El Haouari Mohammed, Bnouham Mohamed, Bendahou Mourad, Aziz Mohammed, Ziyyat Abderrahim, Legssyer Abdelkhaleq, Mekhfi Hassane
Laboratoire de Physiologie et Ethnopharmacologie, UFR 'Physiologie et Pharmacologie', Département de biologie, Faculté des sciences, Université Mohamed Premier, BP 717, 60000 Oujda, Morocco.
Phytother Res. 2006 Jul;20(7):568-72. doi: 10.1002/ptr.1906.
Platelet hyperactivity plays an important role in arterial thrombosis and atherosclerosis. The present study was undertaken to investigate the effects of different extracts of Urtica dioica leaves on platelet aggregation. Rat platelets were prepared and incubated in vitro with different concentrations of the tested extracts and aggregation was induced by different agonists including thrombin (0.5 U/mL), ADP (10 microm), epinephrine (100 microm) and collagen (5 mg/mL). The crude aqueous extract inhibited thrombin-induced platelet aggregation in a dose-dependent manner. At 1 mg/mL, the percent inhibition was 17.1 +/- 4.2%. Soxhlet extraction of the plant leaves with different successive solvents showed that the ethyl acetate extract exhibited the most antiaggregant effect with an inhibition of 76.8 +/- 6.1% at 1 mg/mL. Flavonoids isolated from the plant leaves, produced a strong inhibitory effect on thrombin-induced platelet aggregation with an IC(50) of 0.25 +/- 0.05 and 0.40 +/- 0.04 mg/mL for genins and heterosidic flavonoids, respectively. Flavonoids also markedly inhibited platelet aggregation induced by ADP, collagen and epinephrine. It is concluded that Urtica dioica has an antiplatelet action in which flavonoids are mainly implicated. These results support the traditional use of Urtica dioica in the treatment and/or prevention of cardiovascular disease.
血小板活性亢进在动脉血栓形成和动脉粥样硬化中起重要作用。本研究旨在探讨不同提取物的荨麻叶对血小板聚集的影响。制备大鼠血小板并在体外与不同浓度的受试提取物一起孵育，通过不同激动剂诱导聚集，这些激动剂包括凝血酶（0.5 U/mL）、ADP（10微摩尔）、肾上腺素（100微摩尔）和胶原（5毫克/毫升）。粗水提取物以剂量依赖性方式抑制凝血酶诱导的血小板聚集。在1毫克/毫升时，抑制百分比为17.1±4.2%。用不同连续溶剂对植物叶进行索氏提取表明，乙酸乙酯提取物表现出最强的抗聚集作用，在1毫克/毫升时抑制率为76.8±6.1%。从植物叶中分离出的黄酮类化合物对凝血酶诱导的血小板聚集产生强烈抑制作用，对于苷元和苷类黄酮，其IC50分别为0.25±0.05和0.40±0.04毫克/毫升。黄酮类化合物也显著抑制ADP、胶原和肾上腺素诱导的血小板聚集。得出的结论是，荨麻具有抗血小板作用，其中黄酮类化合物起主要作用。这些结果支持荨麻在治疗和/或预防心血管疾病方面的传统用途。
