Associated Laboratory for Green Chemistry - Clean Technologies and Processes

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Vanadium(V) complexes supported on porous MIL-100(Fe) as catalysts for the selective oxidation of toluene

Publication . Sutradhar, Manas; Marques, Guilherme; Soliman, Mohamed M. A.; Guedes Da Silva, M. Fátima C.; Flores, Daniela S. S.; Granadeiro, Carlos; Balula, Salete; Pombeiro, Armando; Alegria, Elisabete

The vanadium(V) complexes bearing the aroylhydrazone Schiff base 2-hydroxy-N'-((2-hydroxynaphthalen-1-yl) methylene)benzohydrazide ligand [VO(OMe)L] (1) and [Et3NH][VO2L] (2) were synthesized, characterized and supported on porous MIL-100(Fe) forming the 1@MIL-100(Fe) and 2@MIL-100(Fe) composites. The outcome of such immobilizations was assessed by several characterization techniques, namely powder X-ray diffraction, UV/ Vis, FTIR, SEM-EDS, ICP and BET surface area analysis, confirming the successful heterogenization of both va-nadium complexes. They were screened as catalysts towards the oxidation of toluene, under homogenous (1 and 2) and heterogeneous (1@MIL-100 and 2@MIL-100) conditions. The influence of several parameters, namely the type and amount of catalyst or oxidant, reaction time, temperature, and radical trapping, was studied. The main products obtained were benzaldehyde, benzyl alcohol and benzoic acid. Under the optimized conditions, using 1 and 2 as homogeneous catalysts, total yields of 19 and 23%, respectively, were achieved at 80 degrees C after 6 h. Using 1@MIL100(Fe) and 2@MIL100(Fe) composites under heterogeneous conditions, total yields up to 11% after 24 h, were achieved.

2022-08Journal article

Restricted access

Exploring the Hypocholesterolemic Potential of a Fucus vesiculosus Extract: Omic Insights into Molecular Mechanisms at the Intestinal Level

Publication . Rebeca, André; Pacheco, Rita; Santos, Hugo M.; Serralheiro, Maria Luisa

High blood cholesterol levels are a major risk factor for cardiovascular diseases. A purified aqueous extract of Fucus vesiculosus, rich in phlorotannins and peptides, has been described for its potential to inhibit cholesterol biosynthesis and intestinal absorption. In this work, the effect of this extract on intestinal cells' metabolites and proteins was analysed to gain a deeper understanding of its mode of action on lipids' metabolism, particularly concerning the absorption and transport of exogenous cholesterol. Caco-2 cells, differentiated into enterocytes, were exposed to the extract, and analysed by untargeted metabolomics and proteomics. The results of the metabolomic analysis showed statistically significant differences in glutathione content of cells exposed to the extract compared to control cells, along with an increased expression of fatty acid amides in exposed cells. A proteomic analysis showed an increased expression in cells exposed to the extract compared to control cells of FAB1 and NPC1, proteins known to be involved in lipid metabolism and transport. To the extent of our knowledge, this study is the first use of untargeted metabolomics and a proteomic analysis to investigate the effects of F. vesiculosus on differentiated Caco-2 cells, offering insights into the molecular mechanism of the extract’s compounds on intestinal cells.

2024-04-20Journal article

Open access

The hypocholesterolemic potential of the edible algae fucus vesiculosus: Proteomic and quantitative PCR analysis

Publication . André, Rebeca; Pacheco, Rita; Alves, Ana Catarina; Santos, Hugo M. M.; Bourbon, Mafalda; Serralheiro, Maria Luisa

A brown seaweed consumed worldwide, Fucus vesiculosus, has been used to prevent atherosclerosis and hypercholesterolemia, among other uses. However, the mechanisms of action that lead to these effects are not yet fully understood. This work aims to study the in vitro effect of an aqueous extract of F. vesiculosus, previously characterized as rich in phlorotannins and peptides, on the expression of different proteins involved in the synthesis and transport of cholesterol. A proteomic analysis, Western blot, and qRT-PCR analysis were performed to identify protein changes in HepG2 cells exposed to 0.25 mg/mL of the F. vesiculosus extract for 24 h. The proteomic results demonstrated that, in liver cells, the extract decreases the expression of four proteins involved in the cholesterol biosynthesis process (CYP51A1, DHCR24, HMGCS1 and HSD17B7). Additionally, a 12.76% and 18.40% decrease in the expression of two important transporters proteins of cholesterol, NPC1L1 and ABCG5, respectively, was also observed, as well as a 30% decrease in NPC1L1 mRNA levels in the cells exposed to the extract compared to control cells. Our study reveals some of the mechanisms underlying the actions of bioactive compounds from F. vesiculosus that may explain its previously reported hypocholesterolemic effect, future prospecting its use as a functional food.

2023-07-20Research article

Open access