Browsing by Author "Pereira, H."
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- Antileishmanial activity of meroditerpenoids from the macroalgae Cystoseira baccataPublication . Sousa, Carolina Bruno de; Gangadhar, Katkam N.; Morais, Thiago R.; Conserva, Geanne A. A.; Vizetto-Duarte, C; Pereira, H.; Laurenti, Marcia D.; Campino, Lenea; Levy, Debora; Uemi, Miriam; Barreira, Luísa; Custódio, L.; Passero, Luiz Felipe D.; Lago, Joao Henrique G.; Varela, JoãoThe development of novel drugs for the treatment of leishmaniases continues to be crucial to overcome the severe impacts of these diseases on human and animal health. Several bioactivities have been described in extracts from macroalgae belonging to the Cystoseira genus. However, none of the studies has reported the chemical compounds responsible for the antileishmanial activity observed upon incubation of the parasite with the aforementioned extracts. Thus, this work aimed to isolate and characterize the molecules present in a hexane extract of Cystoseira baccata that was found to be bioactive against Leishmania infantum in a previous screening effort. A bioactivity-guided fractionation of the C. baccata extract was carried out and the inhibitory potential of the isolated compounds was evaluated via the MIT assay against promastigotes and murine macrophages as well as direct counting against intracellular amastigotes. Moreover, the promastigote ultrastructure, DNA fragmentation and changes in the mitochondrial potential were assessed to unravel their mechanism of action. In this process, two antileishmanial meroditerpenoids, (3R)- and (3S)-tetraprenyltoluquinol (1a/1b) and (3R)- and (3S)-tetraprenyltoluquinone (2a/2b), were isolated. Compounds 1 and 2 inhibited the growth of the L. infantum promastigotes (IC50 = 44.9 +/- 4.3 and 94.4 +/- 10.1 mu M, respectively), inducing cytoplasmic vacuolization and the presence of coiled multilamellar structures in mitochondria as well as an intense disruption of the mitochondrial membrane potential. Compound 1 decreased the intracellular infection index (IC50 = 25.0 +/- 4.1 mu M), while compound 2 eliminated 50% of the intracellular amastigotes at a concentration > 88.0 mu M. This work identified compound 2 as a novel metabolite and compound 1 as a biochemical isolated from Cystoseira algae displaying antileishmanial activity. Compound 1 can thus be an interesting scaffold for the development of novel chemotherapeutic molecules for canine and human visceral leishmaniases studies. This work reinforces the evidence of the marine environment as source of novel molecules. (C) 2017 Elsevier Inc. All rights reserved.
- Biochemical profile and in vitro neuroprotective properties of Carpobrotus edulis L., a medicinal and edible halophyte native to the coast of South AfricaPublication . Rocha, M. I.; J, Nogueira-Rodrigues; Pereira, C.; Pereira, H.; Silva, Manuela F. G. M.; da Rosa Neng, N.; Nogueira, J. M. F.; Varela, J.; Barreira, Luísa; Custódio,This work reports the nutritional profile and in vitro neuroprotective properties of leaves of Carpobrotus edulis L, a medicinal and edible succulent species native to the coast of South Africa. Biomass was evaluated for proximate composition and for contents in carotenoids, liposoluble pigments and minerals. Hexane, dichloromethane, ethyl acetate and methanol extracts were prepared by Soxhlet extraction from dried biomass and evaluated for in vitro inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), capacity to attenuate hydrogen peroxide (H2O2)-induced injury in the human dopaminergic cell line SH-SY5Y and for anti-neuroinflammatory potential on lipopolysaccharide (LPS)-stimulated microglia cells. Extracts were evaluated for antioxidant activity by four complementary methods, total content of phenolics, tannins and flavonoids. Finally the profile of the main phenolic compounds was determined by high performance liquid chromatography with diode array detection (HPLC-DAD). C edulis has a high moisture content, high levels of crude protein, fibre, ash, carotenoids, calcium and iron and a low fat level. The extracts were able to efficiently scavenge the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), reduce iron and chelate copper and iron ions, and exhibited different levels of phenolic compounds in the order ethyl acetate > methanol > dichloromethane > hexane. The main compounds detected were gallic and salicylic acids and quercetin, all in the ethyl acetate extract. The extracts allowed a dual and potent inhibition of AChE and BuChE. The dichloromethane and methanol extracts had the strongest capacity to prevent cell death induced by H2O2, and the methanol extract had anti-neuronflammatory properties. All together our results suggest that consumption of leaves of C edulis can contribute for a balanced diet, and that they may add to the improvement of cognitive functions. It also suggests possible novel biotechnological applications of C. edulis such as source of molecules and/or products for the food and/or pharmaceutical industries. Studies aiming to the isolation and identification of the bioactive compounds are already in progress. (C) 2017 SAAB. Published by Elsevier B.V. All rights reserved.
- Effect of temperature on growth, photosynthesis and biochemical composition of Nannochloropsis oceanica, grown outdoors in tubular photobioreactorsPublication . Carneiro, M.; Cicchi, B.; Maia, I. B.; Pereira, H.; Zittelli, G. Chini; Varela, João; Xavier Malcata, F.; Torzillo, G.Since temperature is an important factor affecting microalgal growth, photosynthetic rate and biomass composition, this study has accordingly focused on its effects on biomass yield and nighttime biomass loss, as well as photochemical changes, using Nannochloropsis oceanica as model species, grown in two outdoor 50-L tubular photobioreactors (PBR). In two independent trials, cultures were subjected to a diurnal light:dark cycle, under a constant temperature of 28 degrees C and, on the second trial, at 18 degrees C. Changes in culture performance were assessed by measuring growth, lipid and fatty acid composition of the biomass in both morning and evening. Our results revealed that N. oceanica shows a wide temperature tolerance with relevant nighttime biomass loss, that decreased at lower temperatures, at the expenses of its daily productivity. Fluorescence measurements revealed reversible damage to photosystem II in cells growing in the PBR under optimal thermal conditions, whereas microalgae grown at suboptimal ones exhibited an overall lower photosynthetic activity. Lipids were partially consumed overnight to support cell division and provide maintenance energy. Eicosapentaenoic acid (EPA) catabolism reached a maximum after the dark period, as opposed to their saturated counterparts; whereas lower temperatures led to higher EPA content which reached the maximum in the morning. These findings are relevant for the production of Nannochloropsis at industrial scale.
- Effects of LED lighting on Nannochloropsis oceanica grown in outdoor raceway pondsPublication . Carneiro, M.; Maia, Inês Beatriz; Cunha, P.; Guerra, I.; Magina, T.; Santos, Tamara; Schulze, Peter S.C.; Pereira, H.; Malcata, F. X.; Navalho, J.; Silva, J.; Otero, A.; Varela, JoãoGrowth in most microalgal mass cultivation systems is light-limited, particularly in raceway ponds (RWP) where the light path is higher. Artificial lighting can be a promising solution to diminishing dark zones and enhance microalgal productivity. Therefore, our goal was to prevent the cell shift from photosynthesis to a respiration-only stage by resorting to LED illumination. Nannochloropsis oceanica cultures were accordingly grown out-doors in a preliminary small-scaleexperiment, followed by pilot-scale trials. In the former, three 3.0-m(2) RWP were set up under three distinct conditions: 1) without LEDs (control); 2) LEDs turned on during the night; and 3) LEDs turned on for 24 h. In the pilot-scale trial, one of two 28.9-m(2) pilot-scale RWPs was coupled to the best LED setup - determined in the small-scale preliminary experiment - using the same light intensity (normal mode) and half of the intensity (economy mode), with the second RWP serving as a control. In the preliminary experiment, the use of LEDs for 24 h was deemed as not helpful during daytime, before the culture reached asymptotic to 0.5 g DW L-1 - when dark zones appeared during the day due to sunlight attenuation in the 0.1 m-deep cultures. Overall, use of LEDs increased biomass growth chiefly by increasing nighttime productivities - materialized in higher chlorophyll, protein, and carbohydrate productivities in LED-lit cultures. A higher impact of LED lighting was observed under lower sunlight irradiances. A preliminary economic analysis indicates that use of LEDs in RWPs outdoors should be considered for high-value metabolites only.
- Evaluation of oil composition of some crops suitable for human nutritionPublication . Carvalho, Isabel Saraiva de; Miranda, I.; Pereira, H.Interest in Canola, Cannabis, Sunflower, Cardoon and Safflower, was focused on the composition of the fat because of their growing importance for nutritional and pharmaceutical purposes. We have therefore begun the analysis and characterization of their fatty acids (FAs) in different oils extracted from those crops to obtain reliable data on their suitability for both human nutrition and industrial or pharmaceutical purposes. The oil content fluctuated from 243 g/kg for Cardoon, 327 g/kg for Cannabis, 358 g/kg for Safflower, 411 g/kg for Sunflower to 488 g/kg for Canola. The ratio of n-6 to n-3 and total unsaturated to total saturated fatty acids ranged from 1.8 to 78.6 and 4.0 to 12.9, respectively. All five crop oils contained a high concentration of unsaturated fatty acids, namely linoleic acid (LA) and linolenic acid (LNA), which are two of the main representative compounds, known as dietary essential fatty acids (EFA) because they prevent deficiency symptoms and cannot be synthesized by humans. They could be considered, per si, functional foods without any biochemical extra additions. Thus, we conclude that whole crop oils do not differ significantly in their FAs composition; consequently, all seem to be suitable for human nutrition after refined procedure.
- Heterotrophy as a tool to overcome the long and costly autotrophic scale-up process for large scale production of microalgaePublication . Barros, A.; Pereira, H.; Campos, J.; Marques, A.; Varela, J.; Silva, J.Industrial scale-up of microalgal cultures is often a protracted step prone to culture collapse and the occurrence of unwanted contaminants. To solve this problem, a two-stage scale-up process was developed - heterotrophically Chlorella vulgaris cells grown in fermenters (1st stage) were used to directly inoculate an outdoor industrial autotrophic microalgal production unit (2nd stage). A preliminary pilot-scale trial revealed that C. vulgaris cells grown heterotrophically adapted readily to outdoor autotrophic growth conditions (1-m3 photobioreactors) without any measurable difference as compared to conventional autotrophic inocula. Biomass concentration of 174.5 g L-1, the highest value ever reported for this microalga, was achieved in a 5-L fermenter during scale-up using the heterotrophic route. Inocula grown in 0.2- and 5-m3 industrial fermenters with mean productivity of 27.54 ± 5.07 and 31.86 ± 2.87 g L-1 d-1, respectively, were later used to seed several outdoor 100-m3 tubular photobioreactors. Overall, all photobioreactor cultures seeded from the heterotrophic route reached standard protein and chlorophyll contents of 52.18 ± 1.30% of DW and 23.98 ± 1.57 mg g-1 DW, respectively. In addition to providing reproducible, high-quality inocula, this two-stage approach led to a 5-fold and 12-fold decrease in scale-up time and occupancy area used for industrial scale-up, respectively.
- Lipid composition and some bioactivities of 3 newly isolated microalgae (Tetraselmis sp. IMP3, Tetraselmis sp. CTP4, and Skeletonema sp.)Publication . Cardoso, Cátia; Pereira, H.; Franca, J.; Matos, J.; Monteiro, I.; Pousão-Ferreira, P.; Gomes, A.; Barreira, Luísa; Varela, Varela J.; Neng, N.; Nogueira, J. M.; Afonso, C.; Bandarra, N. M.Recently isolated microalgae Tetraselmis sp. IMP3, Tetraselmis sp. CTP4, and Skeletonema sp. were studied. The three novel strains contained relatively high levels of polyunsaturated fatty acids (PUFA) and n3 PUFA. However, highly unsaturated n3 FA contents were relatively low (5.7-13.0% of the total FA). In general, eicosapentaenoic acid (EPA, 20:5 n3) contents were low (< 6.4% of the total FA). However, in Skeletonema biomass, EPA levels were higher than 10% of the total FA. alpha-Linolenic acid (ALA, 18:3 n3) and 16:3 n4 were the main PUFA in Tetraselmis strains and Skeletonema, respectively. High contents of myristic (14:0) and palmitoleic (16:1 n7) acids were found in Skeletonema (exceeding 20% of the total FA in both cases), whereas the Tetraselmis strains were rich in palmitic (16:0), 15-27% of the total FA, and oleic (18:1 n9) acids, 12-19% of the total FA. Linoleic acid (18:2 n6) content was low in Skeletonema (< 1% of the total FA). This microalga had the highest total polyphenol content, reaching 300-400 mg/100 g dw. Gentisic acid was the main phenolic compound in the aqueous and ethanolic extracts of this microalga. The highest antioxidant activity was displayed by Skeletonema. The ferric ion reducing antioxidant power (FRAP) and 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) methods showed higher antioxidant power for Skeletonema sp. extracts, reaching an ABTS reduction of more than 80%. Concerning anti-inflammatory activity, ethanolic extracts of Skeletonema sp. exhibited the highest inhibitory capacity of cyclooxygenase-2 (COX-2), 82 +/- 2%, which compares to 36 +/- 9% in Tetraselmis sp. CTP4 and 45 +/- 5% in Tetraselmis sp. IMP3. Aqueous extracts had always a lower anti-inflammatory capacity, 6-30%. Therefore, these microalgae have potential for multiple applications, ranging from bioactive feedstocks to aquaculture and nutraceutical uses.