Tapioca Plant Holds Hope For Cancer Sufferers

London : The humble tapioca plant contains chemicals that may hold a hope for cancer sufferers according to research done at Newcastle University and in Spain.

The tapioca (cassava) plant provides sustenance for some 500 million people in the developing world, but it is neglected in the west as a possible plant for research because of its low level of use in food item except as the dreaded pudding at public school dinners.

Now genetic science research at Newcastle and in Madrid have shown that a chemical used by the plant to deter grazing animals from nipping it in the bud may also act as destroyer of cancer cells.

Many people in developing countries have been inadvertently crippled by the plant because of improper processing of the tapioca plant.

These people have been poisoned by cyanide produced by the plant in a chemical, and an enzyme, linamarase - both of which it produces.

The chemical linamarin produces hydrogen cyanide when it is broken down by the plant’s linamarase enzyme which is released when the plant is attacked by a grazing animal or human.

Scientists at Newcastle have seen a way of harnessing this destructive power of cyanide in cancer patients where it can be used to destroy some forms of cancer cells.

This may be done by transferring genetic material from the tapioca plant to a virus and introducing it into cancer cells which have been impregnated with linamarin.

Researchers in a collaborating group in Madrid have been able to eradicate completely a brain tumour in a rat after one week by release of small doses of cyanide caused by the breakdown of linamarin by linamarase.

The Madrid group used a modified gene isolated from cassava in Newcastle and transferred it to a retrovirus,giving it the ability to manufacture linamarase.

One promising feature noticed by the team is what they call the "bystander effect" where release of cyanide in one cell also tends to destroy neighbouring cells.

Report from Newcastle University says that there has been promising results for certain types of tumour in further research using human tissue samples.

Professor Monica Hughes, the geneticist at Newcastle Universitywhose work on cassava cyanogenesis (the origin of the chemical cyanide) has been the foundation stone of this technique plants to develop this cancer project further.

Her initial research to find a way of reducing the toxicity of the cassava (tapioca) plant led to success in cloning some of the genes responsible for the cyanogenesis.

On the cancer project, she says: " My next step would be to modify the genetic material with a view to making the treatment more effective when applied to mammalian cells. I believe it would be possible to obtain higher yields of active linamarase, for example."

In another research involving plant at the Medical school of Newcastle University,scientists have been able to isolate a gene responsible for the iron content of plants.

Iron deficiency - as distinct from hunger – is one of the world’s most common malnutrition problem, a problem found even among the well-fed, and affects an estimated 3.7 billion people according to estimated by the world Health Organisation (WHO).

The gene – called FRO2 – was isolated at the Medical School working with Dartmouth College in the United States.

Leader of the Newcastle research team,Professor Nigel Robinson is optimistic about the far-reaching benefits of this identification of the iron absorbing gene in the plant Arabidopsis, or Thale cress a European weed noted for its efficiency in extracting iron from soil.

The problem with iron absorption by plants is that many plant do not produce enough reductase, an enzyme which cannot be absorbed by plant to a ferrous from, which is an essential nutrient.

FRO2 enable the plant to produce the required which will enable it to extract iron even from poor soil which contain large amount of ferric nutrient.

Plant-absorbable ferrous iron cannot be supplied through fertilisers because it rapidly degrades to ferric iron when exposed to air and moisture.

Scientists working on this project are now hoping to increase a plant’s capacity to produce reductase - and therefore able to produce reductase - and therefore able to survive in poor soils and accumulate greter concentration of iron - by manipulating the FRO2 gene to aid selective breeding.

Professor Robinson believes that with further research on FRO2 and several closely – related gene, crops may be manipulated into producing high concentration of iron in part eaten by humans,such as leaves or fruits.

Another fruit of this research may be the discovery of other genes responsible for the uptake of other metals such as copper by plants for use in the "greening" of the earth.

This technique,called phytoremediation, involves the growing of plant on industrial wasteland to absorb - and remove-waste metal from the ground.

This approach to pollutant removal by plant absorption is already widely used in the US.

Source : Wan A. Hulaimi, The New Sabah Times, 26/4/1999