Ricin sources

Toxins are any poisonous substances that can be produced by an animal, plant, or microbe. Because of their complexity, most toxins are difficult to synthesize in large quantities by traditional chemical means. However, they may be harvested from cultured sources or produced by genetically engineered microbes. Toxins are odorless, tasteless, and nonvolatile. Ricin (C16-A036) and saxitoxin (C16-A018) are the only toxins listed in the Chemical Weapons Convention (Schedule 1). 

Almost all Schedule 1 chemicals are soluble in the organic NMR solvents used in verification (see Section 3.1) and can be analyzed by NMR spectroscopy. Saxitoxin (1.A.7) and ricin (1.A.8) differ from the others. Both are derived from natural sources - the former is a paralytic shellfish poison and the latter, a glycoprotein toxin (40). Analytical methods (ROPs) have not been established for either chemical. NMR data... 

The presence of the hydroxy group on ricinoleate (12-hydroxy oleate) underlies many industrial uses, such as the manufacture of lithium grease, plastics, paints, coatings, and cosmetics. Castor oil contains 90% of its fatty acids (FA) as ricinoleate (Achaya et al., 1964) and is the only commercial source of ricinoleate. Since the castor bean contains the toxin ricin and potent allergens, it... 

Chemicals come in all shapes and sizes and derive from a variety of sources. While to many people the words chemical and indeed poison are synonymous with man-made things such as dioxin, organo-phosphates, pesticides, and nerve gas, there are many, many other chemicals that occur naturally These may be produced by plants, for example belladonna in deadly nightshade, and ricin in the castor bean, or bacteria, for example botulinum toxin. Various animals such as snakes and spiders produce toxic venoms, and some poisons occur naturally in the ground, like asbestos, cadmium, and lead. 

Waller, G.R., Negi, S.S. (1958). Isolation of ricin, ricinine, and the allergenic fraction from castor seed pomace from two different sources. J. Am. Oil Chem. Soc. 35 409-12. 

Abrin is a plant source Type 2 RIP. It is found in Abrus precatorius (rosary pea, Indian licorice, jequirity bean). The toxicology of abrin is considered to be very similar to ricin. A similar Abrus toxin is pulchellin, produced by A. pul-chellus (Millard and LeClaire, 2008). The rosary pea has been reported to be more toxic than castor beans (Griffiths et al, 1994). Species sensitivity is variable and horses are considered to be the most sensitive. The mature goat is considered to be a more resistant species and 2 g of seed/kg body weight is reported as a lethal dose. The lethal dose for cattle is reported at 600 mg of seed/kg body weight. It is likely that abrin is denatured in the rumen (Burrows and Tyrl, 2001). 

As an additional source of complexity, the ricin gene is part of a multigene family within the castor bean plant that encodes for the production of pro-ricin (the natural ricin precursor), several apparently inactive polypeptides, and a well-studied, structurally related lectin called R. communis agglutinin I (RCA120) (Tregear and Roberts, 1992 Pinkerton et al., 1999 Helmy and Pieroni, 2000). 

Parker, D.T., Parker, A.C. and Ramachandran, C.K. (1996) Ricin. Joint CB Technical Data Source Book Toxin Agents. U.S. Army Dugway Proving Ground, Utah, Joint Contact Point Directorate. 

The discovery of ricin in the Senate in Washington in 2004, at a Paris railway station in 2003 plus the finding in Afghanistan by a journalist, of a description of ricin purification, demonstrate the reality of its perceived potential as a chemical weapon. The suitability of ricin for this purpose derives from its extreme toxicity to mammalian cells, the fact that the source is naturally... 

Naturally occurring poisons which are also more potent than the nerve gases are found in such sources as snake venoms, among the substances known as arrow poisons, and among toxic proteins found naturally, such as ricin, the toxic protein of the castor bean, and the bacterial toxins, such as tetanus toxin and botulinum toxin. Few of these highly toxic substances appear at present to be useful per se as chemical warfare agents, but intensive research on any of them may well lead the chemist to new toxic substances with military practicality. 

Source Ler, S.G., Lee, F.K., Gopalakrishnakone, P. (2006) Trends in detection of warfare agents detection methods for ricin, staphylococcal enterotoxin B and T-2 toxin. Journal of Chromatography A, 1133,1-12. 

FIGURE 20.9 Protein structure of ricin determined by X-ray crystallography. Source E. Rutenber, et al. (1991) Crystallographic refinement of ricin to 2.5 A. Proteins, 10, 240-250. 

FIGURE 27.5 Biosynthesis of the ricin toxin. Source Rlustration taken from EHSO (2014). 

FIGURE 27.6 Example of the cellular internalization of ricin. The process involves endocytosis by coated pits and vesicles (A) or smooth pits and vesicles, followed by vesicle-endosome fusion (B). Ridn molecules can then return to the cell surface by exocytosis, or the vesicles may fuse to lysosomes for toxin destruction. Source Mustmtions taken from Audi et al. (2005). 

Ricin is derived from a common plant, the castor bean (Ricinus communis), and is native to the Mediterranean and Middle East and cultivated elsewhere as an ornamental plant. It is also the source of castor oil, which has many uses in medicine, food, and industry. Ricin is also a highly potent toxin that can kill a person in amounts as small as a few grains of sand. 

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