Electrochemical Conversion of the Lignin Model Veratryl Alcohol to Veratryl Aldehyde Using Manganese(III)-Schiff Base Homogeneous Catalysts

Lignin and other colored structures need to be bleached after the Kraft process in the pulp industry. Development of environmentally-safe bleaching catalysts or electrocatalysts constitutes an attractive strategy for selective removal of lignin. Seven manganese(III)-complexes with Schiff base ligands 1–7 were synthetized and characterized by different analytical and spectroscopic techniques. The tetragonally elongated octahedral geometry for the manganese coordination sphere and the global µ-aquo dimeric structure were revealed by X-ray diffraction (XRD) studies for 1, Mn2L12(H2O)2(N(CN)2)2 (N(CN)2 = dicyanamide). Complexes 1–4 behave as more efficient peroxidase mimics as compared to 5–7. Electrochemical oxidation of the lignin model veratrylalcohol (VA) to veratrylaldehyde (VAH) is efficiently catalyzed by a type of dimanganese(III) complexes in a chlorine-free medium. The electrocatalytic reaction proceeds through the oxidation of chloride into hypochlorite at alkaline pH along with the formation of hydrogen from water as a subproductThis research was funded by Xunta de Galicia (GRC GI-1584-ED431C2018/13 Suprabioin Research Group, and MetalBIO Network ED431D 2017/01)S

Neuroprotective effects of fluorophore-labelled manganese complexes: determination of ROS production, mitochondrial membrane potential and confocal fluorescence microscopy studies in neuroblastoma cells

In this work, four manganese(II) complexes derived from the ligands H2L1-H2L4, that incorporate dansyl or tosyl fluorescent dyes, have been investigated in term of their antioxidant properties. Two of the manganese(II) complexes have been newly prepared using the asymmetric half-salen ligand H2L2 and the thiosemicarbazone ligand H2L3. The four organic strands and the manganese complexes have been characterized by different analytical and spectroscopic techniques. The study of the antioxidant behaviour of these two new complexes and other two fluorophore-labelled analogues was tested in SH-SY5Y neuroblastoma cells. These four model complexes 1–4 were found to protect cells from oxidative damage in this human neuronal model, by reducing the release of reactive oxygen species. Complexes 1–4 significantly improved cell survival, with levels between 79.1 ± 0.8% and 130.9 ± 4.1%. Moreover, complexes 3 and 4 were able to restore the mitochondrial membrane potential at 1 μM, with 4 reaching levels higher than 85%, similar to the percentages obtained by the positive control agent cyclosporin A. The incorporation of the fluorescent label in the complexes allowed the study of their ability to enter the human neuroblastoma cells by confocal microscopyThe research leading to these results has received funding from the following FEDER cofunded-grants. From Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia, 2017 GRC GI-1682 (ED431C 2017/01), 2018 GRC GI-1584 (ED431C 2018/13), MetalBIO Network (ED431D 2017/01). From CDTI and Technological Funds, supported by Ministerio de Economía, Industria y Competitividad IISCIII/PI19/001248. From Ministerio de Ciencia, Innovación y Universidades, MULTIMETDRUGS (RED2018-102471-T). From European Union, Interreg AlertoxNet EAPA-317-2016, Interreg Agritox EAPA-998-2018, and H2020 778069-EMERTOXS

Estudio de la aplicabilidad de catalizadores biomiméticos con actividad redox en procesos químicos y farmacológicos

En la presente tesis se desarrollan nuevos modelos artificiales que puedan reproducir la actividad de enzimas con actividad redox. Los modelos biomiméticos desarrollados son metalocompuestos de manganeso y oro con diferentes ligandos entre los que se incluyen bases de Shiff, benzoimidazol y tiosemicarbazonas. Estos nuevos compuestos se pueden agrupar en dos grandes aplicaciones que son útiles para la industria química (descomposición fotolítica de la molécula de agua y degradación selectiva de la lignina) o farmacológica : actividad antioxidante (compuestos miméticos de la catalasa y la superóxido dismutasa) y antitumoral.2022-11-2

Abrindo camiños: as nosas pioneiras de ciencias

Nesta comunicación queremos presentar as mulleres pioneiras de Lugo que a finais do século XIX e comezo do XX estudaron carreiras universitarias de Ciencias. Pretendemos dar unha visión do comezo da presenza da muller na universidade e máis concretamente nas carreiras consideradas de ciencias (Farmacia, Medicina, Física, Química, Matemáticas), mostrar o desenvolvemento da súa actividade profesional e que así sexa coñecido o seu labor e valorado na súa xusta medida. É máis importante e destacada do que poderiamos pensar, xa que como veremos temos un bo número de mulleres pioneiras que se prepararon e que desenvolveron a súa profesión dunha maneira seria e calada, que fixo que pasaran case desapercibidas salvo para as mulleres próximas, parentes ou non, e que as tomaron como exemplo para seguir a mesma traxectoria. Con esta visión feminista amosamos ás que hoxe desenvolven a práctica docente e ás novas xeracións o camiño xa feito, para tamén deixar patente o noso agradecemento ás loitadoras polo dereito a facer unha carreira universitaria, á par que as recoñecemos como exemplo e incidimos no que aínda nos queda por conseguir. Rescatar e poñer en valor estas pioneiras é contar esa metade da historia que está por contar, así como sentar as bases sobre as que se basearon e desenvolveron os estudos e profesións das mulleres actuais que nun número pequeno pero importante xa vai formando parte do mundo científico e tecnolóxico, mulleres que cursaron e cursan carreiras STEM ‹Science, Technology, Engineering and Mathematics

Combined effect of caspase-dependent and caspase-independent apoptosis in the anticancer activity of gold complexes with phosphine and benzimidazole derivatives

Since the potential anticancer activity of auranofin was discovered, gold compounds have attracted interest with a view to developing anticancer agents that follow cytotoxic mechanisms other than cisplatin. Two benzimidazole gold(I) derivatives containing triphenylphosphine (Au(pben)(PPh3)) (1) or triethylphosphine (Au(pben)(PEt3)) (2) were prepared and characterized by standard techniques. X-ray crystal structures for 1 and 2 were solved. The cytotoxicity of 1 and 2 was tested in human neuroblastoma SH-SY5Y cells. Cells were incubated with compounds for 24 h with concentrations ranging from 10 µM to 1 nM, and the half-maximal inhibitory concentration (IC50) was determined. 1 and 2 showed an IC50 of 2.7 and 1.6 µM, respectively. In order to better understand the type of cell death induced by compounds, neuroblastoma cells were stained with Annexin-FITC and propidium iodide. The fluorescence analysis revealed that compounds were inducing apoptosis; however, pre-treatment with the caspase inhibitor Z-VAD did not reduce cell death. Analysis of compound effects on caspase-3 activity and reactive oxygen species (ROS) production in SH-SY5Y cells revealed an antiproliferative ability mediated through oxidative stress and both caspase-dependent and caspase-independent mechanisms.Xunta de Galicia | Ref. 2017 GRC GI-1682 (ED431C 2017/01)Xunta de Galicia | Ref. 2018 GRC GI-1584 (ED431C 2018/13)Xunta de Galicia | Ref. MetalBIO Network (ED431D 2017/01)Ministerio de Economía, Industria y Competitividad (España) | Ref. CTQ2015-65707-C2-2-PMinisterio de Economía, Industria y Competitividad (España) | Ref. AGL2016-78728-R (AEI/FEDER, UE)Ministerio de Economía, Industria y Competitividad (España) | Ref. ISCIII/PI16/01830Ministerio de Economía, Industria y Competitividad (España) | Ref. RTC-2016-5507-2Ministerio de Economía, Industria y Competitividad (España) | Ref. ITC-20161072European Commission | Ref. AGRITOX EAPA-998-2018European Commission | Ref. Alertox-Net EAPA-317-2016European Commissio