Browsing by Author "Pereira, Hugo"
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- Bioactive lipids in Dunaliella salina: implications for functional foods and healthPublication . Pais, Rita; Conde, Tiago; Neves, Bruna B.; Pinho, Marisa; Coelho, Marta; Pereira, Hugo; Rodrigues, Alexandre M. C.; Domingues, Pedro; Gomes, Ana Maria; Urbatzka, Ralph; Domingues, Rosário; Melo, TâniaDunaliella salina is a green microalga extensively explored for β-carotene production, while knowledge of its lipid composition is still limited and poorly investigated. Among lipids, polar lipids have been highlighted as bioactive phytochemicals with health-promoting properties. This research aimed to provide an in-depth lipidome profiling of D. salina using liquid and gas chromatography coupled with mass spectrometry. The lipid content was 6.8%, including phospholipids, glycolipids, betaine lipids, sphingolipids, triglycerides, diglycerides, and pigments. Among the total esterified fatty acids, 13.6% were 18:3 omega-3 and 14.7% were 18:1 omega-9. The lipid extract of D. salina showed anti-inflammatory activity by inhibiting cyclooxygenase-2 activity at 100 µg/mL, dose-dependent antioxidant scavenging activity, and antidiabetic activity by inhibiting α-glucosidase activity at 25 and 125 µg/mL. In conclusion, the lipid extract of D. salina has the potential to be used as a functional food ingredient or in the nutraceutical and cosmeceutical industries.
- Impact of fermentation on the antioxidant activity and color of haematococcus pluvialis and porphyridium cruentumPublication . Bassani, Joseane C.; Martins, Valter; Barbosa, Joana; Steffens, Juliana; Backes, Geciane T.; Pereira, Hugo; Pintado, Manuela E.; Morais, Alcina M. M. B.; Teixeira, Paula; Morais, Rui M. S. C.Microalgae are emerging as a promising ingredient for the food industry due to their sustainable cultivation and production of a variety of bioactive compounds, including proteins, lipids, carbohydrates, antioxidant compounds, and pigments [1]. Among the many cataloged species of microalgae, two stand out in research due to their powerful applications in the pharmaceutical, nutraceutical, cosmetic, and food and beverage industries. The first is Haematococcus pluvialis, a unicellular microalga known for its high content of astaxanthin (3,3-dihydroxy-β, β-carotene-4,4- dione), one of the most important natural antioxidants [2]. The second is Porphyridium cruentum, a red marine microalgae that serves as a reservoir of high-value compounds such as carotenoids, sulfated exopolysaccharides (EPSs), β-phycoerythrin (PE), and lipids [3]. Carotenoids and astaxanthins are well-known antioxidants with numerous applications in the food and pharmaceutical industries. However, the application of microalgae in food faces challenges related to their intense flavour and odour. Fermentation of microalgae biomass with bacteria has emerged as a promising strategy to mitigate these problems [4]. However, the fermentation process can modify other characteristics of the biomass.
- Insight into the efficiency of microalgae’ lipidic extracts as photosensitizers for Antimicrobial Photodynamic Therapy against Staphylococcus aureusPublication . Mendonça, Inês; Silva, Daniela; Conde, Tiago; Maurício, Tatiana; Cardoso, Helena; Pereira, Hugo; Bartolomeu, Maria; Vieira, Cátia; Domingues, M. Rosário; Almeida, AdelaideAntibacterial resistance causes around 1.27 million deaths annually around the globe and has been recognized as a top 3 priority health threat. Antimicrobial photodynamic therapy (aPDT) is considered a promising alternative to conventional antibiotic treatments. Algal lipid extracts have shown antibacterial effects when used as photosensitizers (PSs) in aPDT. In this work we assessed the photodynamic efficiency of lipidic extracts of microalgae belonging to different phyla (Bacillariophyta, Chlorophyta, Cyanobacteria, Haptophyta, Ochrophyta and Rhodophyta). All the extracts (at 1 mg mL−1) demonstrated a reduction of Staphylococcus aureus >3 log10 (CFU mL−1), exhibiting bactericidal activity. Bacillariophyta and Haptophyta extracts were the top-performing phyla against S. aureus, achieving a reduction >6 log10 (CFU mL−1) with light doses of 60 J cm−2 (Bacillariophyta) and 90 J cm−2 (Haptophyta). The photodynamic properties of the Bacillariophyta Phaeodactylum tricornutum and the Haptophyta Tisochrysis lutea, the best effective microalgae lipid extracts, were also assessed at lower concentrations (75 μg mL−1, 7.5 μg mL−1, and 3.75 μg mL−1), reaching, in general, inactivation rates higher than those obtained with the widely used PSs, such as Methylene Blue and Chlorine e6, at lower concentration and light dose. The presence of chlorophyll c, which can absorb a greater amount of energy than chlorophylls a and b; rich content of polyunsaturated fatty acids (PUFAs) and fucoxanthin, which can also produce ROS, e.g. singlet oxygen (1O2), when photo-energized; a lack of photoprotective carotenoids such as β-carotene, and low content of tocopherol, were associated with the algal extracts with higher antimicrobial activity against S. aureus. The bactericidal activity exhibited by the extracts seems to result from the photooxidation of microalgae PUFAs by the 1O2 and/or other ROS produced by irradiated chlorophylls/carotenoids, which eventually led to bacterial lipid peroxidation and cell death, but further studies are needed to confirm this hypothesis. These results revealed the potential of an unexplored source of natural photosensitizers (microalgae lipid extracts) that can be used as PSs in aPDT as an alternative to conventional antibiotic treatments, and even to conventional PSs, to combat antibacterial resistance.