Browsing by Author "Afonso, Tiago B."
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- Alginate edible films containing essential oils: characterization and bioactive potentialPublication . Lopes, Ana I.; Melo, Adma; Afonso, Tiago B.; Silva, Sara; Barros, Lillian; Tavaria, Freni K.; Pintado, ManuelaEssential oils (EOs) are natural substances rich in phenolic compounds with notable antimicrobial and antioxidant properties. However, they present some limitations, such as low stability and bioavailability. Incorporating EOs into polymeric films offers a novel approach to overcome these challenges while enhancing their efficacy. In this study, we produced and thoroughly characterized alginate-based edible films incorporated with five different EOs—rosemary, eucalyptus, oregano, sage, and thyme. This is the first comprehensive investigation to include this diverse range of EOs in alginate films. Their antimicrobial and antioxidant activities were also evaluated. The results demonstrated that alginate films containing EOs exhibited significant bioactive properties. Notably, the film incorporated with oregano EO completely inhibited the growth of all tested bacteria and fungi and showed the highest antioxidant activity. Based on these findings, alginate films containing EOs present promising bioactive potential and could serve as biodegradable alternatives to conventional packaging materials, reducing environmental impact. However, further studies are necessary to assess their safety profile and confirm their viability as replacements for traditional food packaging. Future research should focus on evaluating cytotoxicity, genotoxicity, and the practical application of these films in food matrices.
- Alkaline extraction of phenolic compounds from Eucalyptus leaves: influence on antioxidant and antimicrobial activityPublication . Afonso, Tiago B.; Bonifácio-Lopes, Teresa; Costa, Eduardo; Macedo, Tiago; Moreira, Joana; Oliveira, Juliana; Pintado, ManuelaIntroduction: The valorization of agro-industrial by-products is a strategic approach to reducing biomass waste while advancing circular bioeconomy practices. Eucalyptus leaves, an abundant residue from the forestry and pulp industries, are particularly rich in phenolic compounds with well-known antioxidant and antimicrobial activities. These bioactivities highlight the potential of eucalyptus extracts for sustainable applications in the cosmetic and textile industries. However, their efficient recovery requires optimized extraction methodologies capable of disrupting the complex plant matrix and maximizing compound release. The aim of this study was to investigate how variations in eucalyptus particle size and alkali concentration can enhance the recovery of phenolic-rich extracts with bioactive potential. Conclusions: Alkaline extraction proved capable for recovering phenolic compounds from eucalyptus leaves, yielding extracts with relevant antioxidant and antimicrobial activities. However, the extracts showed cytotoxicity at the tested concentrations, highlighting the need for further optimization of extraction parameters and the establishment of safe concentration ranges before potential use in applications such as cosmetics or textiles.
- Antioxidant activity, phenolic profile, cytotoxicity and genotoxicity of plant extractsPublication . Melo, Adma N. F. de; Afonso, Tiago B.; Ribeiro, Tânia; Machado, Manuela; Carvalho, Marta; Carocho, Márcio; Tavaria, Freni; Teixeira, Paula; Barros, Lillian; Pintado, ManuelaThe outbreak of COVID-19 disease caused by SARS-CoV-2 forced the scientific world to search for new alternatives to help control the virus. Plant extracts have natural compounds that might provide a starting point for the research on the use of plants as an excellent source of new antiviral agents against viruses, including COVID-19 to be included in disinfectants, fabrics or other materials. In this study, the polyphenols content (Folin-Ciocalteu), antioxidant capacity (DPPH, ABTS and ORAC) and the phenolic profile (HPLC) of different hydroethanolic (ethanol:H2O 50:50 v/v) extracts of medicinal plants cultivated under controlled conditions in Portugal (echinacea, rosemary, laurel, thyme and rock rose) were determined, as well as the cytotoxicity effect against a keratinocyte cell line using cell viability assay by PrestoBlue and genotoxicity effect using the AMES test. According to the results, total phenolic content ranged from 204.54 ± 1.78 / 274.20 ± 3.14 (mg EAG/g extract) with the rock rose extract presenting the highest content (p < 0.05). The extracts showed a good antioxidant capacity demonstrated by the high values found for ORAC, which ranged 2855.03 ± 9.75 / 5285.35 ± 60.04 µMol Trolox/mg extract. HPLC analysis revealed the presence of different compounds in the extracts such as the kaempferol-O-glucuronide, catechin, protocatechuic acid and galloyl glucoside, representing a potential source of bioactive components with antioxidant capacity. No toxicity was observed towards the keratinocyte cells and none of them showed mutagenic effects. Based on the results of safety and high polyphenols content of the extracts they demonstrate a great potential as antimicrobial agents. This will allow the design of new experiments aimed at evaluating the antiviral activity of these extracts, especially against SARS-CoV-2.
- Antioxidant activity, phenolic profile, cytotoxicity and genotoxicity of plant extractsPublication . Melo, Adma N. F. de; Afonso, Tiago B.; Ribeiro, Tânia; Machado, Manuela; Carvalho, Marta; Carocho, Márcio; Tavaria, Freni; Carvalho, Marta; Teixeira, Paula; Barros, Lillian; Pintado, Manuela
- Be@t: sustainable chemical processes for developing regenerative materials and ingredients in the textile industryPublication . Afonso, Tiago B.; Bonifácio-Lopes, Teresa; Costa, Eduardo M.; Costa, Ana Filipa; Oliveira, Juliana; Pintado, ManuelaIntroduction: The reuse and valorization of waste and by-products generated by other industrial sectors in the textile sector currently represents a strategy of 'sustainable waste minimization,' leading to the achievement of economic development and environmental sustainability goals. In recent years, waste and by-products from industrial processing, e.g., agro-industry, agroforestry, marine, canning, mining, leather, cork industries, among others, have been a source of bioactive compounds with potential application in the textile industry, as it is possible to extract a wide variety of compounds with a broad range of functionalities. A good example is agro-food waste and by-products, which are excellent sources of biological compounds that can be explored as raw materials to replace fossil fuels, complementing the use of forest biomass and adding value in obtaining new bio- based materials that are more versatile and sustainable. In the classification of bio- based materials, there are three major groups that can be valorized: protein- based, polysaccharides, and polyphenols. Among the most common protein- based materials derived from animal sources are keratin, collagen, and gelatin, which are often obtained from waste and by-products of industries like leather industry. These materials present valuable opportunities for sustainable reuse and resource efficiency. The extraction of these types of proteins is generally carried out through alkaline hydrolysis in combination with thermal processes, with or without the use of enzymes. Wastes/by-products from the agrifood industry can also serve as a natural source of functional dyes rich in phenolic compounds. These extracted materials can promote various functionalities of interest when applied to the textile and clothing industry, such as repellency, easy cleaning, anti-odor, flame retardancy, fluorescence, antioxidant, antimicrobial properties, among others. Although some methods for the extraction and valorization of waste and by- products are already described in the literature, one of the difficulties observed relates to scalability, the lack of interaction between industries, and the suitability of ingredients for textile industry processes. Aim: The main objective of this study is to identify the most effective technologies, utilizing diverse raw materials and processes, to develop active agents suitable for application in the textile industry. The goal is to contribute to the creation of greener processes and products that support industrial symbiosis and promote a circular bioeconomy. Materials and methods: Two approaches were tested based on different industrial by-products. These included by-products from the leather and agro-food industries. For the leather by- products the work focused on exploring different enzymes and hydrolysis conditions for the repurposing of leather towards the creation of versatile functional coatings to be re-used within the leather industry. The characterization of the samples was done using different methodologies, including SE-HPLC analyses to determine MWs, hydrolysis percentage (TNBS), total protein (BCA and Kjeldahl) and antioxidant activity (ORAC). The second approach was to extract phenolic compounds from different by-products of the agro-food industry through green and sustainable extraction methodologies. The obtained extracts were then characterized regarding their sugar, total phenolic and flavonoid content, as well as their biological potential as antioxidants and antimicrobials. Their cytotoxicity was also evaluated. Main results: Regarding leather hydrolysis, the results showed that all the enzymes were effective in processing the leather by-product. It was also possible to conclude that Alcalase provided better hydrolysis performance than ProtaBate P and Bromelain. Alcalase showed the highest hydrolysis degree, leading to peptides mixtures with MWs between 10 and 50 kDa and a high antioxidant activity. These results outline the potential of re-using leather by-products to create versatile functional coatings through a circular and more sustainable process. Regarding the extraction of phenolic compounds from different by-products, the results revealed a high variability of results among the different studied parameters. The different extraction methods impacted the extraction of phenolic compounds and other components (aqueous vs hydroethanolic vs ultrasound extraction methods). Sugar content varied significantly among by-products and extraction methods with apple skin aqueous extract having the highest amount of sugar. Total phenolic content of the by-products ranged from 4,4 to 512,9 mg GAE/g and flavonoid content from 2,1 to 287,8 mg CAE/g of sample. Antioxidant activity of the by-products followed the same pattern observed for the total phenolic content. Gram-negative bacteria (E. coli and P. aeruginosa) were more resistance to the extracts than Gram- positive (S. aureus and S. epidermidis). The majority of the extracts showed cytotoxicity against HaCaT cell line at the tested concentrations. Conclusion: The conclusions of this study can be divided regarding the two different approaches. In relation to the leather by-products approach, this study outlines the potential of re-using leather by-products to create versatile functional coatings through a circular and more sustainable process. Regarding the agro-food by- products approach, while more studies are necessary, the results show that some by-products have great potential to be used as sources of functional compounds in the textile industry, especially lemongrass and peanut skin. Different extracts exhibit varying functionalities, with some showing superior antioxidant properties while others demonstrate enhanced antimicrobial activity. This variation underscores the need to select the appropriate extract based on the specific functional requirements of the application. Despite their cytotoxicity at the tested concentrations against the tested cell line, further studies should be conducted to better understand the concentration limits to be applied when dyeing different textiles with these extracts. As a final remark, a sustainable approach within the leather and agro-food industries can be implemented by upcycling side streams through eco-friendly methods to create high-value products. This valorization concept represents a shift from traditional linear production and consumption patterns towards a circular economy. This strategy shift not only contributes to reducing overall waste but also aligns itself with the 12nd UN sustainability goal (Ensure sustainable consumption and production patterns) by the re-use of its own by-products.
- Chemical characterization, cytotoxic evaluation and anti-SARS-CoV2 activity of plant extracts rich in hydrolysable tanninsPublication . Melo, Adma N. F.; Afonso, Tiago B.; Carvalho, Marta; Rodrigues, Cláudia; Ribeiro, Tânia; Carocho, Márcio; Pinto, Miguel Marques; Tavaria, Freni; Teixeira, Paula; Simas, J. Pedro; Barros, Lillian; Pintado, Manuela
- Evaluation of antimicrobial and antioxidant activities of alginate edible coatings incorporated with plant extractsPublication . Lopes, Ana I.; Melo, Adma; Caleja, Cristina; Pereira, Eliana; Finimundy, Tiane C.; Afonso, Tiago B.; Silva, Sara; Ivanov, Marija; Soković, Marina; Tavaria, Freni K.; Barros, Lillian; Pintado, ManuelaPlant extracts (PEs) are natural substances that perform interesting bioactivities. However, they have some limitations. In this work, PEs from licorice, eucalyptus, sage, and thyme were produced and characterized. These extracts showed good bioactive properties. Alginate-based edible coatings and films incorporated with the extracts were produced and their antimicrobial and antioxidant properties were determined. The results showed that the coatings completely inhibited or reduced the growth of all bacteria (E. coli, P. aeruginosa, B. cereus, L. monocytogenes, and S. aureus), except the coating with sage extract. However, only the films incorporated with licorice and eucalyptus could inhibit the growth of Gram-positive bacteria and none of the films were able to inhibit Gram-negative bacteria. The film incorporated with sage extract was the one with the best antifungal property. All films possess a good antioxidant property (ABTS: 942.52–5654.62; DPPH: 1040.67–5162.93 Trolox equivalents (µM)/mg film). Based on the results, it is possible to conclude that alginate coatings and films with PEs present good bioactive properties and can potentially be used as new, biodegradable packages. However, further experiments need to be performed to assess their safety profile, and to prove that they can be a real alternative to traditional food packaging.
- Evaluation of minimum inhibitory concentrations of plant extracts against environmental fungi and dermatophytesPublication . Afonso, Tiago B.; Melo, Adma N. F.; Carvalho, Marta; Ribeiro, Tânia; Pinto, Miguel Marques; Barros, Lillian; Carocho, Márcio; Tavaria, Freni; Teixeira, Paula; Pintado, Manuela
- From waste to worth: upcycling peanut skin via green extraction for bioactive applicationsPublication . Afonso, Tiago B.; Bonifácio-Lopes, Teresa; Costa, Eduardo; Costa, Ana Filipa; Oliveira, Juliana A. S. A.; Pintado, Manuela E.Aim: The valorisation of agro-industrial by-products represents a strategic approach toward reducing food processing waste while fostering circular bioeconomy practices. Peanut skin, a by-product of peanut processing, is particularly rich in phenolic compounds with significant antioxidant and antimicrobial properties, making it a promising candidate for sustainable applications in the cosmetic and textile industries. This study explores the upcycling of peanut skin via eco-friendly extraction technologies to obtain phenolic-rich bioactives suitable for skin-related applications and functional textiles. Method: We investigated the impact of four extraction methodologies - hydroethanolic, aqueous, alkaline, and ultrasound-assisted extraction (UAE) - on the yield and chemical composition of peanut skin extracts. Analytical assessments included quantification of protein, total carbohydrates, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant capacity via the ORAC assay. The phenolic composition was further elucidated through LC-ESI-QqTOF-HRMS. Additionally, the antimicrobial efficacy of the extracts was tested against representative Gram-negative and Gram-positive bacteria. Furthermore, the metabolic impact of the extracts on a human keratinocyte cell line (HaCat) was also assessed to evaluate biocompatibility. Results: Among the methods tested, the UAE yielded the highest total phenolic content (512.93 mg GAE/g DE) and antioxidant activity (2770.17 ?mol TE/g DE). The phenolic profile revealed that peanut-skin extracts were rich in type-A and type-B procyanidin dimers and trimers, with type-A dimers being the most abundant, accounting for up to 36.47% of the total phenolics in UAE. These compounds are known for their strong antioxidant and antimicrobial efficacy. Antimicrobial assays showed that alkaline extracts exhibited the most potent activity, inhibiting Staphylococcus aureus and S. epidermidis at 5 mg/mL and 2.5 mg/mL, respectively. Hydroethanolic and UAE extracts exhibited moderate inhibition at higher concentrations. In contrast, the aqueous extracts were inactive against all tested bacteria. When considering the extracts impact on HaCaT cells, the lowest cytotoxicity was observed for the hydroethanolic extract (500 ?g/mL), and the highest for UAE (62.5 ?g/mL). Conclusion: These findings highlight the potential of UAE for enhancing the recovery of phenolic compounds from peanut skin. The high antioxidant and antimicrobial activities of the enriched extracts, supports their application in skin-related products including textiles.
- Plant extract with bioactive potential against SARS-CoV-2Publication . Melo, Adma N. F.; Afonso, Tiago B.; Carvalho, Marta; Rodrigues, Cláudia; Ribeiro, Tânia; Carocho, Márcio; Pinto, Miguel Marques; Tavaria, Freni; Teixeira, Paula; Simas, J. Pedro; Barros, Lillian; Pintado, ManuelaBackground: The novel disease caused by SARS-CoV-2 has been causing chaos worldwide due to its high mortality, morbidity and contagiousness nature, and therefore forced the scientific world to develop new alternatives to combat and assist the fight against this virus. Plant extracts have bioactive molecules that might provide a starting point for the research on the use of plants as an excellent source of new antiviral agents able to inhibit or neutralize COVID-19. Therefore, the objective of this study was to obtain an extract from a Plant cultivated under controlled conditions in Portugal to be used as an antiviral substance to be applied against COVID-19. Materials/Methods: The plant extract obtained from plant cultivated under controlled conditions in Portugal was extracted by maceration in a hydroethanolic solution under optimized conditions and submitted to freeze drying. The extracts were evaluated for their phenolic profile by high performance liquid chromatography coupled to a diode array detector and a mass spectrometer detector (HPLC-DAD-MS). Antioxidant activity was also measured, and antiviral properties were measured for SARS-CoV-2 in Vero cells. Results. HPLC analysis revealed the presence of different phenolic compounds in the extracts with relevance for caftaric acid, cis-chicoric acid and trans-chychoric acid. The extract showed a good antioxidant capacity demonstrated by the high value found for ORAC of 3202,82 ± 32,52 Trolox/mg extract. Regarding the antiviral activity, the results achieved for the viral titer was 20 PFU/mL, and the antiviral activity for SARS-CoV-2 was 4.02 ± 0.00 Mv and the percentage of reduction was > 99.99%. Conclusion: The results showed that the obtained extract demonstrated consistent results of antiviral activity presenting a potential for applications against the SARS-CoV-2. Further studies are required for validation and application of this extract.