Mountain Research Center

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Nutritional value and chemical composition of purslane leaves in relation to harvest stage

Publication . Polyzos, Nikolaos; Fernandes, Ângela; Dias, Maria Inês; Petropoulos, Spyridon Α.; Ferreira, Isabel C.F.R.; Barros, Lillian

Purslane (Portulaca oleraceae L.) is an omnipresent weed, while it is also considered a common ingredient of the Mediterranean diet due to its high nutritional value with particular reference to omega-3 fatty acids content ln the present study, we evaluated the nutritional value and chemical composition of purslane leaves in relation to harvesting stage. Plants were harvested at three growth stages (29, 43 and 52 days a:fter sowing (DAS)), while leaves were separated from the aerial parts ofthe plant. Leaves contained high amounts of macronutrients, especially at 52 DAS. a-Tocopherol was the main isoform, which increased at 52 DAS, as well as the total tocopherols (values were in the ranges of 197-327 !J.g/l 00 g fresh weight (fw) and 302-481 !J.g/100 g fw, for a-tocopherol and total tocopherols, respectively). Glucose and fructose were the main detected free sugars, while total sugars content ranged between O. 160 g and 0.330 g/100 g fw). Oxalic and total organic acids content increased at late harvesting (52 DAS; 8.6 g and 30.3 g/ 100 g fw for oxalic acid and total organic acids, respectively). Regarding the fatty acids content, leaves were abundant in a-linolenic acid (35.4--54.92%), although a decreasing trend was observed with successive harvesting. Oleracein A and C were the major oleracein derivatives detected in leaves, regardless ofthe harvesting stage (values were in the ranges of8.2-103.0 mg and 21.2-143 mg/100 g dried weight (dw) for oleraceins A and C, respectively), while the highest content was recorded at 29 DAS for both compounds. Hepatotoxicity assays showed no toxicity with Gl50 values being higher than 400 !J.g/rnL for all the harvesting stages. ln conclusion, early harvesting could increase the nutritional value of the final product through increasing the content ofvaluable compounds, such as omega-3 fatty acids, phenolic compounds and oleracein derivatives, while at the sarne time, the contents of anti-nutritional compounds such as oxalic acid are reduced.

2021Conference object

Open access

Red Jambo Flower (Syzygium malaccense L.) as a Potential Bioactive Compound to Obtain Edible Extract: Optimization of Extraction, Toxicity, Antioxidant, and Antimicrobial Potential

Publication . Sousa, Rafael Carneiro de; Rosas, Alexandra Lizandra Gomes; Gonçalves, Glória Caroline Paz; Ramires, Tassiana; Silva, Wladimir Padilha da; Silveira, Tayse Ferreira; Barros, Lillian; Paim, Bruna Trindade; Sousa, Thamyres César de Albuquerque; Meinhart, Adriana Dillenburg

This paper aimed to demonstrate the production of edible extracts from red jambo flowers, cultivated in northeastern Brazil, and investigate their bioactive properties. For this purpose, a multivariate optimization of the extraction process was performed, by solid-liquid extraction, where it was observed that the presence of ethanol, acetone, and polysorbate in the extracting solution had the most significant influence on the extraction process, as opposed to temperature, time, volume of extracting solution, and the use of ultrasound. After the mixture system optimization, the best extraction condition was achieved when the extracting solution was composed of 25% ethanol, 25% acetone, and 50% polysorbate 0.25% in water, resulting in an extract containing 27.11 mg of anthocyanins, 457.69 mg of total carotenoids, and 198.09 mg of, total flavonoids, per 100 g of dried flower. The reducing capacity was 466.8 mg GAE per 100 g of dried flower, and the antioxidant activity was 17.25% against the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical. Through chromatographic analysis, it was possible to identify 10 compounds with bioactive properties (ferulic acid dihexoside, pedunculagin, methyl-dihydroquercetin dihexoside, dimethyl-dihydromyricetin diglucoside, kaempferol-3-O-hexosyl-rutinoside-7-O-rhamnoside, quercetin-O-hexoside-O-hexoside, ellagic acid, quercetin-O-hexoside, hesperetin-O-rutinoside, and diosmetin-O-rhamnoside), with a high prevalence of flavonoids. The extract showed no toxicity in an in vivo model of Galleria mellonella when administered at up to 1.6 g kg(-1) of body mass. The extract exhibited inhibition of Staphylococcus aureus (23 mm), Salmonella Typhimurium (12 mm), and Escherichia coli (12 mm), with inhibition zones close to that of gentamicin for the latter two. This study highlights the promising potential of red jambo flower extract as a valuable source of bioactive compounds with significant antioxidant, antimicrobial, and non-toxic properties. The optimized extraction process yielded extracts rich in bioactive compounds, demonstrating its suitability for various applications in the food industry. Further research is warranted to explore the full range of applications and potential health benefits of this natural extract.

2024Journal article

Restricted access

Nutritional, Chemical, Antioxidant and Antibacterial Screening of Astragalus cicer L. and Astragalus glycyphyllos L. Different Morphological Parts

Publication . Shahrivari-Baviloliaei, Saba; Konopacka, Agnieszka; Pascoalino, Liege; Reis, Filipa S.; Kunkowski, Dawid; Petropoulos, Spyridon A.; Konieczynski, Pawel; Orhan, Ilkay Erdogan; Plenis, Alina; Viapiana, Agnieszka

The chemical composition and biological activity of A. glycyphylos and A. cicer are scarcely investigated. In this study, the nutritional and chemical profiles of A. cicer and A. glycyphyllos, considering their different morphological parts (leaves, fruits and roots), were assessed together with their antioxidant and antibacterial potential. Our results showed that carbohydrates are the major macronutrients in both Astragalus species (above 62 g/100 g dry weight—DW). High amounts of ash (above 4.6 g/100 g DW) and protein (above 13.0 g/100 g DW) were also identified, particularly in leaves and fruits of A. cicer and A. glycyphyllos. Moreover, A. cicer was richer in sugars than A. glycyphyllos, while roots of both Astragalus species were the richest of fatty acids. Ten phenolic compounds were identified, with gallic acid and quercetin being predominant, above 49.84 and 37.27 μg/g DW, respectively. The mineral analysis revealed zinc and iron as the major constituents. Regarding the plants’ antioxidant and antibacterial activity, both Astragalus species had antioxidant potential, and their water extracts showed antibacterial activity against S. aureus and E. coli. Altogether, these results provide insight into the potential of A. glycyphyllos and A. cicer as a source of nutritional benefits and active phytochemicals for many people, and they can be applied in the food sector as foods and as promising sources of natural ingredients.

2025Journal article

Open access

Host-plant preference of Philaenus spumarius, the main European vector of Xylella fastidiosa, and their effect on the insect development

Publication . Ksouri, Nour; Pereira, J.A.; Rodrigues, Isabel

Philaenus spumarius (Linnaeus, 1758) (Hemiptera: Aphrophoridae), commonly known as the meadow spittlebug, has recovered scientists’ attention for decades and has been extensively studied for its biological and ecological interests. However, this species has been rarely associated with significant economic or agricultural damage until the detection of Xylella fastidiosa (Wells et al. 1987) (Xathomonadales: Xanthomonadaceae), a plant pathogenic bacterium, in Europe for the first time in Italy in 2013. Philaenus spumarius has been identified to have a key role in the pathogen's propagation, being its essential transmission vector in Europe. Since currently, there is no cure for X. fastidiosa, vector control is perceived as the main tool to limit the spread of this pathogen. Therefore, understanding the choice of host plants and how they affect vector insect development can be fundamental for implementing approaches to manipulate the behavior of the vector and implement sustainable control strategies. In this sense, this work aims to evaluate the selection of host plants by nymphs and adults of P. spumarius, and their effect on the development of the insect vector. For that, we studied, in field conditions, the effect of four host plants, namely C. myconis S. tenerrimus, C. arvensis, and C. segetum, in the development of P. spumarius. We assessed the olfactory response of nymphs, at different soil humidity (10%, 50%, and 70%), and adults of P. spumarius towards the four plants (and the olive tree, only for the adults). Additionally, the volatile profile of the plants was also assessed, and we developed models to predict the effect of the volatiles produced by these plants on insect behavior. The plant species generally does not significantly affect the insect's morphological parameters. The choice made by P. spumarius nymphs was significantly affected by the plant species and the soil's percentage of water content. Sonchus tenerrimus and C. myconis were the two most chosen plants by the nymphs. The olfactory response of the adults of P. spumarius revealed that the sex of the insects did not influence the choice of plants and that S. tenerrimus was the most preferred plant by females when compared to C. segetum, C. arvensis, and the control. The models suggested that the nymphs and adults of P. spumarius are repelled by D-Limonene. Understanding how these insects interact with their environment is crucial to create effective control strategies.

2023Master thesis

Open access

Chemical features and bioactivities of lactuca canadensis L., an unconventional food plant from Brazilian cerrado

Publication . Liberal, Ângela; Coelho, Carla T.P.; Fernandes, Ângela; Cardoso, Rossana V.C.; Dias, Maria Inês; Pinela, José; Alves, Maria José; Severino, Vanessa G.P.; Ferreira, Isabel C.F.R.; Barros, Lillian

Throughout the world, people’s diet is generally quite restricted regarding the variety of plants used in their daily regime. The Unconventional Food Plant (UFP) Lactuca canadensis L. is an edible species of wild lettuce sparsely described in literature and considered to be native from the eastern and central parts of North America. To valorize this species as potential alternative food, an analysis of its nutritional, chemical, and bioactive properties was performed. The results specify the occurrence of organic acids, mainly quinic acid (127.9 ± 0.6 g/kg dry weight (dw)), polyunsaturated fatty acids (65.3%), among which are linolenic acid (44.4 ± 0.4 %), and tocopherols, mostly α-tocopherol (61.2 ± 0.7 mg/kg dw). Additionally, eight phenolic compounds were also identified, among which luteolin-O-glucuronide was found in larger amounts in both infusion and hydroethanolic extracts (5.46 ± 0.09 and 4.6 ± 0.1 mg/g dw, respectively). Carbohydrates and proteins were the main macronutrients (603 ± 1 and 177.5 ± 0.3 g/kg dw, respectively), followed by ashes (166.5 ± 0.9), indicative of a great amount of minerals. Additionally, good antioxidant and antibacterial activities were detected in the analyzed extracts. In general, our results contribute to extend the range of different, unexploited, and nutritionally balanced plant foods, such as Lactuca canadensis, that can and should be included in the daily diet.

2021Journal article

Open access