Tagetes lucida Cav.: Ethnobotany, phytochemistry and pharmacology of its tranquilizing properties

Abstract

Ethnopharmacological relevance: Morelos State is one of the most important regions of Mexico where several plant species are used in traditional medicine to influence central nervous system (CNS) activity; for example Tagetes lucida Cav.

Aim of the study: To investigate the ethnobotany, phytochemistry and pharmacology of the tranquilizing properties of T. lucida aerial parts.

Material and methods: Data on the medicinal uses of T. lucida were explored by interviewing healers and merchants of local markets in different regions of Morelos State by using a questionnaire. Anxiolytic and/or sedative-like responses of the T. lucida were investigated in experimental models in mice such as: open-field, exploration cylinder, hole-board, plus-maze, and the barbituric-induced hypnosis potentiation. The possible mechanism of action was explored in the presence of WAY100635 (0.32mg/kg, i.p.) and flumazenil (10mg/kg, i.p.) antagonists. A feasible active compound was isolated and identified by using conventional chromatography, including UHPLC and MS (DART) [M+H]+ techniques.

Results: Interviews of healers and merchants from ten local regions of Morelos State showed that they recommended T. lucida as infusion and as tincture for several culture-bound syndromes associated with the CNS. Anxiolytic and sedative-like activities of polar extracts were corroborated in the experimental models; these effects were inhibited in the presence of 5-HT1A and GABA/BDZ receptor antagonists. Dimethylfraxetin was identified as one possible active compound.

Conclusions: The results support the anxiolytic and sedative-like properties of T. lucida in traditional medicine by involving serotonergic and GABAergic neurotransmission and coumarinic constituents.

Keywords: Anxiety; Central nervous system; Coumarins; Diazepam (PubChem CID: 3016); Dimethylfraxetin (6,7,8-Trimethoxycoumarin) (PubChem CID: 3083928); Ethnobotany; Flumazenil (PubChem CID: 3373); Sedative; Sodium pentobarbital (PubChem CID: 23676152); Tagetes lucida; WAY100635 maleate salt (PubChem CID: 11957721).