Dereplication of Lantana trifolia L. leaves and fruits by UFLC-DAD-(+)-ESI-MS/MS and its antifungal and cytotoxic activities.

INTRODUCTION: Lantana trifolia L. (Verbenaceae) is a shrubby plant. In folk medicine, its leaves are used in the form of infusions and syrups to treat angina, coughs, and colds; they are also applied as tranquilizer. Previous studies have reported the antimicrobial potential of the compounds present in L. trifolia leaves. OBJECTIVES: To report the anti-Candida activities of the fractions obtained from the fruits and leaves of two L. trifolia specimens. METHODS: The L. trifolia fractions were submitted to UFLC-DAD-(+)-ESI-MS/MS, and the data were analyzed by using multivariate statistical tools (PCA, PLS-DA) and spectral similarity analyses based on molecular networking, which aided dereplication of the bioactive compounds. Additionally, NMR analyses were performed to confirm the chemical structure of some of the major compounds in the fractions. RESULTS: The ethyl acetate fractions presented MIC values lower than 100 µg mL-1 against the three Candida strains evaluated herein (C. albicans, C. tropicalis, and C. glabrata). Fractions FrPo AcOEt, FrPe AcOEt, and FrPe nBut had MIC values of 1.46, 2.93, and 2.93 µg mL-1 against C. glabrata, respectively. These values resembled the MIC value of amphotericin B, the positive control (0.5-1.0 µg mL-1), against this same strain. Cytotoxicity was measured and used to calculate the selectivity index. CONCLUSION: On the basis of our data, the most active fractions in the antifungal assay were more selective against C. glabrata than against non-infected cells. The analytical approach adopted here allowed us to annotate 29 compounds, nine of which were bioactive (PLS-DA results) and belong to the class of phenolic compounds.

Time-related multivariate strategy for the comprehensive evaluation of microbial chemical data.

INTRODUCTION: In microbial metabolomics, the use of multivariate data analysis (MDVA) has not been comprehensively explored regarding the different techniques available and the information that each gives about the metabolome. To overcome these limitations, here we show the use of Fusarium oxysporum cultured in the presence of exogenous alkaloids as a model system to demonstrate a comprehensive strategy for metabolic profiling. MATHERIALS AND METHODS: F. oxysporum was harvested on different days of incubation after alkaloidal addition, and the chemical profiles were compared using LC-MS data and MDVA. We show significant innovation to evaluate the chemical production of microbes during their life cycle by utilizing the full capabilities of Partial Least Square (PLS) with microbial-specific modeling that considers incubation days, media culture availability, and growth rate in solid media. RESULTS AND DISCUSSCION: Results showed that the treatment of the Y-data and the use of both PLS regression and discrimination (PLSr and PLS-DA) inferred complemental chemical information. PLSr revealed the metabolites that are produced/consumed during fungal growth, whereas PLS-DA focused on metabolites that are only consumed/produced at a specific period. Both regression and classificatory analysis were equally important to identify compounds that are regulated and/or selectively produced as a response to the presence of the alkaloids. Lastly, we report the annotation of analogs from the piperidine alkaloids biotransformed by F. oxysporum as a defense response to the toxic plant metabolites. These molecules do not show the antimicrobial potential of their precursors in the fungal extracts and were rapidly produced and consumed within 4 days of microbial growth.

Mass spectrometry for characterization of homologous piperidine alkaloids and their activity as acetylcholinesterase inhibitors.

RATIONALE: Piperidine alkaloids from Senna spectabilis constitute a rare class of natural products with several biological activities. However, the absence of chromophores makes their structural elucidation by conventional methods a great challenge. In this context, mass spectrometry emerges as a powerful tool for metabolomics studies. METHODS: The piperidine alkaloids (-)-cassine and (-)-spectaline and the semisynthetic derivatives (-)-3-O-acetylcassine and (-)-3-O-acetylspectaline were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in the positive mode and electron ionization mass spectrometry (EI-MS). ESI fragmentation studies were performed with a quadrupole time-of-flight instrument; N2 was used as collision gas. The acetylcholinesterase inhibitory activity of the investigated compounds was evaluated by bioautography and microplate screening assays. RESULTS: ESI-MS/MS and EI-MS provided valuable and complementary information about the structure of the piperidine compounds. Collision-induced dissociation experiments (MS/MS) revealed that neutral elimination of water or acetic acid is the major fragmentation pathway, which agrees with the stereochemistry proposed for (-)-cassine and (-)-spectaline and the semisynthetic derivatives (-)-3-O-acetylcassine and (-)-3-O-acetylspectaline. CONCLUSIONS: The ESI-MS/MS and EI-MS studies allowed us to propose fragmentation mechanisms for piperidine alkaloids and derivatives. Therefore, mass spectrometry is an important tool for characterizing the structure of these compounds and for supporting further metabolomics studies.

Isolation, leishmanicidal evaluation and molecular docking simulations of piperidine alkaloids from Senna spectabilis.

Leishmaniasis is one of the most important neglected tropical diseases (NTDs) that are especially common among low-income populations in developing regions of Africa, Asia, and the Americas. Many natural products, particularly alkaloids, have been reported to have inhibitory activity against arginase, the key enzyme in the pathology caused by Leishmania sp. In this way, piperidine alkaloids (-)-cassine (1), (-)-spectaline (2), (-)-3-O-acetylcassine (3), and (-)-3-O-acetylspectaline (4) were isolated from Senna spectabilis flowers. These compounds (1/2 and 3/4) initially present as homologous mixtures were separated by high performance liquid chromatography and evaluated against the promastigote phase of Leishmania amazonensis. In addition, molecular docking simulations were implemented in order to probe the binding modes of the ligands 1-4 to the amino acids in the active site of L. amazonensis arginase. Alkaloid 2 (IC50 15.81 µg mL-1) was the most effective against L. amazonensis. Compounds 2 and 4, with larger side chain, were more effective against the parasite than compounds 1 and 3. The cell viability test on Vero cells revealed that compound 2 (CC50 66.67 µg mL-1) was the most toxic. The acetyl group in the 3-O position of the parent structures reduced the leishmanicidal activity and the toxicity of the alkaloids. Further, molecular docking suggested that Asn143 is essential for arginase to interact with (-)-spectaline-derived compounds, which agreed with the IC50 measurements. Our findings revealed that S. spectabilis is an important source of piperidine alkaloids with leishmanicidal activity. Moreover, the natural compound 3 has been isolated for the first time. Experimental investigation combined with theoretical study advances knowledge about the enzyme binding site mode of interaction and contributes to the design of new bioactive drugs against Leishmania infection.

Patterns in Wing Morphology and Fluctuating Asymmetry in Eulaema nigrita along an Altitudinal Gradient in the Brazilian Rupestrian Grassland.

Mountain ecosystems experience abrupt abiotic changes that represent environmental filters for many organisms, shaping their phenotypic expressions. However, little is known about the morphological and symmetric adjustments of native bees along altitudinal gradients. We evaluated the changes on wing morphology, wing size, and vein fluctuating asymmetry (FA) of Eulaema nigrita Lepeletier (Apidae: Euglossini) associated with climatic variables along an altitudinal gradient in the rupestrian grassland (known also as campo rupestre or rupestrian field) of Serra do Cipó, Brazil. Seven sampling points along the altitudinal gradient were selected and distributed among 800 and 1400 m.a.s.l., and then, 40 individuals of E. nigrita were collected per each altitudinal point to determine the FA levels and the morphological changes using geometric morphometric techniques. We found that the wing size of E. nigrita decreased with increasing altitude. At the highest altitudes, the levels of FA of the wing veins were greater compared to bees from lower altitudes. We detected significant changes in wing morphology along the altitudinal gradient; bees of lower altitudes showed longer and wider wings than bees of higher altitudes, which had narrower and less elongated wings. Our results show a set of morphological adjustments and phenotypic expressions in E. nigrita associated with the variation in environmental conditions along the altitudinal gradient. We highlight the importance of environmental variables as insect-stressor factors, and that FA and geometric morphometric can be excellent tools for monitoring and evaluating environmental stresses.

In vitro antiviral activity of piperidine alkaloids from Senna spectabilis flowers on Chikungunya virus infection.

BACKGROUND: Chikungunya fever is an endemic disease caused by the Chikungunya virus (CHIKV). To date there is no antiviral treatment against this infection or licensed vaccine to prevent it. Our study aims to evaluate whether (-)-cassine (1) and (-)-spectaline (2), the main alkaloids of Senna spectabilis, display anti-CHIKV activity. Both compounds have been described to be biologically active against neglected tropical diseases, including malaria, leishmaniasis, and schistosomiasis, which emphasizes that these molecules could be repurposed for chikungunya fever treatment. METHODS: The structures of the isolated compounds 1 and 2 were identified by NMR and HRESIMS analyses, and their antiviral activity against CHIKV was assessed by a dose-response assay employing BHK-21 cells and CHIKV-nanoluc, a recombinant virus carrying the nanoluciferase gene reporter. RESULTS: Compound 1 presented CC50 of 126.5 µM and EC50 of 14.9 µM, while compound 2 presented CC50 of 91.9 µM and EC50 of 8.3 µM. The calculated selectivity index (SI) was 8.5 for 1 and 11.3 for 2. CONCLUSION: The data presented herein show that compounds 1 and 2 have potential for being repurposed as anti-CHIKV drug. Our promising in vitro results encourage further in vitro and in vivo assays. This is the first description of the antiviral activity of compounds 1 and 2 against CHIKV infection, which can impact the development of antiviral drug candidates against chikungunya fever, which sometimes can be debilitating.

Dissertações e teses da Enfermagem acerca do Serviço de Atendimento Móvel de Urgência: estudo bibliométrico / Tesis de la Enfermería acerca del Servicio de Atención Móvil de Urgencia: estudio bibliométrico / Nursing dissertations and theses on the Mobile Emergency Care Services: a bibliometric study

RESUMO Objetivo: analisar a produção brasileira de dissertações e teses em enfermagem que abordem o Serviço de Atendimento Móvel de Urgência. Método: estudo bibliométrico realizado por meio do acesso virtual ao Centro de Estudos e Pesquisa em Enfermagem, da Associação Brasileira de Enfermagem, e ao Portal de Teses e Dissertações da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior. A amostra foi composta por quatro teses e nove dissertações. Resultados: verificou-se maior quantitativo de estudos nas regiões Sul (38,5%) e Sudeste (46,2%), o predomínio de estudos descritivo-exploratórios, com abordagem qualitativa, a temática mais explorada foi a saúde do trabalhador no contexto pré-hospitalar móvel e a população mais investigada foram os profissionais. Conclusão: a partir dos indicadores bibliométricos, constatou-se uma limitada quantidade de trabalhos acerca do Serviço de Atendimento Móvel de Urgência nos Programas de Pós-Graduação em Enfermagem e lacunas relativas à temática nas pesquisas desses Programas. Essas constatações podem direcionar a realização de futuros estudos.

RESUMEN Objetivo: analizar la producción brasileña de disertaciones y tesis en enfermería que se refieran al Servicio de Atención Móvil de Urgencia. Método: estudio bibliométrico realizado por medio del acceso virtual al Centro de Estudios e Investigaciones en Enfermería de la Asociación Brasileña de Enfermería y al Portal de Tesis y Disertaciones de la Coordinación de Perfeccionamiento Personal de Nivel Superior. La muestra estaba compuesta por cuatro tesis y nueve disertaciones. Resultados: se ha verificado una mayor cantidad de estudios en las regiones Sur (38,5%) y Sudeste (46,2%). Hubo un predominio de estudios descriptivos-exploratorios, con abordaje cualitativo; la temática más explorada fue la salud del trabajador en el contexto prehospitalario móvil y la población más investigada fue la de los profesionales. Conclusión: a partir de los indicadores bibliométricos fue posible constatar una cantidad limitada de trabajos sobre el Servicio de Atención Móvil de Urgencia en los Programas de Post-Graduación en Enfermería y espacios relativos a la temática en las investigaciones de esos Programas. Esas constataciones pueden direccionar la realización de futuros estudios.

ABSTRACT Objective: to analyze the production of Brazilian Nursing dissertations and theses on the Mobile Emergency Care Service. Method: a bibliometric study performed through the virtual access of the Centro de Estudos e Pesquisa em Enfermagem, da Associação Brasileira de Enfermagem, and Portal de Teses e Dissertações da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior. The sample consisted of four theses and nine dissertations. Results: there was a greater number of studies in the South (38.5%) and Southeast(46.2%), with a predominance in descriptive-exploratory studies, using qualitative approaches, the most explored topics were worker health in the pre-hospital mobile services and professionals were the most investigated population. Conclusion: based on bibliometric indicators, there was a limited amount of papers regarding the Mobile Emergency Care Service in the Nursing Graduate Programs and gaps were found related to the research of these programs. These findings may direct future studies.