Alkaloids from the stem barks of Erythrina stricta

Four previously undescribed erythrinan alkaloids, 8α-acetonylerythristemine, 8α-acetonylerysotrine, 10β-hydroxy-11β-methoxyerysotramidine and 3-epierysotrine, one undescribed pyrrolidine derivative, S-1-(4-hydroxy-3-methoxyphenethyl)-5-hydroxy pyrrolidin-2-one, and one undescribed amide, N-(3-hydroxy-4-methoxyphenethyl)-4-hydroxylbutanamide, along with thirteen known alkaloids were isolated from the stem barks of Erythrina strica Roxb. (Leguminosae). Their structures were identified by extensive analysis of physical, spectroscopic and spectrometric data. It's very interesting that the coexistence of 3-methoxytyramine, erythrinarbine, S-1-(4-hydroxy-3-methoxyphenethyl)-5-hydroxy pyrrolidin-2-one and N-(3-hydroxy-4-methoxyphenethyl)-4-hydroxylbutanamide that may be closely related in biosynthesis, supports the hypothetical biogenetic pathway of pyrrolo [2,1-a]isoquinoline alkaloids. [Display omitted] •Four undescribed erythrinan alkaloids were discovered in Erythrina stricta.•Additionally, one undescribed pyrrolidine derivative and one undescribed amide were obtained.•The coexistence of four alkaloids supports the hypothetical biogenetic pathway of pyrrolo[2,1-a]isoquinoline.