Cortex Phellodendri Extract Relaxes Mouse Airway Smooth Muscle

Abstract

Asthma is a common chronic respiratory disease. Excessive airway obstruction is a cardinal symptom, which results from the contraction of airway smooth muscle cells (ASMCs). It has been reported that berberine, an active ingredient of Cortex Phellodendri extract (CPE), can induce ASMC relaxation. However, we found that non-berberine component of CPE (a n-butyl alcohol extract of Cortex Phellodendri, NBAECP) has also a similar relaxant effect observed in tracheal rings and lung slices. NBAECP completely inhibited precontraction induced by high K+ and ACh in a concentration-dependent manner. The precontraction induced by the former was also inhibited by nifedipine, and which induced by the latter was partially reduced by nifedipine (VDCC inhibitor) and pyrazole 3 (NSCC inhibitor). These results indicate that NBAECP can relax ASMCs via inhibiting VDCC and NSCC and imply that NBAECP might be a potential new drug for asthma therapy.Key words: Cortex Phellodendri; asthma, airway smooth muscle