Caracterización química, evaluación de la actividad antioxiodante y antibacterial del extracto crudo de Psittacanthus cucullaris

Para determinar la naturaleza química de la especie Psittacanthus cucullaris (pajarito o matapalo) se realizó una marcha fitoquímica al extracto crudo de las hojas, encontrándose la presencia de metabolitos como flavonoides, cumarinas, antraquinonas, taninos, triterpenos y alcaloides. Se obtuvieron fracciones de alta, media y baja polaridad a partir de dicho extracto, a las cuales se le determinó el contenido de fenoles totales, la actividad antioxidante mediante técnicas in vitro (DPPH y FRAP), así como también la actividad antibacteriana frente a Pseudonomas aeruginosa ATCC 9027 y Microccocus luteus ATCC 9341. Los valores más altos en el contenido de fenoles totales y de actividad antioxidante correspondieron a la fracción butanólica, la fracción acuosa residual, y la fracción de acetato de etilo. El extracto crudo y las fracciones de alta, media y baja polaridad no presentaron actividad contra las cepas de bacterias ensayadas

Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides

Eight new sulfide-based cyclic peptidomimetic analogues of solonamides A and B have been synthesized via solid-phase peptide synthesis and SN2’ reaction on a Morita–Baylis–Hillman (MBH) residue introduced at the N-terminal of a tetrapeptide. This last step takes advantage of the electrophilic feature of the MBH residue and represents a new cyclization strategy occurring. The analogues were prepared in moderate overall yields and did not show toxic effects on Staphylococcus aureus growth and were not toxic to human fibroblasts. Two of them inhibited the hemolytic activity of S. aureus, suggesting an interfering action in the bacterial quorum sensing similar to the one already reported for solonamides

Estudio fitoquímico preliminar y de actividad antimicrobiana de la especie Lippia alba originaria del Piedemonte Amazónico

Un estudio químico preliminar de extractos de Hexano, Acetato de etilo y Metanol permitió establecer la presencia de flavonoides, taninos, y terpenos presentes en la especie Lippia alba que crece en los alrededores de Florencia-Caquetá, región Sur-oriental de Colombia. La composición de su aceite esencial fue determinada por cromatografía de gases-masas (CG-MS) cuyo análisis permitió indicar por primera vez el quimiotipo Carvona, 1,8-cineol, limoneno; en función de los tres componentes mayoritarios. Tanto extractos como su aceite fueron ensayados de manera preliminar contra las bacterias Pseudomona aeuriginosa, Ralstonia pickettii, Enterobacter cloacae, Staphylococcus aureus, Cándida albicans, y Escherichia coli. El aceite esencial mostró actividad moderada contra todos estos microorganismos mientras que de los extractos solamente el acetato de etilo mostró actividad, también moderada contra el patógeno Escherichia coli

Neuroprotective effects on microglia and insights into the structure–activity relationship of an antioxidant peptide isolated from Pelophylax perezi

© 2022 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly citedTryptophyllins constitute a heterogeneous group of peptides that are one of the first classes of peptides identified from amphibian's skin secretions. Here, we report the structural characterization and antioxidant properties of a novel tryptophyllin-like peptide, named PpT-2, isolated from the Iberian green frog Pelophylax perezi. The skin secretion of P. perezi was obtained by electrical stimulation and fractionated using RP-HPLC. De novo peptide sequencing was conducted using MALDI MS/MS. The primary structure of PpT-2 (FPWLLS-NH2 ) was confirmed by Edman degradation and subsequently investigated using in silico tools. PpT-2 shared physicochemical properties with other well-known antioxidants. To test PpT-2 for antioxidant activity in vitro, the peptide was synthesized by solid phase and assessed in the chemical-based ABTS and DPPH scavenging assays. Then, a flow cytometry experiment was conducted to assess PpT-2 antioxidant activity in oxidatively challenged murine microglial cells. As predicted by the in silico analyses, PpT-2 scavenged free radicals in vitro and suppressed the generation of reactive species in PMA-stimulated BV-2 microglia cells. We further explored possible bioactivities of PpT-2 against prostate cancer cells and bacteria, against which the peptide exerted a moderate antiproliferative effect and negligible antimicrobial activity. The biocompatibility of PpT-2 was evaluated in cytotoxicity assays and in vivo toxicity with Galleria mellonella. No toxicity was detected in cells treated with up to 512 µg/ml and in G. mellonella treated with up to 40 mg/kg PpT-2. This novel peptide, PpT-2, stands as a promising peptide with potential therapeutic and biotechnological applications, mainly for the treatment/prevention of neurodegenerative disorders.This work was financed by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalization (POCI), and by Portuguese funds through FCT - Fundação para a Ciência e a Tecnologia in the framework of the project POCI-01-0145-FEDER-031158 – PTDC/BII-BIO/31158/2017. The authors would like to thank the participation and scientific support of the Unit projects UIDB/50006/2020 | UIDP/50006/2020, and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Universal Faixa ‘B’ (grant number 32103/2018-0). A.P. is a recipient of a post-doctoral grant from the project PTDC/BII-BIO/31158/2017. The authors would like to thank the researcher Roberto Resendes (CiBio, University of the Azores, Ponta Delgada, São Miguel, Azores, Portugal) for the logistical support in the collection of samples. C.P.A acknowledges FCT-MCTES fellowship PD/BD/136860/2018. A.B.-N. and F.C.D.A.L. acknowledge CNPq (grants 420449/2018-3 and 428211/2018-6) for financial support.info:eu-repo/semantics/publishedVersio

Búsqueda de Compuestos Inhibidores de Quorum Sensing (IQS) a Partir de Extractos de Origen Natural. Primera Fase

La búsqueda de sustancias inhibidoras de quorum sensing (IQS) a partir de fuentes naturales resulta interesante por sus aplicaciones en las ciencias biomédicas y en la prevención del fouling. En esta investigación se exploraron 52 extractos de organismos marinos y plantas como fuentes de IQS usando dos biosensores. Esto permitió identificar que aproximadamente la cuarta parte de los extractos marinos son bioactivos. Luego se procedió a seleccionar los tres extractos más activos para su estudio químico. Así, a partir del extracto polar de Cecropia pachystachya, el más activo, se aislaron flavonoides que mostraron inhibición de quorum sensing, sin afectar el crecimiento de microorganismos; lo que sugiere que estos compuestos tienen un gran potencial para su uso en tecnologías antifouling. Asimismo, los extractos de las esponjas Ircinia felix y Svenzea tubulosa presentaron actividad IQS moderada, identificándose mezclas de ácidos grasos como las responsables de la actividad. Para la primera especie además se identificaron algunos furanosesterterpenos, relacionados estructuralmente con moléculas autoinductoras del QS, la cuales mostraron moderada actividad IQS. / Abstract. The searching of quorum sensing inhibitors (QSI) from natural sources is interesting because of the applications in biomedical sciences and preventing fouling. This research explored 52 extracts of marine organisms and plants as sources of QSI using two biosensors. This revealed that approximately quarter of marine extracts evaluated were bioactive. Then it was proceeded to select the three most active extracts for chemical study. Thus, from the polar extract of Cecropia pachystachya, the most active extract, there were isolated flavonoids that showed an important quorum sensing inhibition without affecting the growth of microorganisms, suggesting that these compounds have great potential for use in antifouling technologies. In addition, extracts of the sponges Ircinia felix and Svenzea tubulosa presented moderate QSI, where it was identified a mixture of fatty acids as responsable for bioactivity. For Ircinia felix there were also identified furanosesterterpenes, structurally related with autoinducer molecules of QS, with moderate IQS actyivityMaestrí

Marine organisms as source of extracts to disrupt bacterial communication: bioguided isolation and identification of quorum sensing inhibitors from Ircinia felix

AbstractIn this study, 39 extracts from marine organisms were evaluated as quorum sensing inhibitors, collected in the Colombian Caribbean Sea and the Brazilian Coast including 26 sponges, seven soft corals, five algae and one zooanthid. The results showed that crude extracts from the soft coral Eunicea laciniata, and the sponges Svenzea tubulosa, Ircinia felix and Neopetrosia carbonaria were the most promising source of quorum sensing inhibitors compounds without affecting bacterial growth, unlike the raw extracts of Agelas citrina, Agelas tubulata, Iotrochota arenosa, Topsentia ophiraphidites, Niphates caycedoi, Cliona tenuis, Ptilocaulis walpersi, Petrosia pellasarca, and the algae Laurencia catarinensis and Laurencia obtusa, which displayed potent antibacterial activity against the biosensors employed. The crude extract from the sponge I. felix was fractionated, obtaining furanosesterterpenes which were identified and evaluated as quorum sensing inhibitors, showing a moderate activity without affecting the biosensor's growth