Background and Objective: Recently, nitric oxide (NO) and hydrogen sulfide (H2S)
donating moieties were extensively studied for their role in the vasculature as they are responsible for
many cellular and pathophysiological functioning. The objective of the present study is to evaluate
novel NO and H2S donating chalcone moieties on isolated rat aorta for vasorelaxation, and to
investigate the probable mechanism of action.
Methods: To extend our knowledge of vasorelaxation by NO and H2S donor drugs, here we
investigated the vasorelaxing activity of novel NO and H2S donating chalcone moieties on isolated rat
aorta. The mechanism of vasorelaxation by these molecules was investigated by performing in vitro
cGMP mediated sGC activation assay and using Tetraethylammonium chloride (TEA) as a potassium
channel blocker and Methylene blue as NO blocker.
Results: Both NO and H2S donating chalcone moieties were found to be potent vasorelaxant. The
compound G4 and G5 produce the highest vasorelaxation with 3.716 and 3.789 M of pEC50,
respectively. After the addition of TEA, G4 and G5 showed 2.772 and 2.796 M of pEC50, respectively.
The compounds Ca1, Ca2, and D7 produced significant activation and release of cGMP mediated sGC
which was 1.677, 1.769 and 1.768 M of pEC50, respectively.
Conclusion: The vasorelaxation by NO-donating chalcones was blocked by Methylene blue but it did
not show any effect on H2S donating chalcones. The vasorelaxing potency of NO-donating molecules
was observed to be less affected by the addition of TEA but H2S donors showed a decrease in both
efficacy and potency. The cGMP release was more in the case of NO-donating molecules. The tested
compounds were found potent for relaxing vasculature of rat aorta.