Departamento de Química, Universidade Estadual de Ponta Grossa, UEPG, Ponta Grossa, Brazil.
Departamento de Ciências Farmacêuticas, Universidade Estadual de Ponta Grossa, UEPG, Ponta Grossa, Brazil.
J Ethnopharmacol. 2020 Oct 5;260:113036. doi: 10.1016/j.jep.2020.113036. Epub 2020 May 28.
Cymbopogon citratus (DC.) Stapf (Poaceae) leaves is often consumed as infusion in folk medicine due to its therapeutic properties. This plant is also rich in essential oil, which has several beneficial effects to the human health. It is known that medications commonly used to treat anxiety disorders cause undesirable side effects. Thus, it is important to evaluate the anxiolytic effects of natural products from plants, such as C. citratus, as an alternative therapy to treat these disorders.
The aim of this study was to investigate the anxiolytic properties of C. citratus essential oil (EO), hydroalcoholic extract (E1), citral (CIT), geraniol (GER) and the mixture of these terpenoids, as well as its possible mechanism of action by using zebrafish as an anxiety model.
Adult zebrafish were treated (by immersion) with C. citratus EO, E1, CIT and/or GER. The anxiolytic effects were analyzed by using the light-dark test. The mechanism involved in the anxiolytic effects was further investigated by the coadministration of flumazenil (FMZ), an antagonist of GABA receptors. The total polyphenols (phenolic and flavonoid compounds) content of E1 was determined by using spectrophotometric assays.
All analyzed samples showed a remarkable anxiolytic effect on zebrafish in the highest concentrations, as the animals showed a preference for the light side of the tank. Furthermore, the observed effect of EO, E1, CIT and GER was reversed by pre-treatment with FMZ, suggesting that GABAergic receptors were involved in the anxiolytic effect displayed by these samples. The association between CIT and GER in the lowest studied concentrations showed an interesting synergistic behavior on anxiolytic effect observed in light-dark test. Besides, it was demonstrated that E1 was constituted by phenolic and flavonoid compounds, which could be involved in the observed effect.
This work has proved that the low-cost zebrafish can be an adequate alternative as an animal model to evaluate the anxiolytic effect of C. citratus and its related compounds. Moreover, the involvement of GABA receptors could be responsible for the effect showed by the samples. These obtained results can potentially validate the ethnopharmacological use of C. citratus as a medicinal plant for the treatment of anxiety disorders in folk medicine.
香茅（DC。） Stapf（禾本科）叶子常被民间医学用作浸剂，因为它具有治疗特性。这种植物还富含精油，对人体健康有多种有益作用。众所周知，常用于治疗焦虑症的药物会引起不良副作用。因此，评估香茅等植物天然产物的抗焦虑作用作为治疗这些疾病的替代疗法非常重要。
本研究旨在研究香茅精油（EO）、水醇提取物（E1）、柠檬醛（CIT）、香叶醇（GER）及其萜类混合物的抗焦虑特性，并通过使用斑马鱼作为焦虑模型来研究其可能的作用机制。
用香茅 EO、E1、CIT 和/或 GER 处理成年斑马鱼（通过浸泡）。通过明暗测试分析抗焦虑作用。通过共同给予 GABA 受体拮抗剂氟马西尼（FMZ）进一步研究抗焦虑作用涉及的机制。通过分光光度法测定 E1 中的总多酚（酚类和类黄酮化合物）含量。
所有分析的样品在最高浓度下对斑马鱼均表现出显著的抗焦虑作用，因为动物更喜欢水箱的亮侧。此外，EO、E1、CIT 和 GER 的观察到的作用被 FMZ 预处理逆转，表明 GABA 能受体参与了这些样品显示的抗焦虑作用。在研究的最低浓度下，CIT 和 GER 的联合显示出对明暗测试中观察到的抗焦虑作用的有趣协同行为。此外，证明 E1 由酚类和类黄酮化合物组成，这可能与观察到的作用有关。
这项工作证明，低成本的斑马鱼可以作为评估香茅及其相关化合物抗焦虑作用的合适替代动物模型。此外，GABA 受体的参与可能是样品显示的作用的原因。这些获得的结果可以潜在地验证香茅在民间医学中作为治疗焦虑症的药用植物的民族药理学用途。
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