Low-molecular-weight chromium-binding substance and biomimetic [Cr3O(O2CCH2CH3)(H2O)(3)](+) do not cleave DNA under physiologically-relevant conditions

Chromium(III) tris(picolinate), Cr(pic)(3), is currently a very popular nut ritional supplement; however, at physiologically-relevant concentrations, i t has recently been demonstrated to cleave DNA [J.K, Speetjens, R.A. Collin s, J.B. Vincent, S.A. Woski, Chem. Res. Toxicol. 12 (1999) 483]. A number o f other chromium-containing compounds have been proposed as substitutes for Cr(pic)(3). Of particular interest are low-molecular-weight chromium-bindi ng substance (LMWCr) and [Cr3O(O2CCH2CH3)(6)(H2O)(3)](+) 1. The former comp ound has recently been identified as the biologically active form of chromi um in mammals, activating the kinase activity of insulin receptor in the pr esence of insulin. Complex 1 is a functional biomimetic for LMWCr. Both com pounds have been proposed as possible nutritional supplements and therapeut ics for adult-onset diabetes. This work demonstrates that these complexes, unlike Cr(pic)(3), are poor DNA-cleaving agents and may represent safer mat erials for human consumption. (C) 1999 Elsevier Science Ltd. All rights res erved.