Melatonin scavenges phenylglyoxylic ketyl radicals.
The antioxidant properties of melatonin were tested in this work by EPR technique. It was found that melatonin scavenges phenylglyoxylic ketyl radicals. Its effectiveness was 10-times lower than that of vitamin C. A new method of generation of phenylglyoxylic ketyl radicals by spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propan-2-ol was used.
Sono-photolysis of phenylglyoxylic acid and stability studies of d,l-2,3-diphenyltartaric acid
Abstract Photodecarboxylation and photoreduction of phenylglyoxylic acid as well as the influence of ultrasound on these reactions were studied. Ultrasound considerably enhanced photodecarboxylation of phenylglyoxylic acid in acetonitrile with low content of water (CH 3 CN–H 2 O, 0.5%, v/v). No ultrasound effect was observed at higher content of water. Photoreduction of phenylglyoxylic acid resulted in formation of isomers of 2,3-diphenyltartaric acid. We found out that photosonication had no influence on the rate of formation of 2,3-diphenyltartaric acids but affected only the ratio of d , l and meso isomers of this acid. The thermal instability of 2,3-diphenyltartaric acids can affect the course of photoreduction of phenylglyoxylic acid. Phenylglyoxylic and benzoic acids were the main products after the thermal decomposition of d , l -2,3-diphenyltartaric acid in 2-propanol. The rate of decomposition of d , l -2,3-diphenyltartaric acid was very sensitive to its concentration, temperature and a presence of oxygen as well as water in the reaction mixture. Sonication caused a large decrease of the rate of decomposition of d , l -2,3-diphenyltartaric acid.
THE IRON-ACETOCARMINE METHOD OF FIXING AND STAINING CHROMOSOMES
A short description of this procedure was given in Vol. 55 of the American Naturalist, pp. 573â€”574. The method has now been used almost daily for five years, and certain improvements have suggested themselves. The solution can be prepared by mixing about equal volumes of glacial acetic acid and water. To this is added powdered carmine in excess. The liquid is then â€ ? just brought to boil, cooled, and decanted. To the red solution there are then added a few drops of a solution of ferric hydrate in 50 per cent. acetic acid, to act as a mordant. The amount of iron varies with different objects. Too much produces a precipitate in a short time. The more