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The antiviral potential of algal lectins

Publication . Alvarez, Christian; Félix, Carina; Lemos, Marco F.L.

Algae have emerged as fascinating subjects of study due to their vast potential as sources of valuable metabolites with diverse biotechnological applications, including their use as fertilizers, feed, food, and even pharmaceutical precursors. Among the numerous compounds found in algae, lectins have garnered special attention for their unique structures and carbohydrate specificities, distinguishing them from lectins derived from other sources. Here, a comprehensive overview of the latest scientific and technological advancements in the realm of algal lectins with a particular focus on their antiviral properties is provided. These lectins have displayed remarkable effectiveness against a wide range of viruses, thereby holding great promise for various antiviral applications. It is worth noting that several alga species have already been successfully commercialized for their antiviral potential. However, the discovery of a diverse array of lectins with potent antiviral capabilities suggests that the field holds immense untapped potential for further expansion. In conclusion, algae stand as a valuable and versatile resource, and their lectins offer an exciting avenue for developing novel antiviral agents, which may lead to the development of cutting-edge antiviral therapies.

2023Journal article

Open access

Lidocaine supplementation in clove-oil and 2-phenoxyethanol anesthesia for gilthead seabream (Sparus aurata)

Publication . Tchobanov, Carolina F.; Vaz, Mariana; Pires, Damiana; Passos, Ricardo; Antunes, Luís M.; Baptista, Teresa

Animal welfare and reducing stress during procedures are key objectives for success in animal production. Anesthesia has been used for procedures to reduce animal stress and its negative impact on welfare. This study aimed first to refine the concentrations of the anesthetic clove-oil (CO) and lidocaine (L) in gilthead seabream (Sparus aurata) juveniles (56.0 ± 15.09 g) and then combine clove-oil and 2-phenoxyethanol (2PHE) with the refined concentration of lidocaine. The concentrations of clove-oil (30, 45, and 60 mg L− 1), and the concentrations of lidocaine (2.5, 5, and 7.5 mg L− 1), were evaluated in the refinement trial. Based on these results, a second trial was performed with 45 mg L− 1 CO or 0.4 mL L− 1 2PHE as anesthetics alone or combined with 2.5 mg L− 1 of lidocaine. Results from this work showed an improvement in induction times for 2-phenoxyethanol when lidocaine was added (2PHE 179.53 ± 63.21 s; 2PHE + L 130.65 ± 40.16 s). Recovery time also showed a reduction for clove-oil when lidocaine was used (CO 349.90 ± 123.69 s; CO + L 250.11 ± 51.99 s). The use of lidocaine showed better results, reducing lactate and histological progressive alterations. Lidocaine showed stress-induced oxidative alterations when it was combined with 2-phenoxyethanol. Lidocaine exposure increased ALT, AST, histological regressive alterations for both anesthetics, and gene expression of hsp70 in the gills when clove-oil was used. Further studies are necessary to comprehend the synergistic effects of lidocaine when combined with synthetic and natural anesthetics and to discern potential acute or chronic toxic responses in fish. These insights will be crucial for refining anesthesia protocols and ensuring the well-being of aquatic species in aquaculture practices and research settings.

2024-08Journal article

Open access

Oxidative Stability of Sunflower Oil Enriched with Fig Tree Leaves Bioactive Compounds at Frying Temperature

Publication . Pinteus, Susete; Neves, Marta; Tecelão, Carla; Silva, Susana; Cruz, Alexandra; Bernardino, Susana; Mendes, Vasco; Ribeiro, Vânia; Vaz, Daniela; Campos, Maria Jorge

The pressure imposed by the increase of world’s population and climate change makes it imperative to find sustainable strategies to optimize food resources and decrease waste production based on circular economy principles. This work evaluated the potential of fig tree leaves to reduce the oxidation of sunflower oil when exposed to frying temperatures. The bioactive compounds extracted directly from fig tree leaves were incorporated into the oil at a ratio of 12.5% (m/m), with the assistance of ultrasounds. The supplemented oil was characterized in terms of its total phenolic content (TPC), which was determined using the Folin-Ciocalteu method, and its antioxidant capacity, which was evaluated using both the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay and the ferric reduction antioxidant power (FRAP) assay. Also, the color of the oil and the oxidation products (K232 and K270) were analyzed. Supplementing the oil with fig tree leaves resulted in a higher antioxidant capacity compared to the control, as demonstrated by the DPPH assay (5128 ± 466 vs. 1106 ± 407 µM Trolox eq/kg oil), as well as lower levels of primary and secondary oxidation products. The results suggest that fig tree leaves can be a valuable source of antioxidant compounds with the capacity to improve the nutritional value and oxidative stability of sunflower oil under frying temperatures.

2024Book part

Restricted access

Unveiling the Cultivation of Nostoc sp. under Controlled Laboratory Conditions

Publication . Mouga, Teresa; Pereira, Jéssica; Moreira, Vitória; Afonso, Clélia

Cyanobacteria, photoautotrophic Gram-negative bacteria, play a crucial role in aquatic and terrestrial environments, contributing significantly to fundamental ecological processes and displaying potential for various biotechnological applications. It is, therefore, critical to identify viable strains for aquaculture and establish accurate culture parameters to ensure an extensive biomass supply for biotechnology purposes. This study aims to establish optimal laboratory batch culture conditions for Nostoc 136, sourced from Alga2O, Coimbra, Portugal. Preliminary investigations were conducted to identify the optimal culture parameters and to perform biomass analysis, including protein and pigment content. The highest growth was achieved with an initial inoculum concentration of 1 g.L−1, using modified BG11 supplemented with nitrogen, resulting in a Specific Growth Rate (SGR) of 0.232 ± 0.017 µ.day−1. When exposed to white, red, and blue LED light, the most favourable growth occurred under a combination of white and red LED light exhibiting an SGR of 0.142 ± 0.020 µ.day−1. The protein content was determined to be 10.80 ± 2.09%. Regarding the pigments, phycocyanin reached a concentration of 200.29 ± 30.07 µg.mL−1, phycoerythrin 148.29 ± 26.74 µg.mL−1, and allophycocyanin 10.69 ± 6.07 µg.mL−1. This study underscores the influence of light and nutrient supplementation on the growth of the Nostoc biomass.

2024-04Journal article

Open access

Valorisation of Sargassum muticum through the extraction of phenolic compounds using eutectic solvents and intensification techniques

Publication . Jesus, Bárbara C.; Sáenz de Miera, Blanca; Santiago, Rubén; Martins, Alice; Pedrosa, Rui; Gonzalez-Miquel, Maria; Marrucho, Isabel M.

Seaweeds are naturally abundant and spread all over the globe. They have several biologically active secondary metabolites of great interest. In this work, Sargassum muticum was the algae employed as biomass and the aim was to extract phenolic compounds (PCs) using eutectic solvents (ESs). Several betaine-based, proline-based, and choline-based ESs were tested for the extraction of PCs. All extracts were evaluated according to the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (DPPH). Afterwards, the extracts were characterized using HPLC in terms of 9 target PCs (gallic acid, 3,4-dihydroxybenzoic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, salicylic acid, catechin and quercetin). Proline combined with propylene glycol (Pro[thin space (1/6-em)]:[thin space (1/6-em)]PPG) exhibited a higher yield according to HPLC results, followed by proline[thin space (1/6-em)]:[thin space (1/6-em)]1,2-butanediol (Pro[thin space (1/6-em)]:[thin space (1/6-em)]1,2-But) and choline[thin space (1/6-em)]:[thin space (1/6-em)]citric acid (ChCl[thin space (1/6-em)]:[thin space (1/6-em)]CA). Pro[thin space (1/6-em)]:[thin space (1/6-em)]PPG also presented high selectivity towards salicylic acid, while ChCl[thin space (1/6-em)]:[thin space (1/6-em)]CA towards gallic acid. Optimization studies of water content and temperature were performed for the three best ESs, the optimum conditions being 30% (v/v) water and 60 °C extraction temperature. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) were two intensification methods evaluated to enhance the extraction process, proving their ability to reduce the extraction time when compared with the conventional solid–liquid extraction (SLE) process. In particular, Pro[thin space (1/6-em)]:[thin space (1/6-em)]PPG-based MAE provided a significantly higher extraction yield in comparison with conventional extraction and with the other extraction solvents. In summary, the combination of ESs with intensification techniques was shown to be a valuable valorization strategy of a marine macroalgae waste, in particular Sargassum muticum.

2023Journal article

Open access