Chemical properties and biotoxicity of several chromium picolinate derivatives

As a man-made additive, chromium picolinate Cr(pic) 3 has become a popular dietary supplement worldwide. In this paper Cr(pic) 3 and its new derivatives Cr(6-CH 3 -pic) 3 ( 1 ), [Cr(6-NH 2 -pic) 2 (H 2 O) 2 ]NO 3 ( 2 ) and Cr(3-NH 2 -pic) 3 ( 3 ) were synthesized, and complexes 1 and 2 were characterized by X-ray crystal structure (where pic   =   2-carboxypyridine). The relationship between the chemical properties and biotoxicity of these complexes was fully discussed: (1) The dynamics stability of chromium picolinate complexes mainly depends on the Cr N bonds length. (2) There is a positive correlation between the dynamics stability, electrochemical potentials and generation of reactive oxygen species through Fenton-like reaction. (3) However, no biological toxicity was observed through MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and sub-chronic oral toxicity study for these chromium picolinate compounds. Together, our findings establish a framework for understanding the structure-property-toxicity relationships of the chromium picolinate complexes.