Bioecology Laboratory, Department of Pharmacognosy, R.C. Patel Institute of Pharmaceutical Education and Research, Shirpur, India.
Pharm Biol. 2010 Apr;48(4):417-21. doi: 10.3109/13880200903150427.
Viscum angulatum Heyne ex DC (Viscaceae) is a leafless hemiparasitic shrub traditionally used in Asian countries for the treatment of hypertension. In the present study, the methanol extract of the whole plant was examined for diuretic activity in rats. The activity was evaluated using parameters such as urine volume after 5, 19, and 24 h and urine sodium, potassium, and chloride concentrations. The extract was further scrutinized for polyphenolic compounds and triterpenoids. The extract demonstrated a significant increase in and dose-dependent effect on urine excretion volume in comparison to the normal group in the tested range of 100-400 mg/kg. The extract demonstrated comparable saluretic and higher natriuretic activity (Na(+)/K(+)) compared to the furosemide treated group. However, the Cl(-)/Na(+) + K(+) ratio, which indicates carbonic anhydrase mediated activity, remained unaffected. HPLC and quantitative analysis of the extract revealed that polyphenolic compounds and the triterpenoid, oleanolic acid, are the major phytochemicals, and are proposed to be responsible for the observed diuretic effect. Oleanolic acid has been reported to possess diuretic activity with significant potassium loss in rats. In contrast to pure oleanolic acid, the extract demonstrated a valuable potassium-sparing effect. This suggests modulation of the diuretic effect of oleanolic acid by polyphenolics present in the extract. The observed dose-dependent potassium-sparing diuretic effect is a hereto unreported property of this plant.
槲寄生（Viscum angulatum Heyne ex DC）是桑寄生科槲寄生属的一种无叶半寄生灌木，传统上被亚洲国家用于治疗高血压。在本研究中，我们对该植物的甲醇提取物进行了利尿活性评价。通过检测大鼠在 5、19 和 24 小时后的尿量以及尿钠、钾和氯浓度等参数，对其利尿活性进行评估。此外，我们还对提取物中的多酚类化合物和三萜类化合物进行了分析。与正常组相比，在 100-400mg/kg 的测试范围内，提取物的尿量增加明显，呈剂量依赖性。与呋塞米处理组相比，提取物的利尿和排钠作用相当，但排氯作用（Cl(-)/Na(+)+K(+)）不变。这表明提取物中的多酚类化合物和三萜类化合物（齐墩果酸）可能是其发挥利尿作用的主要活性物质。高效液相色谱法（HPLC）和定量分析表明，多酚类化合物和三萜类化合物（齐墩果酸）是该提取物的主要化学成分，这与提取物的利尿作用有关。有研究报道，齐墩果酸具有利尿作用，会导致大鼠钾的大量流失。与纯齐墩果酸相比，该提取物具有显著的保钾作用。这表明提取物中的多酚类化合物可能调节了齐墩果酸的利尿作用。这种剂量依赖性的保钾利尿作用是该植物迄今为止尚未报道的特性。
