Syntheses,characterization, and biological evaluation of new zinc-and gold-chloroquine diphosphate complexes

Antimalarial drugs such as chloroquine are beneficial agents in systemic lupus and rheumatoid arthritis. In this work, two new chloroquine diphosphate (CQDP) complexes containing Zn(II) and Au(III) of formula Zn(CQDP)(NO₃)₂ (1) and Au(CQDP)Cl₃ (2), respectively, were synthesized and characterized by physico-chemical and spectroscopic methods. To examine their possible anti-inflammatory properties, the new derivatives were tested in the range from 1 to 100 μM on the respiratory burst of isolated human neutrophils (PMNs) as well as in whole blood. In isolated PMNs, complex 1 inhibited the isoluminol-enhanced chemiluminescence (IL-CL) only at the highest concentration tested, whereas in the whole blood assay, 10 μM of this complex was sufficient to significantly inhibit the luminol-enhanced chemiluminescence (L-CL). On the contrary, complex 2 dose-dependently inhibited the IL-CL but affected the L-CL only at 100 μM. In conclusion, both complexes are more active than CQDP and may be useful for future treatment of diseases resulting from exacerbated neutrophil functions.