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Research Project
Mountain Research Center
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Publications
Roots and rhizomes of wild Asparagus: nutritional composition, bioactivity and nanoencapsulation of the most potent extract
Publication . Adouni, Khaoula; Júlio, Ana; Santos-Buelga, Celestino; González-Paramás, Ana M.; Filipe, Patrícia; Rijo, Patricia; Costa Lima, Sofia A.; Reis, Salette; Fernandes, Ângela; Ferreira, Isabel C.F.R.; Fernández-Ruiz, Virginia; Morales, Patricia; Flamini, Guido; Achour, Lotfi; Fonte, Pedro
The nutritional composition and bioactive properties of roots and rhizomes of Asparagus stipularis were evalu-
ated. Antioxidant activity of extracts obtained by infusion was evaluated using free radicals scavenging and
reducing power methods. Porcine liver primary cell was used to check the hepatotoxicity of infusions. Results
revealed that Asparagus samples are likely a source of nutrients, such as dietary fibre and essential fatty acids.
HPLC-DAD-ESI/MS characterization of infusions allowed the identification and quantitation of 7 phenolic
compounds, all hydroxycinnamoyl derivatives, with caffeic acid as the most abundant. Roots infusion contained
the highest amounts of these compounds. It also exhibited the highest antioxidant activity in all assays, with EC50
values of 0.44 ± 0.01, 0.98 ± 0.03 and 0.64 ± 0.01 mg/mL for DPPH, ABTS and FRAP assays, respectively, with
no toxicity towards PLP2 primary cell cultures (GI50 > 400 μg/mL). PLGA nanoparticles loaded with root extract
were prepared using solvent-evaporation double emulsion method. Nanoparticles size was about 260 nm and a
polydispersity index around 0.1, with a zeta potential of about -36 mV, as well as a good encapsulation efficiency
of approximately 83%. Their morphology was analysed by SEM and spherical polymeric nanoparticles with a
smooth surface were observed. FTIR and DSC were also performed, which allowed corroborating the efficacy of
the encapsulation and to confirm the production of a stable and robust system to load Asparagus extracts. The
developed nanoparticles are expected to be used as delivery systems for bioactive compounds of A. stipularis and
they could be used as an innovative dietary supplement.
Volatile profile of Portuguese monofloral honeys: significance in botanical origin determination
Publication . Machado, Alexandra M.; Antunes, Marília; Miguel, Maria Graça; Vilas-Boas, Miguel; Figueiredo, Ana Cristina
The volatile profiles of 51 samples from 12 monofloral-labelled Portuguese honey types were assessed. Honeys of bell heather, carob tree, chestnut, eucalyptus, incense, lavender, orange, rape, raspberry, rosemary, sunflower and strawberry tree were collected from several regions from mainland Portugal and from the Azores Islands. When available, the corresponding flower volatiles were comparatively evaluated. Honey volatiles were isolated using two different extraction methods, solid-phase microextraction (SPME) and hydrodistillation (HD), with HD proving to be more effective in the number of volatiles extracted. Agglomerative cluster analysis of honey HD volatiles evidenced two main clusters, one of which had nine sub-clusters. Components grouped by biosynthetic pathway defined alkanes and fatty acids as dominant, namely n-nonadecane, n-heneicosane, n-tricosane and n-pentacosane and palmitic, linoleic and oleic acids. Oxygen-containing monoterpenes, such as cis- and trans-linalool oxide (furanoid), hotrienol and the apocarotenoid α-isophorone, were also present in lower amounts. Aromatic amino acid derivatives were also identified, namely benzene acetaldehyde and 3,4,5-trimethylphenol. Fully grown classification tree analysis allowed the identification of the most relevant volatiles for discriminating the different honey types. Twelve volatile compounds were enough to fully discriminate eleven honey types (92%) according to the botanical origin.
Harnessing the bioactive potential of Limonium spathulatum (Desf.) Kuntze: insights into enzyme inhibition and phytochemical profile
Publication . Youssef, Seria; Custódio, Luísa; Rodrigues, Maria João; Pereira, Catarina; Calhelha, Ricardo C.; Jekő, József; Cziáky, Zoltán; Ben Hamed, Karim
This study assessed the halophyte species Limonium spathulatum (Desf.) as a possible source of natural ingredients with the capacity to inhibit enzymes related to relevant human health disorders and food browning. Extracts using food-grade solvents such as water and ethanol were prepared by maceration from dried L. spathulatum leaves. They were evaluated for in vitro inhibition activity of enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), α-glucosidase, tyrosinase and lipase, related to Alzheimer’s disease, type-2-diabetes mellitus, skin hyperpigmentation, and obesity, respectively. These extracts were also appraised for in vitro acute toxicity on tumoral and non-tumoral cell lines and their chemical composition by high-performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS/MS). The extracts were more effective towards BChE than AChE. The best results were obtained with the hydroethanolic and water extracts, with IC50 values of 0.03 mg/mL and 0.06 mg/mL, respectively. The hydroethanolic extract had the highest capacity to inhibit α-glucosidase (IC50: 0.04 mg/mL), higher than the positive control used (acarbose, IC50 = 3.14 mg/mL). The ethanol extract displayed the best inhibitory activity against tyrosinase (IC50 = 0.34 mg/mL). The tested samples did not inhibit lipase and exhibited low to moderate cytotoxic activity against the tested cell lines. The hydroethanolic extract had a higher diversity of compounds, followed by the ethanol and water samples. Similar molecules were identified in all the extracts and were mainly hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids. Taken together, these results suggest that L. spathulatum should be further explored as a source of bioactive ingredients for the food, cosmetic, and pharmaceutical industries.
Antigenotoxic properties of the halophyte Polygonum maritimum L. highlight its potential to mitigate oxidative stress-related damage
Publication . Oliveira, Daniela; Dias, Maria Inês; Barros, Lillian; Custódio, Luísa; Oliveira, Rui
Long-term exposure to dietary xenobiotics can induce oxidative stress in the gastrointestinal tract, possibly causing DNA damage and contributing to the initiation of carcinogenesis. Halophytes are exposed to constant abiotic stresses, which are believed to promote the accumulation of antioxidant metabolites like polyphenols. The aim of this study was to evaluate the antioxidant and antigenotoxic properties of the ethanol extract of the aerial part of the halophyte Polygonum maritimum L. (PME), which can represent a dietary source of bioactive compounds with potential to attenuate oxidative stress-related damage. The PME exhibited a high antioxidant potential, revealed by the in vitro capacity to scavenge the free radical DPPH (IC50 = 2.29 +/- 0.10 mu g/mL) and the improved viability of the yeast Saccharomyces cerevisiae under oxidative stress (p < 0.001, 10 min). An antigenotoxic effect of PME against H2O2-induced oxidative stress was found in S. cerevisiae (p < 0.05) with the dominant deletion assay. In vitro colorimetric assays and LC-DAD-ESI/MSn analysis showed that PME is a polyphenol-rich extract composed of catechin, (epi)catechin dimer and trimers, quercetin and myricetin glycosides. Hence, P. maritimum is a source of antioxidant and antigenotoxic metabolites for application in industries that develop products to provide health benefits.
Volatile characterization of honey with dominance of Bupleurum spinosum pollen
Publication . Elamine, Youssef; Machado, Alexandra M.; Estevinho, Letícia M.; Lyoussi, Badiâa; Figueiredo, Ana Cristina; Miguel, Maria
Moroccan honey with Bupleurum spinosum (Apiaceae/Umbelliferae) as the main pollen source is locally known as Zantaz honey. In the present work, the volatiles from 18 honeys of this type, were isolated by hydrodistillation and analysed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS), for volatiles quantification and identification. The percentage composition of the volatiles and pollen profiling was used to determine the relationship between the different samples by cluster analysis. Two poorly correlated clusters were defined in volatiles analysis. Cluster A, with 17 out of the 18 samples, included four subgroups dominated by straight-chain hydrocarbons and fatty acids in variable proportions. Cluster B included just one sample, with 1-phenyldodec-1-en-3-one as the main component. Mono- and sesquiterpene hydrocarbons, as well as oxygen-containing mono- and sesquiterpenes occurred always B. spinosum and Populus sp. pollen. The one sample from Cluster B was moderately correlated with Cluster A and showed the lowest percentage of B. spinosum pollen. Pollen volatiles analysis would be relevant in assessing the presence of putative pollen volatile marker compounds and the importance of pollen profile on honey volatiles.
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Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
6817 - DCRRNI ID
Funding Award Number
UIDB/00690/2020