Magnetism in a 2D Hybrid Ruddlesden-Popper Perovskite through Charge Redistribution Driven by an Organic Functional Spacer.

Two-dimensional Ruddlesden-Popper (RP) perovskites are emerging materials offering great synthetic versatility and remarkable features due to the tunability of their crystal structure. We present a novel strategy to provide magnetism in a 2D RP perovskite using histidine molecules as a spacer, which could induce charge rebalancing at the interface of the inorganic layer. We observe that the amide and imidazole groups are close to Pb ions. The interaction with the imidazole indicates that this functional group, possibly assisted by the carboxyl close to the vicinity of the amine terminal, is inducing charge rearrangement from Pb2+ to paramagnetic Pb3+ ions, resulting in a positive magnetic moment. This magnetized 2D hybrid perovskites can be classified as a novel class of promising materials showing a magnetic moment at their interface, which may result in intriguing physical properties due to a delicate balance between magnetism and a quantum well confinement effect in the inorganic layer.

Cytotoxic and genotoxic potential of geraniol in peripheral blood mononuclear cells and human hepatoma cell line (HepG2).

Geraniol is an acyclic monoterpene alcohol present in the essential oil of many aromatic plants and is one of the most frequently used molecules by the flavor and fragrance industries. The literature also reports its therapeutic potential, highlighting itself especially as a likely molecule for the development of drugs against cancer. In view of these considerations, this study was designed to evaluate the cytotoxic and genotoxic potential of geraniol, in an in vitro protocol, using two types of human cells: one without the ability to metabolize (peripheral blood mononuclear cells - PBMC), and the other with this capability (human hepatoma cell line - HepG2) through the comet assay and the micronucleus test. Four concentrations (10, 25, 50, and 100 µg/mL) were selected for the genotoxic assessment for PBMC and three (1.25, 2.5, and 5 µg/mL) for HepG2 cells based on cytotoxicity tests (MTT assay). Results showed that geraniol did not present genotoxic or clastogenic/aneugenic effects on both cell types under the conditions studied. However, caution is advised in the use of this substance by humans, since a significant reduction in viability of HepG2 and a marked decrease in cell viability on normal PBMC were verified.

Teor e composição química do óleo essencial de erva-baleeira (Varronia curassavica Jaqc. ) em função dos horários de coleta / T: Content and chemical composition of the essential oil of 'erva-baleeira' (Varronia curassavica Jaqc. ) as a function of harvesting times

RESUMO A erva-baleeira (Varronia curassavica Jaqc.) é uma importante planta medicinal, com ocorrências em vários biomas brasileiros, dela é possível extrair óleo essencial utilizado na produção de fitoterápicos. O objetivo deste trabalho foi estudar o efeito do horário de coleta das folhas sobre o teor e os constituintes químicos do óleo essencial da V. curassavica. As folhas foram obtidas da coleção do germoplasma do Horto Medicinal do Instituto de Ciências Agrárias da Universidade Federal de Minas Gerais (ICA/UFMG). Os tratamentos constaram de cinco horários de coleta (6:00, 9:00, 12:00, 15:00 e 18:00 horas) e três repetições, utilizando o delineamento experimental inteiramente casualizado. O óleo essencial foi extraído pelo método de hidrodestilação, utilizando-se o sistema Clevenger e a constituição química determinada por cromatografia em fase gasosa acoplada à espectrometria de massas (CG/EM). O teor do óleo essencial não sofreu influencia do horário de coleta. Entretanto, o horário de coleta influenciou a composição química do óleo essencial de erva-baleeira. Os compostos majoritários em todos os horários de coleta foram β-cariofileno (22,6 a 27,4%), elixeno (14,9 a 17,2%) e γ-muuroleno (9,1 a 9,8%). Já o composto de menor abundância relativa, sabineno (1,1 %), apresentou ocorrência apenas as 6 h da manhã.

ABSTRACT The erva-baleeira (Varronia curassavica Jacq.) is an important medicinal plant which occurs in several Brazilian biomes, from which it is possible to extract essential oil used in the production of herbal medicines. The objective of this study was to observe the effect of the collection schedule for the leaves on the content and the chemical constituents of the essential oil of V. curassavica. The leaves were obtained from the germplasm collection of the Medicinal Garden of the Institute of Agricultural Sciences at the Federal University of Minas Gerais (ICA/UFMG). The treatments consisted of five collection schedules (6:00 and 9:00 AM, and 12:00, 3:00, and 6:00 PM) and three replications, using a completely randomized design. The essential oil was extracted by the hydrodistillation method, using the Clevenger system, and the chemical composition was determined by gas chromatography with mass spectrometry (GC/MS). The harvest time did not influence the content of the essential oil. However, the collection schedule did influence the chemical composition of the essential oil of erva-baleeira. The major compounds at all collection times were β-caryophyllene (22.6 to 27.4%), xylene (14.9 to 17.2%) and γ-muurolene (9.1 to 9.8%). The compound of lowest relative abundance, sabinene (1.1%), was found only at 6 AM.