Analysis of Natural Toxins

Toxins are natural venoms produced by the metabolic activities of living organisms. These compounds can be small molecules, peptides, or proteins and are capable of causing damage when introduce into the body. This definition includes a wide range of molecules with different structure and activity, such as mycotoxins, produced by fungus marine toxins, produced by dinoflagellates and venoms (peptidic toxins) secreted by some animals, such as snakes, scorpions, and bees. 

Mycotoxins are secondary metabolites of fungi, belonging essentially to the Aspergillus, Penicillium, and Fusarium genera, that can be found as food contaminants. These products are responsible for many different 

Toxin group Producer (genus) Effect Analysis Present in 

Aflatoxins Aspergillus Carcinogenic, aflatoxicosis HPLC-FLD TLC ELISA Cereals, figs, nuts, tobacco 

Citrinin Penicillium, Aspergillus, Monascus Nephrotoxic ELISA Rice 

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Gunatilaka AA. Natural products from plant-associated microorganisms distribution, structural diversity, bioactivity, and imph-cations of their occurrence. J. Nat. Prod. 2006 69 509-526. Porter JK. Ergot alkaloids and alkaloids from other endophytes, responsible for causing toxic syndrome in cattle after eating contaminated grass. Prikl. Biokhim. Mikrobiol. 1993 29 51-55. Porter JK. Analysis of endophyte toxins fescue and other grasses toxic to livestock. J. Anim. Sci. 1995 73 871-880. 

Detection of six trichothecenes DON, DAS, T-2 toxin, HT-2 toxin, neosolaniol (NSL), fusarenone-x (F-X) is shown here. This method has been used for quantitation of DON in corn, wheat, wheat bran, and mixed feeds. The precision of the method was measured by repetitive analysis of naturally contaminated samples. Recovery was measured from samples spiked with DON standards. 

Because it is only relatively recently that the chemical nature of shellfish poisons has become known, new tests that can chemically detect the toxins have also only recently been developed. The analysis of OA group toxins usually involves determination of both the free and esterified toxin, or the hydrolysis of the esterified toxins back to free toxins, and the analysis of total toxin content. When hydrolysis is completed, both free toxin and free plus esterified ( total ) toxin can be determined. In this case, the proportion of esterified toxin can be calculated by subtracting the free toxin from the total toxin result. 

Molyneux, R. J., and James, L. F. 1991a. Swainsonine, the Locoweed Toxin Analysis and Distribution. In Toxicology of Plant and Fungal Compounds-Handbook of Natural Toxins, Vol.6, Keeler, R. R, and Tu, A. T., eds. New York, Marcel Dekker. pp. 191-214. 

The detection and analysis, including quantification, of cyanobacterial toxins are essential for monitoring their occurrence in natural and controlled waters used for agricultural purposes, potable supplies, recreation and aquaculture. Risk assessment of the cyanobacterial toxins for the protection of human and animal health, and fundamental research, are also dependent on efficient methods of detection and analysis. In this article we discuss the methods developed and used to detect and analyse cyanobacterial toxins in bloom and scum material, water and animal/clinical specimens, and the progress being made in the risk assessment of the toxins. 

With the development of HPLC, a new dimension was added to the tools available for the study of natural products. HPLC is ideally suited to the analysis of non-volatile, sensitive compounds frequently found in biological systems. Unlike other available separation techniques such as TLC and electrophoresis, HPLC methods provide both qualitative and quantitative data and can be easily automated. The basis for the HPLC method for the PSP toxins was established in the late 1970 s when Buckley et al. (2) reported the post-column derivatization of the PSP toxins based on an alkaline oxidation reaction described by Bates and Rapoport (3). Based on this foundation, a series of investigations were conducted to develop a rapid, efficient HPLC method to detect the multiple toxins involved in PSP. Originally, a variety of silica-based, bonded stationary phases were utilized with a low-pressure post-column reaction system (PCRS) (4,5), Later, with improvements in toxin separation mechanisms and the utilization of a high efficiency PCRS, a... 

Williams PRD and Hammitt JK (2001) Perceived risks of conventional and organic produce pesticides, pathogens and natural toxins . Risk Analysis, 21, 319-330. 

This structure for saxitoxin (15) was presented at the first Conference on Poisonous Dinoflagellates at Boston, Mass, in November 1974 and published in the Journal of the American Chemical Society, March, 1975 (16). On the basis of this structure, Tanino et al. (17) with Kishi at Harvard University synthesized d,l-saxi-toxin and it was found active in blocking sodium channels in the same manner as natural saxitoxin. Later Bordner et al. (18) working with Rapoport confirmed our structure for saxitoxin with an X-ray analysis of saxitoxin ethyl hemiketal. 

An excellent review of methods in mycotoxin analysis was published by the FAO (29), and yearly updates on analytical methods are provided by the General Referee Report, Committee on Natural Toxins, published in the Journal of AO AC International. 

Only two reported applications of Nano-probe technology appeared in 2002. The first was a report detailing the solution of the 3D structure of small scorpion toxins present in nano-molar amounts in venom by Delepierre.216 The other report by Wang et a I.2 1 reviewed the application combined application of LC-NMR and Nano-probe technologies for the analysis of mixtures of natural products. 

Sherlock, I.R., James, K.J., Caudwell, EB., and MacKintosh, C. 1997. The first identification of microcystins in Irish lakes aided by a new derivatisation procedure for electrospray mass spectrometric analysis. Natural Toxins 5 247-254. 

A seventh novel alkaloidal toxin, pinnamine, was isolated and pnrified from the viscera of the Okinawan bivalve Pinna muricata (Takada et al. 2000). Its gross stmctnre, clarified by a detailed analysis of NMR and CD spectra, includes a 9-azabicyclo[4.2.1]nonane pharmacophoric element (Fig. 18.6A). Further synthetic studies have not only confirmed the absolute stereochemistiy of the molecule, but have also allowed stereocontrolled access to a non-natural congener, 5-epi-pinnamine, of the natural product (Kigoshi et al. 2001 Hjelmgaard et al. 2005). 

Seto, Y., Tsunoda, N., Kataoka, M., Tsuge, K., Nagano, T. (2000). Toxicological analysis of victim s blood and crime scene evidence samples in the sarin gas attack caused by the Aum Shinrikyo cult. In Natural and Selected Synthetic Toxins - Biological Implications (A.T. Tu, W. Gaffield, eds), pp. 318-32. American Chemical Society, Washington, DC. 

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