Bebeerine alkaloids

Bebeerine and its allies (p. 363) are also derived from menispermaceous plants, but as their botanical source needs attention in some detail, and in view of their importance as close associates of the curare alkaloids, they are dealt with separately at the end of this section. 

Bebeerine, CjjHjgOjNj. This alkaloid has been described imder various names, pelosine, chondrodendrine, chondodendrine and curine (Z-form) whose origin is described elsewhere (pp. 363 and 374). It crystallises with one molecule of benzene, m.p. 161°, or 213° (solvent-free) or from methyl alcohol, m.p. 214°, and has [ajn 298° (EtOH) for the d- or Z-form (Scholtz ). Spath et recorded m.p. 221-221-5° (vac.) for both forms and + 332° and — 328° for the d- and Z-forms, in pyridine. 

It was clearly established by Scholtz that the empirical formula, CjgHjjOaN, represented the composition of bebeerine, that on this basis the alkaloid contained one hydroxyl, one methoxyl and one methylimino group and that its behaviour with acylating agents indicated the presence of a methyltetrahydroisoquinoline nucleus. These results were confirmed... 

These results show that bebeerine is represented by (I Rj = R3 = H and Rj = R = Me). See also curine (Z-bebeerine), dealt with as a curare alkaloid (p. 374). 

Para, Tube or Bamboo Curare. This variety was packed in sections of bamboo, but this almost traditional information needs modification since tube curare became a commercial article. It is now a viscous, solid or even powdered extract, exported in sealed tins. In view of the relationship established between bebeerine, curine, and tubocurarhie, the active alkaloid of this variety of curare, the suggestion was made, first by Spath, Leithe and Ladeck, and more definitely by King that its botanical source should be sought among the Brazilian Menispermaceae, and as shown later the search for the source of the d-tubocurarine found in this variety of curare has been narrowed down to Chondrodendron tomentosum, or possibly a closely related species liable to be confused with it. 

Alkaloids of the Menispermaceae Coclaurine, Dauricine, Magnoline, Tetrandrine, Bebeerine, etc.. ... 

The alkaloid content of curare is from 4% to 7%. The most important constituent in menispermaceous curare is the bis-benzyltetrahydroisoquinoline alkaloid (+)-tubocurarine (Figure 6.48). This is a monoquaternary ammonium salt, and is water soluble. Other main alkaloids include non-quaternary dimeric structures, e.g. isochondrodendrine and curine (bebeerine) (Figure 6.48), which appear to be derived from two molecules of (R)-N-methylcoclaurine, with the former also displaying a different coupling mode. The constituents in loganiaceous curare (from calabash curare, i.e. Strychnos toxifera) are even more complex, and a series of 12 quaternary dimeric strychnine-like alkaloids has been identified, e.g. C-toxiferine (toxiferine-1) (see page 359). 

Curine d-Chond(r)odendrine, rf-bebeerine, aristolochine fC36 alkaloid) 436-05-5 X... 

The investigations resulting in the elucidation of the constitution of these alkaloids were reviewed previously (1, 2). The absolute configuration of the alkaloids was determined in 1962 by comparison of their cleavage products wdth specimens of known absolute configuration (9) (Section I). Bebeerine and curine were found to have structures iS -CXX and R -CXXI, respectively. In d-chondrocurine (GXXII) and tubo-curarine (CXXIV) the configuration at C-1 is S and R at C-1. ... 

Thirdly, if the bimolecular dehydrogenation of II takes place between the 12-hydroxyl and 8 -hydrogen on the one hand and between the 7-hydroxyl and the ll -hydrogen on the other the structure XXIV is formed. To this class belong the alkaloids bebeerine, chondrofoline, curine, tubo-curarine chloride, and chondocurine. 

In 1843 Maclagen (56) found two compounds of basic nature in Nectan-dra roots from British Guiana. One of these, an amorphous yellow powder, he named bebeerine (bebirine). Some time later a yellow powder was isolated from Buxus sempervirens L., whose fibers and leaves were used as a remedy for intermittant fever. This powder which was named buxin proved to be identical with bebeerine. Finally, the alkaloid known as pelosine which occurs in the roots of Cissampelos pareira L. and Radix pareira bravae was found to be identical with bebeerine (56, 59). Bebeerine also occurs in Chondodendron platyphyllum, Ch. microphyllum, Abula candicans Rich. Ch. candicans Sandwith) (68), and Pleogyne cunninghamii (136), as well as in the commerical powder known as bebeerum purum. 

In 1936 Faltis and coworkers (67, 69) pointed out that the name bebeerine was not a desirable one because the original source of this alkaloid, the commercial powder bebeerum purum, was actually a preparation of Chondodendron species. They therefore renamed the alkaloid chondodendrine. However, other workers (68, 76, 77) adhered to the older name. 

The physiological action of dextro, levo, and racemic forms of bebeerine has been studied (61, 62). Injections of solutions of their salts into animals brought results dependent upon the animal and upon the rotation of the alkaloid. The dextro form was found to be much more toxic to rabbits, cats, and white mice than the other forms, while in dogs it had little effect. 

Of the three alkaloids d-tubocurarine chloride, bebeerine, and curine (74, 76, 78, 80) the first has the strongest curarizing action. d-Tubocura-rine chloride produces complete paralysis of the frog when doses of 0.5 mg. per kilogram are administered (76). It seems to cause typical respiratory paralysis in mammals. LTubocurarine chloride is many times weaker in curariform activity than its enantiomorph d-tubocurarine chloride (123). 

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