Genus erythrina

The beanlike seeds of the trees and shrubs of the genus Erythrina, a member of the legume family, contain substances that possess curare-like activity. The plants are widely distributed in the tropical and subtropical areas of the American continent, Asia, Africa, and Australia, but apparently they are not used by the natives in the preparation of arrow poisons. Of 105 known species, the seeds from more than 50 have been tested, and all were found to contain alkaloids with curariform properties. Erythroidine, from E. americana, was the first crystalline alkaloid of the group to be isolated. It consists of at least two isomeric alkaloids, a and P-erythroidine both are dextrorotatory. Most experimental and clinical study has centered on the b form because it is more readily obtainable in pure state. P-Erythroidine is a tertiary nitrogenous base. Several hydrogenated derivatives of p-erythroidine have been prepared of these, dihydro-P-erythroidine has been studied most carefully and subjected to clinical trial. Conversion of P-erythroidine into the quaternary metho salt (p-erythroidine methiodide) does not enhance, but rather almost entirely, abolishes its curariform activity this constitutes a notable exception to the rule that conversion of many alkaloids into quaternary metho salts results in the appearance of curare-like action. 

BIOACTIVE NON-ALKALOIDAL CONSTITUENTS FROM THE GENUS ERYTHRINA... 

The genus Erythrina comprises around one hundred and ten species of orange oi red flowered trees, shrubs and herbaceous plants. It is divided into five sub-genera and twenty-six sections, largely on the basis of morphology, especially the colour and shapes of the flowers and fruits and of inflorescence characteristics. They are found throughout the tropical and semi-tropical... 

Seven stilbenoids have, so far, been reported from the genus Erythrina, namely oxyrcsveratrol [62-63J, dihydrooxyresveratrol [62], burttinol D [64], latissimbenzofuran [24,65], bidwillol B [11], eryepogin F [29] and eryvarinL [30]. 

Isoflavones form the largest class of metabolites ever reported from the genus Erythrina with pterocarpans trailing close at second. They however form the second largest class of bioactive compounds from the genus after the pterocarpans. This class shows the widest diversity of activity among all reported bioactive compounds. 

Table 15 Anti-MRSA Activity of Pterocarpans from the Genus Erythrina...

The survey revealed that the genus Erythrina was very rich in secondary metabolites particularly of the flavonoids class. The bioactivity profile represented the various classes fairly reasonably but it became apparent that a number of these isolates have not yet been tested for biological activity. The challenge remains for researchers to carry more work on these to fill in the knowledge gaps that still exist. 

Folkers K, Unna K (1938) Erythrina Alkaloids, n. A Review, and New Data on the Alkaloids of Species of the Genus Erythrina. J Am Pharm Assoc 27 693... 

Neill, D. The genus Erythrina taxonomy, distribution and ecological differentiation. In Erythrina in the New and Old Worlds Westley, S. B. Powell, M. H. Nitrogen Fixing Tree Research Reports, 1993, Special issue, 15-25. 

Erythrina alkaloids isoquinoline alkaloids, usually tetracyclic, found exclusively in the legume genus Erythrina. 

From Erythrina crystagalli cv. Maruba deiko, erythraline, erythrinine, and ery-thratine were isolated (77). Examination by TLC demonstrated that these alkaloids are present in all heartwood, bark, and roots. Many other Erythrina alkaloids have been isolated from plants of the genus Erythrina (Leguminosae), but most have been obtained from leaves and fruits. 

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