Introduction: Quercetin is a flavonoid compound found in many medicinal plants. Antispasmodic effect of quercetin has been reported in ileum and uterus smooth muscles but not in bladder. Therefore, the objective of this research was to investigate relaxant effect of quercetin in rabbit isolated bladder. Methods: Male rabbit was asphyxiated with carbon dioxide and then sacrificed. The whole bladder was dissected out and placed in oxygenated Tyrode’ s solution. Isolated bladder was cut into longitudinal strips and placed in an organ bath for contraction studies. Contractions were induced with KCl (20mM), acetylcholine (5µ M) and electrical field stimulation (EFS). Full inhibitory concentration– response curve was constructed for quercetin following addition of above spasmogens. Quercetin was added into the organ bath with 2 fold increments in concentration until maximum response was achieved. Nifedipine was used as positive control group and equivalent volume of quercetin vehicle (water + DMSO) was used as negative control group. Results: Quercetin (4 μ g/mL to 640 μ g/mL) in a concentration dependent manner inhibited isolated bladder strips contracted by KCl (IC50=159± 25 μ g/mL), acetylcholine (IC50=43± 9. 1 μ g/ mL) and EFS (IC50=38± 9. 3 μ g/mL). In the highest used concentration, quercetin completely removed contractile responses to KCl, acetylcholine and electrical filed stimulation (EFS). Nifedipine totally inhibited KCl response (IC50=115± 36 ng/mL) but only partially inhibited acetylcholine and EFS responses. Conclusion: These results confirm the relaxant effect of quercetin on rabbit bladder and if similar effects are seen in human studies, then quercetin would be a suitable drug candidate to be investigated for bladder incontinence.

Objectives: This study aimed to investigate the vascular effect of geraniol, a monoterpene essential oils that is found in some medicinal plants, in rat thoracic aorta. Methods: The thoracic aorta was isolated, cut into rings, mounted in organ-bath chambers containing Krebs’s solution (37oC, 95%O2 and 5%CO2) and equilibrated in resting tension (2g) for 60 min. Isometric tension was recorded under the treatments with vasoconstrictors, geraniol, and various drugs as pharmacological interventions. The effect of geraniol on the contractions evoked by noradrenaline (10mM) was tested after 20 min pre-incubation of aortic rings with increasing concentrations of geraniol in the bath. In various experiments the endothelium-intact or-denuded aortic rings contracted by 80 mM potassium chloride. When contraction was stable geraniol was applied. Relaxation was expressed as % reduction or reversal of initial contraction induced by vasocative agents. The possible participation of nitric oxide (NO), intracellular cyclic GMP and prostacyclin in the relaxant effects of geraniol, were studied by incubating (for 20 min) some rings with the NO synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME, 200 mM), methylene blue(10 mM) and indomethacin (10mM), respectively. Results: Geraniol in dose dependent manner reduced the contractile response to noradrenalin and relaxed of KCl induced active tone in rat aorta. Relaxant effects of geraniol on the KCl induced contraction was not modified by L-NAME, methylene blue and indomethacin. Conclusion: In conclusion geraniol induced dose dependent relaxation in rat aorta, which was endothelium-independent.

Asafoetida (Ferula asafoetida) an oleo-gum-resin belongs to the Apiaceae family which obtained from the living underground rhizome or tap roots of the plant. F. assa-foetida is used in traditional medicine for the treatment of variety of disorders. Asafoetida is used as a culinary spice and in folk medicine has been used to treat several diseases, including intestinal parasites, weak digestion, gastrointestinal disorders, asthma and influenza. A wide range of chemical compounds including sugars, sesquiterpene coumarins and polysulfides have been isolated from this plant. This oleo-gum-resin is known to possess antifungal, anti-diabetic, anti-inflammatory, anti-mutagenic and antiviral activities. Several studies investigated the effects of F. asafoetida gum extract on the contractile responses induced by acetylcholine, methacholin, histamine and KCl on different smooth muscles. The present review summarizes the information regarding the relaxant effect of asafetida and its extracts on different smooth muscles and the possible mechanisms of this effect.