The emergence of Multi-Drug-Resistance (MDR) has become a major global clinical problem. The emergence of an innovative bioorganic antimicrobial platform is an interesting alternative to combat microbial resistance, and therefore transition metal complexes are being investigated.
In this work, two complexes of trans-palladium(II) with organoselenium compounds as their ligands were investigated., PdSe1, [Pd(L1)2Cl2], (L1 = 5- (phenylselanylmethyl) -dihydrofuran-2 (3H) -one)) and PdSe3, [Pd(L3)2Cl2], (L3 =2,2-dimethyl-3-(phenylselanylmethyl)-tetrahydro-2H-pyran). Their antimicrobial and antioxidant activity as well as the effect of the formed biofilm of selected bacteria were studied. Antimicrobial activity was tested by determining the minimum inhibitory concentrations (MIC) and minimum microbicidal concentration (MMC) using the resazurin microdilution plate method The effect of complexes and ligands on formed biofilm of S. aureus ATCC 25923, S. aureus, and P. aeruginosa was determined. The in vitro antioxidant activity of the complexes was determined based on the neutralizing capacity of DPPH radicals expressed as EK50
The investigated complexes showed significantly higher antimicrobial activity than the corresponding ligands. The most significant activity was shown on Pseudomonas aeruginosa. Complexes showed a lower effect on tested bacteria formed biofilm than the tested ligands. Complex Pd-Se1 showed a better effect on the tested biofilm of S. aureus, while complex Pd-Se3 showed a significant effect on the tested biofilm of P. aeruginosa. The antioxidant activity of all organoselenium trans-palladium(II) complexes is significant, with the PdSe1 complex being more active. These complexes have the potential to be further investigated as metallodrugs.
