Rosa damascena Miller essential oil relaxes rat thoracic aorta through the NO-cGMP-dependent pathway

This study aimed to investigate the effects of Rosa damascena Mill. essential oil on the vascular activity of rat thoracic aorta and its underlying mechanisms.

Experiments were performed using the isolated tissue bath model and Wistar rats. 0.1, 1, 10, and 100 µg/mL concentrations of rose oil were administered in all groups. To determine the vasoactive effects of rose oil, submaximal contractions were conducted by applying 10^-5 M PE and 45 mM KCl separately in both endothelium-intact and -denuded segments. Time-matched distilled water groups were formed for control. To evaluate the role of endothelium-derived vasodilative factors, endothelium-intact segments were incubated with nitric oxide synthase inhibitor L-NAME, soluble guanylate cyclase inhibitor ODQ, and a non-selective cyclooxygenase inhibitor INDO. The statistical significance level was considered as p < 0.05.

1, 10, and 100 µg/mL rose oil doses led to vasorelaxation in thoracic aortas precontracted with 10^-5 M PE (p: 0.029, p: 0.000, p: 0.000, respectively). In precontracted thoracic aortas with 45 mM KCl, the significant effect of rose oil persisted, albeit slightly diminished. When the endothelium was removed, the relaxant effect of rose oil was partially reduced, but still significant (p: 0.035, p: 0.028, p: 0.000, respectively). Preincubations with L-NAME and ODQ significantly attenuated rose oil-induced relaxation of endothelium-intact aortas precontracted with 10^-5 M PE. In contrast, preincubation INDO did not modulate rose oil-induced relaxation.

In conclusion, it was shown for the first time that rose oil can significantly mediate vasorelaxation in both PE and KCl precontracted rat thoracic aortas. Rose oil induced vasodilation with or without endothelium in a concentration-dependent manner. It was also shown that rose oil-induced vasorelaxant effects were reduced by L-NAME or ODQ pretreatment, but not modulated by INDO. These results demonstrated that rose oil-induced endothelium-dependent vasodilation is mediated by the NO-cGMP-dependent pathway.