Schwarz M J, Houghton P J, Rose S, Jenner P, Lees A D
Department of Pharmacy, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NN, UK.
Pharmacol Biochem Behav. 2003 Jun;75(3):627-33. doi: 10.1016/s0091-3057(03)00129-1.
Dopamine deficiency is characteristic of Parkinson's disease (PD) and treatments aim at elevating levels by administration of its precursor L-dihydroxyphenylalanine (L-DOPA), or inhibiting monoamine oxidases (MAOs), thus preventing its breakdown. Reports of improvements in PD patients treated with Banisteriopsis caapi extracts stimulated investigation of B. caapi stem extract and its two ingredients, harmine and harmaline for these activities. Tests for MAO inhibition using liver homogenate showed that extract and harmaline showed a concentration-dependent inhibition of MAO A (IC(50) 1.24 microg/ml and IC(50) 4.54 nM, respectively) but had little effect on MAO B activity. The extract at 2.5 mg/ml caused a highly significant increase in release of [3H]dopamine from rat striatal slices, as did 200 microM harmine and 6 microM harmaline. In both these experiments, the amount of harmine present could not account for the total activity of the extract. The ability of harmine and harmaline to stimulate dopamine release is a novel finding. These results give some basis to the reputed usefulness of B. caapi stem extract in the treatment of PD.
多巴胺缺乏是帕金森病（PD）的特征，治疗旨在通过给予其前体L-二羟基苯丙氨酸（L-DOPA）来提高多巴胺水平，或抑制单胺氧化酶（MAO），从而防止其分解。用卡皮木提取物治疗帕金森病患者有改善效果的报道激发了对卡皮木茎提取物及其两种成分——哈尔明和哈尔马灵这些活性的研究。使用肝脏匀浆进行的MAO抑制试验表明，提取物和哈尔马灵对MAO A呈现浓度依赖性抑制（IC(50)分别为1.24微克/毫升和4.54纳摩尔），但对MAO B活性影响很小。2.5毫克/毫升的提取物以及200微摩尔的哈尔明和6微摩尔的哈尔马灵均使大鼠纹状体切片中[3H]多巴胺的释放显著增加。在这两个实验中，提取物中的哈尔明含量都无法解释提取物的全部活性。哈尔明和哈尔马灵刺激多巴胺释放的能力是一个新发现。这些结果为卡皮木茎提取物在帕金森病治疗中的公认有效性提供了一些依据。
