Pharmacological effects and underlying molecular mechanisms of fennel

In the current Master's thesis it was investigated the pharmacological effects of fennel (Foeniculum vulgare) extract (solvent: 60% ethanol; ethanolic fennel extract; ERE; 10-40 µl/ml) in the lower esophagus of isolated mouse (Swiss albino, male, 25-30 g). In in vitro qualitative studies, the relaxation-inducing effect of ERE was observed in isolated mouse lower esophageal strips precontracted with carbachol (CCh; 10 µM), and the underlying molecular mechanisms (roles of the cholinergic system, nitrergic system, potassium channels, and L-type calcium channels) were investigated. In addition, relaxation responses of ERE were compared with the relaxation responses of fennel extract with milli Q (MRE; solvent: milli Q; ultra pure water). In addition, the anti-inflammatory and antioxidant effects of ERE were also investigated in the related tissues by in vitro quantitative studies. In in vitro qualitative experiments, mice were euthanized by cervical dislocation under anesthesia and their lower esophagus was isolated, then lower esophagus was stripped and placed in a 10 ml organ bath containing Krebs-Henseleit solution gassed with 5% CO2+95% O2 at 37oC washing by applying 0.5g-tonus. The answers were recorded in a computer-equipped pharmacological data analysis system (BIOPAC, MP35 Data Acquisition System) with an isometric transducer. In in vitro quantitative experiments, isolated mouse lower esophageal tissues were homogenized after incubation (40 min) with ERE (40 μl/ml) and the effects of fennel on cyclooxygenase (COX) and superoxide dismutase (SOD) in the supernatants were analysed by using ELISA (Enzyme linked immunosorbent assay) method. In in vitro qualitative experiments, ERE in precontracted isolated mouse lower esophageal strips produced significant relaxation responses that were dose (10-40 µl/ml) dependent and statistically significant compared to control. The percent relaxation responses produced by the ERE (10-40 µl/ml) were much greater than the relaxation responses generated by the MRE (10-40 µl/ml). Atropine (10 µM), a nonselective competitive blocker of cholinergic-muscarinic receptors, statistically significantly inhibited the relaxation responses at all applied concentrations of ERE. Nw-nitro-L-arginine (L-NOARG; 10 µM), a nitric oxide synthase (NOS) enzyme inhibitor, statistically significantly inhibited relaxation responses at the lowest concentration of ERE (10 µl/ml). However, higher concentrations (20-30 µl/ml) inhibited ERE responses in a statistically non-significant way. This inhibitory effect of L-NOARG was more pronounced in relaxation responses at lower concentrations of ERE. Indeed, L-NOARG did not affect the relaxation responses at the highest concentration of ERE (40 µl/ml). Tetraethylammonium (TEA; 10 µM), a non-specific, reversible blocker of potassium channels, had a similar effect to the effects of L-NOARG on the relaxation responses of ERE (10-40 µl/ml) in the related tissues, and the lowest concentration of ERE (10 µl/ml). Verapamil, an L-type Ca2+ channel blocker (10 µM) statistically significantly inhibited relaxation responses at all administered concentrations of ERE. In in vitro quantitative experimental studies, ERE (40 µl/ml) statistically significantly decreased the COX-2 enzyme level. ERE at the same concentration caused an increase in SOD1 enzyme level. However, this increment was not statistically significant. In conclusion; in vitro qualitative experimental findings suggest the role of cholinergic pathway, nitrergic pathway, K+ channel and Ca2+ channel activations in the relaxation responses induced by ERE in precontracted isolated mouse lower esophagus. In addition, experimental findings suggest that ERE has an anti-inflammatory effect at the applied concentration (40 µl/ml), but not an antioxidant effect.