Percorrer por autor "Silva, Aurora"
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- Antimicrobial Activity of Natural Extracts: The Problem of Mathematical Modeling †Publication . Silva, Aurora; Lourenço-Lopes, Catarina; Carpena, Maria; García-Oliveira, Paula; Echave, Javier; Chamorro, Franklin; Barciela, Paula; Simal-Gandara, Jesus; Barroso, Maria Fátima; Prieto, Miguel A.The antimicrobial activity of plants, algae, and derived extracts has been a subject of interest for the scientific community. Algae extracts have demonstrated their potential as a source of natural antimicrobial agents. Because of their antibacterial capacity and low toxicity, algae extracts have been studied as natural preservatives in food and cosmetic formulations. The use of these extracts has the potential to minimize the use of synthetic preservatives, which may be harmful to both human health and the environment. Nonetheless, the use of end-point techniques to calculate the minimal inhibitory concentration instead of creating growth inhibition curves usually leads to an absence of mathematical modeling procedures on the bacterial inhibition behavior of natural extracts. The goal of mathematical modeling is to describe the relationship between the concentration of an inhibitory agent (such as a drug or a toxin) and the growth rate of a population. For this purpose, the data obtained during the growth of six different bacteria in the presence of different concentrations of Ascophyllum nodosum (L.) extracts were recorded over 24 h. Later, the collected data were modeled based on different classical sigmoidal models, e.g., Weibull, logistic, and Gompertz, that were applied to define the critical growth phases and infer the kinetic parameters. The obtained parameters led to the conclusion that the inhibition mechanisms behind the antibacterial effects of the algae extracts are diverse towards different microorganisms. The presence of the extract led to a diminution of the specific growth velocity in some cases such as Staphylococcus epidermidis while in the replication of other bacteria such as Bacillus cereus, the extension of the lag phase was the predominant inhibition mechanism.
- Characterization of Phenolic Compounds of Arnica montana Conventional ExtractsPublication . Garcia-Oliveira, Paula; Chamorro, Franklin; Donn, Pauline; Garcia-Perez, Pascual; Seyyedi-Mansour, Sepidar; Silva, Aurora; Echave Álvarez, Javier; Simal-Gandara, Jesus; Cassani, Lucia; Prieto Lage, Miguel A.Arnica montana L. (Asteraceae family) is a plant commonly used in traditional medicine, and several reports have characterized this plant’s bioactivities, especially its phenolic compounds. These compounds are well known for their numerous beneficial biological properties. Consequently, industry stakeholders from the feed, food, cosmetic, and pharmaceutical sectors are seeking extracts rich in phenolic compounds, which could be interesting for the development of bio-based applications. The objective of the present study was to characterize the phenolic profile of this species to lay the groundwork for further optimization studies to obtain the highest amount of phenolic compounds. Therefore, A. montana was extracted with an ethanol/water ratio of 80:20 (v/v) at room temperature for 1 h, and phenolic compounds were identified and quantified through UPLC (HPLC Dionex Ultimate 3000) with a mass detector (TSQ Quantis). In the extract, phenolics belonging to different groups were identified, namely eriodictyol-O-glucuronide (flavanone), hispidulin and luteolin (flavones), kaempferol and 6-methoxykaempferol, (flavonols), p-coumaric, feruloylquinic, caffeoylquinic, and dicaffeoylquinic isomers (hydroxycinnamic acids). However, only four of them could be quantified: kaempferol and the three hydroxycinnamic acids. The total phenolic content (mg/g of dry sample) was estimated to be 27.34 mg/g, with the most prevalent compounds being the dicaffeoylquinic acids (accounting for 79.5% of the total phenolics). It has been demonstrated that dicaffeoylquinic acids present anti-inflammatory and antioxidant activities, which have been linked to several beneficial effects. Thus, obtaining phenolic-rich extracts of A. montana may allow us to exploit this plant’s significant biological properties, and it could be a new ingredient for developing new applications in the nutraceutical, cosmetic, and/or pharmaceutical industries.
- Evaluation of the potential of medicinal plant extracts for the development of new bakery productsPublication . Barral Martínez, Marta; Cassani, Lucia; Carpena Rodríguez, María; Garcia-Oliveira, Paula; Silva, Aurora; Barroso, Fátima; Finimundy, Tiane C.; Simal-Gandara, Jesus; Prieto Lage, Miguel A.; Barros, LillianMedicinal plants have been traditionally used throughout time as therapeutic treatments. These plants possess different compounds with antioxidant, anti-inflammatory and antimicrobial properties of industrial interest. In particular, the plants Achillea millefolium L., Arnica montana L., Calendula of icinalis L., Chamaemelum nobile L. All. and Taraxacum of icinale F.H. Wigg. belonging to the Asteraceae family, have shown relevant applications including food preparation, dyes, cosmetics, and traditional remedies, although their consumption is currently decreasing [1]. However, the extracts of this type of plants are mostly applied by the food industry as preservatives, due to their antioxidant and antimicrobial properties that prevent food spoilage and microbial growth, preserving the organoleptic characteristics of various products, such as meat, dairy products, or bakery products [2]. The aim of this study was to develop new ingredients derived from these plants, which may be of interest to the food industry, more specifically in bakery. For this, a study of their main bioactivities of interest such as antioxidant and antimicrobial capacity was carried out. The results obtained for antioxidant activity, through the thiobarbituric acid reactive substances (TBARS) assay, indicated that the extracts of A. millefolium showed exceptional activity, with an EC50 value of 0.013 mg/mL whereas the extracts of A. montana, C. nobile and C. of icinalis showed similar EC50 values (0.2, 0.2 and 0.25 mg/mL, respectively). On the other hand, A. montana extract showed the highest antibacterial and antifungal effects, with minimum bactericidal and fungicidal concentrations ranging from 0.25-0.5 mg/mL and 0.5-1 mg/mL, respectively. Overall, this study provides scientific evidence for the evaluation of the potential of medicinal plant extracts for the development of new bakery products.
- Fucoxanthin’s optimization from undaria pinnatifida using conventional heat extraction, bioactivity assays and in silico studiesPublication . Lourenço-Lopes, Catarina; Fraga-Corral, Maria; Soria-Lopez, Anton; Núñez Estévez, Bernabé; Barral Martínez, Marta; Silva, Aurora; Li, Ningyang; Liu, Chao; Simal-Gandara, Jesus; Prieto Lage, Miguel A.Brown macroalgae are a potential source of natural pigments. Among them, Undaria pinnatifida is recognized for its high concentration of fucoxanthin (Fx), which is a pigment with a wide range of bioactivities. In this study, three independent parameters were optimized for conventional heat extraction (CHE) to maximize the recovery of Fx from Undaria pinnatifida. Optimal conditions (temperature = 45 °C, solvent = 70%, and time = 61 min) extracted 5.1 mg Fx/g dw. Later, the bioactivities of the Fx-rich extracts (antioxidant, antimicrobial, and neuroprotective) were assessed using in vitro and in silico approaches. In vitro assays indicated that Fx has a strong antioxidant capacity and even stronger antimicrobial activity against gram-positive bacteria. This data was supported in silico where Fx established a high binding affinity to DR, a Staphylococcus aureus protein, through aa ALA-8, LEU-21, and other alkane interactions. Finally, the in vitro enzymatic inhibition of AChE using Fx, was further supported using docking models that displayed Fx as having a high affinity for aa TYR72 and THR 75; therefore, the Fx extraction behavior explored in this work may reduce the costs associated with energy and solvent consumption. Moreover, this paper demonstrates the efficiency of CHE when recovering high amounts of Fx from Undaria pinnatifida. Furthermore, these findings can be applied in different industries.
- A HPLC‐DAD method for identifying and estimating the content of fucoxanthin, β‐carotene and chlorophyll a in brown algal extractsPublication . Lourenço-Lopes, Catarina; Fraga-Corral, Maria; Garcia-Perez, Pascual; Carreira-Casais, Anxo; Silva, Aurora; Simal-Gandara, Jesus; Prieto Lage, Miguel A.Seaweeds are photosynthetic organisms that have high contents of pigments. The coloration of each alga is defined by the content and combination of pigments synthesized, which varies among species and environmental condi- tions. The most abundant pigments in algae are chlorophylls and carotenoids, lipophilic molecules that can be used as natural colorants and have high acceptance by consumers. In this work, a simple and short hands-on time HPLC-DAD method for identifying and estimating the pigment content of algal extracts, specifically fucoxanthin, 𝛽-carotene and chlorophyll a was carried out. Using this optimized method, a pigment screening was performed on the ethanolic extracts obtained by ultrasound-assisted extraction from nine brown algal from the Atlantic coastline: Ascophyllum nodosum, Bifurcaria bifurcata, Fucus spiralis, Himanthalia elongata, Laminaria saccharina, Laminaria ochroleuca, Pelvetia canaliculata, Sargassum muticum and Undaria pinnatifida . HPLC results permitted to highlight L. saccharina and U. pinnatifida as promising sources of these three target pigments containing a total amount of 10.5 –11.5 mg per gram of dry weight. Among them, the most abundant one was fucoxanthin, an added-value compound with a high potential to be commercially exploited by different industries, such as the food, cosmetic, and pharmaceutical sectors.
- Metabolite Profiling of Macroalgae: Biosynthesis and Beneficial Biological Properties of Active CompoundsPublication . Carpena, María; Pereira, Cláudia S.G.P.; Silva, Aurora; Barciela, Paula; Jorge, Ana Olívia Serra; Perez-Vazquez, Ana; Pereira, Antia Gonzalez; Barreira, João C.M.; Oliveira, Beatriz; Prieto Lage, Miguel A.Macroalgae are known as abundant sources of phytochemicals, which offer a plethora of beneficial biological properties. Besides being the most notable classes of compounds found in macroalgae, phlorotannins, bromophenols, and terpenoids comprise some of the most relevant for their biological properties. Phlorotannins, mainly prevalent in brown algae and structurally characterized as complex polyphenolic compounds derived from phloroglucinol units, possess robust antioxidant, anti-inflammatory, antitumor, and cytotoxic activities, modulated by factors such as the degree of polymerization and environmental conditions. Bromophenols, halogenated compounds found in algae and other marine organisms, exhibit significant antioxidant and antiviral properties. Their diverse structures and bromination patterns contribute to their potential as therapeutic and chemical defense agents. Pigments (chemically described as primary terpenoids) play a critical role in light absorption and energy transfer in macroalgae and are divided into three main groups: (i) carotenoids, which are primarily found in brown algae and provide photoprotective and antioxidant benefits; (ii) chlorophylls, known for facilitating the conversion of light into biological energy; and (iii) phycobilins, which are mostly found in red algae and play important roles in light absorption and energy transfer, besides providing remarkable health benefits. Finally, secondary terpenoids, which are particularly abundant in red algae (e.g., the Rhodomelaceae family) are central to cellular interactions and exhibit significant antioxidant, antimicrobial, antidiabetic, and anti-inflammatory properties. This study represents a detailed analysis of the biosynthesis, structural diversity, and biological activities of these macroalgae metabolites, emphasizing their potential biological properties.
- Natural antioxidants from marine sources and their application in foodsPublication . Silva, Aurora; Carpena, Maria; Grosso, Clara; Barciela, Paula; Pereira, Antía González; Cassani, Lucia; Barroso, Maria F.; Simal-Gandara, Jesus; Prieto Lage, Miguel A.This chapter provides an overview of recent studies assessing the antioxidant potential of marine organisms and their bioactive compounds to be incorporated into food products and supplements. Emphasis was given to marine flora, especially micro- and macroalgae and marine invertebrates, namely sponges, seagrasses, sea cucumbers, jellyfishes, crustaceans, and mollusks. The most relevant compounds such as vitamins A and C, polysaccharides, peptides and amino acids, phenolic compounds, and pigments (carotenoids and chlorophylls) were highlighted. Due to their biologically active compounds, these species have already been incorporated into food products available in the market like dairy products, yogurts, cookies, bread, pasta, and sausages, among others, creating a more sustainable and healthier alternative to synthetic preservatives and additives.
- Pigment composition of nine brown algae from the iberian northwestern coastline: influence of the extraction solventePublication . García-Pérez, Pascual; Lourenço-Lopes, Catarina; Silva, Aurora; González Pereira, Antía; Fraga-Corral, Maria; Zhao, Chao; Xiao, Jianbo; Simal-Gandara, Jesus; Prieto Lage, Miguel A.Brown algae are ubiquitously distributed in the NW coastline of the Iberian Peninsula, where they stand as an underexploited resource. In this study, five solvents were applied to the extraction of pigments from nine brown algae, followed by their determination and quantification by HPLC-DAD. A total of 13 compounds were detected: Six were identified as chlorophylls, six were classified as xanthophylls, and one compound was reported as a carotene. Fucoxanthin was reported in all extracts, which is the most prominent pigment of these algae. Among them, L. saccharina and U. pinnatifida present the highest concentration of fucoxanthin (4.5–4.7 mg g-1 dry weight). Ethanol and acetone were revealed as the most efficient solvents for the extraction of pigments, showing a maximal value of 11.9 mg of total pigments per gram of dry alga obtained from the ethanolic extracts of H. elongata, followed by the acetonic extracts of L. ochroleuca. Indeed, ethanol was also revealed as the most efficient solvent according to its high extraction yield along all species evaluated. Our results supply insights into the pigment composition of brown algae, opening new perspectives on their commercial exploitation by food, pharmaceutical, and cosmeceutical industries.
- Recent advances in biological properties of brown algae-derived compounds for nutraceutical applicationsPublication . Silva, Aurora; Cassani, Lucia; Grosso, Clara; Garcia-Oliveira, Paula; Morais, Stephanie L.; Echave Álvarez, Javier; Carpena Rodríguez, María; Xiao, Jianbo; Barroso, Fátima; Simal-Gandara, Jesus; Prieto Lage, Miguel A.The increasing demand for nutraceuticals in the circular economy era has driven the research toward studying bioactive compounds from renewable underexploited resources. In this regard, the exploration of brown algae has shown significant growth and maintains a great promise for the future. One possible explanation could be that brown algae are rich sources of nutritional compounds (polyunsaturated fatty acids, fiber, proteins, minerals, and vitamins) and unique metabolic compounds (phlorotannins, fucoxanthin, fucoidan) with promising biological activities that make them good candidates for nutraceutical applications with increased value-added. In this review, a deep description of bioactive compounds from brown algae is presented. In addition, recent advances in biological activities ascribed to these compounds through in vitro and in vivo assays are pointed out. Delivery strategies to overcome some drawbacks related to the direct application of algae-derived compounds (low solubility, thermal instability, bioavailability, unpleasant organoleptic properties) are also reviewed. Finally, current commercial and legal statuses of ingredients from brown algae are presented, considering future therapeutical and market perspectives as nutraceuticals.