RESUMO
Four calamenene sequiterpenes, (+)-(7R,10S)-15-hydroxycalamenene (3), (+)-(7R,10S)-2,15-dihydroxycalamenene (4), (+)-(7R,10S)-2-hydroxy-15-calamenal (5), (+)-(7R,10S)-15-calamenal (6), along with the amorphane sesquiterpene (+)-(1S,6R,7R,10S)-1-hydroxy-3-oxo-amorph-4-ene (16), have been isolated from the Madagascan shrub Tarenna madagascariensis (Rubiaceae) and their structures determined by spectroscopic methods and chemical correlations. Furthermore, five known related sesquiterpenes [(+)-(7R,10S)-2-hydroxycalamenene (1), (+)-(7R,10S)-3-hydroxycalamenene (2), (-)-alpha-cadinol (13), cadinenal (14), 6-epicadinenal (15)], and three known lignans [(-)-hinokinin, (-)-dihydrocubebin, (-)-cubebin] were also isolated from the same plant. This is the first report of compounds 3, 4, 5, 6, and 16 from a natural source.
Assuntos
Rubiaceae/química , Sesquiterpenos/química , Terpenos/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Sesquiterpenos Policíclicos , Sesquiterpenos/isolamento & purificação , Terpenos/isolamento & purificaçãoRESUMO
A C16 norsesterterpenoid (euplectellodiol, 1) and a norditerpenoid (2) have been isolated from the marine sponges Mycale euplectelloides and Diacarnus megaspinorhabdosa, respectively. Their structures have been determined by spectroscopic methods. Compounds 1 and 2 are new natural products.
Assuntos
Poríferos/química , Terpenos/química , Animais , Indonésia , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Oceanos e Mares , Terpenos/isolamento & purificaçãoRESUMO
A new pentacyclic triterpene, 11alpha-acetoxy-20,24-epoxy-25-hydroxy-dammar-3-one (1), has been isolated from the African tree Combretum nigricans, together with the known corresponding diol, 20,24-epoxy-11alpha, 25-dihydroxy-dammar-3-one (2). They are responsible, at least in part, for the cytotoxic activity of the methanolic extract of the plant.
