Fernanda Oliveira Lima

Nanostructured Systems Containing Rutin: In Vitro Antioxidant Activity and Photostability Studies

The improvement of the rutin photostability and its prolonged in vitro antioxidant activity were studied by means of its association with nanostructured aqueous dispersions. Rutin-loaded nanocapsules and rutin-loaded nanoemulsion showed mean particle size of 124.30 ± 2.06 and 124.17 ± 1.79, respectively, polydispersity index below 0.20, negative zeta potential, and encapsulation efficiency close to 100%. The in vitro antioxidant activity was evaluated by the formation of free radical ·OH after the exposure of hydrogen peroxide to a UV irradiation system. Rutin-loaded nanostructures showed lower rutin decay rates [(6.1 ± 0.6) 10−3 and (5.1 ± 0.4) 10−3 for nanocapsules and nanoemulsion, respectively] compared to the ethanolic solution [(35.0 ± 3.7) 10−3 min−1] and exposed solution [(40.1 ± 1.7) 10−3 min−1] as well as compared to exposed nanostructured dispersions [(19.5 ± 0.5) 10−3 and (26.6 ± 2.6) 10−3, for nanocapsules and nanoemulsion, respectively]. The presence of the polymeric layer in nanocapsules was fundamental to obtain a prolonged antioxidant activity, even if the mathematical modeling of the in vitro release profiles showed high adsorption of rutin to the particle/droplet surface for both formulations. Rutin-loaded nanostructures represent alternatives to the development of innovative nanomedicines.

Substrate-free Determination of the Radical Scavenging Activity of Phenolic Compounds by Photochemical Generation of Hydroxyl Radicals and HPLC-UV Detection

This paper describes the study of the radical scavenging activity of the natural antioxidants rutin, quercetin, caffeic acid, ferulic acid, and resveratrol by using a substrate-free chromatographic method based on the generation of •OH radicals by the photolysis of H2O2 in a photochemical reactor. The comparative studies permitted the classification of some phenolic compounds regarding their in vitro radical scavenging properties (rutin > caffeic acid ≈ quercetin>ferulic acid > resveratrol). The results obtained by the proposed HPLC-UV/H2O2 photolysis method could be well corroborated by the other methods, which employ the generation of free radicals with different reactivity (ROO•, , and DPPH•). Furthermore, the reverse-phase chromatographic separation of the antioxidants from their sub-products generated after attacking with HO• radicals improved advantageously the selectivity of the measured signal used for calculating the radical scavenging activity.

A capillary zone electrophoretic method for the determination of hypoglycemics as adulterants in herbal formulations used for the treatment of diabetes

Adulteration of antidiabetic herbal medicines with hypoglycemic drugs has been reported as a recurrent practice throughout the world. In this context, a new method for the determination of metformin, chlorpropamide, glibenclamide and gliclazide by capillary zone electrophoresis (CZE) with capacitively coupled contactless conductivity detection (C4D) is described in this paper. The proposed method was applied to the evaluation of adulterants in samples of herbal formulations commercialized by compounding pharmacies for the treatment of diabetes mellitus. The method was shown to be suitable for the simultaneous evaluation of hypoglycemics as adulterants using a 20 mmol L−1 sodium acetate solution at pH 10.0 as the working electrolyte. The method allows for the quantification of the adulterants in concentrations higher than 0.24 mg per capsule for metformin, 0.42 mg per capsule for chlorpropamide, 0.15 mg per capsule for glibenclamide and 0.33 mg per capsule for gliclazide.

High-performance liquid chromatographic analysis of biogenic amines in pharmaceutical products containing Citrus aurantium

A reverse-phase (RP)-HPLC method is reported for determining L-tyrosine, p-octopamine, synephrine, tyramine and hordenine as chemical markers of the species Citrus aurantium in raw material, dry extracts and phytotherapeutic herbal formulations. Using RP-HPLC with diode array detection (DAD) and gradient elution, the amines were determined in 12 different products from different Brazilian states labelled as containing C. aurantium. The presence of the amines was confirmed by mass spectrometry using electrospray ionisation (ESI-MS/MS). This RP-HPLC method allowed the separation of the amines from complex mixtures containing caffeine, ephedrine, salicin and other raw materials (e.g. Garcinia camboja, Phaseolus vulgaris, Caralluma fimbriata, Cassia nomane, Ephedra sp. and Cordia ecalyculata). The method proved useful and selective for inspecting herbal medicines containing p-synephrine and structural analogues. The herbal products analysed had a p-synephrine content ranging from 0.005 to 4.0% (w/w).

REFORÇANDO PRÁTICAS PEDAGÓGICAS EXPERIMENTAIS A PARTIR DA REVITALIZAÇÃO DE UM LABORATÓRIO DE CIÊNCIAS

O presente trabalho relata uma atividade de revitalizacao do laboratorio de Ciencias de uma escola da rede publica de educacao no municipio de Palmeira das Missoes-RS. Para concretizar essa proposta, duas academicas do Curso de Ciencias Biologicas da Universidade Federal de Santa Maria reorganizaram o espaco laboratorial da instituicao de ensino para incentivar a preparacao de modalidades didaticas diferenciadas pelos professores. O laboratorio apresentou mudanca significativa em sua estrutura desde o inicio ate o final da revitalizacao. O ambiente que antes era utilizado para suprir a necessidade de espaco fisico de salas de aulas e tambem como deposito apresentou ao final, as condicoes necessarias para a realizacao de aulas diferenciadas. Um questionario sobre as concepcoes dos professores sobre as aulas experimentais tambem foi aplicado e nele os docentes julgaram importante esse tipo de atividade, mas alegam que os fatores que anteparam o desenvolvimento dessas praticas sao o despreparo, falta de materiais, equipamento e a indisponibilidade de tempo. Diante disso, um manual com sugestoes de atividades praticas foi elaborado para tornar as aulas mais dinâmicas e dar ao ensino de Ciencias um cunho mais diferenciado e experimental.

Phytochemical evaluation and in vitro antioxidant and photo-protective capacity of Calendula officinalis L. leaves

The plant Calendula officinalis L. is widely applied due to its medicinal properties, which are mainly dermatological and ornamental. The goal of this study is to assess the phytochemical components in a hydroethanolic extract (HECO) from the leaves of Calendula officinalis L. using UV-VIS spectrophotometry and thin layer chromatography (TLC), as well as to identify and quantify the components related to its antioxidant capacity employing high performance liquid chromatographic (HPLC). The antioxidant capacity evaluation was performed using the DPPH method for superoxide and hydroxyl radicals. The photo-protective capacity was evaluated by UVspectrophotometry in order to determine the in vitro Sun Protection Factor(SPF). The results show the plant’s strong antioxidant activity (DPPH and hydroxyl methods), which we believe to be related to the presence of flavonoids (24.67 mg/g), polyphenols (33.90 mg/g), condensed tannins (27.30 mg/g), and the amount of rutin (37.25 mg/g), and quercetin (6.09 mg/g) found during the study. The HECO presented a good antioxidant capacity, most likely due to the polyphenols, flavonoids, and tannins in its contents. However, the obtained SPF of 1.89 ± 0.05 does not allow the plant to be classified as a stand-alone sunscreen, and more studies are needed in order to test its ability to enhance sunscreens in existing cosmetic formulations.

O projeto político-pedagógico e o plano de ensino de ciências em uma Escola Kaingang

A Escola Estadual Indigena de Ensino Fundamental Gomercindo Jete Tehn Ribeiro localiza-se em Tenente Portela, na Terra Indigena Guarita, Km 10, Rodovia RS 330. Observou-se o Projeto Politico-Pedagogico e o Plano de Ensino de Ciencias dos anos finais. A escola almeja uma educacao voltada ao aluno indigena, que valorize o conjunto de experiencias oriundas de seu grupo familiar, os conhecimentos culturais e as relacoes que ele faz com o meio. Com o estudo bibliografico acerca do assunto, verificou-se que no Plano de Ensino nao constam conteudos curriculares propriamente indigenas conforme consta no Projeto Politico-Pedagogico. Dentre algumas legislacoes em âmbito nacional, a Constituicao Federal de 1988, a Lei de Diretrizes e Bases da Educacao (LD BEN) – Lei no 9.394/96 reconhecem aos indigenas o direito a diferenca cultural atraves da criacao de capitulos especificos e elegem a pluralidade cultural como um tema transversal.

EXPOSIÇÃO A AGROTÓXICOS E RADIAÇÃO UV COMO FATORES DE RISCO AO TRABALHADOR RURAL

Os agrotoxicos e a radiacao UV sao fatores de risco ocupacional para a saude dos trabalhadores rurais. Este estudo entrevistou 69 trabalhadores rurais durante a safra verao de 2006, em municipios da Regiao Noroeste do Estado do Rio Grande do Sul. A entrevista levantou dados sobre o perfil socio-demografico, os tipos de agrotoxicos utilizados, a historia ocupacional, os sintomas referidos pelo contato com agrotoxicos e a exposicao aos raios solares. Os resultados mostraram que 68,1 % dos trabalhadores rurais tiveram menos que 8 anos de educacao formal, os agrotoxicos do tipo inseticida foram utilizados com maior frequencia, sendo os piretroides e os organofosforados os mais frequentes. 29,0 % dos trabalhadores entrevistados nao utilizam nenhum tipo protecao durante a aplicacao e apenas 1,4 % dos trabalhadores rurais usam equipamanto de protecao individual (EPI) completo. 52,1% dos trabalhadores rurais ja apresentaram algum sintoma durante ou apos aplicacao de agrotoxicos na lavoura e 59,4 % se expoem mais que 8 horas/dia e 62,3 % no horario das 10-16 horas. Os dados apontam um uso inadequado dos agrotoxicos por agricultores gauchos.