Occurrence and isolation

Toxic principles are quite common in the family Liliaceae. The better knovm poisonous genera include Rhodea of the subtribe Aspidistrinae, Urginea, Scilla, Muscari, Camassia, and Omithogalum of the subfamily 

PLANT MATERIALS EBBONEOtrSLY BEPOBTED TO CONTAIN COLCHICINE 

Plant Reference reporting presence of colchicine Reference containing evidence refuting original claiin 

It is a relatively recent observation that Colchicum species contain numerous chemical constituents of diverse chemical properties. Recognition of this fact has led to more efficient methods of isolation. In addition to neutral, phenolic, and basic alkaloids, 0. autumnale contains fatlike substances which are removed by a preliminary ligroin extraction of the pulverized, dry material. From such an extraction of the flowers of C. autumnale, Santavy and Herout (293) have isolated a paraffin, Ca7-28H5g 58, m.p. 58-60° an alcohol, CaaH450H, m.p. 66-67° and a phytosterol, m.p. 139-140°. Benzoic, salicylic, and 2-hydroxy-6-methoxybenzoic acids may be separated from the alkaloid mixture by virtue of their solubility in ether and aqueous base (294). The alkaloids themselves may be separated into neutral, phenolic, or basic fractions by standard extraction techniques. Pure alkaloids may be obtained from each fraction by fractional crystallization and chromatography on 

Twenty kflograms of finely powdered, dry conns of C. autumncde were extracted first at room temperature and then at higher temperatures (max. 70°). A total of 60 1. of ethanol was used in the series of extractions. The extract was concentrated on a water bath and finally under reduced pressure at 100°. The oily concentrate was diluted to a volume of 4 1. with water and washed four times with 2-1. portions of ether. The ether extract was washed with 300-ml. portions of water, 3% hydrochlorie acid, water, 4% sodium carbonate, and finally with two 300-ml. portions of water. The aqueous solution was acidified with hydrochloric acid to pH 2-3 and extracted six times with 500-ml. portions of chloroform. Concentration of the chloroform extract afforded 48 g. of neutral and phenolic, chloroform-soluble materials. The aqueous solution was basified with ammonium hydroxide and extracted fom times with SOO-ml. portions of chloroform to yield 14.4 g. of basic, chloroform-soluble substances. The remaining aqueous solution was neutralized to pH 7 with hydrochloric acid (cooling) and concentrated to a volume of 1 1. Five extractions of this concentrate with 500-ml. portions of chloroform-ethanol (2 1) afforded 4.5 g. of material, probably of glycosidic nature. 

The occurrence of paralytic shellfish poisons was once considered to be a problem confined mostly to northern temperate waters. It is now found widespread in both northern and southern hemispheres including subtropical to tropical waters (7P). 

Saxitoxin (1) was the first toxin brought to a pure form (20). The purification procedure was based upon the toxin s ability to bind tightly to weakly acidic resins. A single chromatography on a carboxylate resin such as Amberlite IRC-50 was capable of raising the specific toxicity of the extract several hundred times. Repeated chromatography on carboxylate resins and subsequent chromatography on acidic alumina afforded pure saxitoxin as an amorphous dihydrochloride. 

To date twelve toxins including saxitoxin have been isolated from various sources. The isolated toxins and their chromatographic and electrophoretic behavior are summarized in Table 1. Those toxins whose origins were identified as Gonyaulax spp. were named serially gonyautoxin-I — -VIII (abbreviated GTX-I — -VIII or GTX — GTXg). Neosaxitoxin 

Toxin Rf a b phoresis Rm Major Sources References for First Reports 

Neosaxitoxin (2) 0.70 0.54 7 Gonyaulax spp. Aphanizomenon flos-aquae shellfish, crabs, etc. (26) 

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