1, 473.7, and 505.3 nm to lycopene from guava and HPLC-DAD analysis by C30 at 472 nm identified the presence of lycopene in the nanoemulsion. This lycopene nanoemulsion presented thermal stability at room temperature, as well as on concentration when stored for one year. Also significantly inhibited (p < 0.05) the edema formation, with maximum inhibitory effect at 50 mg/kg by oral and intraperitoneal route and reduced neutrophil migration in paw tissue. The lycopene nanoemulsion can be a potential candidate for investigation and therapy of various diseases, including inflammation because this lycopene nanoemulsion presented therapeutics application for inflammatory diseases, and has also potential to be used as ointment and/or cream additive for topic applications.
This research reports, for the first time, the immobilization of an enzyme - Rhus vernificera laccase - on cashew gum (CG) nanoparticles (NPs) and its application as a biological layer in the design and development of an electrochemical biosensor. Laccase-CG nanoparticles (LacCG-NPs) were prepared by the nanoprecipitation method and characterized by UV-Vis spectrophotometry, atomic force microscopy, scanning electron microscopy, attenuated total reflectance-Fourier-transform infrared spectroscopy, circular dichroism, cyclic voltammetry, and electrochemical impedance spectroscopy. The average size and stability of the NPs were predicted by DLS and zeta potential. The ATR-FTIR results clearly demonstrated an interaction between –NH and –OH groups to form LacCG-NPs. The average size found for LacCG-NPs was 280 ± 53 nm and a polydispersity index of 0.309 ± 0.08 indicated a good particle size distribution. The zeta potential shows a good colloidal stability. The use of a natural product to prepare the enzymatic nanoparticles, its easy synthesis and the immobilization efficiency should be highlighted. LacCG-NPs were successfully applied as a biolayer in the development of an amperometric biosensor for catechol detection. The resulting device showed a low response time (6 s), good sensitivity (7.86 μA μM−1 cm−2), wide linear range of 2.5 × 10−7–2.0 × 10−4 M, and low detection limit (50 nM).
21 May 2021 in Somma Revista Cientifica do Instituto Federal de Educação Ciência e Tecnologia do Piauí
The Escola Família Agrícola Santa Ângela (EFASA) has a differentiable target audience, the student who lives in the countryside, and, because of this, it has a different perspective about the teaching form on curricular components of science to this public. Inthis context, the work aimed to describe the realization of the science fair at the EFASA school, to investigate the impact of the science fair, and its contributions to the teaching-learning process through the activities developed in this fair. The questionnaire online was applied through WhatsApp. After we elucidated and obtained the students' signatures in Informed Assent Termand Informed Consent Term only of their respective legal Guardians, students answered the questions. The data were arranged in graphs and tables. The students' responses were decisive for verifying that science fair can contribute positively to an experience of sciences acquiring knowledge, and it also was as a practical activity characterized. The results showed that the studentshave acted in a joined and organized way to pass on, produce and obtain knowledge during the science fair. Thus, the science fair could be a pedagogical strategy of teaching in science because it would provide practical, contextualized, and interdisciplinary learning among academic subjects of natural science, geography, and mathematics.