Fe(III) and Cu(II) Complexes of Chlorogenic Acid: Spectroscopic, Thermal, Anti-/Pro-Oxidant, and Cytotoxic Studies

• Published in: Materials Vol. 15; no. 19; p. 6832
• Main Authors: Kalinowska, Monika, Gryko, Kamila, Gołębiewska, Ewelina, Świderski, Grzegorz, Lewandowska, Hanna, Pruszyński, Marek, Zawadzka, Małgorzata, Kozłowski, Maciej, Sienkiewicz-Gromiuk, Justyna, Lewandowski, Włodzimierz
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.10.2022; MDPI
• Subjects: Acids; antioxidant activity; Antioxidants; Aqueous solutions; Bioavailability; caffeoylquinic acid; Cancer; Catechol; Chelating agents; Chlorogenic acid; Coffee; Coordination compounds; Copper; Food; Fruits; Hydroxyl groups; Iron; Ligands; Lipids; Metabolism; Metabolites; metal complexes; Metals; Oxidation; Oxidative stress; Oxidizing agents; phenolic compounds; Polyphenols; Proteins; Small intestine; Spectrophotometry
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15196832

Complexes of chlorogenic acid (5-CQA) with copper(II) and iron(III) were synthesized in a solid state and examined by means of FT-IR, thermogravimetric, and elemental analyses. The molar stoichiometric ratios of metal:ligand for the solid forms of the complexes were established as Cu(II):L = 1:2 and Fe(III):L = 2:3 (L: 5-CQA), with the possible coordination through the carboxylate group and the hydroxyl group from the catechol moiety. In an aqueous solution at pH = 7.4, the composition of the complexes was Cu(II):L = 1:1, and Fe(III):L = 1:1 and 1:2. The Cu(II) and Fe(III) complexes with 5-CQA showed lower antioxidant properties, as estimated by the spectrophotometric methods with DPPH•, ABTS•+, and HO• radicals, than the ligand alone, whereas in the lipid peroxidation inhibition assay, the metal complexes revealed a higher antioxidant activity than 5-CQA. Cu(II) 5-CQA showed the highest pro-oxidant activity in the Trolox oxidation assays compared to the other studied compounds. The lipophilic parameters of the compounds were estimated using the HPLC method. 5-CQA and its complexes with Fe(III) and Cu(II) were not toxic to HaCaT cells in a tested concentration range of 0.15–1000 nM after a 24 h incubation time.