9 resultados para Tocopherol

em Instituto Politécnico de Bragança


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Borututu ( Cochlospermum angolensis Welw.) is a widespread tree in Angola used since antiquity by traditional healers for the prevention and treatment of hepatic diseases and for the prophylaxis of malaria [1]. This plant is mostly consumed as infusions but is also available as dietary supplements, such as piiis, capsules, and syrups, among others. In the present study, the aim was to evaluate the proximate composition and energetic contribution of borututu as weii as its composition in hydrophilic (sugars and organic acids) and lipophilic (fatty acids and tocopherols) compounds, given the fact that this plant is directly introduced in some dietary supplements. Furthermore, the bioactivity (antioxidant, hepatoprotective and antimicrobial activities) of three different formulations of borututu (infusion, pills, and syrup) was assessed and compared, and since plant beneficial properties are often ascribed to phenolic compounds [2], the phenolic profile of the formulations was also analysed. Carbohydrates (88 g/100 g) and fat (2.5 g/100 g) were the major and tl1e minor components of the studied borututu dry barks, respectively, with an energetic contribution of 384 kcal/100 g. Fructose was the most abundant sugar (1.3 g/100 g), foilowed by sucrose, trehalose and glucose (1.1, 0.98 and 0.79 g/100 g, respectively). Oxalic (0.70 g/100 g), malic (0.63 g/100 g) and citric (0.57 g/100 g) acids were present in higher amounts but shikimic and fumaric acids were also detected. Among the fatty acids found in borututu, a prevalence of saturated fatty acids (SF A; 48.2%) was observed, whereas polyunsaturated (PUFA) and monounsaturated (MUFA) fatty acids were detected in relative percentages of 30.9% and 20.8%, respectively. P-tocopherol was the most abundant of the four isoforms found in the sample, foiiowed by o-, a- and y-tocopherol, present in concentrations of 597,43, 3.7 and 2.0 g/100 g, respectively. Borututu infusion revealed the highest antioxidant activity, with EC50 values ranging from 20 to 600 J.lg/mL and was the only formulation inhibiting the growth of an HepG2 ceii line, with a Gl5o value of 146 J.lg/mL. This formulation.also revealed the best antimicrobial capacity and proved to be able to inhibit the growth of Escherichia coli, E. coli ESBL, Staphylococcus aureus and Pseudomonas aeruginosa, with MIC values of 50, 6.2, 1.6 and 25 mg!mL, respectively. Pills revealed activity against some of the studied bacterial strains and the syrup did not reveal antimicrobial activity at the studied concentration. Eilagic acids, methyl ellagic acids, eucaglobulinlglobulusin B and (epi)gaiiocatechin-0-gallate were the compounds present in all the different formulations. The highest concentration of phenolic compounds was found in the infusion extract. Protocatechuic acid was the most abundant phenolic compound in the infusions, the only preparation where it was detected, whereas ( epi)gaiiocatechin- 0-gallate was the main phenolic in the pills and eucaglobulinlglobulusin in the syrup. In a general way, borututu proved to be a good source of phytochemicals such as phenolic compounds, with the infusions revealing the best bioactive properties.

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Mushrooms are very perishable foods due to their high susceptibility to moisture loss, changes in color and texture, or microbiological spoilage. Drying is considered as the most appropriate method to prevent these alterations, but it has some limitations, such as shrinkage, enzymatic and non-enzymatic browning reactions, and oxidation of lipids and vitamins. Irradiation might effectively attenuate the undesirable changes caused by drying process, ensuring also higher shelf-life of mushrooms and their decontamination [I]. In the present work, the combined effects of electron-beam irradiation (at 0, 0.5, 1 and 6 kGy doses) and storage time (at 0, 6 and 12 months) were evaluated and compared. Macrolepiota procera (Scop.) Singer wild samples were obtained in Tnis-os-Montes, in the Northeast of Portugal, and dried at 30 •c in an oven. Subsequently, the samples were divided in four groups: control (non-irradiated, 0 kGy); sample 1 (0.5 kGy); sample 2 (1 kGy) and sample 3 (6 kGy). The irradiation was performed at the lNCTInstitute of Nuclear Chemistry and Technology (lNCT), in Warsaw, Poland. Moisture, protein, fat, carbohydrates and ash were determined following standard procedures. Free sugars and tocopherols were determined by high performance liquid chromatography coupled to a refraction index detector (HPLC-RI) and a fluorescence detector, respectively; fatty acids were determined by gas-liquid chromatography with flame ionization detection (GC-FID). Antioxidant activity was evaluated in the methanolic extracts by in vitro assays measuring DPPH (1,1-diphenyl-2- picrylhydrazyl) radical scavenging activity, reducing power, inhibition of ~-carotene bleaching and inhibition oflipid peroxidation using thiobarbituric acid reactive substances (TBARS) assay. Total phenolics were also determined by the Folin-Ciocalteu assay. All the parameters showed a decrease tendency with storage time. Trehalose and y-tocopherol were preserved with 1 kGy dose. Electron-beam irradiation did not impart additional changes to most of the chemical and antioxidant parameters of M. procera dried samples. This is a very promising result, since electron-beam irradiation might attenuate most unwanted changes caused by drying, maintaining its long-term effectiveness.

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Vaccinum myrtillus L. belongs to Ericaceae family, being commonly known for its sweet small fruits: the blueberries. Widely consumed in fresh, these fruits are also used in jams and marmalades due to their digestive and hypoglycemic properties and also due to the presence of several bioactive compounds [!]. Therefore, it has become a very appealing matrix in the development of functional products that, beyond their nutritional properties, will add a long-term beneficial physiological/health effect [2]. In the present work, three novel blueberry based products developed by RBR Foods Company (Portugal), were characterized in terms of their nutritional and chemical properties: carbohydrates, ash, proteins, fat and energetic value (following official methods of food analysis), fatty acids profile (by CG-FID), soluble sugars (by HPLCRI), organic acids (by HPLC-DAD) and tocopherols (by HPLC-fluorescence). The products result from a mixture of the fruits with rose petals (PI), marigold petals (P2) and apple and goji berries (P3). The blueberry fruits were used as control sample. The nutritional profile of the novel products was very similar to the control sample: the carbohydrates were the most abundant macronutrient, followed by proteins and total fat. Regarding sugars, fructose, glucose and sucrose were identified in all the samples. P 1 and P2 didn't show significant differences in comparison to the control, however, P3 revealed a lower concentration of sugars. In terms of fatty acids composition, all the studied samples presented higher contents in polyunsaturated fatty acids, especially due to the contribution of linoleic and alinolenic acids. The results of tocopherols revealed that the control sample only presented two isoforrns of tocopherols, a- and y-tocopherol, being the same observed in P3. However, P 1 revealed the presence of all the isoforrns of tocopherols, while P2 was lacking otocopherol; which is related with the contribution of rose and marigold petals, respectively. The a-tocopherol isoforrn was the most abundant in all the studied samples. Overall, this work contributed to the nutritional characterization of novel blueberry based products and is a part of a wider project that aims the detailed study of these products, namely their potential to be used as functional foods.

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Wild strawberry, Fragaria vesca L., belongs to Rosaceae family and is commonly found in roadsides and slopes [1]. The most consumed parts of this plant are its sweet small fruits, which constitute a source of vitamins and phenolic compounds, being also used in infusions due to their organoleptic properties and for the treatment of some intestinal disorders [2, 3]. In the present work, F. vesca fruits were evaluated for their nutritional value and further used in the preparation of infusions. The chemical composition of the fruits and corresponding infusions was determined in terms of soluble sugars, organic acids, tocopherols, folates (by HPLC coupled to different detectors), phenolic compounds (by HPLC-DAD/ESI-MS) and mineral elements (atomic absorption spectroscopy). Some of these bioactive compounds were correlated with antioxidant and antibacterial properties evaluated either in infusions as also in hydromethanolic extracts. Carbohydrates were the main macronutrients in the fruits, followed by fat and proteins. Regarding the fatty acids, polyunsaturated fatty acids showed higher prevalence, mainly due to the presence of D-linolenic (Cl8:3n3) and y-linolenic (Cl8:3n6) acids. Sucrose and citric acid were, respectively, the main sugar and organic acid found in the fruits and in its infusions. The microelement found in higher amounts in both samples was manganese, while potassium and calcium were the macroelements present in higher levels in the fruits and infusions, respectively. Both samples presented folates and tocopherols, being ytocopherol the main isoform detected in the fruits, while a-tocopherol was the only isoform quantified in the infusion. The hydromethanolic extract prepared from the fruits gave higher antioxidant and antibacterial activities, namely against Escherichia coli and Pseudomonas aeruginosa, than the infusion; it also showed capacity to inhibit the formation of bacterial biofilm. Both bioactivities are highly correlated with the presence of phenolic compounds, in which the major are ellagic acid derivatives (sanguiin hlO) followed by tlavan 3-ols ((+)catechin) and anthocyanin compounds (pelargonidin-3-glucoside). Although fruits of wild F. vesca are mainly consumed in fresh, this study also proves the potentiality of their infusions as a source of bioactive molecules and properties.

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The antioxidant potential of mushrooms is mainly attributed to their composition in polysaccharides, phenolic compounds, tocopherols and some organic acids [1]. Phenolic compounds contribute directly to the antioxidative action and play an important role in stabilizing lipid peroxidation [2]; exhibit a wide range of bioactive properties such as anti-allergenic, anti-inflammatory and antimicrobial, which have been in part related to their antioxidant activity [3]. Tocopherols are important fatsoluble antioxidants, acting in the cellular membrane; due to their role as scavenger of free radicals protecting human cells against degenerative malfunctions [4]. Some organic acids are very common in natural matrices; malic acid contributes to a pleasantly sour taste and is often used as a food additive; citric acid is known due to its antibacterial and antioxidant properties and fumaric acid is important because of its antioxidant, anti-inflammatory, antimicrobial and acidifying properties [5]. The purpose of the present study was to analyze antioxidant and related compounds (phenolic compounds, tocopherols and organic acids) of Polyporus squamosus (Huds.) Fr. samples originated from two different origins (Portugal and Serbia). Specimens of P. squamosus were collected in Bragança (Northeast Portugal) and Jabučki rit (Northern Serbia) during April 2015 and 2012, respectively. Phenolic compounds, organic acids and tocopherols were determined by high performance liquid chromatograph (HPLC) coupled to a diode array detector (DAD), in the two first cases, and a fluorescence detector in the last one. With respect to phenolic and related compounds, p-hydroxybenzoic and cinnamic acids were identified in both samples; the first one predominates in the sample from Portugal, while cinnamic acid was more abundant in the sample from Serbia. Tocopherols (α-, β and γ-isoforms) were found in the sample from Serbia, but in the sample from Portugal, γ-tocopherol was not identified. This sample showed the highest total tocopherols content, and revealed the highest level of β-tocopherol; γ- tocopherol predominated in the sample from Serbia. Among organic acids, it was possible to quantify oxalic, malic and fumaric acids in both samples. Malic acid was found in higher amounts in the sample from Serbia. Overall, the present study shows that mushroom samples from different origins have dissimilar results, but are both rich in bioactive compounds, being a valuable source for the development of natural medicines and nutraceuticals.

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In recent years the interest in naturally occurring compounds has been increasing worldwide. Indeed, many of the bioactive compounds currently used as medicines have been synthesized based on the structure of natural compounds [1]. In order to obtain bioactive fractions and subsequently isolated compounds derived from natural matrices, several procedures have been carried out. One of these is to separate and assess the concentration of the active compound(s) present in the samples, a step in which the chromatographic techniques stand out [2]. In the present work the mushroom Sui/Ius granulatus (L.) Roussel was chemically characterized by chromatographic techniques coupled to different detectors, in order to evaluate the presence of nutritional and/or bioactive molecules. Some hydrophilic compounds, namely free sugars, were identified by high performance liquid chromatography coupled to a refraction index detector (HPLC-RI), and organic and phenolic acids were assessed by HPLC coupled to a photodiode array detector (HPLC-PDA). Regarding lipophilic compounds, fatty acids weredetermined by gas chromatography with a flame ionization detector (GC-FID) and tocopherols by HPLC-fluorescence detection. Mannitol and trehalose were the main free sugars detected. Different organic acids were also identified (i.e. oxalic, quinic and fumaric acids), as well as phenolic acids (i.e. gallic and p-hydroxybenzoic acids) and the related compound cinnamic acid. Mono- and polyunsaturated fatty acids were the prevailing fatty acids and a-, ~- and ~-tocopherol were the isoforms of vitamin E detected in the samples. Since this species proved to be a source of biologically active compounds, the antioxidant and antimicrobial properties were evaluated. The antioxidant activity was measured through the reducing power, free radical's scavenging activity and lipid peroxidation inhibition of its methanolic extract, and the antimicrobial activity was also tested in Gram positive and Gram negative bacteria and iri different fungi. S. granulatus presented antioxidant properties in all the performed assays, and proved to inhibit the growth of different bacterial and fungal strains. This study is a first step for classifying S. granulatus as a functional food, highlighting the potential of mushrooms as a source of nutraceutical and biologically active compounds.

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After harvest, plants remain living organisms with the capacity to carry out metabolic processes. Thus, from the moment they are detached from the source of nutrients, they become entirely dependent on their own organic reserves [1]. Postharvest changes cannot be stopped, but they can be slowed within certain limits. Therefore, this study was conducted to evaluate the effects induced by storage in the profiles of sugars, organic acids and tocopherols of two leafy vegetables. Wild samples of watercress (Nasturtium officinale R. Br.) and buckler sorrel (Rumex induratus Boiss. & Reut.), from the Northeastern region of Portugal, were analyzed after harvest (control) and after storage in sterilized packages (using the passive modification mode) at 4ºC for 7 or 12 days, respectively. Analyses were performed by high-performance liquid chromatography (HPLC) using different detectors, i.e., a refraction index detector (RID) for free sugars, a photodiode array detector (PDA) for organic acids, and a fluorescence (FP) detector for tocopherols. The storage time decreased the levels of fructose, glucose and total sugars in both leafy vegetables and increased the total organic acids content. The decrease of these sugars can be related to its use by the plant to produce the required energy. Ascorbic acid was detected in buckler sorrel and decreased with storage; while the amount of malic acid increased in both species. Curiously, all the tocopherol isoforms increased in watercress, while buckler sorrel just present higher values of γ- and δ- tocopherols. In fact, the de novo synthesis of these bioactives compounds can be a plant strategy to fight against the reactive species that are produced during storage. The knowledge of the behavior of these compounds during storage that was achieved with this study [2] may contribute to the development of more effective preservation strategies for leafy vegetables.

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The wild mushroom Leucopaxillus candidus (Bres.) Singer was studied for the first time to obtain information about its chemical composition, nutritional value and bioactivity. Free sugars, fatty acids, tocopherols, organic and phenolic acids were analysed by chromatographic techniques coupled to different detectors. L. candidus methanolic extract was tested regarding antioxidant potential (reducing power, radical scavenging activity and lipid peroxidation inhibition). L. candidus was shown to be an interesting species in terms of nutritional value, with high content in proteins and carbohydrates, but low fat levels, with the prevalence of polyunsaturated fatty acids. Mannitol was the most abundant free sugar and β-tocopherol was the main tocopherol isoform. Other compounds detected were oxalic and fumaric acids, p-hydroxybenzoic and cinnamic acids. The methanolic extract revealed antioxidant activity and did not show hepatoxicity in porcine liver primary cells. The present study provides new information about L. candidus.

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The phytochemical profiles and bioactivities of red, white and pink globe amaranth (Gomphrena haageana K., Gomphrena globosa var. albiflora and Gomphrena sp., respectively), much less studied than the purple species (G. globosa L.), were compared. The chemical characterization of the samples included the analysis of macronutrients and individual profiles of sugars, organic acids, fatty acids, tocopherols, and phenolic compounds. Their bioactivity was evaluated by determining the antioxidant and anti-inflammatory activities; the absence of cytotoxicity was also determined. Red and pink samples showed the highest sugar content. Otherwise, the white sample gave the highest level of organic acids, and together with the pink one showed the highest tocopherol and PUFA levels. Quercetin-3-O-rutinoside was the major flavonol in white and pink samples, whereas a tetrahydroxy-methylenedioxyflavone was the major compound in the red variety, which revealed a different phenolic profile. The pink globe amaranth hydromethanolic extract revealed the highest antioxidant activity, followed by those of red and white samples. The anti-inflammatory activity was more relevant in red and pink varieties. None of the samples presented toxicity in liver cells. Overall, these samples can be used in bioactive formulations against inflammatory processes and in free radical production.