Synthesis of Selenium(0) and Zinc(II) Biomolecules in Nano-Structured Forms as New Antioxidant Agents: Chemical and Biological Studies

Abstract

In this paper, two new complexes of selenium caffeine, [Se(Caf)₄], and zinc α-tocopherol, [Zn(α-Tpl)₂(NO₃)₂], are synthesized. The structures of complexes are characterized by IR, Raman and ¹H NMR spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and thermogravimetric (TG/DTG) analysis. According to conductivity measurements the complexes are non-electrolytes. Spectroscopic studies of Se⁰ caffeine complex indicate its monodentate coordination via nitrogen atom N⁹ at 1: 4 molar ratio metal-to-ligand. In [Zn(α-Tpl)₂(NO₃)₂], α-Tpl chelate is coordinated as a monodentate ligand via oxygen atom of the hydroxyl group with 1: 2 metal-to-ligand molar ratio. The percentage scavenging activity of hydroxyl radical (IC₅₀ = 0.21 and 0.32 µg/mL), DPPH (0.17 and 0.30 µg/mL) and superoxide anion scavenging activity (0.18 and 0.32 µg/mL) indicate that selenocaffeine complex is of higher potential antioxidant activity than zinc(II) α-tocopherol complex.