Browsing by Issue Date, starting with "2015-07-21"
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- Acetylcholinesterase Inhibitory Activity of Extracts from Angolan Medicinal PlantsPublication . Fernandes, Nelson; Canelo, Laura; Mendonca, Dina; Mendonça, AntónioPlants are considered important sources of new chemical entities that can be used in the development of novel therapeutic drugs for the symptomatic treatment of Alzheimer’s disease. The inhibition of acetylcholinesterase by 38 extracts from 13 medicinal plants used in Angola folk medicine are presented: Adenodolichos huillensis (roots and leaves); Boscia microphylla (leaves); Croton gratissimus (aerial part); Gymnosporia senegalensis (branches); Hymenodictyon floribundum (barks); Parinari capensis (leaves); Peucedano angolense (aerial part); Phragmanthera glaucocarpa (roots); Rhus kirkii (leaves); Solanecio mannii (branches); Solanum incanum (fruit); Tinnea antiscorbutica (aerial part) and Xylopia odoratissima (leaves). TLC bioautographic assay and Ellman’s method were used. The best results for IC50 were obtained with the toluene extract of B. microphylla leaves (0.55 ± 0.01 mg/mL) and the methanol extract of G. senegalensis branches (0.30 ± 0.00 mg/mL). The aqueous extract of the leaves of P. capensis also demonstrated acetylcholinesterase inhibitory activity in the two methods used. In conclusion, the medicinal plants P. capensis, B. microphylla and G. senegalensis represent promising sources of natural compounds with acetylcholinesterase inhibitory properties.
- Synthesis, functionalization and characterization of UV-curable lactic acid based oligomers to be used as surgical adhesivesPublication . Santos, João; Marques, Dina; Alves, Patrícia; Correia, Tiago R.; Correia, Ilídio Joaquim Sobreira; Baptista, Cristina Maria dos Santos Gaudêncio; Ferreira, PaulaThe synthesis, functionalization and characterization of low molecular weight L-lactic acid based oligomers to be used as new UV-curable bioadhesives are presented herein. Prepolymers hydroxyl terminated were produced by L-lactic acid dehydration with 1,4-butanediol. The prepolymer was further modified with photoreactive sites by adding an isocyanate-functional unsaturated acrylic ester, which was used for the first time in the biomedical field (LAROMER® LR 9000). Films were afterwards produced upon UV irradiation for 120 s, using a biocompatible photoinitiator (Irgacure® 2959), and finally characterized. The synthesized films exhibited a moderate swelling ratio, suitable for the envisioned application. DSC analysis confirmed an increase in Tg values after each synthesis step. Nevertheless, the film Tg remains lower than the physiological and room temperature. TGA confirmed an improved stability of films at high temperatures. The in vitro degradation tests showed their susceptibility to hydrolysis at 37 °C, suitable for short-term uses. Preliminary evaluation of the adhesion capacity suggested that the synthesized material may be effective in sustaining wound closure and repair. The surface energy was also measured and its value was lower than the ones from blood or skin which supports the previous statement. Blood compatibility studies, cell viability assays (using human dermal fibroblasts) and bacterial inhibition tests (using two bacteria models) were performed. The results indicated that cured adhesive is bio/haemocompatible and possesses antimicrobial activity. Altogether, characterization results showed that the produced material presented a set of properties suitable for biomedical applications, particularly as a surgical adhesive.