Studies on tracheorelaxant and anti-inflammatory activities of rhizomes of Polygonatum verticillatum
1 Department of Pharmacy, University of Peshawar, Peshawar 25120, Pakistan
2 Natural Product Research Division, Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi 74800, Pakistan
3 National Institute of Health, Islamabad 45500, Pakistan
4 Gandhara College of Pharmacy, Gandhara University, Peshawar, Pakistan
5 Molecular Brain Research Group, Robarts Research Institute, Department of Physiology & Pharmacology, Faculty of Medicine, University of Western Ontario, 100 Perth Drive, London, ON N6A 5K8, Canada
6 Department of Pharmacology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
7 Department of Basic Medical Sciences, Faculty of Pharmacy, Gomal University, D.I. Khan-29050, Khyber-Pakhtoonkha, Pakistan
8 Department of Pharmacy, Hazara University, Havelian Campus, Abbottabad, Pakistan
BMC Complementary and Alternative Medicine 2013, 13:197 doi:10.1186/1472-6882-13-197Published: 29 July 2013
The present study describes the tracheorelaxant and anti-inflammatory effects of Polygonatum verticillatum which may support its medicinal use in hyperactive airway complaints and inflammatory disorders.
The tracheorelaxant activity of crude extract of the rhizomes of P. verticillatum (PR) was assessed in isolated guinea-pig tracheal tissues immersed in tissue organ bath filled with Tyrode’s solution and a continuous supply of carbogen gas (95% O2 and 5% CO2). The contractile and relaxant responses of the tissue were measured using isometric transducers coupled with Power-Lab data acquisition system. The anti-inflammatory effect was evaluated in carrageenan-induced rat paw edema model, while the lipoxygenase inhibitory activity was performed in the in-vitro assay. Various chromatographic and spectroscopic techniques were used for the isolation and characterization of pure molecules.
In isolated guinea-pig tracheal preparations, PR caused complete inhibition of the high K+ (80 mM) and carbachol-induced contractions however, it was more potent against K+ than CCh, similar to verapamil. Pretreatment of the tissue with PR, displaced the Ca2+ concentration-response curves to the right, similar to that induced by verapamil, indicating the presence of Ca2+ channel blocking like activity. When tested on carrageenan-induced rat paw edema, PR demonstrated a marked reduction in edema with 65.22% protection at 200 mg/kg, similar to aspirin. In the in-vitro assay, PR showed lipoxygenase inhibitory activity (IC50: 102 ± 0.19 μg/mL), similar to baicalein. Bioactivity-guided fractionation led to the isolation of 2-hydroxybenzoic acid and β-sitosterol.
These results indicate that the plant possesses tracheorelaxant, mediated possibly through a Ca2+ channel blockade mechanism, and anti-inflammatory activities, which may explain the medicinal use of this plant in airway disorders and inflammation.