Department of Biomedical Sciences, University of Nottingham Malaysia Campus, Semenyih 43500, Malaysia.
School of Pharmacy, University of Nottingham Malaysia Campus, Semenyih 43500, Malaysia.
Phytomedicine. 2018 Mar 15;42:172-179. doi: 10.1016/j.phymed.2018.03.025. Epub 2018 Mar 13.
Lignosus rhinocerotis (Cooke) Ryvarden is a popular medicinal mushroom used for centuries in Southeast Asia to treat asthma and chronic cough. The present study aimed to investigate the effect of this mushroom on airways patency.
The composition of L. rhinocerotis TM02 cultivar was analyzed. Organ bath experiment was employed to study the bronchodilator effect of Lignosus rhinocerotis cold water extract (CWE) on rat isolated airways. Trachea and bronchus were removed from male Sprague-Dawley rats, cut into rings of 2 mm, pre-contracted with carbachol before adding CWE into the bath in increasing concentrations. To investigate the influence of incubation time, tissues were exposed to intervals of 5, 15 and 30 min between CWE concentrations after pre-contraction with carbachol in subsequent protocol. Next, tissues were pre-incubated with CWE before the addition of different contractile agents, carbachol and 5-hydroxytrptamine (5-HT). The bronchodilator effect of CWE was compared with salmeterol and ipratropium. In order to uncover the mechanism of action of CWE, the role of beta-adrenoceptor, potassium and calcium channels was investigated.
Composition analysis of TM02 cultivar revealed the presence of β-glucans and derivatives of adenosine. The extract fully relaxed the trachea at 3.75 mg/ml (p < 0.0001) and bronchus at 2.5 mg/ml (p < 0.0001). It was observed that lower concentrations of CWE were able to fully relax both trachea and bronchus but at a longer incubation interval between concentrations. CWE pre-incubation significantly reduced the maximum responses of carbachol-induced contractions (in both trachea, p = 0.0012 and bronchus, p = 0.001), and 5-HT-induced contractions (in trachea, p = 0.0048 and bronchus, p = 0.0014). Ipratropium has demonstrated a significant relaxation effect in both trachea (p = 0.0004) and bronchus (p = 0.0031), whereas salmeterol has only affected the bronchus (p = 0.0104). The involvement of β-adrenoceptor and potassium channel in CWE-mediated airway relaxation is ruled out, but the bronchodilator effect was unequivocally affected by influx of calcium.
The bronchodilator effect of L. rhinocerotis on airways is mediated by calcium signalling pathway downstream of G-coupled protein receptors. The airway relaxation effect is both concentration- and incubation time-dependent. Our findings provide unequivocal evidence to support its traditional use to relieve asthma and cough.
红缘拟层孔菌（Cooke）Ryvarden 是一种流行的药用蘑菇，在东南亚地区已使用了几个世纪，用于治疗哮喘和慢性咳嗽。本研究旨在探讨这种蘑菇对气道通畅性的影响。
分析了红缘拟层孔菌 TM02 品种的成分。采用器官浴实验研究红缘拟层孔菌冷水提取物（CWE）对大鼠离体气道的支气管扩张作用。从雄性 Sprague-Dawley 大鼠中取出气管和支气管，切成 2mm 的环，用卡巴胆碱预收缩，然后在浴中加入浓度递增的 CWE。为了研究孵育时间的影响，在随后的方案中，在 CWE 浓度之间用卡巴胆碱预收缩后，组织暴露于 5、15 和 30min 的间隔时间。接下来，在加入不同收缩剂卡巴胆碱和 5-羟色胺（5-HT）之前，用 CWE 预孵育组织。将 CWE 的支气管扩张作用与沙美特罗和异丙托溴铵进行比较。为了揭示 CWE 的作用机制，研究了β-肾上腺素能受体、钾和钙通道的作用。
TM02 品种的成分分析表明存在β-葡聚糖和腺嘌呤衍生物。提取物在 3.75mg/ml 时完全松弛气管（p<0.0001），在 2.5mg/ml 时完全松弛支气管（p<0.0001）。结果表明，较低浓度的 CWE 能够完全松弛气管和支气管，但在浓度之间的孵育间隔较长。CWE 预孵育显著降低了卡巴胆碱诱导收缩的最大反应（在气管中，p=0.0012，在支气管中，p=0.001），以及 5-HT 诱导收缩的最大反应（在气管中，p=0.0048，在支气管中，p=0.0014）。异丙托溴铵在气管（p=0.0004）和支气管（p=0.0031）中均显示出显著的松弛作用，而沙美特罗仅影响支气管（p=0.0104）。CWE 介导的气道松弛作用不涉及β-肾上腺素能受体和钾通道，但钙内流明确影响支气管扩张作用。
红缘拟层孔菌对气道的支气管扩张作用是通过 G 蛋白偶联受体下游的钙信号通路介导的。气道松弛作用具有浓度和孵育时间依赖性。我们的研究结果提供了确凿的证据支持其传统用途，以缓解哮喘和咳嗽。
