Curare preparation

Alkaloids of Chondrodendron tomentosum. Butcher has examined a curare prepared by Indians of the Upper Amazon, in which the only plant used was Chondrodendron tomentosum, Ruiz and Pavon. From it he isolated the known alkaloids, d-tjochondrodendrine (p. 365), d-wochondro-... 

This pale-yellow quaternary alkaloid, picrate mp 189°, [a]D of chloride — 930° (in water), was first isolated from a calabash curare (12) it was subsequently isolated from other calabash curare preparations (34, 35) and has been identified chromatographically in extracts from the bark of S. mitscherlichii (33) and other Strychnos species (7). The identification of C-fluorocurarine is greatly helped by its deep-blue fluorescence in UV-light. Analyses of the crystalline iodide and anthraquinone sulfonate showed its molecular formula to be C2oH23N20+ (12), which is in agreement with all subsequent work. The properties of C-fluorocurarine, particularly its low toxicity and high Rc values, suggest that it is a C20 alkaloid rather than a double molecule. This was confirmed (102) by application of the partial quaternization method to one of its derivatives (see subsequent discussion) the method cannot be applied to C-fluorocurarine itself, since on pyrolysis it is not smoothly demethylated to the... 

Principal paralytic alkaloids present in an alternative form of curare, calabash curare, prepared from the bark of Strychnos toxifera. Used to be packed in calabashes or gourds, hence the C (for calabash) in the name. Used as an arrow poison. Actions similar to tubocurarine. 

Crum Brown and Fraser (6) in 1868 attributed curariform activity to the onium ion. Even at that early date, they suggested therapeutic possibilities of synthetic quaternary salts which could be prepared of constant purity and effectiveness. Boehm (7, 8) first showed that the active alkaloids of curare preparations are quaternary ammonium compounds. Since these discoveries, a great many quaternary compounds have been investigated, and even the simplest quaternary ammonium salts, as well as sul-fonium, phosphonium, arsonium, and stibonium salts, exhibit curare activity (9). Quaternary ammonium compounds widely varied in character have been found to exhibit curare activity. Hunt and Renshaw and collaborators (10, 11) have published a series of papers on onium compounds and their effects on the autonomic nervous system. In addition to curare action, they were shown to exhibit muscarinic and nicotinic actions in varying degrees. 

Ing and coworkers (23) used isolated sartorius nerve-muscle preparations for determination of intensity of curare preparations. They measured the... 

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.. ... 

Gill (27, 28) found that Boehm s classification became invalid shortly after his investigations, because the Indians began to use various types of containers for their preparations. Almost all curare preparations were and... 

Although alkaloids with curarizing activity usually are dimers, a monomeric alkaloid with curarizing activity, vene-curine (51), has been isolated from the curare prepared by the Hoti tribe of Venezuela (Quetin-Leclercq et al., 1989). 

Calabash curare, prepared from plants of the genus Strychnos, is packed in hollow gourds. It contains a large number of alkaloids and is extremely poisonous. The alkaloids contain an indole ring system and can be divided into 3 types the yohimbine type (e.g. mavacur-ine), the strychnine type (e.g. Wieland-Gumlich aldehyde) andthehfrindole type (e. g. calabash toxiferin-I). 

Figure 6. In a curarized preparation which blocks the early IPSP, stimulation of Lj q at 15/sec between arrows produces a late synaptic potential in L3 which in this cell reverses at -76 mV.

During their ethnobotanical researches. Prance and his coworkers (66, 171) have noted the ingredients of the curares prepared by a number of tribes about whom there has so far been little information. Two of the formulas they were able to acquire are given below. The bulleted plant names have been kindly supplied by Prof. Prance. 

Chondrodendron tomentosum Ruiz et Pavon is a large liane, up to 20 m long, with yellow green flowers its stems may be round or flat. As Table 1.2 makes clear, it is the species characteristic of curares prepared in the Montana, from the Colombia/Ecuador border region as far south as Huanuco in Peru. Interestingly, the plant has a much wider distribution (140, 234) and it has been collected in Panama, Colombia, Ecuador, Peru, and Bolivia, and in Brazil (on the Rio Jurua in the western part of the State of Amazonas). 

Seven species are known to have been used in curares prepared in the Montana as well as the northern and western Amazon regions of Brazil. 

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