La ciudad como experiencia de conocimiento: nuevas metodologías de aprendizaje, iniciación a la investigación y extensión universitaria a partir de la historia urbana

Memoria que recoge las actividades desarolladas en el proyecto de Innovación docente 327 de 2020 con título La ciudad como experiencia de conocimiento: nuevas metodologías de aprendizaje, iniciación a la investigación y extensión universitaria a partir de la historia urbana y dirigido por Rubén Pallol Trigueros

Développement de nouvelles approches méthodologiques en Chromatographie de Partage Centrifuge en vue de la purification de molécules d intérêt

REIMS-BU Santé (514542104) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Different Ways to On-Line Hyphenate Centrifugal Partition Chromatography and Mass Spectrometry: Application to Prenylated Xanthones from Garcinia mangostana

Centrifugal partition chromatography is a liquid-liquid separation method well adapted for the fractionation or purification of natural compounds from plant extracts. However, following the preparative isolation, the fractions collected must be analysed by high-performance thin-layer chromatography or high-performance liquid chromatography to evaluate their composition and/or their purity. These additional steps are time-consuming and increase the risk of compound degradation. In order to get an instantaneous analysis of fraction content with structural information on the phytochemicals eluted, it is possible to hyphenate on-line centrifugal partition chromatography with mass spectrometry. Depending on the complexity of the extract, two different kinds of centrifugal partition chromatography-mass spectrometry coupling can be performed: centrifugal partition chromatography-mass spectrometry or centrifugal partition chromatography-high-performance liquid chromatography-mass spectrometry coupling. In the first case, one part of the centrifugal partition chromatography effluent is directly introduced in the mass spectrometry ionisation source to identify the eluted compounds, while in the second case, it is directed to a high-performance liquid chromatography-mass spectrometry system where compounds are first separated thanks to high-performance liquid chromatography and then identified using mass spectrometry

Preparative isolation of glucosinolates from various edible plants by strong ion-exchange centrifugal partition chromatography

International audienceGlucosinolates (GSLs) are a class of phytochemicals found in all calciferous plants (Brassicaceae) family as well as in the whole order of Brassicales (syn. Capparales). GSLs and their hydrolysis products (e.g. isothiocyanates) are known to play a defensive role by protecting the plant against exterior aggressions and may be potent antitumor, anticancer, antioxidant and antibiotic agents. In order to obtain pure GSLs standards for developing research, an efficient two-step method was developed to preparatively isolate and separate GSLs from papaya (Carica papaya), upland cress (Barbarea verna), cauliflower (Brassica oleracea L. var. botrytis L.), and broccoletti seeds (Brassica rapa ruvo). In this process, solvent extraction was followed by a strong anion-exchange centrifugal partition chromatography protocol. TLC, HPLC-PDA, ESI-MS and NMR analysis of the collected fractions, demonstrated that the GSLs from papaya and upland cress seeds (i.e. glucotropaeolin and gluconasturtiin, respectively) as well as all the GSLs from cauliflower and broccoletti seeds (i.e. sinigrin, glucoiberin, glucoiberverin, gluconapin, glucobrassicanapin and gluconasturtiin) can be purified in a single chromatographic step. Gram amounts of pure reference standards were obtained. These results will facilitate investigation of the biological activities and the isolation of such compounds in other crucifers. (C) 2011 Published by Elsevier B.V

Bio-Guided Targeting for Preservative and Anti-Ageing Cosmetic Ingredient Development

To develop a new antioxidant, antibacterial and natural cosmetic ingredient without cytotoxicity to skin cells, bioactive molecules contained in Kalanchoe pinnata leaf methanolic extract were targeted using semi-preparative HPLC fractionation linked to biological activity tests. Chromatographic effluent was collected at the column outlet into a 96 deep-well microplate, filling successively all the wells. After freeze-drying, the microplate was ready to use for different biological tests such as antimicrobial activity on microorganisms, skin cell viability and antioxidant activity on human keratinocyte cells. The injection of only 2.64 mg of crude extract into the HPLC system reveals a good correlation between the chromatographic peaks and the different biological activities. One fraction is mainly of interest since good antibacterial and antioxidant activities without cytotoxicity are observed. The analysis of this fraction using mass spectrometry allows the identification of glycoside derivatives of quercetin, isorhamnetin and kaempferol. Thus, a correlation between biological activity and the presence of these flavonoids is obtained. This screening method allows a rapid fractionation associated with a biological activity evaluation and a first molecular identification, saving time by limiting sample treatments and solvent consumption

Marine versus Non-Marine Bacterial Exopolysaccharides and Their Skincare Applications

Bacteria are well-known to synthesize high molecular weight polysaccharides excreted in extracellular domain, which constitute their protective microenvironment. Several bacterial exopolysaccharides (EPS) are commercially available for skincare applications in cosmetic products due to their unique structural features, conferring valuable biological and/or textural properties. This review aims to give an overview of bacterial EPS, an important group of macromolecules used in cosmetics as actives and functional ingredients. For this purpose, the main chemical characteristics of EPS are firstly described, followed by the basics of the development of cosmetic ingredients. Then, a focus on EPS production, including upstream and downstream processes, is provided. The diversity of EPS used in the cosmetic industry, and more specifically of marine-derived EPS is highlighted. Marine bacteria isolated from extreme environments are known to produce EPS. However, their production processes are highly challenging due to high or low temperatures; yield must be improved to reach economically viable ingredients. The biological properties of marine-derived EPS are then reviewed, resulting in the highlight of the challenges in this field

Blocking negative effects of senescence in human skin fibroblasts with a plant extract

Skin aging: Plant extract blocks negative effects of senescence A plant extract from the goldenrod (Solidago virgaurea) ameliorates the negative influence of senescent cells, which accumulate in the skin with aging and create a tissue environment that leads to an impaired skin structure and contributes to tumour formation. Ingo Lämmermann and a team of scientists under the lead of Johannes Grillari at the University of Natural Resources and Life Sciences, Vienna, Austria, screened several plant extracts for their potential to attenuate such detrimental effects of senescent cells on the skin. One extract from S. virgaurea indeed delayed the aging process of skin cells in vitro and reduced the secretion of tumour promoting molecules and pro-inflammatory factors, thereby ameliorating the negative influence on nearby cells. Thus, the investigated plant extract represents a promising possibility to block the age-associated loss of tissue functionality in human skin