Picolinic acid is a pyridine compound with a carboxyl side chain at the 2-position. It is an isomer of nicotinic acid, which has the carboxyl side chain at the 3-position. It is a catabolite of the amino acid tryptophan. Picolinic acid acts as a chelating agent of elements such as chromium, zinc, manganese, copper, iron, and molybdenum in the human body. It is involved in phenylalanine, tryptophan, and alkaloid production,[citation needed] and for the quantitative detection of calcium.The acid is believed to form a complex with zinc that may facilitate the passage of zinc through the gastrointestinal wall and into the circulatory system. A study of rats found that dietary picolinic acid increases the turnover and excretion of zinc. Other results suggest that picolinic acid is a chelator which interacts with metals aside from zinc.
-K668.gif)