Potato glycoalkaloids: true safety or false sense of security?

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Abstract

As one of the major agricultural crops, the cultivated potato is consumed each day by millions of people from diverse cultural backgrounds. A product of global importance, the potato tuber contains toxic glycoalkaloids (GAs) that cause sporadic outbreaks of poisoning in humans, as well as many livestock deaths. This article will discuss some aspects of the potato GAs, including their toxic effects and risk factors, methods of detection of GAs and biotechnological aspects of potato breeding. An attempt has been made to answer a question of vital importance – are potato GAs dangerous to humans and animals and, if so, to what extent?

Section snippets

Potato GAs and health

During the past two decades, the toxic effects of GAs have gained increasing interest. The toxicity data from in vitro and animal studies indicate that chaconine is the most toxic alkaloid of the potato GAs [1]. It is teratogenic, exhibiting strong lytic properties and inhibiting acetylcholinesterase (AChE) and butyrylcholinesterase activities [6]. At lower doses, the toxicity of GAs in humans causes mainly gastrointestinal disturbances such as vomiting, diarrhea and abdominal pain. However, at

Determination of potato GA levels in foodstuffs and biological fluids

The existing methodologies for GA detection have already been reviewed and critically evaluated [1], so our discussion will focus on the methods that have been developed recently in our laboratory.

A new method for the detection of solanaceous GAs, based on pH-sensitive field-effect transistors and platinum interdigitated planar electrodes as transducers, coupled to butyrylcholinesterase, has been developed recently 14, 15 (Y.I. Korpan et al., unpublished). It has been shown that α-solanine,

Biotechnological aspects of potato breeding

Market standards either specify or restrict the selection of the variety of potatoes to be grown, although many of these varieties have limitations. Therefore, the problem of breeding and evaluating new varieties is of great importance. In addition, new lines of potato must meet or exceed the market quality standards. They should have host-plant resistance to Colorado potato beetle, late blight, verticillium wilt, viruses and storage diseases, as well as a low content of GAs and glucose. The GA

Concluding remarks

An analysis of the literature proves that GAs, the natural components of potato, clearly are toxic to both humans and animals. The concentration of GAs in potatoes destined for human consumption in many countries, 200 mg kg−1 – which is generally accepted as a ‘total alkaloid taste standard’ – has a ‘zero’ safety threshold. One reason for this conclusion is best stated by the words of Parnell et al. [25], in a paper published 20 years ago: ‘Many authors have assumed without further evidence

Acknowledgements

We thank NATO (Grant # LST.CLG.977342) and INTAS (Grant # 00–00151) for funding the experimental research in this field.

Glossary

Glossary

Chitinase:
an enzyme that breaks down chitin, which is a polysaccharide that forms the hard outer shell of arthropods (e.g. insects, spiders and crustaceans) and the cell walls of fungi and some algae.
Chloropropane:
ethyl chloride.
Cytotoxic:
chemicals that are directly toxic to cells, preventing their reproduction or growth. Cytotoxic agents can, as a side effect, damage healthy, non-cancerous tissues or organs that contain a high proportion of actively dividing cells, for example, bone marrow and

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