Browsing by Author "Dias, Alberto C.P."
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- Development, characterization, antioxidant and hepatoprotective properties of poly(Ɛ-caprolactone) nanoparticles loaded with a neuroprotective fraction of Hypericum perforatumPublication . Oliveira, Ana Isabel; Pinho, Cláudia; Fonte, Pedro; Sarmento, Bruno; Dias, Alberto C.P.Quercetin and biapigenin are antioxidant and neuroprotective compounds present in Hypericum perforatum, with potential application in neurodegenerative diseases. Quercetin has shown to have excellent antioxidant activities. Biapigenin possesses a distinctive mechanism of action, preventing the onset of calcium deregulation and mitochondrial dysfunction. The main aim of this study was to establish a new delivery system encapsulating H. perforatum neuroprotective fraction, isolated from it,containing quercetin and biapigenin into poly(Ɛ-caprolactone) (PCL) nanoparticles. It also aimed to study its hepatoprotective potential. Different formulation parameters were optimized, resulting in a stable formulation of polymer:compounds ratio 1:0.1 with a mean particle size of 185nm, zeta potential around -20mV and association efficiency close to 100%. Compounds in vitro release, under physiological conditions, showed an initial burst followed by a sustained release. The antioxidant functional properties of these compounds were not altered by encapsulation. PCL-loaded nanoparticles protected HepG2 cells from intrinsic compound toxicity at high concentrations. Depending on the incubation regimen, quercetin-biapigenin PCL-loaded nanoparticles or free compounds were more effective in protecting HepG2 cells against tert-butylhydroperoxide-induced toxicity. This is the first report of the encapsulation of a quercetin-biapigenin mixture in a polymeric matrix, specifically, in PCL, with synergic anti-oxidant and hepatoprotective effects.
- New drugs from traditional medicines: pharmacological evaluation of plant extracts from Chapada Diamantina (Brazil)Publication . Pinho, Cláudia; Oliveira, Ana; Paraíso, Nilson; Carvalho, Ana C.; Calçada, Carla; Lima, Cristovao F.; Dias, Alberto C.P.Plants are rich sources of medicines and Brazil is among the most biodiverse nations in the world.