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- Metabolic profiling and antibacterial activity of Eryngium pristis Cham. & Schltdl. - prospecting for its use in the treatment of bacterial infectionsPublication . Fernandes, Laura Silva; Costa, Ygor Ferreira Garcia da; Bessa, Martha Eunice de; Ferreira, Adriana Lucia Pires; Corrêa, José Otávio do Amaral; Del-Vechio Vieira, Glauciemar; Sousa, Orlando Vieira de; Araújo, Ana Lúcia Santos de Matos; Castilho, Paula C.; Alves, Maria SilvanaMorbidity and mortality of the infected patients by multidrug-resistant bacteria have increased, emphasizing the urgency of fi ght for the discovery of new innovative antibiotics. In this sense, natural products emerge as valuable sources of bioactive compounds. Among the biodiversity, Eryngium pristis Cham. & Schltdl. (Apiaceae Lindl.) is traditionally used to treat thrush and ulcers of throat and mouth, as diuretic and emmenagogue, but scarcely known as an antimicrobial agent. With this context in mind, the goals of this study were to investigate the metabolic profi le and the antibacterial activity of ethanolic extract (EE-Ep) and hexane (HF-Ep), dichloromethane (DF-Ep), ethyl acetate (EAF-Ep) and butanol (BF-Ep) fractions from E. pristis leaves. Gas Chromatography-Mass Spectrometry (GC-MS) was performed to stablish the metabolic profi le and revealed the presence of 12 and 14 compounds in EAF-Ep and HF-Ep, respectively. β-selinene, spathulenol, globulol, 2-methoxy-4-vinylphenol, α-amyrin, β-amyrin, and lupeol derivative were some of phytochemicals identifi ed. The antibacterial activity was determined by Minimal Inhibitory Concentration (MIC) using the broth micro-dilution against eight ATCC® and fi ve methicillin-resistant Staphylococcus aureus (MRSA) clinical strains. HF-Ep was the most eff ective (MIC ≤ 5,000 μg/μL), being active against the largest part of tested Gram-positive and Gram-negative bacterial strains, including MRSA, with exception of Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 9027) and (ATCC 27853). These results suggest that E. pristis is a natural source of bioactive compounds for the search of new antibiotics which can be an interesting therapeutic approach to recover patients mainly infected by MRSA strains.
- Effects of hydroxycinnamic acids on the glycolysis pathwayPublication . Serina, J.; Fernandes, M. X.; Castilho, P. C.Glycolysis is a metabolic pathway vital to the production of energy and some organisms rely on it solely to meet their energy requirements. It is also a central pathway in the metabolism of carbohydrates and a source of therapeutic targets against diabetes and cancer. Caffeoylquinic acids (CQAs) have been extensively studied for their role in the treatment and prevention of diabetes (and cancer) but their mechanisms of action remain mostly unknown. As such, molecular docking was used to find possible targets of CQAs in the glycolysis pathway. The molecular docking assays showed that CQAs were docked preferably to the Rossman fold (nicotinamide adenine dinucleotide — NAD(H) binding site) of oxidoreductases, that use NAD(H) as a cofactor, than to any other site. In-vitro assays were then performed using two NAD(H) dependent oxidoreductases from glycolysis (alcohol dehydrogenase and L-lactate dehydrogenase) in order confirm if CQAs would compete with the cofactor to inhibit the reaction. The results from these assays indicate that CQAs can act as both inhibitors and activators of NAD(H) dependent oxidoreductases of the glycolysis pathway.
- Fish processing industry residues: a review of valuable products extraction and characterization methodsPublication . Ideia, Pedro; Pinto, Joana; Ferreira, Rui; Figueiredo, Leandro; Spínola, Vítor; Castilho, Paula C.Fish processing industry has experienced significant growth, playing an important role in the world economy. The increased exploration of marine resources contributes to the generation of considerable amounts of biowaste, which ends up as discards. In the face of the resultant disposal and environmental problems, many efforts have been made to deal with the fishery waste in more efficient ways. Nowadays, these by-products are regarded as important sources of high added value compounds, such as hydroxyapatite, collagen, gelatin, lipids, enzymes, hydrolysates and bioactive peptides, with great potential for human health applications. The present paper aims to review the current methods of extraction and characterization of added value products from fish by-products, as well as their actual and potential applications.
- Caffeoylquinic acids as inhibitors for HIV-I protease and HIV-I integrase: a molecular docking studyPublication . Serina, João C.; Castilho, Paula C.; Fernandes, Miguel X.Caffeoylquinic acids are ubiquitous phenolic compounds with several health benefits to humans and they have been shown to be promisinganti-HIV compounds. In this work, molecular docking was used to study the inhibition of HIV-I integrase and protease using caffeoylquinic acids. It was possible to establish that the naturally occurring caffeoylquinic acids are not suitable as inhibitors for protease but are very good inhibitors for integrase. A new binding site was found for 3, 4-O-di-Caffeoylquinic acid between the chains of HIV-I integrase that could possibly lead to a disruption of the catalytic process of HIV-I integrase.
- Hypoglycemic, anti-glycation and antioxidant in vitro properties of two Vaccinium species from Macaronesia: A relation to their phenolic compositionPublication . Spínola, Vítor; Pinto, Joana; Castilho, Paula C.Vaccinium cylindraceaeum (Azores blueberry) and V. padifolium (Madeira blueberry) are two Portuguese endemic species, which phytochemical composition and beneficial properties lack scientific validation. In this work, their potential in vitro inhibitory effects against key enzymes linked to type 2 diabetes and obesity and glycation of proteins were evaluated. Anthocyanins were predominant in fruits, while hydroxycinnamic acids (in particular 5-O-caffeoylquinic acid) and flavonoids were the main compounds in leaves. Vaccinium extracts showed effective inhibitions of glucosidases and glycation of proteins and mild activity towards α-amylase and pancreatic lipase (by comparison with reference compounds). Phenolic composition was strongly correlated with reported bioactivities. In fact, 5-O-caffeoylquinic can be considered one of the main hypoglycemic and anti-glycation agents of analysed extracts. Consumption of both Vaccinium species should be encouraged since berries could offer a dietary option in the prevention and control of diabetes and obesity, while leaves are good candidates for development of nutraceuticals.
- Release of health-related compounds during in vitro gastro-intestinal digestion of okara and okara fermented with Lactobacillus plantarumPublication . Quintana, Gabriel; Spínola, Vítor; Martins, Gonçalo N.; Gerbino, Esteban; Gómez-Zavaglia, Andrea; Castilho, Paula C.Okara is a highly perishable by-product remaining after filtration of the smashed soybeans seeds in the production of soymilk. Due to its nutritional value, different approaches have been developed to use it as functional ingredient. Fermentation of okara appears as an interesting strategy to preclude spoilage, providing a more stable matrix to be incorporated in the formulation of functional foods. Okara has antioxidant compounds but the effect of fermentation, and their bioaccessibility still need to be investigated. To achieve this aim, the phenolic compounds (as determined by TPC and TFC assays) and the antioxidant properties (as determined by ABTS ·+, DPPH · , O2·- assays) of okara and okara fermented with Lactobacillus plantarum CIDCA 83114 were assessed both before and after exposure to simulated gastro-intestinal conditions. Before digestion, okara showed higher values of TPC and TFC than the fermented counterpart. Although a decrease of TPC and TFC was observed after exposing okara to gastric conditions, no significant differences between okara and fermented okara were detected. No further decrease of TPC were observed in intestinal conditions. Okara showed higher antioxidant activity than fermented okara. There was a considerable decrease in the antioxidant activity for both samples when exposed to gastric and intestinal conditions. A good correlation between TFC and antioxidant activities was detected, suggesting that flavonoids play an important role as antioxidants. As a whole, this work provides a solid support for the stability of phytochemicals along the digestive process of both okara and fermented okara.
- Targeting NF-κB signaling pathway in cancer by dietary polyphenolsPublication . Khan, Haroon; Ullah, Hammad; Castilho, Paula Cristina Machado Ferreira; Gomila, Antoni Sureda; D'Onofrio, Grazia; Filosa, Rosanna; Wang, Fang; Nabavi, Seyed Mohammad; Daglia, Maria; Silva, Ana Sanches; Rengasamy, Kannan R. R.; Ou, Juanying; Zou, Xiaobo; Xiao, Jianbo; Cao, HuiBeing a transcription factor, NF-κB regulates gene expressions involving cell survival and proliferation, drug resistance, metastasis, and angiogenesis. The activation of NF-κB plays a central role in the development of inflammation and cancer. Thus, the down-regulation of NF-κB may be an exciting target in prevention and treatment of cancer. NF-κB could act as a tumor activator or tumor suppressant decided by the site of action (organ). Polyphenols are widely distributed in plant species, consumption of which have been documented to negatively regulate the NF-κB signaling pathway. They depress the phosphorylation of kinases, inhibit NF-κB translocate into the nucleus as well as interfere interactions between NF-κB and DNA. Through inhibition of NF-κB, polyphenols downregulate inflammatory cascade, induce apoptosis and decrease cell proliferation and metastasis. This review highlights the anticancer effects of polyphenols on the basis of NF-κB signaling pathway regulation.
- Composition and acaricidal activity of Laurus novocanariensis and Laurus nobilis essential oils against Psoroptes cuniculiPublication . Macchioni, Fabio; Perrucci, Stefania; Cioni, Pierluigi; Morelli, Ivano; Castilho, Paula; Cecchi, FrancescaThe major components of Laurus nobilis and L. novocanariensis leaf oils were identifi ed and their acaricidal activity against Psoroptes cuniculi evaluated. Monoterpenes were predominant in L. nobilis oil (91.8%), while ses quiterpenes were only 1.4%. The main components of this oil were 1,8-cineole (39.2%), α-terpinyl acetate (11.3%), sabinene (10.6%) and linalool (7.4%). The acaricidal activity of L. nobilis oil, at a concentration of 10%, led to a mortality rate of 73%; at 5% the average activity was signifi cantly reduced to 51%, while dilutions of 2.5%, 1.25% and 0.625% were ineffective. Laurus novocanariensis oil, compared to L. nobilis, was richer in sesquiterpenes; the main constituents were α-pinene (10.4%), 1,8-cineole (9.6%) and β-selinene (7.2%). After 24 h of contact, the oil of L. novocanariensis killed all the mites when used at 10% and 5% concentrations. At lower concentrations the mortality signifi cantly decreased; a dilution of 0.625% was ineffective.
- Acid-modified clays as green catalysts for the hydrolysis of hemicellulosic oligosaccharidesPublication . Vilcocq, Léa; Spínola, Vítor; Moniz, Patrícia; Duarte, Luís C.; Carvalheiro, Florbela; Fernandes, César; Castilho, PaulaThe hydrolysis of hemicellulosic oligosaccharides (OS) was investigated using acid-activated clays (prepared from natural Porto Santo montmorillonite clay) as catalysts. Acid activation was performed in HCl solution or with aluminium exchange. The clay catalysts were characterized by XRD, N2 adsorption isotherms, CEC, FTIR, titration of acid sites in water and adsorption of sugars and disaccharides. They were tested for the hydrolysis of a model compound, maltose, and of OS-rich liquor from rice straw fractionation. The HCl-activated clays were the most efficient catalysts for maltose hydrolysis. It was demonstrated that the hydrolysis of OS into monomer sugars over a clay catalyst is technically feasible and that this reaction leads to the selective removal of glucose, arabinose and acetic acid side groups from the OS structure, thus yielding simpler xylo-oligosaccharide chains. Furthermore, no significant conversion of monomer sugars into furans was observed.
- An improved and fast UHPLC-PDA methodology for determination of L-ascorbic and dehydroascorbic acids in fruits and vegetables. Evaluation of degradation rate during storagePublication . Spínola, Vítor; Mendes, Berta; Câmara, José S.; Castilho, Paula C.This study provides a versatile validated method to determine the total vitamin C content, as the sum of the contents of L-ascorbic acid (L-AA) and dehydroascorbic acid (DHAA), in several fruits and vegetables and its degradability with storage time. Seven horticultural crops from two different origins were analyzed using an ultra-high-performance liquid chromatographic-photodiode array (UHPLC-PDA) system, equipped with a new trifunctional high strength silica (100% silica particle) analytical column (100 mm × 2.1 mm, 1.7 μm particle size) using 0.1% (v/v) formic acid as mobile phase, in isocratic mode. This new stationary phase, specially designed for polar compounds, overcomes the problems normally encountered in HPLC and is suitable for the analysis of large batches of samples without L-AA degradation. In addition, it proves to be an excellent alternative to conventional C18 columns for the determination of L-AA in fruits and vegetables. The method was fully validated in terms of linearity, detection (LOD) and quantification (LOQ) limits, accuracy, and inter/intra-day precision. Validation experiments revealed very good recovery rate of 96.6 ± 4.4% for L-AA and 103.1 ± 4.8 % for total vitamin C, good linearity with r(2)-values >0.999 within the established concentration range, excellent repeatability (0.5%), and reproducibility (1.6%) values. The LOD of the method was 22 ng/mL whereas the LOQ was 67 ng/mL. It was possible to demonstrate that L-AA and DHAA concentrations in the different horticulture products varied oppositely with time of storage not always affecting the total amount of vitamin C during shelf-life. Locally produced fruits have higher concentrations of vitamin C, compared with imported ones, but vegetables showed the opposite trend. Moreover, this UHPLC-PDA methodology proves to be an improved, simple, and fast approach for determining the total content of vitamin C in various food commodities, with high sensitivity, selectivity, and resolving power within 3 min of run analysis.