Synthesis, physico‐chemical characterization and bioevaluation of Ni(II), Pd(II), and Pt(II) complexes with 1‐(o‐tolyl)biguanide: Antimicrobial and antitumor studies

Abstract

New complexes of type [M(tbg)2]Cl2 [tbg = 1‐(o‐tolyl)biguanide; M = Ni(II), Pd(II), and Pt(II)] were synthesized and characterized to develop new biologically active compounds. The features of the complexes were assigned from microanalytical and thermal data. The NMR, FT‐IR, and UV‐Vis spectra were established by comparison with HtbgCl. All complexes exhibit a square‐planar geometry resulting from the chelating behavior of tbg. The HtbgCl and [Ni(tbg)2]Cl2 complexes were fully characterized by single‐crystal X‐ray diffraction. The HtbgCl species crystallize in the monoclinic C2/c spatial group, while the Ni(II) complex adopts an orthorhombic Pna21 spatial group. The structure is stabilized by a complex hydrogen bonds network. The in vitro antimicrobial assays revealed improved antimicrobial activity for complexes in comparison with the ligand against both planktonic and biofilm embedded microbial cells. The most efficient compound, showing the largest spectrum of antimicrobial activity, including Gram‐positive and Gram‐negative bacteria, as well as fungal strains, in both planktonic and biofilm growth states was the Pd(II) complex, followed by the Pt(II) complex. The Pt(II) compound exhibited the most significant antiproliferative activity on the human cervical cancer SiHa cell line, inducing a cell cycle arrest in the G2/M phase.

New Cobalt (II) Complexes with Imidazole Derivatives: Antimicrobial Efficiency against Planktonic and Adherent Microbes and In Vitro Cytotoxicity Features

“…The range of tested concentrations prepared from a stock solution in dimethyl-sulfoxide (DMSO) (10 mg/mL) was from 1000 to 1.9 µg/mL. After incubating the tested compounds with standard microbial suspensions at 0.5 MacFarland density (1.5 × 10 8 microbial cells/mL) for 24 h at 37 °C, the MIC was established as being the lowest concentration of the compound that inhibited the visible microbial growth in the wells, in comparison with the untreated culture [ 32 , 33 ].…”

“…In this purpose, the plates were emptied and then washed three times with sterile phosphate buffered saline (PBS) to remove the planktonic cells, and the remaining adherent cells were fixed for 5 min with cold methanol, stained for 20 min with 0.1% aqueous solution of crystal violet, and resuspended in acetic acid 33%. The MBEC corresponded to the lowest concentration that inhibited the microbial adherence, in comparison with the untreated culture [ 32 , 33 ].…”

“…The tumor cells treated with 50 and 100 µg/mL cobalt complexes, for 72 h were harvested with trypsin, fixed in cold ethanol (70%), and stained with 50 µg/mL propidium iodide containing 100 µg/mL RNAse A Acquisition was performed using Beckman Coulter flowcytometer (Beckman Coulter, Nyon, Switzerland) and analyses was done using FlowJo software 7.2.5. (Ashland, CA, USA) [ 21 , 32 ].…”

Metal Complexes—A Promising Approach to Target Biofilm Associated Infections

“…The most recent data concerning these aspects are presented in this review, with highlights on examples of complexes with antibiotics [ 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 ], N-heterocycle derivatives [ 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 ], Schiff bases [ 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 ], biguanides [ 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , …”

Insight on Ni(II) and Cu(II) complexes of biguanide derivatives developed as effective antimicrobial and antitumour agents

“…The assessment of the complexes influence on the microbial ability to colonize an inert substratum with the establishment of the minimal biofilm eradication concentration (MBEC) was performed by the microtitter method, following previously described protocols. [27][28][29] The absorbance at 490 nm was measured with an Apollo LB 911ELISA reader (Berthold Technologies GmbH & Co. KG, Waltham, MA, USA). All experiments were performed in triplicates.…”