Bronchodilator activity of aerial parts of Polygonatum verticillatum augmented by anti-inflammatory activity: attenuation of Ca²⁺ channels and lipoxygenase.

Polygonatum verticillatum is commonly used for the treatment of asthma and inflammation. The current study was aimed to scrutinize the pharmacological profile of methanolic extract of the aerial parts (PA). Isolated tracheal preparations were used for the evaluation of bronchodilatory activity, whilst the in vivo carrageenan-induced paw oedema test and an in vitro lipoxygenase (LOX) inhibitory assay were used for the assessment of the anti-inflammatory profile of PA. When tested against carbachol and K⁺ (80 mM)-induced contractions, PA caused complete inhibition of isolated rabbit tracheal preparations in a dose-dependent mode, similar to verapamil. While elucidating possible mechanism, PA shifted the Ca²⁺ concentration-response curves to the right, analogous to that produced by verapamil, confirming a Ca²⁺ channel blocker-like activity. PA provoked profound reduction in paw oedema with a maximum protection of 60.87% at 200 mg/kg i.p. in a dose-dependent manner which was augmented by its prominent LOX inhibitory activity (IC₅₀ : 125 µg/mL). These findings authenticated its therapeutic potential in the treatment of asthmatic and inflammatory conditions.