Erythrine alkaloids

Two erythrine alkaloids, erythristemine (46)80 and erythrinine (47),81 contain 4-methoxy and 4-hydroxy groups, respectively, in a tetra-hydroisoquinoline ring, albeit highly substituted. 

Phenolic oxidative coupling of the diphenolic bis(phenethyl)amine 101 to the 11-membered ring structure (102) controls the formation of the isoquinoline system at the stage of iminium salt 103 and explains the 7,8-substitution pattern in the isoquinoline part of cularine alkaloids (40, 63). However, to date, no such precursors have been isolated from natural sources. Moreover, phenolic oxidative coupling of synthetic precursors such as 101, using a variety of one electron oxidation reagents, gives rise to polymerized compounds or products with the skeleton of erythrine alkaloids (104) (68). 

Table XLVI. Sub-type XVIII.a - 1,6-Didehydro Erythrine Alkaloids.

Table XLVII. Sub-type XVIII.b - 1,2-Didehydro Erythrine Alkaloids.

Table XLVIII. Sub-type XVIII.c - 1,2,6,7-Tetradehydro Erythrine Alkaloids.

Bloodroot Sanguinaria canadensis) is also mentioned as another remedy for cancer. It was used in London hospitals in the nineteenth century by a doctor who had learned of it from Indians living near Lake Superior. It was confirmed in the laboratory that alkaloids derived from bloodroot, for example, sanguarine and chel-erythrine, produced tumor reduction in mice. 

The genus Cocculus shows one of the greatest diversities in alkaloid types among the genera in the family Menispermaceae. Some one hundred and thirty-five alkaloids of thirteen different classes were isolated, with the following distribution BIQ, Bis-BIQ, PROAPO, APORPHIN, ARISTO, PROTOB, HIRSUTI, COHIRSI, MORPHIN, ERIBIDI, ERYTHRIN, PAVIN and OTHERS. 

The second type in terms of number is ERYTHRIN. Twenty-five alkaloids of this type were isolated. Of these alkaloids, nineteen were isolated from one... 

The genus Pachygone was created in 1851 by Miers (96), and currently comprises twelve species widely distributed throughout the world. From three species with phytochemical studies described in the literature, were isolated alkaloids of the types BIQ, Bis-BIQ, PROAPO, APORPHIN, PROTOB and ERYTHRIN. 

This genus Hyperbaena is mono-specific, the only species described is H. columbica, a shrub native to Cuba. From this species only four alkaloids were isolated, two ERYTHRIN (erythroculine and 3-demethoxy-2a,3a-methylenedioxyerythroculine), one PROTOB (tetrahydropalmatine) and one ERIBIDI (protostephanine). 

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