Synthesis, characterization, and biological activity of some complex combinations of nickel with α-ketoglutaric acid and 1-(o-tolyl)biguanide

Abstract

The four divalent nickel complexes having α-ketoglutaric acid (H 2 A) and 1-( o -tolyl)biguanide (TB) ligands have been synthesized, characterized, and tested for antibacterial and antitumor activity. The proposed formulas for these complexes are [Ni(TB)(HA)(H 2 O) 2 ]Cl ( C1 ), [Ni(TB)(HA)(H 2 O) 2 ]Br ( C2 ), [Ni(TB)(HA)]NO 3 ·H 2 O ( C3 ), and [Ni(TB)(HA)]CH 3 COO ( C4 ), where HA represents deprotonated H 2 A. For the four complexes and for the ligands used in the synthesis, the antibacterial activity against Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 and antitumor activity in HeLa tumor cells were tested. A moderate cytotoxic effect of C3 and C4 complexes has been observed on the development and metabolic activity of HeLa cells, whereas C1 and C2 ligands have a very low effect on them. The synthesized complexes (obtained) inhibit adherence to the inert substrate of bacterial strains S. aureus and P. aeruginosa ; therefore, they may be candidates for (potential) therapeutic applications.