Browsing by Issue Date, starting with "2023-09-21"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Advances in Pancreatic Cancer treatment by Nano-Based drug delivery systemsPublication . Viegas, Cláudia; Patrício, Ana B.; Prata, João; Fonseca, Leonor; Macedo, Ana S.; Duarte, Sofia O. D.; Fonte, PedroPancreatic cancer represents one of the most lethal cancer types worldwide, with a 5-year survival rate of less than 5%. Due to the inability to diagnose it promptly and the lack of efficacy of existing treatments, research and development of innovative therapies and new diagnostics are crucial to increase the survival rate and decrease mortality. Nanomedicine has been gaining importance as an innovative approach for drug delivery and diagnosis, opening new horizons through the implementation of smart nanocarrier systems, which can deliver drugs to the specific tissue or organ at an optimal concentration, enhancing treatment efficacy and reducing systemic toxicity. Varied materials such as lipids, polymers, and inorganic materials have been used to obtain nanoparticles and develop innovative drug delivery systems for pancreatic cancer treatment. In this review, it is discussed the main scientific advances in pancreatic cancer treatment by nano-based drug delivery systems. The advantages and disadvantages of such delivery systems in pancreatic cancer treatment are also addressed. More importantly, the different types of nanocarriers and therapeutic strategies developed so far are scrutinized.
- Mechanosynthesis of bioactive compounds based on natural scaffoldsPublication . Mardanov, Aladdin; Bonifácio, Vasco D.B.; Cavaco , Isabel M.P.A.This thesis explored the use of mechanochemistry as a green methodology to prepare bioactive molecules. The synthetic methodology searched the preparation of different classes of compounds, using organic reactions comprising acylation and substitution reactions. The main focus of the work was the development of a robust methodology that could lead to the preparation of bioactive compounds, based on natural scaffolds, optimizing the existing protocol by removing solvents, reducing reaction time, and energy. For this purpose work considers manufacturing of compounds and the formation of their intermediates using mechanochemistry. Nevertheless, the main area of focus is testing of this reactions and synthetic pathways to form new APIs based on natural compounds or optimize existing reactions by removing solvent use, reducing reaction time, and energy use, since the aim is to make processes follow green chemistry and sustainable manufacturing practices. In other words, the idea beyond the manufacturing is to use compounds found in nature (extracted from vegetation). Coumarins were selected as key scaffolds due to their interesting properties, showing evidence of biological activity, especially their derivatives. In this work, coumarins were first synthesized and then acylated to produce derivatives compounds with enhanced bioactivity. The synthesis of coumarins from salicylaldehydes was attempted by mechanosynthesis but discarded due to lower yields, attributed to the lower temperatures reached under ball milling conditions. This reaction step was investigated using ultrasound irradiation, which proved to be successful, and showed to be an alternative methodology to the conventional approach using water under refluxing conditions. Coumarins acylation was performed using mechanochemistry, with good yields, under solventless conditions, no external heating, and reduced reactions times. This methodology allowed the synthesis of two new coumarins (biscoumarins) and four new coumarin derivatives. The mechanosynthesis of flavonoid derivatives was also investigated, with good results. Finally, the mechanosynthesis of benzoin derivatives was explored, but in this case the target compounds were not observed.
- Exploring the medicinal halophytes Limonium Aagarvense and Polygonum maritimum AS sources of cosmetic ingredientsPublication . Romero, Héctor; Rodrigues, Maria João; Pereira, Catarina GuerreiroThe cosmetic industry is constantly searching for innovations, especially novel natural active ingredients that meet the ever-changing consumer’s expectations. Among the variety of cosmetic products, the skincare category aims mainly at cleaning the skin, preserving the skin’s moisture balance, stimulating skin metabolism, and protecting the skin from agents as radiation or environmental pollutants. Several challenges force the cosmetic and skincare sector to eagerly look for innovative solutions. Keeping up with the consumers demands specially regarding sustainability, offering a functional product, and providing a pleasant sensorial experience while wearing the product are among the reasons that thrust the research and development in cosmetics. The solutions come from many fronts, covering factors such as packaging, process design, product formulation, and raw materials. In this sense, the obtention of bioactive molecules from natural sources has been explored as a transversal solution to these challenges. It is extensively recorded that plants have been used for traditional medicinal applications in many forms, namely beverages, ointments, tinctures, and many others. Research on traditional medicinal herbs has uncovered that these contain a plethora of compounds with therapeutic applications. The exploitation of these species as sources of therapeutic compounds has been explored by the pharmaceutical, food sectors, and the one that concerns this work, the cosmetic sector. With the development of advanced extraction techniques, the use of medicinal plants as sources of active cosmetic ingredients has been continuously unlocked. The species’ origin is not restricted, quite opposite, these come from all corners of the world and from a wide span of ecosystems. The marine environment is the host of a completely different variety of species, mainly due to the contrasting difference between the life conditions under which life develops. It is estimated that barely 8% of sea biodiversity is known. Lately, marine organisms have begun to be used as sources of novel ingredients to develop increasingly innovative products, including halophyte species. Halophytes, considered extremophiles due to their capacity of growing and thriving in extreme conditions as intensive radiation exposure periods and high salinity environments, have been reported to contain a panoply of powerful antioxidant compounds. Present in the Algarve coast, Limonium algarvense Erben (sea lavender) and Polygonum maritimum L. (sea knotgrass) are two halophyte species which have been profiled as botanical sources of molecules against, inflammation, diabetes, neurodegenerative diseases, and skin ageing. Hence, this work prepared and evaluated innovative herbal extracts containing mixtures of sea lavender and sea knotgrass at different ratios, aiming at their valorisation as sources of novel cosmetic ingredients. For that, aqueous extracts, obtained through an ultrasound assisted technique, were evaluated for their chemical and functional properties, including antioxidant activity on DPPH•, ABTS•+ , O2- , and HO• radicals, chelating activity on copper, and inhibition of enzymes related to cosmetic uses, namely tyrosinase, lipase and elastase. All samples had relevant activity as radical scavengers, being the sea lavender extract the most active on DPPH• and O2- radicals (EC50 = 0.15 mg/mL and 0.22 mg/mL, respectively). Sea knotgrass extract on its own, showed the higher scavenging activity on ABTS•+ (EC50 = 0.56 mg/mL). The mixture at 1:3 ratio had the best copper chelating activity (EC50 = 0.533 mg/mL) among all. Contrastingly, the mixture at 3:1 ratio had the best performance over HO• radical (EC50 = 0.063 mg/mL). Regarding the enzymatic inhibitory assays, whilst the sea lavender extract had the best performance on tyrosinase inhibition (EC50 = 0.183 mg/mL), the sea knotgrass extract was the only one showing an inhibitory activity towards elastase (EC50 = 8.07 mg/mL). None of the tested extracts showed activity over lipase. Analysing further, the 1:3 mixture showed an additive effect (SE = 1) on the copper chelation, whereas and the mixture at 3:1 ratio had a synergistic effect on the HO• radical scavenging activity (SE = 0.2). All the other extracts had SE values over 1, meaning an antagonistic effect. The extracts were analysed by liquid chromatography – high resolution mass spectrometry. A total of 300 features were identified and flavonoids constituted the major chemical class in the mixtures. Sea lavender proved to have a larger chemical variety than sea knotgrass, since there were more compounds identified in its extract. In few cases, the compounds were only identified in the pure sea lavender or sea knotgrass extracts and once mixed, they were not identified any more. Contrastingly, in other cases the presence of extracts was concentration dependent, augmenting or decreasing as the ratio of one or another extract did, pointing to either sea lavender or sea knotgrass as main contributors of that chemical compounds. Mostly all species had been identified in previous works regarding sea lavender, sea knotgrass, and Limonium/Polygonum genus’, respectively. To the best of our knowledge sinensin was identified for the first time in both sea lavender, sea knotgrass extracts as well as in their respective genus. Sinensin was also the only compound that was identified in larger proportion in the mixtures than in the lone extracts. Compared with previous findings, the most active extracts in this study exhibited lower antioxidant and enzymatic inhibitory activities. Nonetheless, the main differences between previous methods and the ones reported in this work rely on the extraction method, solvent, biomass origin, organ used for extraction, and irrigation. Additionally, we presently report anti-elastase activity from sea knotgrass extract, a result that was not obtained in previous reports regarding its inhibitory activity. The possible reasons for which the extracts showed less potent antioxidant and enzymatic inhibitory capacity are attributed to the solubility of the active compounds, the origin of the plant material (wild collected or greenhouse grown), and salinity. Albeit the activities of the aqueous extracts were lower, they still endow promising activities, hence holding the advantage of dismissing organic solvents in the extraction process. Overall, the results indicate that the sea lavender extract, and their mixture with sea knotgrass at 1:3 and 3:1 ratios are suitable sources of active compounds for the cosmetic industry given their performance as radical scavengers, metal chelators, as well as antiwrinkles and anti-hyperpigmentation properties.
- Effect of composting on biodegradation of compostable and conventional microplastic by bacterial communities from sewage sludgePublication . Alcivar, Adriana Rosaura Gonzalez; Beltrán, Isabel Marín; Costa, Maria ClaraMicroplastics (MP) threaten the aquatic and terrestrial ecosystems. Several studies have reported that wastewater treatment plants (WWTPs) are one of the main sources of MP to the ocean, even though they remove up to 98% of MPs from the influent (Carr et al., 2016; Murphy et al., 2016; Simon et al., 2018; Talvitie et al., 2017). Most of these MPs are not really eliminated but end up in the sewage sludge. This sludge is normally used as fertilizer in agricultural soils, after a composting process. However, current regulation does not consider the concentration of MP in sludge before their application on natural soils. This work focused on evaluating the effect of composting on MP particles. For this, we spiked sewage sludge from a European WWTP with MP films (2 mm-2 ) from a polyethylene terephthalate (PET) bottle and a compostable (according to the seller) bag of polyethylene (CPE). The experimental set-up consisted of: sludge spiked with 40 PET MP, sludge spiked with 40 CPE MP. These two treatments were repeated but inoculating a bacterial isolate from the genus Bacillus. Sludge with no added MP or bacterial inoculum was used as control. Samples were kept at 50ºC for 60 days, and organic matter content, pH, C:N ratio, the change in the functional groups of MP, and changes in the bacterial community were monitored monthly. Results showed that 40 MP had no effect on the composting process. There were differences among peaks indicating chemical changes and biodegradation for PET and CPE MP. After 60 days, scanning electron microscopy revealed adhering biofilms and a hole for CPE MP submitted to bioaugmentation treatment but did not decompose as expected. The concentration of MPs in the sludge after 60 days was 27 MP by g-1 , compared to 4 MP by g-1 at the beginning. Polyester (28%) was the most abundant polymer and fibers (84%) the most common shape.