Physiological Action of Tellurium

Physiological Action of Tellurium compounds in solution generally possess a "metallic" taste, but the tellurites and tellurates do not exert any very poisonous action, although human beings appear more sensitive to the compounds than dogs and are easily indisposed by small quantities. A striking effect of these compounds is the persistent garliclike odour they impart to the breath and excreta, said to be due to methyl telluride. When saliva is incubated with telluric acid and hydrazine hydrate, the colloidal tellurium formed immediately flocculates and at the same time the diastasic-like action of the saliva is destroyed. Nascent selenium produces a similar effect.

Free tellurium and insoluble tellurium compounds resist bacterial action, but the soluble tellurites and tellurates are decomposed by micro-organism growths, with development of a dark discoloration and in some cases the characteristic garlic odour. The free element in the finely divided condition, and also certain tellurium compounds, have a curative effect on the disease syphilis, although in certain cases treatment is complicated by the occurrence of undesirable reactions.

Certain tellurium derivatives of the aliphatic β-diketones, for example, cyclotelluropentane-3:5-diones of the type



where R, R', and R'' represent hydrogen or alkyl radicals, exhibit powerful bactericidal action which, however, is greatly diminished in the presence of serum. Such compounds, which are obtained by condensation of the diketone with tellurium tetrachloride in chloroform solution, have been employed successfully in the treatment of cystitis and eye infections, and may be prepared on a pharmaceutical scale.