Robert Schaer

Publications (2)4.24 Total impact

• Article: Flavonoids inhibit angiogenic cytokine production by human glioma cells.

  Sandra Freitas, Silvia Costa, Camila Azevedo, Gerson Carvalho, Songeli Freire, Pedro Barbosa, Eudes Velozo, Robert Schaer, Marcienne Tardy, Roberto Meyer, Ivana Nascimento
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  ABSTRACT: VEGF and TGF-β1 are cytokines that stimulate tissue invasion and angiogenesis. These factors are considered as molecular targets for the therapy of glioblastoma. Bevacizumab, a recombinant humanized monoclonal antibody developed against VEGF, inhibits endothelial cell proliferation and vessel formation. Flavonoids obtained from Dimorphandra mollis and Croton betulaster have been described as proliferation inhibitors of a human glioblastoma derived cell line. VEGF and TGF-β1 levels were dosed by ELISA in a GL-15 cell line treated with bevacizumab and also with the flavonoids rutin, 5-hydroxy-7,4'-dimethoxyflavone, casticin, apigenin and penduletin. Rutin reduced the VEGF and TGF-β1 levels after 24 h but not after 72 h. The other flavonoids significantly reduced TGF-β1 production. Bevacizumab reduced only the VEGF levels in the supernatant from GL-15 cultures. These results suggest that the flavonoids studied, and commonly used in popular medicine, present an interesting subject of study due to their potential effect as angiogenic factor inhibitors.
  Phytotherapy Research 06/2011; 25(6):916-21. · 2.09 Impact Factor
• Source

  Available from: Songeli Menezes Freire

  Article: The flavonoid rutin but not the alkaloid arborinine induces apoptosis in a B-cell hybridoma cell line.

  Renata Roseghini, Georgenes Morato Falcão, José Fernando Oliveira Costa, Jorge Clarêncio, Ivana Nascimento, Eudes Velozo, Robert Schaer, Vera Vale, Silvia Lima Costa, Maria de Fátima Dias Costa, Marcienne Tardy, Roberto Meyer, Songelí Menezes Freire
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  ABSTRACT: The effects of arborinine, an alkaloid extracted from Erthela bahiensis and of rutin, a flavonoid obtained from Dimorphandra mollis (Benth.), Brazilian medicinal plants, on the viability and function of a murine B-cell hybridoma as a tumor model were investigated. The flavonoid rutin at 50 microM induced an increase in the number of apoptotic cells of one- to fivefold and reductions in cellular proliferation and monoclonal antibody production. Less but still significant necrosis was also induced by rutin under the same experimental conditions. On the other hand, the alkaloid arborinine exerted no significant effects on the studied parameters.
  Planta Medica 03/2009; 75(5):488-93. · 2.15 Impact Factor