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- Health promoting properties of blueberries: a reviewPublication . Silva, Sara; Costa, Eduardo M.; Veiga, Mariana; Morais, Rui M.; Calhau, Conceição; Pintado, ManuelaWith the strengthening of the link between diet and health, several foodstuffs have emerged as possessing potential health benefits such as phenolic rich fruits and vegetables. Blueberries, along with other berries, given their flavonoid and antioxidant content have long since been considered as a particularly interesting health promoting fruit. Therefore, the present work aimed to compile the existing evidences regarding the various potential benefits of blueberry and blueberry based products consumption, giving particular relevance to in vivo works and epidemiological studies whenever available. Overall, the results demonstrate that, while the evidences that support a beneficial role of blueberry and blueberry extracts consumption, further human based studies are still needed.
- Effects of whey peptide extract on the growth of probiotics and gut microbiotaPublication . Yu, Ya-Ju; Amorim, Manuela; Marques, Cláudia; Calhau, Conceição; Pintado, M. E.Whey peptide extract with molecular weight below 1 kDa was investigated in microplate assay, and viable cells, as well as metabolic activity were determined to evaluate augmented growth of probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium animalis). Results illustrated that whey peptide extract 1% (w/v) has the capacity to stimulate the proliferation of both probiotic bacteria tested, further supported by the faster generation of metabolic products. The effect of whey peptide extract on the modulation of gut microbiota was also examined inWistar rats fed either with a standard or a high-fat diet, assessed via 16S ribosomal RNA expression of gut microbiota by quantitative PCR. Relative abundance of Lactobacillus spp., Bifidobacterium spp. and Bacteroidetes was significantly increased by whey peptide extract in rats fed with a standard diet. These results highlight an additional unexploited positive effect of whey peptide extract on gut microbiota modulation.
- Antihypertensive effect of spent brewer yeast peptidePublication . Amorim, M.; Marques, C.; Pereira, J. O.; Guardão, L.; Martins, M. J.; Osório, H.; Moura, D.; Calhau, C.; Pinheiro, H.; Pintado, M.Numerous studies have investigated dietary approaches to prevent chronic lifestyle-related diseases, including hypertension. Spent brewer's yeast is the second largest byproduct originated by the brewing industry and it deserves considerable attention because of its high nutritional value, ca. 40% of its dry mass is rich in protein which can be hydrolyzed into biologically active peptides. To upgrade this byproduct, the aim of this study was initially in vitro assessment of biological properties, e.g. ACE inhibition and antioxidant activity, and then, the in vivo effect in short-term oral antihypertensive effect of hydrolyzed yeast fractions on a well characterized model to study hypertension - Spontaneously Hypertensive Rats (SHR). Here, it was demonstrated that the fraction with molecular weight below 3 kDa containing tri and tetra- peptides with hydrophobic amino acid residues - SPQW, PWW and RYW, causes the most noticeable decrease in systolic, diastolic and mean blood pressure of SHR and shows highest antioxidant effect. These properties highlight the potential use of yeast extract as nutraceutical or functional food ingredient for the management and treatment of hypertension with antioxidant effect.
- Anthocyanin extraction from plant tissues: a reviewPublication . Silva, S.; Costa, E. M.; Calhau, C.; Morais, R. M.; Pintado, M. E.Anthocyanins have gathered the attention of the scientific community mostly due to their vast range of possible applications. They have been the center point of the research in many different fields, among which is food development, where their innate coloring, antioxidant capacity, and biological potential open interesting venues to the development of new food additives and functional foodstuffs. As the range of application grows, so does the necessity to obtain these compounds, and since they are naturally occurring, the most common way to obtain anthocyanins is to extract them from different plant sources, such as fruits and flowers. Several efforts have been made to develop methods that allow for better extraction yields and higher purification rates therefore this review aims to compile the information regarding extraction and purification procedures in a comprehensive manner.
- Effect of chronic consumption of blackberry extract on high-fat induced obesity in rats and its correlation with metabolic and brain outcomesPublication . Meireles, Manuela; Rodríguez-Alcalá, Luís M; Marques, Cláudia; Norberto, Sónia; Freitas, Joana; Fernandes, Iva; Mateus, Nuno; Gomes, Ana Maria; Faria, Ana; Calhau, ConceiçãoFlavonoids have been presented as potential protectors against metabolic and cognitive dysfunction. However, mechanisms underlying these 'claims' have not been sufficiently explored. To analyse the effect of long-term supplementation with blackberry extract (BE) in the context of a high-fat or a standard diet, Wistar rats were divided into 4 groups (n = 6) fed with a standard or a high-fat diet, with or without BE supplementation at 25 mg per kg body weight per day. A high-fat diet significantly impaired glucose tolerance and increased body weight, caloric ingestion, very-low-density lipoprotein, triglycerides and cholesterol. Furthermore, it was observed that a high-fat diet increased dopamine content in the prefrontal cortex and decreased brain derived neurotrophic factor (BDNF) levels both in the prefrontal cortex and in plasma. BE supplementation only affected some of these aspects. BE slightly improved glucose metabolism and significantly decreased levels of lactate, independent of diet. BE decreased levels of BDNF and also interacted with the dopaminergic system, increasing dopamine turnover in the striatum, and reverting dopamine content induced by a high-fat diet in the prefrontal cortex. This study shows that, despite some particular benefits of anthocyanin supplementation, some long-term effects may not be desirable and further studies are needed to optimize ingestion conditions.
- Fermentation of bioactive solid lipid nanoparticles by human gut microfloraPublication . Madureira, Ana Raquel; Campos, Débora; Gullon, Beatriz; Marques, Cláudia; Rodríguez-Alcalá, Luís M.; Calhau, Conceição; Alonso, Jose Luis; Sarmento, Bruno; Gomes, Ana M.; Pintado, M. E.Solid lipid nanoparticles (SLNs) can be used for oral delivery of phenolic compounds in order to protect them from the harsh conditions of digestion and improve their bioavailability in the intestinal epithelium. Recently, the production and characterization of SLNs loaded with rosmarinic acid (RA) and herbal extracts was performed for future use as functional food ingredients. Diet components have been shown to have a huge impact on gut microbiota viability and metabolic activity. Hence, SLNs loaded with RA, sage and savoury extracts have been evaluated for their effect on intestinal microbiota growth and the metabolic products generated. Fermentations in anaerobic batch cultures using volunteer human faeces were performed during 24 h. Dynamic bacterial population changes were analysed using PCR-real time, as well as the generation of fatty acids and the quantification of phenolic compounds by analytical methods. Solid lipid nanoparticles released phenolic compounds at non-inhibitory bacterial growth concentrations. Released herbal extract phenolic compounds showed a beneficial effect on gut microbiota growth (e.g. bifidogenic effects) and were used as substrates. Acetate, formate, lactate and butyrate were produced in higher concentrations. The released phenolic compounds also induced PUFA and trans fatty acids metabolic activity, the production of saturated fatty acids, as well of potential beneficial conjugated linoleic acid isomers. Solid lipid nanoparticles modulate gut microbiota and metabolic activities.
- Effect of in vitro digestion upon the antioxidant capacity of aqueous extracts of Agrimonia eupatoria, Rubus idaeus, Salvia sp. and Satureja montanaPublication . Gião, Maria S.; Gomes, Susana; Madureira, Ana R.; Faria, Ana; Pestana, Diogo; Calhau, Conceição; Pintado, Manuela E.; Azevedo, Isabel; Malcata, F. XavierAn in vitro digestion/Caco-2 cell culture model was used to assess the stability and bioavailability of phenolic compounds in aqueous extracts of four herbal infusions, traditionally used as functional drinks in Portugal. Alterations in antioxidant power were monitored by ABTS +, whereas the profile of phenolic compounds was ascertained by HPLC-DAD. The bioavailability of rutin – an important flavonoid present in such extracts, and thus a representative of those compounds, was assessed across Caco-2 cells via LC– MS/MS. Our results indicate that several antioxidant compounds are not affected by the (simulated) digestive process, whereas others undergo decreases in their activity throughout said process; a few have their antioxidant capacity hampered under stomach-like conditions. It was also found that rutin can be transported across the Caco-2 cell barrier.
- Effects of extracts of selected medicinal plants upon hepatic oxidative stressPublication . Gião, M.S.; Pestana, D.; Faria, A.; Guimarães, J.T.; Pintado, M.E.; Calhau, C.; Azevedo, I.; Malcata, F.X.Aqueous extracts of a few medicinal plants traditionally used in Portugal have been assayed for their effects upon hepatic oxidative stress in mice. Previous in vitro studies had allowed characterization of agrimony, sage, savory, and raspberry in terms of overall antioxidant capacity and phenolic content. In the present study, the antioxidant effect and safety of these four plants were evaluated in vivo. For this purpose, mice ingested extracts in aqueous form (or water, used as the control) for 4 weeks; damage to lipids, proteins, and DNA was evaluated by oxidative cell biomarkers by the end of that period. Levels of hepatic glutathione and activities of enzymes involved in metabolism thereof were also determined. Finally, catalase and superoxide dismutase (SOD) activities were quantified, as these enzymes play a crucial role in antioxidant defense. When compared with the control, both raspberry and savory produced significant lipid protection; however, protein damage was significantly lower only in raspberry-treated animals. On the other hand, DNA damage was prevented only by savory. All plants led to a decrease in catalase activity, whereas all but sage also produced a decrease in SOD activity. With regard to glutathione levels and activities of enzymes involved in its metabolism, the aforementioned extracts exhibited different effects. In general, raspberry appeared to be the most promising extract, followed by savory, sage, and agrimony, sorted by decreasing performance in protection; the latter was even slightly toxic. Hence, the plants tested possess compounds with interesting biological activities that may support eventual inclusion in food or feed as functional additives.
- Antimicrobial, antiadhesive and antibiofilm activity of an ethanolic, anthocyanin-rich blueberry extract purified by solid phase extractionPublication . Silva, Sara; Costa, Eduardo M.; Mendes, M.; Morais, R. M. S. C.; Calhau, Conceição; Pintado, M. E.Aims: The present work aimed to characterize the impact of an anthocyaninrich blueberry extract upon the growth, adhesion and biofilm formation of several pathogens including some multiresistant bacteria. Methods and Results: A group comprised of reference strains and clinical multiresistant isolates of Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Acinetobacter baumannii and Staphylococcus aureus, were used to screen for antimicrobial activity. Microbial growth was determined through the measurement of the optical density while adhesion and biofilm formation was determined using the standard crystal violet staining procedure. The results showed that, while blueberry extract was only effective in hindering the growth of Staph. aureus and E. coli, it was capable of significantly inhibiting biofilm formation and bacterial adhesion for all micro-organisms tested. Conclusions: The extract demonstrated a considerable potential as a natural, alternative antimicrobial capable of either interfering with microbial growth or hamper the adhesion to surfaces, with Staph. aureus proving to be the most susceptible micro-organism. Significance and Impact of the Study: The overall study demonstrates the potential of anthocyanin extracts as natural effective alternative antimicrobial agents. Additionally, the extract’s capacity to reduce adhesion without reducing bacterial growth reduces the likeliness of resistance development while reducing the probability of infection.
- In vitro ACE-inhibitory peptide KGYGGVSLPEW facilitates noradrenaline release from sympathetic nerve terminals: relationship with the lack of antihypertensive effect on spontaneous hypertensive ratsPublication . Marques, Cláudia; Amorim, Maria Manuela; Pereira, Joana Odila; Guardão, Luísa; Martins, Maria João; Pintado, Manuela Estevez; Moura, Daniel; Calhau, Conceição; Pinheiro, HélderThis study aimed to validate the antihypertensive activity of the angiotensin-converting enzyme (ACE)-inhibitor whey protein hydrolysate (WPH) obtained through the action of proteolytic enzymes fromCynara Cardunculus. The antihypertensive activity of WPH fractions containing peptides with molecularweight below 3 kDa (Whey < 3 kDa) and 1 kDa (Whey < 1 kDa) along with the antihypertensive activity ofthree potent ACE-inhibitory peptide sequences (DKVGINYW, DAQSAPLRVY and KGYGGVSLPEW), previ-ously identified in WPH, were also investigated. In parallel, the influence of KGYGGVSLPEW (the mostpotent ACE-inhibitory peptide sequence) on AT1receptors (a common pharmacological target of anti-hypertensive therapies beyond ACE), was evaluated. The effect of WPH and fractions (300 mg/kg) andpeptide sequences (5 mg/kg) on systolic, diastolic and mean blood pressure was evaluated by telemetryon Spontaneously Hypertensive Rats (SHR), after single oral administration. Despite their ACE-inhibitoryeffect in vitro, neither WPH, Whey <3 kDa, Whey <1 kDa or peptide sequences exhibited antihyperten-sive activity. In addition, KGYGGVSLPEW was not only devoid of AT1receptor antagonism but, on thecontrary, had a similar effect to that of Ang II by facilitating the noradrenaline release from sympatheticnerve terminals. In vitro ACE blockade does not always correlate with antihypertensive activity and food-derived peptides cannot be classified as antihypertensive agents based exclusively on in vitro assays. Theabsence of an antihypertensive effect may also be a result of the interaction of these compounds withother components of the systems involved in the blood pressure control.