Uncoupling and inhibition properties of 3,4-seco-friedelan-3-oic acid isolated from Maytenus imbricata

• Autor(a) principal: Barbosa, Luiz Claúdio de Almeida
• Data de Publicação: 2007
• Outros Autores: Silva, Silvia Ribeiro de Souza e, Silva, Grácia Divina de Fátima, Duarte, Lucienir Pains, King-Diaz, Beatriz, Archundia-Camacho, Francisco, Lotina-Hennsen, Blas
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: https://doi.org/10.1016/j.pestbp.2006.06.008; http://www.locus.ufv.br/handle/123456789/23283
• topic: Maytenus imbricata; Triterpenes; Photosystem II; Uncoupler-inhibitor; 3,4-Seco-friedelan-3-oic acid

3,4-Seco-friedelan-3-oic acid was isolated from Maytenus imbricata (Celastraceae). At low concentrations it inhibited non-cyclic electron transport and ATP synthesis in spinach chloroplasts, i.e., it behaved as a Hill reaction inhibitor, and at high concentrations it acts as an uncoupler by enhancing uncoupled electron transport and Mg2+–ATPase activity. 3,4-Seco-friedelan-3-oic acid did not inhibit PSII electron transport from DPC to DCPIPox and photosystem I activity, but it enhanced from TMQH2 to MV, corroborating its action as uncoupler. It inhibits electron flow through PSII from water to sodium silicomolybdate. The whole results indicate that the 3,4-seco-friedelan-3-oic acid target is at the OEC complex enzyme, the donor side of PSII. The fluorescence decay data shows the formation of the K-band, which match this result, acting as inhibitor at the donor side of PSII and it as an uncoupler.