Tube curare, alkaloids

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. 

These results seemed to establish with certainty that the active component of tube curare is derived from Chondrodendron tomentosum, but the matter again became doubtful when King reported that in the stems of a carefully authenticated specimen of the plant, collected at Tarapoto in Peru, he had found 1-curine and Z-tubocurarine chloride. This is the first recorded natural occurrence of the latter and seems to indicate either that the alkaloidal components of the plant are not constant in character, or that the botanical description of Chondrodendron tomentosum covers two species containing the dextro- and Icevo- quaternary alkaloids respectively. 

The bisbenzylisoquinolines have been the subject of many pharmacological studies, motivated originally by the knowledge that quaternary alkaloids of this type are the active constituents of tube curare. Certain nonquaternary bisbenzylisoquinolines, notably belonging to the curine group, are also smooth muscle re-laxants many bisbenzylisoquinolines are hypotensive, and a few possess anti-... 

The active principles of curare were early recognized to be water-soluble quaternary alkaloids. Tube-curare was studied by King, who isolated (3) the crystalline quaternary bisbenzylisoquinoline alkaloid, d-tubocurarine (I), in 1935. The main plant constituent of tube-curare is the bark of menispermaceous plants, particularly of the genus Chondro-dendron, and d-tubocurarine was later isolated (4) from C. tomentosum. Further work led to the isolation and structural elucidation of many more bisbenzylisoquinoline alkaloids from these sources (5). 

The development and use of muscle relaxants, to allow a reduction in the level of anesthesia during surgery, follows entirely from studies of South American arrow poisons (44)and particularly from the isolation by King (45) of pure D-tubocurarine (29) in the 1930s, from tube curare. Another of the South American blowpipe poisons, calabash curare, was used for similar purposes and developed (46,47), to give alcuronium (30) from the alkaloid C-toxiferine 1 (31). Both types of curare paralyze skeletal muscle by a similar mechanism, antagonizing the effect of acetylcholine at the neuromuscular junction (48). 

Plant extract used by South American Indians to prepare poison arrows. Sold with different names (e.g. Tube-curare) depending on the container used for packaging. Toxicologically active principle is the alkaloid tubocurarine chloride. Muscle relaxant, toxic by respiratory paralysis and hypotension competitive blocker ACh receptor in muscle. 

A considerable amount of information had been accumulated on curare, the South American arrow poisons, before 1900. The results of the early work were very inaccurate because of the complexity and variation of the composition of the mixtures of alkaloids involved. Boehm (7, 8) distinguished the types of curare preparations by the type of container in which they were packed. They were (a) para, tube, or bamboo curare, packed in bamboo tubes (b) pot curare, exported in small earthenware pots and (c) gourd or calabash curare, packed in small gourds. Boehm prepared active curarizing samples from these materials, tubocurarine from tube curare, protocurarine from pot curare, and curarine from gourd curare. These were impure, non-crystalline alkaloids which, for the most part, were quaternary ammonium compounds. The curarine of Boehm is the material used in much of the early experimental work.. ... 

In 1935, King (55) isolated a pure alkaloid, which he named d-tubocurarine, from a tube curare of unknown botanical origin. The word "tube" refers to the container in which the South American natives transported their plant extract. It was almost 10 years later that the botanical source for d-tubocurarine was clearly identified as Chondodendron tomentosum. The structure that King assigned to tubocurarine possessed two nitrogen atoms, both of which were quaternary ammonium salts (e.g., a b/s-quaternary ammonium compound). It was not until 1970 that the... 

So-called tube curares (because they are stored in bamboo tubes) often are prepared from the menispermaceous plant Chondrodendron tomentosum. These extracts are prepared and used in localized areas of the upper Amazon and Colombia. Most of the active alkaloids are bisbenzylisoquinoline alkaloids. The major alkaloid is tubocurarine (97), a quaternary species. 

Pot and tube curare are raAer sin ar, and not highly poisonous. They are prepared from plants of the genus Chonodendron and are stored in clay pots or bamboo tubes. The alkaloids arc isoquinolines, the most important being the quaternary bisbenzyl-iso-quinoline, tubocurarine. 

Alkaloids of Paka, Tube, ok Bamboo Curare, From this variety. 

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