Synthesis, spectral, DFT modeling, cytotoxicity and microbial studies of novel Zr(IV), Ce(IV) and U(VI) piroxicam complexes

Synthesis, characterization, molecular modeling studies, and biological evaluation of metal piroxicam complexes (M = Ni(II), Pt(IV), Pd(II), Ag(I)) as antibacterial and anticancer agents

Four piroxicam metal complexes; NiL2 , PtL2 , PdL2 , and AgL were synthesized and characterized by different techniques with enhanced antibacterial and anticancer activity. Regarding in vitro antimicrobial activity, complex NiL2 displayed potent antibacterial effect against Escherichia coli and Pseudomonas aeruginosa that was 1.9-folds higher than piroxicam (minimum inhibitory concentration [MIC] = 31.85, 65.32 µM), respectively. In case of G+ve bacteria, complex PtL2 had potent activity on Staphylococcus aureus which was 2.1-folds higher than piroxicam (MIC = 43.12 µM), while activity of complex AgL against Enterococcus faecalis was threefolds higher than piroxicam (MIC = 74.57 µM. Complexes PtL2 and PdL2 exhibited higher inhibition of DNA gyrase than piroxicam (IC50  = 6.21 µM) in the range of 1.9-1.7-folds. The in vitro antiproliferative activity depicted that all investigated complexes showed better cytotoxic effect than piroxicam, specifically Pt and Pd complexes which had lower IC50 values than piroxicam on human liver cancer cell line HepG2 by 1.8 and 1.7-folds, respectively. While Pd and Ag complexes showed 2 and 1.6-folds better effect on human colon cancer cell line HT-29 compared with piroxicam. Molecular modeling studies including docking on Stranded DNA Duplex (1juu) and DNA gyrase enzyme (1kzn) that gave good insight about interaction of complexes with target molecules, calculation of electrostatic potential map and global reactivity descriptors were performed.

Heteroleptic complexes of cocaine/TMEDA with some f block metals: Synthesis, DFT studies, spectral, thermal, cytotoxicity and antimetastatic properties

A series of new three heteroleptic complexes of the general formula [Ln(Cn)(TMEDA)Cl(OH₂)]·2Cl·xH₂O, (where Ln = La(III), Er(III) and Yb(III), Cn = cocaine and TMEDA = N,N,N',N'-tetramethylethylenediamine) were synthesized, structurally characterized by elemental analysis, spectroscopic methods, molar conductivity and mass spectrometry. Thermal properties of the synthesized complexes and their kinetic thermodynamic parameters were studied. Theoretical calculations including geometry optimization, electronic structure and electronic and thermal energies were carried out using DFT and TD-DFT calculations at B3LYP/LANL2DZ level of theory and the different quantum chemical parameters were calculated. The in vitro antiproliferative activity of the newly synthesized complexes was assessed by MTT assay on MCF-7 and HepG-2 cancer cell lines. Yb(III) complex showed promising cytotoxic activity comparable to that of cisplatin on both cell lines with minimum effect on human normal cells. Further molecular mechanistic investigations showed that Yb(III) complex is an apoptotic inducer as it raises the caspase-3 and caspase-9 cellular level in the MCF-7 cell line. Furthermore, it showed an elevating effect on the level of the tumor suppressor nuclear proteins P21 and P27 concentrations in MCF-7 cells. Moreover, Yb(III) complex hindered the cellular scavenger system of the reactive oxygen species through reducing the glutathione peroxidase (GPx) cellular level imperiling MCF-7 cells by unmanageable oxidative stress. In addition to its cytotoxic effect, Yb(III) complex showed antimetastatic properties as it decreased the cellular levels of matrix metalloproteinases MMP-3 and MMP-9. These results showed that the Yb(III) complex is a promising cytotoxic metal-based agent that exerts its action through various molecular mechanisms with minimum effects on normal cells and with additional antimetastatic properties.

A Ce(iii) complex potently inhibits the activity and expression of tyrosine phosphatase SHP-2

Four new Ce(iii) complexes 1-4 with tridentate NNO-donor Schiff base ligands have been designed and successfully synthesized. These complexes were characterized by elemental analysis, IR, and ESI-MS, with formulas of [Ce(HL1)2(NO3)3]·2CH3OH (1), [Ce(L2)2(NO3)]·3H2O (2), [Ce(HL3)(L3)(NO3)Br]·H2O (3) and [Ce(L4)2(NO3)]·3H2O (4), in which ligands HL1-HL4 are respectively N'-[(1E)-pyridin-2-ylmethylidene]pyrazine-2-carbohydrazide (HL1), 2-(1-(salicyloylhydrazono)ethyl)pyrazine (HL2), N'-[(1E)-pyridin-2-ylmethylidene]pyridine-2-carbohydrazide (HL3) and 2-(1-(salicyloylhydrazono)ethyl) pyridine (HL4). X-ray single crystal diffraction analysis indicates that complex 1 crystallizes in the monoclinic system with the space group C2/c and the structure of complex 1 consists of a monomeric Ce(iii) species with a Ce(iii) moiety bonded to two tridentate Schiff base ligands, three nitrates and solvents. These complexes effectively inhibit the enzyme activities of PTPs (SHP-1, SHP-2, TCPTP and PTP1B), among which complex 3 shows the most potent inhibition of SHP-2 with the lowest IC50 value of 0.61 μM and displays obvious selectivity towards SHP-2. Its inhibition potency against SHP-2 was approximately 17, 4, and 5 fold higher than that against SHP-1, TCPTP and PTP1B, respectively. Further study discloses that complex 3 inhibits SHP-2 in a competitive manner. Fluorescence measurements indicate that complex 3 tightly binds to SHP-2 with a molar ratio of 1 : 1 and a binding constant of 5.45 × 105 M-1. Western blot experiments show that complex 3 promotes the phosphorylation of the SHP-2 substrate by the combination of the inhibition of the activity and expression of SHP-2. Moreover, complex 3 decreases the survival rate of A549 cells to 35.12% at 100 μM and induces apoptosis with an apoptosis rate of 12.06% at 50 μM. All these results suggest that complex 3 is a potential bi-functional inhibitor of the activity and expression of tyrosine phosphatase SHP-2.