Chimie des substances naturelles, CNRS UMR 8076 BioCIS, LabEx LERMIT, F-92296 Châtenay-Malabry, France.
J Ethnopharmacol. 2011 Nov 18;138(2):432-8. doi: 10.1016/j.jep.2011.09.016. Epub 2011 Sep 21.
Leaves of Boerhavia diffusa (Nyctaginaceae), Baphia nitida, Cassia occidentalis, Desmodium adscendens (Fabaceae), and root bark of Dichrostachys cinerea (Fabaceae) are used in Ivory Coast for the treatment of asthma. The aim of this study was to evaluate the potential airway relaxant activity of different extracts of these plants.
Extracts of different polarities (H(2)O, EtOH/H(2)O, MeOH and CH(2)Cl(2)) were obtained from these five plants. Their ex vivo relaxant activity was tested in mice isolated trachea precontracted with carbachol (1 μM).
Cumulative concentrations of most extracts induced moderate to strong relaxation, the methanolic extracts being the most potent and the polar extracts the most active at the concentrations used, supporting the traditional use of these five plants as anti-asthmatic remedies. We further investigated the molecular and cellular mechanisms of the mouse trachea relaxant effect of the aqueous-alcoholic extract of Dichrostachys cinerea root bark, the most potent extract. Its effect was not modified in the presence of β-adrenoceptor antagonists (propranolol or ICI 118,551) or a PKA inhibitor (H89). By contrast, it was decreased after depolarization-induced precontraction (with 80 mM KCl), in the presence of some K(+) channels blockers [4-aminopyridine as voltage-dependent K(+) (K(v)) channel blocker and tetraethylammonium chloride as large conductance Ca(2+)-activated K(+) (BK(Ca)) channel blocker, but not with glibenclamide, an ATP-sensitive K(+) (K(ATP)) channel blocker] or after epithelium removal.
The mouse tracheal relaxant effect of Dichrostachys cinerea EtOH/H(2)O extract was independent of β(2)-adrenoceptors activation and cAMP/PKA pathway, but dependent on epithelium and K(+) channels, namely K(v) and BK(Ca) channels. Further investigation will be required to identify the component(s) responsible for this airways relaxant activity.
在象牙海岸，Boerhavia diffusa（Nyctaginaceae）、Baphia nitida、Cassia occidentalis、Desmodium adscendens（Fabaceae）的叶子和Dichrostachys cinerea（Fabaceae）的根皮被用于治疗哮喘。本研究旨在评估这些植物不同提取物的潜在气道舒张活性。
从这 5 种植物中提取不同极性（H2O、EtOH/H2O、MeOH 和 CH2Cl2）的提取物。在预先用卡巴胆碱（1 μM）收缩的小鼠离体气管中测试其体外舒张活性。
大多数提取物的累积浓度诱导了中度至强的舒张，其中甲醇提取物最为有效，极性提取物在使用浓度下最为活跃，这支持了将这 5 种植物作为抗哮喘药物的传统用途。我们进一步研究了最有效提取物 Dichrostachys cinerea 根皮水醇提取物对小鼠气管舒张作用的分子和细胞机制。在β-肾上腺素能受体拮抗剂（普萘洛尔或ICI 118,551）或蛋白激酶 A 抑制剂（H89）存在的情况下，其作用没有改变。相反，在用 80 mM KCl 进行去极化预收缩后，其作用降低，同时使用一些 K+通道阻滞剂[4-氨基吡啶作为电压依赖性 K+（Kv）通道阻滞剂和四乙基氯化铵作为大电导钙激活 K+（BKCa）通道阻滞剂，但不能用格列本脲，即三磷酸腺苷敏感的 K+（KATP）通道阻滞剂]或去除上皮后。
Dichrostachys cinerea EtOH/H2O 提取物对小鼠气管的舒张作用不依赖于β2-肾上腺素能受体的激活和 cAMP/PKA 途径，但依赖于上皮和 K+通道，即 Kv和 BKCa通道。需要进一步研究以确定导致这种气道舒张活性的成分。
