Synthesis, characterization and biological activity of new Ni(II), Pd(II) and Cr(III) complex compounds with chlorhexidine

Abstract

Six new coordination compounds of Ni(II), Pd(II) and Cr(III) with chlorhexidine, 1,1′-hexamethylenebis[5-(4-chlorophenyl)biguanide], were prepared, characterized and examined for their potential as antimicrobial agents, as well as for their antioxidant activity. The metal complexes correspond to the formulas: [Ni(CHX)]Cl 2 •2H 2 O, [Ni(CHX)]Br 2 •2H 2 O, [Ni(CHX)](CH 3 COO) 2 •C 2 H 5 OH, [Pd(CHX)][PdCl 4 ]•2H 2 O, [Pd(CHX)](CH3COO) 2 and [Cr(CHX)Cl 2 ](CH 3 COO), where CHX = chlorhexidine. Investigations on the in vitro antimicrobial activity of the complexes indicated that all have high activity against the tested bacteria, but are less active against fungi. Among the six complexes, those of Pd(II) showed the highest antibacterial activity, [Pd(CHX)][PdCl 4 ]•2H 2 O being more active against Gram-positive and Gram-negative bacteria than chlorhexidine diacetate. The antioxidant activity of the metal complexes was investigated by photochemiluminescence and the results showed that the palladium(II) complexes have high antioxidant activities.

Biguanide is a modifiable pharmacophore for recruitment of endogenous Zn2+ to inhibit cysteinyl cathepsins: review and implications

“…Some of the non-biological metal species might be relevant to medicinal or other applications of protease inhibition, e.g. platinum, vanadium, chromium, iridium, paladium, nickel, technetium, lanthanum, cesium, yttrium, samarium, and others (Woo et al 1999; Patrinoiu et al 2003; Fuks et al 2011; Al-Saif and Refat 2013; Badea et al 2013; Beygzadeh et al 2013; Shahabadi and Heidari 2014; Refat et al 2015; Mahmoud et al 2016; Chen et al 2018; Mihalache et al 2018). Metal toxicity is an obvious concern.…”