Background:
Currently ruthenium complexes are immerging as effective anticancer agents due to
their less toxicity, better antiproliferative and antimetastatic activity, better stability in cellular environment and
most importantly variable oxidation and co-ordination states of ruthenium allows binding this molecule with a
variety of ligands. So in past few years researchers have shifted their interest towards organoruthenium complexes
having good fluorescent profile that may be applicable for cancer theranostics. Nowadays, photodynamic
therapy has become more acceptable because of its easy and effective approach towards killing cancer
cells.
Objective:
Objective of this review article is to shed light on synthesis, characterization, stability and fluorescence
studies of various ruthenium [Ru(II) and Ru(III)] complexes and different bioactivity studies conducted
with the synthesized compounds to test their candidacy as potent chemotherapeutic agents.
Methods:
Various heterocyclic ligands containing N,O and S as heteroatom mainly were prepared and
subjected to complexation with ruthenium-p-cymene moiety. In most cases [Ru(η6-p-cymene)(µ-Cl)Cl]2 was
used as ruthenium precursor and the reactions were conducted in various alcohol medium such as methanol,
ethanol or propanol. The synthesized complexes were characterized by 1H NMR and 13C NMR spectroscopy,
GC-MS, ESI-MS, elemental analysis and single crystal X-ray crystallography methods. Fluorescence study and
stability study were conducted accordingly using water, PBS buffer or DMSO. Stable compounds were
considered for cell viability studies. To study the efficacy of the compounds in ROS generation as
photosensitizers, in few cases, singlet oxygen quantum yields in presence of light were calculated. Suitable
compounds were selected for in vitro & in vivo antiproliferative, anti-invasive activity studies.
Result:
Many newly synthesized compounds were found to have less IC50 compared to a standard drug cysplatin.
Those compounds were also stable preferably in physiological conditions. Good fluorescence profile
and ROS generation ability were observed for few compounds.
Conclusion:
Numerous ruthenium complexes were developed which can be used as cancer theranostic agents.
Few molecules were synthesized as photosensitizers which were supposed to generate reactive singlet oxygen
species in targeted cellular environment in presence of a particular type of light and thereby ceasing cancer cell
growth.