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Kojic acid (KA), an important compound with medical, cosmetic, and industrial applications, was loaded in 3-aminopropyltriethoxysilane-functionalized silica nanoparticle (MSNAPTES-KA5). This nanoparticle with acid was prepared to evaluate its application as a drug delivery system due to its interesting characteristic as large surface area, high pore volume, and good biocompatibility. The samples were characterized using different techniques that demonstrate success in the functionalization and loading process, as can be seen from the results obtained by FTIR, XPS, TGA, and CHN, that confirmed the presence of APTES and KA in the nanoparticles. KA drug loading was estimated using UV-Vis, TGA, and CHN, which revealed 12% loading of KA in the nanoparticles that showed slow rate of release. Antimicrobial assay was performed to evaluate the antimicrobial activity of the samples against different microorganisms. The results showed greater MSNAPTES-KA5 antibacterial activity than free-kojic acid for Candida albicans and Staphylococcus aureus. In relation to the acetylcholinesterase (AChE) inhibition assay; a higher inhibition of MSNAPTES-KA5, than the inhibition with free-kojic acid was observed. In addition, MSNAPTES-KA5 sample was also effective in inhibiting tyrosinase, proving the efficiency of the MSNAPTES base. These studies afford evidence of the possible beneficial biological activities of MSNAPTES-KA5 nanoparticle in pharmaceutical applications.

Here, we present a new application of desorption electrospray ionization (DESI) and laser ablation electrospray ionization (LAESI) mass spectrometry imaging to assess the spatial location of organic compounds, both polar and nonpolar, directly from rock surfaces. Three carbonaceous rocks collected from an aquatic environment and a berea sandstone subjected to a small-scale oil recovery experiment were analyzed by DESI and LAESI. No rock pretreatment was required before DESI and LAESI analyses. DESI detected and spatially mapped several fatty acids and a disaccharide on the surfaces of carbonaceous rocks, and various nitrogenated and oxygenated compounds on the surfaces of berea sandstone. In contrast, LAESI using a 3.4 μm infrared laser beam was able to detect and map hydrocarbons on the surfaces of all rock samples. Both techniques can be combined to analyze polar and nonpolar compounds. DESI can be used first to detect polar compounds, as it does not destroy the rock surface, and LAESI can then be used to analyze nonpolar analytes, as it destroys a layer of the sample surface. Both techniques have the potential to be used in several scientific areas involving rocks and minerals, such as in the analysis of industry-derived contaminants in aquatic sediments or in small-scale rock–fluid interaction experiments.

The synthesis and phytotoxic activity of a series of tyrosol 1,2,3-triazole derivatives are reported herein. Target compounds were synthesized through the copper­(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC), known as click reaction, and these were tested for phytotoxic activity on leaves of wild poinsettia (Euphorbia heterophylla), fleabane (Conyza sumatrensis), and tropical spiderwort (Commelina benghalensis). These are three highly noxious agricultural weeds that challenge available weed control methods, including the use of chemical herbicides. Twenty-five compounds were synthesized and tested. None of the compounds showed phytotoxic activity against C. benghalensis and C. sumatrensis, but almost all of them produced yellowing, bleaching, and necrosis on leaves of E. heterophylla. Two of the tyrosol 1,2,3-triazole derivatives produced more extensive lesions than those produced by the commercial herbicide diquat, used as a positive control (p ≤ 0.05). When applied on leaves of E. heterophylla, these compounds interfered with the stomatal conductance, net photosynthesis, internal carbon concentration, transpiration rate, water-use efficiency, and chlorophyll A and B contents. The interference of such compounds on such photosynthesis-related variables indicates that tyrosol 1,2,3-triazole derivatives may be capable of lowering the competitiveness of E. heterophylla and acting as additional tools for managing this competitive weed in agricultural lands.

Tetranychus urticae Koch is a polyphagous pest that is widely distributed throughout the world and causes considerable damage to crops in northeastern Brazil. The effects of the essential oil from Aristolochia trilobata L., selected constituents, and an artificial mixture (sulcatyl acetate, limonene, linalool, and p-cymene) on T. urticae in terms of fumigant action, residual contact, and fecundity were investigated under laboratory conditions. The results were compared with eugenol, Azamax®, and Ortus® as positive controls. Gas chromatography–mass spectrometry analysis of the oil revealed a predominance of monoterpenes, with sulcatyl acetate (24.57% ± 0.40%) as the major component, followed by linalool (10.80% ± 0.27%). Toxicity varied with the method employed. Through fumigation, the A. trilobata oil was about 2.18-fold more toxic than the artificial mixture, whereas no significant difference between the two products was found with regard to residual contact. Regarding the selected compounds, the mite was most susceptible to linalool and p-cymene by fumigation and residual contact, respectively. The plant-based (Azamax®) and synthetic (Ortus®) acaricidal agents were more toxic than the products tested. Moreover, low concentrations of the products investigated herein had no effect on mite survival, but a significant effect was found on the quantity of eggs laid by females. The A. trilobata oil and artificial mixture are promising natural acaricidal agents that have more than one mode of action (fumigation and residual contact) and exert an effect on fecundity. However, further studies are needed to evaluate the cost–benefit ratio for use on organic crops and protected environments in northeastern Brazil.

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