Catechol Oxidase, Phosphatase-Like Activity, DNA/BSA Binding Studies of RuII Complexes of S-Allyldithiocarbazate: Synthesis and Spectral Studies

Ponnusamy Selvakumar,Raju Nandhakumar,Nanjan Nanjundan,Ramaswamy Narayanasamy,Krishnaswamy Velmurugan

doi:10.21577/0103-5053.20160318

Abstract

New ruthenium(II) complexes with formulae [RuCl(CO)(PPh3)2L1] and [RuCl(CO)(PPh3)2L2] (L1 = S-allyl-4-methoxy benzylidene hydrazine carbodithioate, L2 = S-allyl-1-naphthylidene hydrazine carbodithioate) have been synthesized and characterized by elemental analysis, Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), UV-Vis, electrospray ionization (ESI)-mass spectral studies. Both the Schiff base ligands are coordinated to ruthenium through azomethine nitrogen (C=N) and thiolato sulfur donor atoms in the thiolate form. On the basis of spectral data obtained, an octahedral structure has been assigned to all the new complexes, satisfied by coordination of donor atoms N and S. The stability of complexes in solution was determined by molar conductivity measurements. The interaction of the two complexes with calf thymus (CT) DNA was investigated by fluorescence spectroscopic and viscometric methods. Bovine serum albumin (BSA) protein was examined by fluorescence spectroscopic methods. These techniques indicate that the two metal complexes bind to DNA via intercalation mode and BSA bind with static interaction. Catecholase and phosphatase like activities promoted by these two complexes under physiological conditions have been studied. In vitro anticancer activities have been demonstrated by 3,4,5-dimethylthiazolyl-2-2,5-diphenyltetrazolium bromide (MTT) assay, acridine orange/ethidium bromide (AO/EB) and diamidino-2-phenylindole (DAPI) staining against HeLa cancer cell line.

Highlights

The use of chiral metal complexes to probe the structure of DNA is an active area of research at the interface of chemistry and biology.[1]
The mechanism of above ruthenium complexes has been most widely studied in order to establish the basis for their unique properties, whch three relevant main features are: (i) they have the ability to interact with serum proteins, such as albumin and transferrin that endows to have tumor seeking properties;[8] (ii) activation of ruthenium(III) through intracellular reduction to allow generation of toxic ruthenium(II) species[9] and (iii) tumor site reactions prefer protein binding instead of DNA binding, it gives contrast to the behavior of platinum(II) complexes, such as cisplatin.[10]
We have reported two new ruthenium complexes comprising p-methoxybenzaldehyde and 1-naphthaldehyde based S-allyldithiocarbazate, together with their binding ability towards calf thymus (CT) DNA/bovine serum albumin (BSA) protein

Summary

Introduction

The use of chiral metal complexes to probe the structure of DNA is an active area of research at the interface of chemistry and biology.[1]. EB displacement experiments were performed by monitoring changes in the fluorescence intensity on the emission wavelength (λem) 604 nm and the excitation wavelength (λex) 550 nm, after aliquot addition of tested compounds to an aqueous solution of EB-DNA.

Results

Conclusion