Old arsenic now laced with health benefits, says study

A brittle steel-grey element, arsenic is not very poisonous in its natural state. But the adverse properties of its compounds, or arsenicals, have been known for more than 2,000 years and made it a virtual synonym for poisoning and sudden death.

One of these compounds, white-coloured arsenic oxide, is extremely toxic and was for many centuries the murderer’s poison of choice as it was notoriously difficult to detect in corpses. Scientists only developed a reliable test in the 19th century.

Along with cyanide and strychnine, white arsenic won such a terrible reputation that in France it was dubbed ‘‘inheritance powder’’ because so many people used the tasteless and odourless substance to murder rich relatives so they would inherit sooner.

Arsenic can kill quickly if consumed in large quantities, although small long-term exposure can lead to a much slower death. In earlier centuries, symptoms of arsenic poisoning have been easily confused with those of many other illnesses.

Despite its reputation as a first-rate poison, it does have a better side and scientists have recently discovered several beneficial uses.Arsenic’s role in the treatment of disease is long and varied. Doctors have used arsenicals at various stages in history to treat sleeping sickness, tuberculosis and skin diseases, among other illnesses.

While arsenic’s use in contemporary medicine has been severely curtailed, it still plays a role in treating severe parasitic diseases. Outside medicine, it is a key component of semi-conductor devices, mainly in the form of gallium arsenide.

In the last few years, arsenic has won praise from the medical community after its trioxide, used for centuries by traditional Chinese herbalists to fight disease, was shown to have beneficial effects on certain cancers— particularly acute promyelocytic leukaemia (APL). People suffering from this blood disorder have a mutatedgene that creates a malformed protein in their bodies and interferes with the normal growth and death of certain white blood cells.

(Reuters)