Browsing by Author "Pereira, P."
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- Antioxidant Capacity and Identification of Bioactive Compounds of Myrtus communis L. Extract Obtained by Ultrasound-Assisted ExtractionPublication . Pereira, P.; Cebola, M.J.; Oliveira, M.C.; Bernardo-Gil, M. G.Ultrasound-assisted extraction was used to investigate the polyphenolic compounds, particularly anthocyanins, present in myrtle alcoholic extracts. This type of extract is typical in the making of liqueurs obtained from herbs or plants, especially medicinal plants. The leaf extracts were found to contain flavonoids from the quercetin and myricetin families. Besides these, the berry extracts also showed the presence of anthocyanins, hydrolysable tannins and quinic acid. The antioxidant capacity was studied using the ORAC and TEAC methods and the polyphenol content was measured using the Folin–Ciocalteu method. The results showed that the values produced by the ORAC and TEAC methods were in agreement and that the antioxidant capacity correlated with the polyphenol content. The results showed that the leaf extracts exhibited higher antioxidant capacity than the berry extracts. The extraction method was easily implementable, and proved to be a swift method for obtaining bioactive compounds from vegetable matrices.
- Effect of cinnamon powder addition to a Portuguese custard tart (Pastel de Nata) on healthy adults’ postprandial glycemiaPublication . Moncada, M. M.; Bernardo, M. A.; Silva, M. L.; Jorge, A.; Pereira, P.; Brito, J.; Singh, J.; Mesquita, M. F.Background and Objective: Cinnamon is a spice used over the years in cooking to impart aromatic, flavor and taste properties to food and beverages. Moreover, cinnamon has been used for its medicinal properties due to its potential phenolic content, which can protect against cardio-metabolic diseases. Previous studies reported an improvement of postprandial glycemia after addition of cinnamon powder to a high-sugar meal. The study aims at investigating the effect of adding cinnamon powder to a Portuguese custard tart (Pastel de Nata) on the postprandial glycemic response in healthy subjects. Subjects and Methods: After review board and Ethic Committee of the State approval, thirty-two healthy human subjects were assigned in a controlled study and randomly allocated into 2 groups: 16 subjects ingested a custard tart with cinnamon powder (cinnamon group) and 16 subjects ingested a custard tart alone (control group). Blood glucose concentrations were measured before interventions and after 30, 60, 90 and 120 minutes. Chemical analysis was performed to quantify the total phenolic content and antioxidant activity. Results: The postprandial blood glucose (PBG) area under the curve (AUC) was significantly lower (p = 0.0005) in the cinnamon group (599.2 ± 9.1) compared to the AUC of the control group (645.7 ± 7.7). The administration of cinnamon powder to the custard tarts slightly decreased PBG mean values compared to custard tart without cinnamon powder, although it did not reach statistical significance (p = 0.273). Cinnamon addition to custard tart improved the total phenolic content (1278.7 ± 0.7 compared to 253.7 ± 22.8 mg/L gallic acid) and antioxidant properties, increasing 4.4 times the capacity of free-radical scavenger compared with custard tart without cinnamon (IC50). Conclusion: The addition of cinnamon powder to custard tart could be beneficial to glycemic control.
- Extraction Optimization and Structural and Thermal Characterization of the Antimicrobial Abietane 7α-Acetoxy-6βhydroxyroyleanonePublication . Bernardes, C.; Garcia, C.; Pereira, F.; Mota, J.; Pereira, P.; Cebola, M.J.; Reis, C.; Correia, I.; Piedade, M.F.; Piedade, M.The abietane 7α-acetoxy-6β-hydroxyroyleanone (AHR), obtained from plant extracts, is an attractive lead for drug development, given its known antimicrobial properties. Two basic requirements to establish any compound as a new drug are the development of a convenient extraction process and the characterization of its structural and thermal properties. In this work seven different methods were tested to optimize the extraction of AHR from Plectranthus grandidentatus. Supercritical fluid extraction (SFE) proved to be the method of choice, delivering an amount of AHR (57.351 μg·mg-1) approximately six times higher than the second best method (maceration in acetone; 9.77 μg·mg-1). Single crystal X-ray diffraction analysis of the ARH molecular and crystal structure carried out at 167 ± 2 K and 296 ± 2 K showed only a single phase, here dubbed form III (orthorhombic space group P21212), at those temperatures. The presence of two other polymorphs above room temperature was, however, evidenced by differential scanning calorimetry (DSC). The three forms are enantiotropically related, with the form III → form II and form II → form I transitions occurring at 333.5 ± 1.6 K and 352.0 ± 1.6 K, respectively. The fact that the transitions are reversible suggests that polymorphism is not likely to be an issue in the development pharmaceutical formulations based on ARH. DSC experiments also showed that the compound decomposes on melting at 500.8 ± 0.8 K. Melting should therefore be avoided if, for example, strategies to improve solubility based on the production of glassy materials or solid dispersions are considered.
- HPLC/MS identification of the polyphenols present in an extract of Myrtus communis L. obtained by supercritical fluid extractionPublication . Pereira, P.; Cebola, M.J.; Oliveira, M.C; Bernardo-Gil, M.GNeste trabalho, estudámos um extrato obtido por extração de fluido supercrítica (ESC) usando um método mais simples de adição de co-solvente (etanol). Em vez de usar uma bomba de líquidos, que é o processo mais comum, o etanol foi introduzido diretamente na célula de extração, imediatamente após o carregamento da célula com a amostra de planta. Pretendeu-se investigar se esta alteração teria algum efeito na composição do extrato obtido. As condições experimentais utilizadas foram: temperatura 48 °C, pressão 10 MPa, caudal de fluido supercrítico (FSC) 130,71 dm3h-1 (0,238 kgh-1) e um volume de etanol de 104 cm3. Os compostos identificados por HPLC MS neste extrato foram o ácido quínico, o ácido quínico 3,5-di-O-galato, o ácido 3,4,5-galoilquinico, a miricetina galactósido-galato, a quercetina-galactósido-galato, a miricetina-galactósido e a quercetina-ramnósido).
- Influence of temperature and light on total phenolic compounds during natural orange juice storagePublication . Capitão, C.; Coutinho, D.; Dias, B.; Ramalho, R.; Pereira, P.
- Omega-3 therapeutic supplementation in a patient with metastatic adenocarcinoma of the pancreas with muscle mass depletionPublication . Ramalho, R.; Ramalho, P.; Couto, N.; Pereira, P.Pancreatic adenocarcinoma has an extremely poor prognosis. With the best available treatments, the median overall survival duration is still less than 1 year. Most patients develop anorexia and major muscle mass loss that interfere with chemotherapy tolerance and survival. In this paper, we present a case in which these problems were a major concern. A multidisciplinary approach with chemotherapy and close nutritional support permitted better control of the disease and longer survival. We also review the literature on nutritional interventions that show an improvement in quality of life and survival in these patients.
- Parvifloron D from Plectranthus strigosus Cytotoxicity Screening of Plectranthus spp. ExtractsPublication . Garcia, C.; Ntungwe, C.; Rebelo, A.; Bessa, C.; Stankovic, T.; Dinic, J.; Díaz-Lanza, A.; Reis, C.; Roberto, A.; Pereira, P.; Cebola, M. J.; Saraiva, L.; Pesic, M.; Duarte, N.; Rijo, P.The Plectranthus genus is commonly used in traditional medicine due to its potential to treat several illnesses, including bacterial infections and cancer. As such, aiming to screen the antibacterial and cytotoxic activities of extracts, sixteen selected Plectranthus species with medicinal potential ere studied. In total, 31 extracts obtained from 16 Plectranthus spp. were tested for their antibacterial and anticancer properties. Well di usion method was used for preliminary antibacterial screening. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of the five most active acetonic extracts (P. aliciae, P. japonicus, P. madagascariensis var. “Lynne”, P. stylesii, and P. strigosus) were determined. After preliminary toxicity evaluation on Artemia salina L., their cytotoxic properties were assessed on three human cancer cell lines (HCT116, MCF-7, and H460). These were also selected for mechanism of resistance studies (on NCI-H460/R and DLD1-TxR cells). An identified compound—parvifloron D—was tested in a pair of sensitive and MDR-Multidrug resistance cancer cells (NCI-H460 and NCI-H460/R) and in normal bronchial fibroblasts MRC-5. The chemical composition of the most active extract was studied through high performance liquid chromatography with a diode array detector (HPLC-DAD/UV) and liquid chromatography–mass spectrometry (LC–MS). Overall, P. strigosus acetonic extract showed the strongest antimicrobial and cytotoxic potential that could be explained by the presence of parvifloron D, a highly cytotoxic diterpene. This study provides valuable information on the use of the Plectranthus genus as a source of bioactive compounds, namely P. strigosus with the potential active ingredient the parvifloron D.
- Supercritical Fluid Extraction vs Conventional Extraction of Myrtle Leaves and Berries: Comparison of Antioxidant Activity and Identification of Bioactive CompoundsPublication . Pereira, P.; Cebola, M. J.; Oliveira, M. C.; Bernardo-Gil, M. G.In this work, the antioxidant capacity of extracts of Portuguese myrtle (Myrtus communis L.) is being studied over a period of three years. The samples were leaves of myrtle collected at the flowering stage and berries sampled at an early ripened stage. Supercritical fluid extraction (SFE) extracts were obtained at 23 MPa, 45 °C and a CO2 flow of 0.3 kg h−1 using ethanol as co-solvent with a flow rate of 0.09 kg h−1. Hydrodistillation was carried out in a Clevenger type apparatus and the aqueous phase was extracted with diisopropylether having obtained what is hereby designated as liquid phase extract (LPE). The antioxidant capacity of all the extracts was determined by using three different methods: the Folin–Ciocalteu, the Trolox Equivalent Antioxidant Capacity (TEAC) and the Oxygen Radical Absorbance Capacity (ORAC). The results show that the SFE extracts present a significantly higher antioxidant capacity. The extracts were characterized and quantified by HPLC-DAD-MS/MS methods. The bioactive compounds identified in all the extracts were phenolic acids (only in the LPE extracts), flavonoids and anthocyanins (only in the SFE extracts). The results indicate that the higher antioxidant capacity of the SFE myrtle extracts is mainly correlated with the concentration of flavonol glycosides, the myricetin-O-glycosides.
- Undernutrition in institutionalized elderly patients with neurological diseases: comparison between different diagnostic criteriaPublication . Miranda, D.; Cardoso, R.; Gomes, R.; Guimarães, I.; Abreu, D. de; Godinho, C.; Pereira, P.; Domingos, J.; Nona, N.; Ferreira, J. J."Objectives: To determine and compare the frequency of undernutrition in institutionalized elderly patients with neurological diseases at admission using different nutritional assessment tools. Design: Cross-sectional observational study. Setting: One long-term care institution specialized in neurodegenerative diseases. Participants: 92 Elderly people (aged ≥ 65 years) with at least one neurological condition. Measurements: Mini Nutritional Assessment (MNA), body mass index (BMI), mid-arm (MAC) and calf circumferences (CC) were used for nutritional status assessment. Presence and severity of dysphagia, polypharmacy and feeding difficulties were also assessed. Results: According to MNA, 77.1% of the participants were undernourished at admission. BMI identified 46.8%, MAC identified 44.6% and CC identified 22.8% of undernourished participants. Undernutrition was more frequent in Alzheimer’s disease, stroke and dementia syndromes. 63% had dysphagia for at least one food consistence and most of these patients were malnourished. MNA revealed best concordance with BMI and MAC than with CC. BMI and feeding difficulties were the major risk factors for undernutrition. Conclusion: Undernutrition prevalence in institutionalized elderly with neurological diseases at admission is high. Nutritional assessment tools revealed low concordance between them."