New insulinomimetic zinc(II) complexes of nicotinamide and its derivatives: X-ray structure and biochemical activity

Three Zn(II) complexes with nicotinamide(na), nicotinemethylamide(nma), and nicotineethylaniide(nea) were found to have in vitro insulinomimetic activ ities. X-ray structure analysis of [Zn(nea)(2)(H2O)(2)(SO4)], showed that e ach nitrogen atom of two nea molecules locates trans, and the two water mol ecules and each oxygen atom of the two sulfates coordinate to a Zn(II) ion, forming an octahedral geometry of Zn(N2O4) unit in an inorganic polymer cr ystal. The Zn(II) complexes with na, nma, and nea exhibited higher insulino mimetic activities, respective IC50 values (50% inhibition concentration of the complex in the free fatty acids release from rat adipocytes) being 1.3 4, 1.12, and 0.96 mM, than that of ZnSO4 (IC50 = 1.52 mM).