Reversal of fungitoxicity of 8-quinolinols and their copper(II) bischelates. II. Reversal of the action of 8-quinolinol by DL-alpha-lipoic acid.

The effect of amino acids and derivatives, Krebs cycle acids and related compounds, fatty acids, and vitamins and related compounds on the toxicity of 8-quinolinol and bis(8-quinolinolato)copper(II) to Aspergillus oryzae (ATCC 1011) was studied. Only aliphatic thiol-containing compounds (cysteine, glutathione, dithioerythritol, and dithiothreitol) and DL-alpha-lipoic acid protected against 8-quinolinol but not its copper(II) bischelate. It is suggested that 8-quinolinol inhibits lipoic acid biosynthesis, and the mode of fungitoxicity of 8-quinolinol is different from that of bis(8-quinolinolato)copper(II).

Preventive effect of diethyldithiocarbamate on experimental diabetes produced by dithisone and 8-oxychinoline.

Diethyldithiocarbamate sodium (DDC)--a compound forming complexes with metal ions-did not change the structure of endocrine pancreas and did not affect the glycemia after the repeated administration of a dose of 250 mg kg-1 while a single dose of 500 or 1000 mg kg-1 increased the glycemia for 2 to 4 h in most of rabbits tested. DDC injected in similar doses prevented a diabetogenic action of dithisone and of a number of 8-oxichinoline derivatives. This effect appeared very rapidly and persisted for several hours being dependent on a dose of DDC and on the interval between its administration and the injection of diabetogenic compounds. It was concluded that DDC forms stable complexes with zinc ions in pancreatic beta-cells which appear to be resistant towards the action of diabetogenic compounds directed selectively to the blocking of zinc ions too and thus to the development of experimental diabetes.