Papers by Alfredo Carvalho Aires
Scientia Horticulturae, Apr 1, 2019
Effects of preharvest sprays of calcium with and without traditional and novel growth regulators ... more Effects of preharvest sprays of calcium with and without traditional and novel growth regulators (gibberellic acid, abscisic acid and salicylic acid, glycine betaine and a biostimulant (Ascophyllum nodosum)) on quality and sensory attributes of 'Skeena' and 'Sweetheart' sweet cherries were investigated at harvest. Experiments were carried out during 2015 and 2016 in a Portuguese orchard. Spray treatment effects were affected by cultivar and year, with spray treatments eliciting more responses in 2016 and for 'Sweetheart' cherries. Abscisic acid spray treatment showed small effects on quality attributes at harvest. Gibberellic and salicylic acid increased fruit weight, while glycine betaine with calcium increased fruit weight, appearance and colour development. The spray treatments did not affect the soluble sugars, while salicylic acid and Ascophyllum nodosum with calcium increased total organic acid levels. Gibberellic acid and glycine betaine sprays are candidates to increase quality attributes at harvest for two important commercial cherry cultivars.
Reuse potential of vegetable wastes (broccoli, green bean and tomato) for the recovery of antioxidant phenolic acids and flavonoids
International Journal of Food Science and Technology, Nov 24, 2016
Summary The aim of this study was to evaluate the potential use of crop wastes (stems and leaves)... more Summary The aim of this study was to evaluate the potential use of crop wastes (stems and leaves) from broccoli, beans and tomato to extract antioxidant polyphenols. Two different methods of extraction were performed: ultrasound (40 kHz) and conventional with 70 °C. In both methods, alkaline and acidic solvents were used. The polyphenol composition was assessed by HPLC-DAD/UV-VIS, and the 2,2-diphenyl-1-picrylhydrazyl assay was used to measure the antioxidant activity. The results showed a significant variation of polyphenol composition and antioxidant activity with the type of sample, pH of solvent and extraction method. Also it was possible to observe that acidic methanol and 70 °C enables the extraction of significant amounts of phenolic acids and flavonoids. Based in our results, broccoli, green bean and tomato wastes can be used to extract antioxidant polyphenols, and the use of such wastes to extract polyphenols can be an opportunity to develop an environmental friendly management's systems creating incoming for producers and agro-food sector.
Waste Management, Feb 1, 2016
The aim of the current study was to evaluate the potential of chestnut peels to produce pomaces e... more The aim of the current study was to evaluate the potential of chestnut peels to produce pomaces enhanced with tannins to be used in the formulations of wood adhesives, leather tanning or as natural antioxidants in food, cosmetic and pharmaceutical industry. An analytical procedure was planned as 2 factorial design to analyze the influence of solvent (water, Na 2 SO 3 and NaOH at different concentrations of 1, 2, 4, and 8% in water) and extraction time (30, 60, and 120, 240, 480 and 960 min) on extraction yield, pH, Stiasny index, and tannins. HPLC-diode array detector equipped with an ionization mass spectrophotometer was used to assess the polyphenol composition. Our results showed that both extraction properties and phytochemicals were significantly affected (P < 0.001) by all independent factors. The main tannins identified were the hydrolyzable gallic acid, vescalagin castalagin and ellagic acid, and the condensed epigallocatechin, catechin and epicatechin. The solvent 1% Na 2 SO 3 was more effective to extract the condensed tannins whilst hydrolyzable tannins were extracted efficiently by 1% NaOH. The multivariable analysis and the Pearson's correlation coefficients showed a direct association between Stiasny number and the average levels of condensed tannins.
Phytochemistry, Jul 1, 2020
During the last years halogenated compounds have drawn a lot of attention. Metabolites with one o... more During the last years halogenated compounds have drawn a lot of attention. Metabolites with one or more halogen atoms are often more active than their non-halogenated derivatives like indole-3-acetic acid (IAA) and 4-Cl-IAA. Within this work, bacterial flavin-dependent tryptophan halogenase genes were inserted into Brassica rapa ssp. pekinensis (Chinese cabbage) with the aim to produce novel halogenated indole compounds. It was investigated which tryptophan-derived indole metabolites, such as indole glucosinolates or potential degradation products can be synthesized by the transgenic root cultures. In vivo and in vitro activity of halogenases heterologously produced was shown and the production of chlorinated tryptophan in transgenic root lines was confirmed. Furthermore, chlorinated indole-3-acetonitrile (Cl-IAN) was detected. Other tryptophan-derived indole metabolites, such as IAA or indole glucosinolates were not found in the transgenic roots in a chlorinated form. The influence of altered growth conditions on the amount of produced chlorinated compounds was evaluated. We found an increase in Cl-IAN production at low temperatures (8°C), but otherwise no significant changes were observed. Furthermore, we were able to regenerate the wild type and transgenic root cultures to adult plants, of which the latter still produced chlorinated metabolites. Therefore, we conclude that the genetic information had been stably integrated. The transgenic plants showed a slightly altered phenotype compared to plants grown from seeds since they also still expressed the rol genes. By this approach we were able to generate various stably transformed plant materials from which it was possible to isolate chlorinated tryptophan and Cl-IAN.
Antimicrobial Susceptibility of Aeromonas Spp. Isolated from Pig Ileum Segments to Natural Isothiocyanates
Medicinal Chemistry, Jul 1, 2013
With this study we intend to evaluate the effects of 8 different glucosinolate hydrolysis product... more With this study we intend to evaluate the effects of 8 different glucosinolate hydrolysis products including isothiocyanates as antibacterial compounds against Aeromonadaceae, isolated from intestinal segments of pigs collected directly from slaughter-houses in the North of Portugal. Four Aeromonas species, A. allosaccharophila, A. hydrophila, A. media and A. veronii were identified. Using disc-diffusion bioassay all compounds were tested at 6 different doses (0.015, 0.15, 0.75, 1.5 and 3.0 µmoles) in dimethyl-sulfoxide (DMSO). Antibiotic standard (gentamicin) and DMSO (negative control) were included in all experiments. Minimum and maximum dose inhibitions (in µmoles) were assessed. To our knowledge, this is the first study of antimicrobial activity of glucosinolate hydrolysis products against Aeromonas species. The results showed that glucosinolate hydrolysis products and particularly the isothiocyanates have antimicrobial activity, which was proportional to the concentration used. However, not all revealed the same tendency, which means that the chemical structure of each compound is fundamental to understand their effectiveness. Among the different isothiocyanates the benzylisothiocyanate, sulforaphane and 2-phenylethylisothiocyanate were the most effective in vitro inhibitors of bacterial growth. This in vitro study provides enough data to demonstrate the potential use of these natural dietary chemicals for treating infectious diseases caused by Aeromonas spp.
Journal of Applied Microbiology, Jun 1, 2009
Aims: The aim of the study was to evaluate the in vitro antibacterial effects of glucosinolate hy... more Aims: The aim of the study was to evaluate the in vitro antibacterial effects of glucosinolate hydrolysis products (GHP) against plant pathogenic microorganisms namely Agrobacterium tumefaciens, Erwinia chrysanthemi, Pseudomonas cichorii, Pseudomonas tomato, Xanthomonas campestris and Xanthomonas juglandis. Methods and Results: Using a disc diffusion assay, seven different doses of 10 GHP were tested against each bacteria. The results showed that the isothiocyanates were potent antibacterials, whilst the other GHP were much less efficient. Moreover, the antibacterial effects were dose-dependent, increasing with the dose applied; 2-phenylethylisothiocyanate and sulforaphane showed the strongest inhibitory effects. The overall results show a great potential for using the isothiocyanates as an alternative tool to control undesired bacterial growth in plants. Conclusions: Glucosinolate hydrolysis products and more specifically the isothiocyanates: benzylisothiocyanate, 2-phenylethylisothiocyanate, the isothiocyanate Mix and sulforaphane, were effective phytochemicals against the in vitro growth of the phytopathogenic bacteria. The antibacterial activity exhibited by these phytochemicals reinforces their potential as alternatives to the traditional chemical control of phytopathogenic bacteria. Significance and Impact of the Study: This current in vitro study is the first providing comparative data on GHP as potential control agents for plant pathogenic bacteria. However, more studies are needed to determine their possible allelopathic impacts e.g. inhibition of plant growth and negative effects on beneficial soil bacteria and fungi (mycorrhizae).
Antimicrobial and Antioxidant Activity of Phenolic Compounds Extracted from Wine Industry By-Products of <em>Tinto Cão</em> Variety
Proceedings of 6th International Electronic Conference on Medicinal Chemistry, Nov 5, 2020
Multidrug-resistant bacteria are a significant threat to public health and new classes of antibio... more Multidrug-resistant bacteria are a significant threat to public health and new classes of antibiotics and approaches to treatment are needed. Several studies showed that natural plantderived compounds could be a promising mean to fight microbial resistance but only a few were conducted with antibiotic resistant bacteria. Therefore, the aim of this study was to extract phenolic compounds from the leaves, fruits and tree trunk of Platanus hybrida and evaluate their antimicrobial activity against antibiotic resistant bacterial strains. The polyphenolic compounds were extracted using a water/ethanol (20:80) mixture. Two grams of powder of each sample was extracted with 100 mL of solvent by stirring for 2h. The extracts were redissolved in dimethyl sulfoxide (DMSO) to a final concentration of 100 mg/mL. Antimicrobial susceptibility assay was performed using Kirby-Bauer disc diffusion method and was tested against ten different bacteria: Listeria monocytes, Bacillus cereus, Enterococcus faecium, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Salmonella enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli. The fruits had the highest antibacterial activity showing a minimum inhibitory concentration (MIC) of 10mg/mL, contrary to the tree trunk that showed the lowest antibacterial activity. None of the extracts showed antimicrobial properties against S. enteritidis, E. faecium and E. faecalis. These results show that, P. hybrida's phenolic compounds act as antibacterial agents which may become useful therapeutic tools and represent a source for the development of novel antimicrobials. However, they were not effective against all bacteria which shows that polyphenols, alone, might not substitute antibiotics.
Atividade Antimicrobiana do Óleo Essencial de Myrtus Communis L. na Microbiota Patogénica e Deteriorativa de Carne Bovina de Raça Maronesa
Bacterial resistance is a significant threat to public health and new classes of antibiotics and ... more Bacterial resistance is a significant threat to public health and new classes of antibiotics and approaches to treatment are needed. It has been shown that natural plant-derived compounds can constitute a new alternative to fight microbial resistance but only a small number of studies were performed with antibiotic resistant bacterial strains. Therefore, in our work, we extracted phenolic compounds from the leaves, fruits and tree trunk of Platanus hybrida and evaluated their antibacterial activity against ten different multidrug-resistant bacteria. Two grams of each powder sample were weighed, and the extraction of the phenolic compounds was carried out with 100 mL of an ethanol and water (80:20) mixture by stirring for 2h. The extracts were redissolved in dimethyl sulfoxide (DMSO) and 100 mg/mL was the final concentration obtained. To test the antimicrobial activity of the phenolic compounds we used the Kirby-Bauer disk diffusion method. This method was performed against Listeria monocytes, Bacillus cereus, Enterococcus faecium, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Salmonella enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli. The fruits had the highest antibacterial activity showing a minimum inhibitory concentration (MIC) of 10 mg/mL, contrary to the tree trunk that showed the lowest antibacterial activity. None of the extracts showed antimicrobial properties against S. enteritidis, E. faecium and E. faecalis. These results show that, P. hybrida's phenolic compounds may be an interesting therapeutic alternative. However, given that they haven't shown results against all bacteria, they only represent a possible start of the development of new classes of antibiotics.
Applied Microbiology
Macrofungi have been previously studied for their nutritional value and medicinal properties. How... more Macrofungi have been previously studied for their nutritional value and medicinal properties. However, despite wild mushrooms being a great source of beneficial bioactive compounds, the literature exploring their biotechnological application as nutraceuticals, cosmeceuticals and nutricosmetics is scarce. In this work, the species Butyriboletus regius, Ganoderma lucidum, Inonotus hispidus, Lanmaoa fragrans, Pisolithus tinctorius, Suillellus luridus, Suillellus mendax and Xerocomus subtomentosus were characterized according to their phenolic composition, antioxidant capacity, antimicrobial activity and cosmeceutical potential. For that purpose, dried and ground mushrooms were extracted with ethanol (40% v/v) using ultrasound-assisted extraction. Of the eight mushrooms analyzed, I. hispidus and P. tinctorius stood out for their high content of phenolic compounds, high antioxidant capacity and anti-hyaluronidase activity. Regarding antimicrobial activity, both mushrooms showed good inhi...
Foods
The possibility that nut intake may defend human health is an interesting point of view and has b... more The possibility that nut intake may defend human health is an interesting point of view and has been investigated worldwide. Consequently, nuts are commonly promoted as healthy. In recent decades, the number of investigations proposing a correlation between nut consumption and a decrease in the risk of key chronic diseases has continued to increase. Nuts are a source of intake of fiber, and dietary fiber is associated with a reduced occurrence of obesity and cardiovascular diseases. Nuts likewise provide minerals and vitamins to the diet and supply phytochemicals that function as antioxidant, anti-inflammatory, and phytoestrogens agents and other protective mechanisms. Therefore, the main goal of this overview is to summarize current information and to describe the utmost new investigation concerning the health benefits of certain nuts.
ECMC 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
International Journal of Environmental Research and Public Health
Home gardening has a long history that started when humans became sedentary, being traditionally ... more Home gardening has a long history that started when humans became sedentary, being traditionally considered an accessible source of food and medicinal plants to treat common illnesses. With trends towards urbanization and industrialization, particularly in the post-World War II period, the importance of home gardens as important spaces for growing food and medicinal plants reduced and they began to be increasingly seen as decorative and leisure spaces. However, the growing awareness of the negative impacts of agricultural intensification and urbanization for human health, food quality, ecosystem resilience, and biodiversity conservation motivated the emergence of new approaches concerning home gardens. Societies began to question the potential of nearby green infrastructures to human wellbeing, food provisioning, and the conservation of traditional varieties, as well as providers of important services, such as ecological corridors for wild species and carbon sinks. In this context. ...
Frontiers in Nutrition, 2022
Multidrug-resistant ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pne... more Multidrug-resistant ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) has become the most recurrent global cause of skin and soft-tissue infections, belonging to the WHO priority pathogens list. Successful therapy remains challenging and entails the assessment of novel and successful antibiotics. In this study, mushrooms are considered a valuable and unique source of natural antimicrobial compounds. Therefore, this study aimed to evaluate the antimicrobial and antibiofilm properties of Boletus edulis (B. edulis) and Neoboletus luridiformis (N. luridiformis) aqueous and methanolic extracts against ESKAPE isolates from clinical wound infections. Disk diffusion and microdilution methods were used to assess the antimicrobial activity. Phytochemical characterization was achieved by analysis of total phenols, orthodiphenols content, and antioxidant activity as well as by high-per...
Generation of Aromas and Flavours, 2018
Aromas and flavours play an important role in horticultural crops' quality, namely in fruits. Pla... more Aromas and flavours play an important role in horticultural crops' quality, namely in fruits. Plant breeders have made considerable advances producing cultivars with higher yields, resistant to pests and diseases, or with high nutritional quality, without paying enough attention to flavour quality. Indeed, consumers have the perception that fruit aromas and flavours have declined in the last years. Attention is given nowadays not only to flavoured compounds but also to compounds with antioxidant activity such as phenolic compounds. Fruit flavour is a combination of aroma and taste sensations. Conjugation of sugars, acids, phenolics, and hundreds of volatile compounds contribute to the fruit flavour. However, flavour and aroma depend on the variety, edaphoclimatic conditions, agronomical practices and postharvest handling. This chapter reviews the aromas and flavours of the most important fruits and discusses the most recent advances in the genomics, biochemistry and biotechnology of aromas and flavours.
Sweet Cherry
Temperate Fruits, 2020
Gaia Scientia, 2016
Neste trabalho avaliou-se o efeito de diferentes tipos de extractos da planta de rosmaninho (Rosm... more Neste trabalho avaliou-se o efeito de diferentes tipos de extractos da planta de rosmaninho (Rosmarinus officinalis) ricos em compostos fenólicos, no crescimento e na fisiologia da microalga Chlorella vulgaris. Os extractos foram obtidos por infusão aquosa a quente e a frio, esta ultima com dois períodos de extração (5 e 21 dias). Os ensaios foram desenvolvidos em culturas batch com extratos à concentração de 10%, 25% e 30% (v/v). Os resultados mostraram para os extractos a frio que o crescimento da microalga foi afetado apenas com extratos de 21 dias, levando ao aumento da taxa específica de crescimento (μ) e da densidade celular, bem como da concentração de clorofila a (Chl a) e do teor em proteinas, numa relação direta com a concentração de extrato testada. A exposição aos extractos a quente apesar de levar ao aumento de µ e da densidade celular final de C. vulgaris, concomitantemente induziu alguma toxicidade a nível fisiológico, visível pela diminuição dos teores de Chl a e pro...
Stems: A Sweet Cherry By-Product with High Potential
Sweet cherry is one of the most appreciated fruit by consumers in the temperate areas of Europe, ... more Sweet cherry is one of the most appreciated fruit by consumers in the temperate areas of Europe, due to its organoleptic characteristics, but also by the consumers’ awareness of their health benefits. Worldwide sweet cherry production has been increasing in the last years (2010–2019, latest FAO available data) from 2 to 2.60 million tons, with Turkey, USA, Chile as the main producers accounting for about 50% of the total world production, and Chile, China and USA the main exporters. Portugal is also well-known producer of sweet cherries, with latest data referring 19563 tons of cherries annually, providing some of the first cherries of Europe. During sweet cherry processing, large amounts of by-products are generated. There is no substantial use of this waste, which increase environmental and managements costs each year to deal with the excess of such residues. Although sweet cherry stems are widely recognized by traditional medicine, with several properties, namely as sedative, diu...
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Papers by Alfredo Carvalho Aires