Browsing by Author "Rocha, Joao"
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- Combination of hyaluronic acid and PLGA particles as hybrid systems for viscosupplementation in osteoarthritisPublication . Mota, Ana Henriques; Direito, Rosa; Carrasco, Marta P.; Rijo, Patricia; Ascensao, Lia; Viana, Ana Silveira; Rocha, Joao; Eduardo-Figueira, Maria; Rodrigues, Maria Joao; Custódio, Luísa; Kuplennik, Nataliya; Sosnik, Alejandro; Almeida, Antonio Jose; Gaspar, Maria Manuela; Reis, Catarina PintoHyaluronic acid (HA) is commonly used through intra-articular administration for viscosupplementation in osteoarthritis and other disorders. HA is generally supplied as an injection commonly reported as painful, with strong limitations after treatment. In this study, an alternative delivery system was constructed based on HA hydrogel and poly(lactic-co-glycolic acid) (PLGA) particles with oleic acid. Development studies included the determination of particle toxicity, hemolytic activity, in vitro and in vivo anti-inflammatory activity using macrophages and a murine model, respectively. This study showed that empty PLGA particles presented a mean size of 373 nm, while particles containing HA and oleic acid showed a marked particle size increase. The HA association efficiency was of 73.6% and 86.2% for PLGA particles without and with oleic acid, respectively. The in vitro HA release from PLGA particles revealed a sustained profile. Particles showed a good in vitro cell compatibility and the risk of hemolysis was less < 1%, ensuring their safety. The in vivo anti-inflammatory study showed a higher inhibition for HA-loaded PLGA particles when compared to HA solution (78% versus 60%) and they were not different from the positive control, clearly suggesting that this formulation may be a promising alternative to the current HA commercial dosage form.
- Synchronous insight of in vitro and in vivo biological activities of Sambucus nigra L. extracts for industrial usesPublication . Mota, Ana Henriques; Andrade, Joana M.; Rodrigues, Maria Joao; Custódio, Luísa; Bronze, Maria Rosario; Duarte, Noelia; Baby, Andre; Rocha, Joao; Gaspar, Maria Manuela; Simoes, Sandra; Carvalheiro, Manuela; Fattal, Elias; Almeida, Antonio Jose; Reis, Catarina PintoThere is a re-emerging interest in natural products as reputable sources of new active pharmaceutical ingredients. This study synchronously reports in vitro, with more than one cell line, and in vivo biological activities of extracts obtained from Sambucus nigra. Using several solvents and techniques, eighteen extracts were obtained from fresh and dried berries, and fresh flowers. The flavonoid content and identification were determined using HPLC-MS/MS. The extracts were then screened for antioxidant activity, total polyphenol content, collagenase, elastase, tyrosinase and acetylcholinesterase inhibition as well as photoprotection. In vitro and in vivo (murine model) anti-inflammatory activity and cytotoxicity (skin and monocytic cells) were also studied. The most promising extracts were those obtained from fresh flowers using either ultrasounds or methanol. These extracts showed similar results to positive controls, particularly the antioxidant activity (74.5 +/- 1.6 %), collagenase inhibition (93.6 +/- 0.6 %), photoprotection (Sun Protection Factor > 50), in vitro anti-inflammatory activity (96.9 +/- 2.9 %), as well as oral/topical anti-inflammatory activity. The ultrasounds/ethanol extract of fresh flowers presented higher collagenase inhibition (88.3 +/- 2.8 %) and in vitro anti-inflammatory activity (101.8 +/- 1.5 %). Cytotoxicity testing confirmed the safety. Chemical characterization allowed the deduction of a correlation between extract composition and biological activities, suggesting a straightforward application in the development of novel products subject to further investigation.
- Zooming in with QSPR on Friedel-Crafts acylation reactions over modified BEA zeolitesPublication . Aleixo, Odrigo; Elvas-Leitao, Ruben; Martins, Filomena; Carvalho, Ana P.; Brigas, Amadeu; Nunes, Ricardo; Fernandes, Auguste; Rocha, Joao; Martins, Angela; Nunes, NelsonThe catalytic behaviour of hierarchical BEA zeolites with Si/Al ratio of 12.5 and 32 was studied in Friedel-Crafts acylation reactions using furan, anisole and pyrrole as substrates and acetic anhydride as acylating agent. Hierarchical BEA samples were submitted to alkaline and alkaline + acid treatments. Kinetic modelling using nonlinear regressions applied to a simplified Langmuir-Hinshelwood equation showed that the Si/Al ratio of the parent materials strongly influenced the catalytic behaviour. Catalytic results were correlated with physicochemical properties using a Quantitative Structure-Property Relationship (QSPR) methodology. This approach provided detailed information about the role of key properties on the catalytic behaviour, and pointed out which properties should be modified through direct synthesis and/or post-synthesis treatments to obtain materials with optimized catalytic performance.