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Background The possible mechanism(s) of inotropic and chronotropic effects of the extract from Rosa damascena ( R. damascena ) on heart was examined . Methods Inotropic and chronotropic effects of four concentrations of the extract from R. damascena and isoprenaline were examined in isolated guinea-pig hearts perfused through aorta in a Langendorff model . All measurements were performed in three different groups: 1) In the presence and absence of propranolol, 2) In the presence and absence of methacholine and 3) In the presence of diltiazem (n = 12 for each group). Results In all groups both isoprenaline and the extract caused an increase in heart rate and contractility (p < 0.05 to p < 0.001). Only in group 1, the final concentration of isoprenaline in the absence of propranolol caused significant greater increase in heart rate compared to the extract (207.6 ± 11.0 compared to 162.6 ± 11.8, p < 0.01). The percent increase in heart contractility due to the final concentration of the extract in the absence (362.4 ± 36.9 compared to 227.7 ± 31.6, p < 0.01) and presence of propranolol (577.1 ± 62.9 compared to 357.5 ± 45.6, p < 0.001) in group 1 and absence (403.7 ± 42.1 compared to 244.8 ± 18.9, p < 0.005) and presence of methcholine (499.88 ± 64.64 compared to 323.90 ± 44.49, p < 0.05) in groups 2 was significantly greater than the increase caused by isoprenaline. Conclusions The results of this study suggest that inotropic and chornotropic effect of R. damascena is possibly due to the stimulatory effect of this plant on beta-adrenoceptors.

The possible mechanism(s) of inotropic and chronotropic effects of the extract from Rosa damascena (R. damascena) on heart was examined. Inotropic and chronotropic effects of four concentrations of the extract from R. damascena and isoprenaline were examined in isolated guinea-pig hearts perfused through aorta in a Langendorff model. All measurements were performed in three different groups: 1. In the presence and absence of propranolol, 2. In the presence and absence of methacholine, and 3. In the presence of diltiazem (n = 12 for each group). In all groups both isoprenaline and the extract caused an increase in heart rate and contractility (p < 0.05 to p < 0.001). Only in group 1, the final concentration of isoprenaline in the absence of propranolol caused significant greater increase in heart rate compared to the extract (207.6 ± 11.0 compared to 162.6 ± 11.8, p < 0.01). The results of this study suggest that inotropic and chornotropic effect of R. damascena is possibly due to the stimulatory effect of this plant on beta-adrenoceptors.

Objective(s)In the present study, the effects of aqueous-ethanolic extract from Rosa damascena on heart rate and contractility were examined. Materials and Methods Isolated guinea-pig hearts were perfused through aorta in a Langendorff mode. Heart rate (HR) and contractility were determined in the presence of four concentrations of the extract (0.1, 0.2, 0.4 and 1.0 mg %) and isoprenaline (1, 10, 100 nM and 1 µM) in comparison with baseline values in the presence and absence of propranolol (n= 10 for each group). ResultsBoth isoprenaline and the extract caused increase in heart rate and contractility (P< 0.05 to P< 0.001). The percent increased in HR due to the final concentration of isoprenaline in the absence of propranolol was significantly greater than that of the extract (P< 0.01). Propranolol caused significant reduction in both HR and contractility (P< 0.05 for both) but this effect was significantly reversed by isoprenaline and the extract (P< 0.05 to P< 0.001). The percent increased in heart contractility due to the final concentration of the extract in the absence and presence of propranolol was significantly greater than that of isoprenaline (P< 0.05 for both cases). There was significant correlation between both HR and heart contractility with concentration of isoprenaline and the extract (P< 0.05 to P< 0.001). ConclusionIn conclusion this study showed a relatively potent inotropic and chornotropic effect for Rosa damascena on isolated guinea-pig heart.