Coimbra Chemistry Center

Funder

Organizational Unit

Publications

Edible flowers of Helichrysum italicum: Composition, nutritive value, and bioactivities

Publication . Primitivo, Maria João; Neves, Marta; Pires, Cristiana L.; Cruz, Pedro F.; Brito, Catarina; Rodrigues, Ana C.; Carvalho, Carla C. C. R. de; Mortimer, Megan M.; Moreno, Maria João; Brito, Rui M. M.; Taylor, Edward J.; Millson, Stefan H.; Reboredo, Fernando; Campos, Maria; Vaz, Daniela C.; Ribeiro, Vânia

Helichrysum italicum (H. italicum) is a halophyte shrub with bright yellow flowers with a strong curry-like aroma. The essential oils of H. italicum have been used in the production of cosmetics and pharmaceuticals, due to their antiallergic and anti-inflammatory properties. In the agri-food sector, H. italicum flowers can be used for seasoning and flavoring food, and as natural food preservatives. Here, we report on the composition, bioactive compounds, and nutritive value of H. italicum flowers. Flowers were mainly composed of carbohydrates (>80 % dry weight), followed by minerals (6.31 ± 0.95 % dw), protein (5.44 ± 0.35 % dw), and lipids (3.59 % ± 0.53 % dw). High percentages of Fe, Zn, Ca, and K were found in the flower material, along with a high content in antioxidants, polyphenols, and carotenoids, as corroborated by the nuclear magnetic resonance (NMR) data. Flowers were mainly composed of saturated fatty acids (SFAs) (54.50 ± 0.95 % of total FA), followed by polyunsaturated fatty acids (PUFAs) (37.73 ± 1.25 % of total FA) and monounsaturated fatty acids (MUFAs) (7.77 ± 0.34 %), as detected by gas chromatography mass spectrometry (GC–MS). The omega-6 PUFA linoleic acid (22.55 ± 0.76 % of total FA) was the most abundant fatty acid found. Flower extracts showed antimicrobial activity against Saccharomyces cerevisiae and Komagataella phaffii, as well as against Gram-negative (Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus) bacteria. H. italicum flower material was nontoxic to human intestinal Caco-2 model cells at concentrations up to 1.0 % w/v.

2022Journal article

Restricted access

BSA-PEG Hydrogel: A Novel Protein-Ligand Binding 3D Matrix

Publication . Coelho, Carlos D. F.; Jesus, João A.; Vaz, Daniela C.; Lagoa, Ricardo; Moreno, Maria João

Hydrogel materials have good biomimetic properties and high potential for biomedical and bioanalytical applications. In this work, a hydrogel of serum albumin crosslinked with poly-(ethylene glycol) was prepared and characterized for its water content, protein structure and stability. The ability of the hydrogel to bind small molecule ligands with different hydrophobicity was evaluated using a homologous series of amphiphiles (NBD-Cn, n = 4, 6 and 8) and the calculated binding affinities were similar to that of free protein in solution. Overall, the results indicate this type of hydrogel system as a convenient tool for studying the binding of xenobiotics to tissue proteins.

2022-08-25Journal article

Open access

Transthyretin mutagenesis: impact on amyloidogenesis and disease

Publication . Almeida, Zaida L.; Vaz, Daniela C.; Brito, Rui M. M.

Transthyretin (TTR), a homotetrameric protein found in plasma, cerebrospinal fluid, and the eye, plays a pivotal role in the onset of several amyloid diseases with high morbidity and mortality. Protein aggregation and fibril formation by wild-type TTR and its natural more amyloidogenic variants are hallmarks of ATTRwt and ATTRv amyloidosis, respectively. The formation of soluble amyloid aggregates and the accumulation of insoluble amyloid fibrils and deposits in multiple tissues can lead to organ dysfunction and cell death. The most frequent manifestations of ATTR are polyneuropathies and cardiomyopathies. However, clinical manifestations such as carpal tunnel syndrome, leptomeningeal, and ocular amyloidosis, among several others may also occur. This review provides an up-to-date listing of all single amino-acid mutations in TTR known to date. Of approximately 220 single-point mutations, 93% are considered pathogenic. Aspartic acid is the residue mutated with the highest frequency, whereas tryptophan is highly conserved. “Hot spot” mutation regions are mainly assigned to β-strands B, C, and D. This manuscript also reviews the protein aggregation models that have been proposed for TTR amyloid fibril formation and the transient conformational states that convert native TTR into aggregation-prone molecular species. Finally, it compiles the various in vitro TTR aggregation protocols currently in use for research and drug development purposes. In short, this article reviews and discusses TTR mutagenesis and amyloidogenesis, and their implications in disease onset.

2024Journal article

Open access

Morphological and Molecular Profiling of Amyloid-β Species in Alzheimer’s Pathogenesis

Publication . Almeida, Zaida L.; Vaz, Daniela C.; Brito, Rui M. M.

Alzheimer’s disease (AD) is the most common form of dementia around the world (~ 65%). Here, we portray the neuropathology of AD, biomarkers, and classifcation of amyloid plaques (difuse, non-cored, dense core, compact). Tau pathology and its involvement with Aβ plaques and cell death are discussed. Amyloid cascade hypotheses, aggregation mechanisms, and molecular species formed in vitro and in vivo (on- and of-pathways) are described. Aβ42/Aβ40 monomers, dimers, trimers, Aβ‐derived difusible ligands, globulomers, dodecamers, amylospheroids, amorphous aggregates, protofbrils, fbrils, and plaques are characterized (structure, size, morphology, solubility, toxicity, mechanistic steps). An update on AD-approved drugs by regulatory agencies, along with new Aβ-based therapies, is presented. Beyond prescribing Aβ plaque disruptors, cholinergic agonists, or NMDA receptor antagonists, other therapeutic strategies (RNAi, glutaminyl cyclase inhibitors, monoclonal antibodies, secretase modulators, Aβ aggregation inhibitors, and anti-amyloid vaccines) are already under clinical trials. New drug discovery approaches based on “designed multiple ligands”, “hybrid molecules”, or “multitarget-directed ligands” are also being put forward and may contribute to tackling this highly debilitating and fatal form of human dementia.

2024-10-24Journal article

Open access

Fortified chocolate mousse with powder and extract from Moringa oleifera leaves for nutritional value improvement

Publication . Gomes, Olívia J.S.; Leitão, Anabela; Gaspar, Marisa C.; Vitorino, Carla; Sousa, João J.S.; Sousa, Hermínio C. de; Braga, Mara E.M.; Gando-Ferreira, Licínio M.

This study focuses on the characterisation and incorporation of Moringa oleifera leaf powder (MOP) from Luanda (Angola) and its extract (MOE) in fortified chocolate mousse. Dark green (DG) leaves presented superior nutritional values compared to other leaves. DG contained a higher concentration of mineral salts (10 ± 1 mg/100 g of dry leaves), phenolic compounds (267 ± 4 mg GAE/g), vitamins (1.9 ± 0.2 mg/g of dry extract) and strong antioxidant capacity (IC50, 115 ± 8 µg/mL). Therefore, DG leaves were used to fortify the chocolate mousse. The leaves were prepared in three samples: control, 2 % MOP (w/w) and 2 % MOE (v/v). Textural and rheological analysis of chocolate mousse samples revealed a pseudoplastic profile for all samples, with decreased texture attributes and viscosity due to the incorporation. The sensory evaluation demonstrated that MOP and MOE samples presented 93 % and 88 % resemblance to the original product regarding general acceptance, respectively.

2024-05Journal article

Open access