Medicinal plants for the "nerves": a review of ethnobotanical studies carried out in South Brazil

ABSTRACT Among the medicinal purposes for which plants have been used is the treatment of “nerves". The objective of this study was to search for species of plants used in the state of Rio Grande do Sul (South Brazil) for the relief of symptoms related to central nervous system (CNS) disorders. Twenty-seven ethnobotanical studies were compiled, in which a total of 94 species were cited. The five most cited species were Cymbopogon citratus (81.5 %), Melissa officinalis (77.7 %), Aloysia citriodora (66.6 %), Matricaria chamomilla (62.9 %) and Passiflora edulis (51.8 %). Scientific studies have corroborated the popular use of these plants as sedatives, but most studies are preclinical and very few have been clinical (M. chamomilla and M. officinalis), and these were mainly exploratory or were performed against placebo. In addition to efficacy data, there are also indications of toxicity for M. chamomilla and P. edulis. In conclusion, there is a great diversity of plant species used in the treatment of symptoms related to CNS disorders, and they are most frequently used as a sedative. Data indicate that M. officinalis possesses clinical efficacy in the treatment of symptoms associated with anxiety without signs of toxicity.

摘要
植物的药用用途之一为缓解神经相关病症。本研究旨在检索巴西南部南里奥格兰德州（Rio Grande do Sul）用于缓解中枢神经系统（CNS）紊乱相关症状的植物物种。本研究整合了27项民族植物学研究，共计引用94种植物物种。其中被引用次数最多的5种植物分别为：香茅（Cymbopogon citratus，占比81.5%）、柠檬香蜂草（Melissa officinalis，占比77.7%）、柠檬马鞭草（Aloysia citriodora，占比66.6%）、母菊（Matricaria chamomilla，占比62.9%）以及西番莲（Passiflora edulis，占比51.8%）。
已有科学研究证实上述植物作为镇静剂的民间应用价值，但现有相关研究多为临床前研究，仅有极少部分为临床研究（涉及母菊与柠檬香蜂草），且此类临床研究多为探索性研究，或采用安慰剂对照设计。除疗效数据外，研究还显示母菊与西番莲存在潜在毒性指征。
综上，用于缓解中枢神经系统（CNS）紊乱相关症状的植物物种种类丰富，其中最常用的为镇静类植物。研究数据表明，柠檬香蜂草在治疗焦虑相关症状方面具有临床疗效，且未出现毒性迹象。