RESUMO
New groups of polyindolenine alkaloids have been isolated from new species of the tribe Psychotriae (Rubiaceae). The cyto-inhibitory effects of these compounds on tumoral cell lines have been thoroughly investigated and thus allow the statement of relationships between some original structural patterns and the observed biological effects.
Assuntos
Alcaloides/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Hepáticas Experimentais/patologia , Animais , Antineoplásicos/farmacologia , Isomerismo , Peso Molecular , Polímeros , Ratos , Estereoisomerismo , Relação Estrutura-Atividade , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
Four new alkaloids, representing the first members of new groups of polyindolinic alkaloids, have been isolated from the aerial parts of CALYCODENDRON MILNEI along with other alkaloids. The names vatine, its stereoisomer vatine A, vatamine, and vatamidine are proposed. They are polymers of six, seven, and eight N(b)-methyltryptamine units, respectively.
RESUMO
Quadrigemine B, quadrigemine A, isopsychotridine C and psychotridine, isolated from PSYCHOTRIA FORSTERIANA, are potent inhibitors of the aggregation of washed human platelets induced by ADP, collagen or thrombin. The four compounds are active in the 1-10 microM range. The quadrigemine-type alkaloids do not increase the level of platelet cyclic AMP, either alone or in the presence of 20 nM prostaglandin E, (PGE (1)), an activator of adenylate cyclase. The characteristics of the pharmacological action of these compounds suggest that they act at a later stage in platelet activation, possibly through an interaction with cytoskeletal proteins.