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Spasmolytic Action of Diplotropin, a Furanoflavan from Diplotropis ferruginea Benth., Involves Calcium Blockade in Guinea-Pig Ileum

2005; De Gruyter; Volume: 60; Issue: 10 Linguagem: Inglês

10.1515/znb-2005-1013

1865-7117

Julianeli Tolentino de Lima, Jackson Roberto Guedes da Silva Almeida, José Maria Barbosa‐Filho, Temilce Simões de Assis Cantalice, Marcelo Sobral da Silva, Emídio Vasconcelos Leitão da Cunha, Raimundo Braz-Filhod, Bagnólia Araújo da Silva,

Ethnobotanical and Medicinal Plants Studies

Diplotropis ferruginea Benth. (Fabaceae) is a tree popularly known in Northeastern Brazil as “sucupira-preta”. In the present work, the isolation, identification and pharmacological activity of a furanoflavan-type flavonoid (2,3-trans-3,4-trans)-3,4,5,8-tetramethoxy-(6,7,2”,3”)-furanoflavan, which received the trivial name diplotropin is reported. The structure was determined by means of spectroscopic techniques, especially EIMS and 1D and 2D NMR. Diplotropin (10 −8 −3 · 10 −4 M) inhibited the phasic contractions induced by both acetylcholine (IC 50 = 4.6±0.8 · 10 −5 M) and histamine (IC 50 = 2.3±1.1 · 10 −5 M) in guinea-pig ileum. Diplotropin relaxed the ileum pre-contracted with KCl (EC 50 = 3.9±1.1 · 10 −6 M), acetylcholine (EC 50 = 3.7±1.6 · 10 −6 M) and histamine (EC 50 = 4.4±1.4 · 10 −5 M) in a concentration-dependent manner. As the maintenance of tonic contraction induced by these contractile agents involves Ca 2+ influx through voltage-dependent Ca 2+ channels, it is suggestive that this relaxation may be due to the blockade of Ca 2+ influx through those channels. This hypothesis was confirmed by the observation that diplotropin antagonized (pD’ 2 = 4.83±0.37) CaCl 2 induced contractions in Ca 2+ -free depolarizing medium (IC 50 = 1.5±0.8 · 10 −5 M).