Erythrinoid and indol alkaloids isolated from the seeds of Erythrina rubrinervia Kunth: Chemotaxonomic significance

In the present work, we report the isolation of five alkaloids from the seeds of Erythrina rubrinervia. Four of the isolated alkaloids are erythrinoid type alkaloids which were identified as erysodine (1), erysovine (2), erythraline (3) and erysotrine (4), plus an indolic alkaloid which was identified as hypaphorine (5). The analysis of spectroscopic data for the alkaloid L-hypaphorine shows that the published structure (5a) must be revised, and the correct structure is that depicted as the structure 5c. The chemical structures were elucidated by full spectroscopic analysis. The chemotaxonomic significance of those findings in the genus Erythrina is also discussed.