Anticancer Activities of Mononuclear Ruthenium(II) Coordination Complexes

Abstract

Ruthenium compounds are highly regarded as potential drug candidates. The compounds offer the potential of reduced toxicity and can be tolerated in vivo. The various oxidation states, different mechanism of action, and the ligand substitution kinetics of ruthenium compounds give them advantages over platinum-based complexes, thereby making them suitable for use in biological applications. Several studies have focused attention on the interaction between active ruthenium complexes and their possible biological targets. In this paper, we review several ruthenium compounds which reportedly possess promising cytotoxic profiles: from the discovery of highly active compounds imidazolium [trans-tetrachloro(dmso)(imidazole)ruthenate(III)] (NAMI-A), indazolium [trans-tetrachlorobis(1H-indazole)ruthenate(III)](KP1019), and sodium trans-[tetrachloridobis(1H-indazole)ruthenate(III)] (NKP-1339) to the recent work based on both inorganic and organometallic ruthenium(II) compounds. Half-sandwich organometallic ruthenium complexes offer the opportunity of derivatization at the arene moiety, while the three remaining coordination sites on the metal centre can be functionalised with various coordination groups of various monoligands. It is clear from the review that these mononuclear ruthenium(II) compounds represent a strongly emerging field of research that will soon culminate into several ruthenium based antitumor agents.

η6-(2-phenoxyethanol) ruthenium(II)-complexes of 2,2′-bipyridine and its derivatives: Solution speciation and kinetic behaviour

“…The pH dependent UV-Vis spectra in In order to get a deeper insight into the formation of the intermediate species 1 H NMR spectra were recorded at various pH values (Fig. 6), which also refer to the presence of more than one kind of hydrolysis products.…”

“…During the last two decades a significant amount of work has been published in the field of ruthenium metallodrugs for application as anticancer agents due to the relevant cytotoxicity exhibited by many of these compounds against several cancer cell lines [1][2][3][4][5]. Particular attention has been given to the families of the so called piano-stool geometries where the stool is formed by the 'η 5 -C 5 H 5 ' or 'η 6 -C 6 H 6 ' bonded to the ruthenium centre and the three legs are represented by sigma coordinated ligands.…”

Cytotoxic hydrogen bridged ruthenium quinaldamide complexes showing induced cancer cell death by apoptosis

“…[6][7][8][9][10][11][12][13][14][15][16] Ruthenium-based complexes are some of the most promising, with reported selective potency in vitro and in vivo. [17][18][19][20][21][22] McGowan et al have synthesised a range of ruthenium metal complexes for their uses as anticancer agents. [23][24][25][26] The work published on ruthenium quinaldamides showed that under inert atmosphere conditions, the filtering over NH4PF6 yielded the ruthenium quinaldamide monomers.…”

Recent developments in the nanostructured materials functionalized with ruthenium complexes for targeted drug delivery to tumors

“…18 As listed in Table 2, although a large number of Ru complexes have shown great promise as potential antitumor agents, only three complexes, NAMI-A, KP1019, and NKP1339 (Table 3), have entered clinical trials. 16,19,20 Clinically, all the three complexes exhibited promising anticancer activities with minimal side effects; an ideal property of a good anticancer drug (Table 3). In addition, these complexes have octahedral coordination geometry with respect to the Ru(III) metal center; however, they exhibit different biological activities despite their structural and chemical similarities.…”

“…In addition, these complexes have octahedral coordination geometry with respect to the Ru(III) metal center; however, they exhibit different biological activities despite their structural and chemical similarities. 19 Recently, 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-functionalized Ru(II) polypyridyl complexes were screened for their efficiency as theranostic photosensitizers for cancer treatment. 21 The presence of a redox-sensitive TEMPO moiety enhanced the intracellular fluorescence of TEMPOfunctionalized Ru(II) complexes in photodynamic treatment, which was observed using confocal microscopy and flow cytometry.…”