Chloroform Extract of Artemisia annua L. Relaxes Mouse Airway Smooth Muscle.

Jun Huang,Li-Qun Ma,Congli Cai,Nana Wen,Jinhua Shen,Qing-Hua Liu,Yongle Yang,Wan Zhou

doi:10.1155/2017/9870414

Abstract

Artemisia annua L. belongs to the Asteraceae family, which is indigenous to China. It has valuable pharmacological properties, such as antimalarial, anti-inflammatory, and anticancer properties. However, whether it possesses antiasthma properties is unknown. In the current study, chloroform extract of Artemisia annua L. (CEAA) was prepared, and we found that CEAA completely eliminated acetylcholine (ACh) or high K+-elicited (80 mM) contractions of mouse tracheal rings (TRs). Patch-clamp technique and ion channel blockers were employed to explore the underlying mechanisms of the relaxant effect of CEAA. In whole-cell current recording, CEAA almost fully abolished voltage-dependent Ca2+ channel (VDCC) currents and markedly enhanced large conductance Ca2+-activated K+ (BK) channel currents on airway smooth muscle cells (ASMCs). In single channel current recording, CEAA increased the opening probability but had no effect on the single channel conductance of BK channels. However, under paxilline-preincubated (a selective BK channel blocker) conditions, CEAA only slightly increased BK channel currents. These results indicate that CEAA may contain active components with potent antiasthma activity. The abolished VDCCs by CEAA may mainly contribute to the underlying mechanism through which it acts as an effective antiasthmatic compound, but the enhanced BK currents might play a less important role in the antiasthmatic effects.

Highlights

Millions of people suffer from asthma worldwide; the prevalence of this disease is increasing along with the increase in air pollution [1]
We observed that chloroform extract of Artemisia annua L. (CEAA) inhibited the high K+-induced contraction in a dosedependent manner on mouse tracheal rings (TRs)
After washing out of CEAA, the high K+-induced contraction recover by 35.9% ± 3.5%. This result indicated that CEAA exerted a long-term effect on high K+-induced contractions of airway smooth muscle (ASM)

Summary

Introduction

Millions of people suffer from asthma worldwide; the prevalence of this disease is increasing along with the increase in air pollution [1]. According to the World Health Organization, asthma is becoming a major economic, social, and healthcare burden throughout the world and has been identified as a public health priority [2]. One of the characteristic features of asthma is hyperresponsiveness of airway smooth muscle (ASM) [3]. The preferred first-line treatment for asthma is still β2 adrenergic receptor (β2 AR) agonists combined with glucocorticoids, but this therapeutic strategy causes multiple severe side-effects, including palpitations, tremors, headache, cardiovascular death, and cardiac failure [4,5,6,7]. Many patients who receive this treatment suffer from repeated asthmatic attacks [8]. It is necessary to develop novel drugs with increased efficacy but fewer side-effects for antiasthma treatments

Methods

Results

Discussion

Conclusion