Tuesday, 25 July 2017 13:44

Ruthenium-conjugated chrysin analogues modulate platelet activity, thrombus formation and haemostasis with enhanced efficacy

doi:  10.1038/s41598-017-05936-3

 

Divyashree Ravishankar,1 Maryam Salamah,1 Alda Attina,1 Radhika Pothi,1 Thomas M. Vallance,1 Muhammad Javed,1 Harry F. Williams,1 Eman M. S. Alzahrani,1 Elena Kabova,1 Rajendran Vaiyapuri,2 Kenneth Shankland,1 Jonathan Gibbins,3 Katja Strohfeldt,1 Francesca Greco,1 Helen M. I. Osborn,Sakthivel Vaiyapuri1

 

1School of Pharmacy, University of Reading, Reading, UK

2School of Pharmacy, University of Reading Malaysia, Johar, Malaysia

3Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK

 

Abstract

The constant increase in cardiovascular disease rate coupled with significant drawbacks of existing therapies emphasise the necessity to improve therapeutic strategies. Natural flavonoids exert innumerable pharmacological effects in humans. Here, we demonstrate the effects of chrysin, a natural flavonoid found largely in honey and passionflower on the modulation of platelet function, haemostasis and thrombosis. Chrysin displayed significant inhibitory effects on isolated platelets, however, its activity was substantially reduced under physiological conditions. In order to increase the efficacy of chrysin, a sulfur derivative (thio-chrysin), and ruthenium-complexes (Ru-chrysin and Ru-thio-chrysin) were synthesised and their effects on the modulation of platelet function were evaluated. Indeed, Ru-thio-chrysin displayed a 4-fold greater inhibition of platelet function and thrombus formation in vitro than chrysin under physiologically relevant conditions such as in platelet-rich plasma and whole blood. Notably, Ru-thio-chrysin exhibited similar efficacy to chrysin in the modulation of haemostasis in mice. Increased bioavailability and cell permeability of Ru-thio-chrysin compared to chrysin were found to be the basis for its enhanced activity. Together, these results demonstrate that Ru-thio-coupled natural compounds such as chrysin may serve as promising templates for the development of novel anti-thrombotic agents.