RESUMO
BACKGROUND: The percutaneous absorption test aims to estimate the passage of a substance across the skin. The absorption process can be described in three steps: (a) penetration of a substance into the skin layer, followed by (b) penetration from one layer into another (permeation) and finally (c) resorption into the vascular system. In vivo and in vitro models are available but owing to ethical reasons as well as the latter providing greater feasibility, in vitro models are preferred. AIMS: This present study reviews the natural membranes (human skin and animal models: pig, rabbit, rat, hairless mouse, guinea-pig and mouse), artificial skin equivalents and synthetic membranes that are currently being used for in vitro percutaneous absorption studies of UV filters, in order to provide the researcher with a greater insight when selecting membrane models for given experimental conditions.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Modelos Animais , Absorção Cutânea/efeitos dos fármacos , Absorção Cutânea/fisiologia , Testes Cutâneos/métodos , Protetores Solares/administração & dosagem , Protetores Solares/farmacocinética , Administração Tópica , Animais , Humanos , Especificidade da Espécie , Raios UltravioletaRESUMO
The effect of the pH of the mobile phase in HPLC analysis of hyperforin was investigated. Working with an extract of St. John's Wort (Hypericum perforatum L.) that is rich in hyperforin, significant differences were observed in conventional chromatograms depending on whether the mobile phase was acidic or alkaline. Chromatogram changes were paralleled by changes in the UV spectrum of the hyperforin peak. The structural changes in hyperforin occur in the chromatographic column itself, as has been confirmed by UV spectroscopy performed on a sample of purified hyperforin, which showed that the UV spectrum is indeed dependent on the pH of its environment.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Hypericum/química , Floroglucinol/análogos & derivados , Espectrofotometria Ultravioleta/métodos , Terpenos/química , Compostos Bicíclicos com Pontes/química , Concentração de Íons de Hidrogênio , Estrutura Molecular , Floroglucinol/químicaRESUMO
We recently reported that resveratrol, a grape-derived polyphenol, in vitro induces the apoptosis of leukemic B-cells and simultaneously inhibits the production of endogenous nitric oxide (NO) through inducible NO synthase (iNOS) down-regulation. The same results were observed in the present study with not only acetate derivatives of polyphenols, particularly the pentaacetate of -viniferin (resveratrol dimer), but also with a synthetic flavone (a diaminomethoxyflavone) in both leukemia B-cell lines and B-cell chronic lymphocytic leukemia (B-CLL) patients' cells. Moreover, flavopiridol, another flavone already known for its pro-apoptotic properties in B-CLL cells, was also found to down-regulate both iNOS expression and NO production. Thus, inhibition of the NO pathway during apoptosis of leukemia B-cells appears a common mechanism for several compounds belonging to two distinct families of phytoalexins, the flavones and grape-derived polyphenols.
Assuntos
Apoptose/efeitos dos fármacos , Flavonoides/farmacologia , Leucemia de Células B/patologia , Óxido Nítrico/metabolismo , Fenóis/farmacologia , Transdução de Sinais/efeitos dos fármacos , Anexina A5/metabolismo , Caspase 3 , Caspases/metabolismo , Divisão Celular/efeitos dos fármacos , Regulação para Baixo , Regulação Leucêmica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Leucemia de Células B/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias , Óxido Nítrico Sintase , Óxido Nítrico Sintase Tipo II , Polifenóis , Proteínas Proto-Oncogênicas c-bcl-2 , Células Tumorais CultivadasRESUMO
Two lactone compounds have been isolated from the leaves and branches of ylang-ylang (Cananga odorata forma genuina Hook. f. et Thomson, Annonaceae). One was already known as isosiphonodin 1. The other, canangone 2, is a new terpenoid spirolactone with an unusual backbone. Its structure has been established as 6-hydroxy-1-oxo-2-oxaspiro[4.5]dec-7-ene-8-carbaldehyde by using 1-D and 2-D NMR.
