Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Cosmeceutical potential of grateloupia turuturu: using low-cost extraction methodologies to obtain added-value extractsPublication . Félix, Carina; Félix, Rafael; Carmona, Ana M.; Januário, Adriana P.; Dias, Pedro D.M.; Vicente, Tânia F. L.; Silva, Joana; Alves, Celso; Pedrosa, Rui; Novais, Sara C.; Lemos, Marco F.L.The invasive macroalga Grateloupia turuturu is known to contain a diversity of bioactive compounds with different potentialities. Among them are compounds with relevant bioactivities for cosmetics. Considering this, this study aimed to screen bioactivities with cosmeceutical potential, namely, antioxidant, UV absorbance, anti-enzymatic, antimicrobial, and anti-inflammatory activities, as well as photoprotection potential. Extractions with higher concentrations of ethanol resulted in extracts with higher antioxidant activities, while for the anti-enzymatic activity, high inhibition percentages were obtained for elastase and hyaluronidase with almost all extracts. Regarding the antimicrobial activity, all extracts showed to be active against E. coli, S. aureus, and C. albicans. Extracts produced with higher percentages of ethanol were more effective against E. coli and with lower percentages against the other two microorganisms. Several concentrations of each extract were found to be safe for fibroblasts, but no photoprotection capacity was observed. However, one of the aqueous extracts was responsible for reducing around 40% of the nitric oxide production on macrophages, showing its anti-inflammatory potential. This work highlights G. turuturu’s potential in the cosmeceutical field, contributing to the further development of natural formulations for skin protection.
- Mechanisms of action of Asparagopsis armata ethanolic extract against the shrimp pathogen Vibrio parahaemolyticusPublication . Dias, Pedro David Martins; Lemos, Marco Filipe Loureiro; Félix, Carina Rafaela Faria da CostaEnvironmental pollution, climate change and natural resource scarcity are some societal challenges that, nowadays, new sustainable production systems must respond to. For that, a greener bioeconomy concept based on biotechnological innovations should be implemented, creating new value chains and implementing the concept of Circular Economy. One example of creating new value chains from the environment is giving biotechnological value for invasive species as the macroalgae Asparagopsis armata. Asparagopsis armata have already shown a variety of biotechnological applications, as in food and feed industries, including antimicrobial, antioxidant, among many other activities. In the aquaculture context, the inclusion of an ethanolic extract from this macroalgae in the feed of Litopenaeus vannamei showed higher survival rates (above 50%) when shrimps were infected with Vibrio parahaemolyticus, an increase in immunological responses, and a significant increase on the shelf life of the feed was also obtained. The main goal of this dissertation was to unveil the potential mechanisms of action of this ethanolic extract facing Vibrio parahaemolyticus, using two complementary approaches, biochemical assays and real time quantification of several genes potentially involved. The results obtained for the antimicrobial activity revealed that the ethanolic extract at 2mg/mL can totally inhibit the growth of V. parahaemolyticus, presenting MIC and MBC at this concentration, showing a similar pattern in the time-kill assay, performed to evaluate the growth of the bacteria in the presence of the extract at different concentrations along time. Regarding the viability activity, an increase of the activity was found in the presence of 1 mg/mL along time, while at 2mg/mL no viability activity was observed. The leakage of intracellular proteins through the bacterial membrane showed higher concentrations in the extracellular matrix when V. parahaemolyticus was in contact with the 2 mg/mL concentration and the biofilm formation was inhibited by the presence of the extract at the same concentration, both situations showing a similar behavior of the antibiotic control. Considering the real time quantification of genes related with basal functions (rpoS) and genes related to virulence (tuf, toxR, luxR, pirA and pirB), increasing concentrations showed to increase the gene expression in general, with the exception of pirB gene. These results indicate that in the presence of 1/4 MIC concentration, V.parahaemolyticus had the necessity to increase the expression of genes that may contribute to the survival of the cells. Conjugating all the data obtained in this study, important clues regarding the potential mechanisms of action of A. armata extract were deciphered, contributing not only to understand their antimicrobial potential but also to define crucial future work to entirely unveil the mechanism of action associated to this extract.