A thermodynamic study on the interaction between RH-23 peptide and DMPC-based biomembrane models

Investigation of the interaction between drugs and biomembrane models, as a strategy to study and eventually improve drug/substrate interactions, is a crucial factor in preliminary screening. Synthesized peptides represent a source of potential anticancer and theragnostic drugs. In this study, we investigated the interaction of a novel synthesized peptide, called RH-23, with a simplified dimyristoylphosphatidylcholine (DMPC) model of the cellular membrane. The interaction of RH-23 with DMPC, organized either in multilamellar vesicles (MLVs) and in Langmuir-Blodgett (LB) monolayers, was assessed using thermodynamic techniques, namely differential scanning calorimetry (DSC) and LB. The calorimetric evaluations showed that RH-23 inserted into MLVs, causing a stabilization of the phospholipid gel phase that increased with the molar fraction of RH-23. Interplay with LB monolayers revealed that RH-23 interacted with DMPC molecules. This work represents the first experimental thermodynamic study on the interaction between RH-23 and a simplified model of the lipid membrane, thus providing a basis for further evaluations of the effect of RH-23 on biological membranes and its therapeutic/diagnostic potential

Antioxidant Properties of Lippia alba Essential Oil: A Potential Treatment for Oxidative Stress-Related Conditions in Plants and Cancer Cells

Lippia alba (Mill.) N.E.Br. ex Britton and P. Wilson is used in folk medicine of Central and South America for its biological activities: i.e., antifungal, antibacterial, antiviral, and anti-inflammatory. Based on ethnopharmacological information and the increasing interest in this species, this work aimed to test a possible wide use of its essential oil (EO) in pharmaceutical and horticultural applications. Therefore, we focused the attention on the antioxidant activity of the oil as a possible tool to overcome the oxidative stress in both applications. For this purpose, we have chosen three aggressive breast cancer cell lines and two horticultural species (Solanum lycopersicum L. and Phaseolus acutifolius L.) that are very sensitive to salt stress. We determined the antioxidant activity of L. alba EO through the quantification of phenols and flavonoids. Regarding tomato and bean plants under salt stress, L. alba EO was used for the first time as a seed priming agent to enhance plant salt tolerance. In this case, the seed treatment enhanced the content of phenolic compounds, reduced power and scavenger activity, and decreased membrane lipid peroxidation, thus mitigating the oxidative stress induced by salt. While in breast cancer cells the EO treatment showed different responses according to the cell lines, i.e., in SUM149 and MDA-MB-231 the EO decreased proliferation and increased antioxidant activity and lipid peroxidation, showing high cytotoxic effects associated with the release of lactate dehydrogenase, vice versa no effect was observed in MDA-MB-468. Such antioxidant activity opens a new perspective about this essential oil as a possible tool to counteract proliferation in some cancer cell lines and in horticulture as a seed priming agent to protect from oxidative damage in crops sensitive to salinity

Responsabilidade social corporativa e o desempenho de mercado de empresas brasileiras

Purpose – This research aimed to analyze the relationship between Corporate Social Responsibility (CSR) and the market performance of Brazilian companies.Design/methodology/approach – A descriptive, documentary and quantitative research was carried out using panel data regression. The analysis period covered 2010 to 2018 and the sample comprised 41 companies.Findings – The results revealed that investments in external CSR and the fact that companies are listed on the ISE index increase their market value. The CSR information of Brazilian companies aimed at investments made for a society helps to increase market performance.Research limitations/implications – It should be noted that the results cannot be generalized for all Brazilian companies. This research contributes to the accounting and CSR literature, by analyzing the benefits of CSR on companies' market performance.Practical implications – The findings assist investors in the decision-making process, as companies that have CSR actions have positive impacts on their value, operational efficiency and the ability to generate financial performance.Social implications – The results have social implications, as they reinforce the importance of companies investing in CSR, which can improve their market value and benefit society with practices aimed at social well-being.Originality/value – CSR was analyzed in several aspects in the accounting literature. However, the focus of the relationship between CSR and specifically market performance has been little explored in Brazil, a fact that denotes research value.Objetivo - Esta pesquisa objetivou analisar a relação entre a Responsabilidade Social Corporativa (RSC) e o desempenho de mercado de empresas brasileiras.Desenho/metodologia/abordagem - Realizou-se uma pesquisa descritiva, documental e quantitativa a partir da regressão de dados em painel. O período de análise abrangeu 2010 a 2018 e a amostra compreendeu 41 empresas.Resultados - Os resultados revelaram que os investimentos em RSC externa e o fato das empresas estarem listadas no índice ISE aumentam o seu valor de mercado. As informações de RSC das empresas brasileiras voltadas aos investimentos realizados para a sociedade auxiliam para com o aumento do desempenho de mercado. Limitações/implicações da pesquisa – Destaca-se que os resultados não podem ser generalizados para todas as empresas brasileiras. Esta pesquisa contribui para com a literatura contábil e de RSC, ao analisar os benefícios da RSC no desempenho de mercado das empresas.Implicações práticas – Os achados auxiliam os investidores no processo de tomada de decisão, visto que as empresas que possuem ações de RSC apresentam reflexos positivos em seu valor, eficiência operacional e capacidade de gerar desempenho financeiro.Implicações sociais – Os resultados apresentam implicações sociais, pois reforçam a importância de as empresas investirem em RSC, o que pode melhorar o seu valor de mercado e beneficiar a sociedade com práticas que visam o bem-estar social.Originalidade/valor – A RSC foi analisada sob diversos aspectos na literatura contábil. Contudo, o foco da relação entre RSC e especificamente o desempenho de mercado foi pouco explorado no Brasil, fato que denota valor a pesquisa.

CHEMICAL COMPOSITION OF TEN ESSENTIAL OILS FROM CALOPHYLLUM INOPHYLLUM LINN AND THEIR TOXICITY AGAINST ARTEMIA SALINA

Essential oils from ten different parts of Calophyllum inophyllum were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) to study their chemical compositions. The yields were between 0.219 and 0.506 %. A total of 102 compounds were identified in the ten C. inophyllum essential oils, which are mostly monoterpenes, sesquiterpenes and their oxygenated derivatives. The numbers and percentages of identified compounds varied in the different parts of the plant: leaf (71, 54.94%), leaf stalk (22, 79.55%), flower (25, 51.24%), seed (25, 89.39%), seed-coat (69, 73.80%) fruit-pulp (15, 46.10%), stem wood (55, 59.40%), stem bark (9, 69.38%) root wood (51, 58.73%), and root bark (24, 74.66%). High content of cymene, terpinene, and limonene in the oils may be responsible for the vast ethno-medicinal applications of the plant. Toxicity experiments show that the oils were fairly toxic. Each part after 24 hours of exposure against Artemia salina gave the following LC50 values in μg/mL: leaf (68.8740 μg/mL), leaf-stalk (102.5692 μg/mL), flower (114.4410 μg/mL), seed (132.2324 μg/mL), seed coat (137.1206 μg/mL), fruit-pulp (135.0350 μg/mL) stem wood (126.1410 μg/mL), stem bark (149.7237 μg/mL), root wood (110.6539 μg/mL) and root bark (110.6539 μg/mL). The chemical compositions and toxicity levels of these ten Calophyllum inophyllum essential oils are reported for the first time in literature

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements