Nouveaux alcaloïdes isoquinoléiques isolés d'une Lauraceae bolivienne: Aniba canelilla H.B.K.

Abstract

Eleven benzyltetrahydroisoquinoline alkaloids, with an original substitution pattern, were isolated from the stem bark of Aniba canelilla H.B.K. (Lauraceae). Structural studies of these compounds including 1H, 13C, nOe difference, COSY H–H and C–H, and COLOC nuclear magnetic resonance spectroscopy led to the identification of four benzylisoquinolines, monosubstituted on ring C with an hydroxyl at C-11, (−)-norcanelilline 2, (+)-canelilline 3, anicanine 4, and canelillinoxine 5; two tetrahydroprotoberberines monosubstituted on ring D at C-9, (−)-anibacanine 6 and (+)-manibacanine 8; two tetrahydroprotoberberines monosubstituted on ring D at C-11, (−)-pseudoanibacanine 7 and (+)-pseudomanibacanine 9; and three protoberberines with the same substitution pattern on rings A and D with a methyl substituent at the 8α or 8β position, (−)-α-8-methylpseudoanibacanine 10, (−)-β-8-methylpseudoanibacanine 11, and (−)-α-8-methylanibacanine 12. An examination of all isolated alkaloids suggests the existence of two enzymatic systems in A. canelilla. In the first enzymatic system, reticuline- and coclaurine-type alkaloids are involved in the bioconversion of classical proaporphine and aporphine alkaloids. In the second system, canelilline-type alkaloids are intermediate in biosynthesis of anibacanine and pseudoanibacanine protoberberine alkaloids.